Mona Kristiansen Beyer

• Sommernes, Jon Håvard; Beyer, Mona Kristiansen; Asvall, Jørund & Sundseth, Jarle (2026). Acute paraplegia following epidural analgesia: diagnostic pitfalls in distinguishing pneumorrhachis from surgical mass lesions. Illustrative case. Journal of Neurosurgery: Case Lessons. 12(6). doi: 10.3171/CASE26351. Full text in Research Archive
• MacIntosh, Bradley J; Morberg, Pål; Murugesu, Elakkyen; Beyer, Mona K.; Larsen, Karianne & Skogen, Karoline [Show all 13 contributors for this article] (2026). Automated volume estimate of the brain’s lateral ventricles reveals a persistent association with cognitive performance among stroke survivors. Cerebral Circulation - Cognition and Behavior. ISSN 2666-2450. 11. doi: 10.1016/j.cccb.2026.100556. Full text in Research Archive Show summary

  Background: Post-stroke cognitive impairment (PSCI) is a significant barrier to recovery. While computed tomography (CT) is the dominant modality for acute stroke diagnosis, it can also quantify brain anatomy, such as lateral ventricular volume (LVV). This study investigates whether initial LVV is associated with Montreal Cognitive Assessment (MoCA) scores over long-term follow-up. Methods: Initial head CT, longitudinal MoCA, and functional assessments were collected at sites from the Norwegian COgnitive impairment After STroke (Nor-COAST) study. LVV was estimated using an established deep learning segmentation tool. Associations between initial LVV and repeat MoCA were tested across four timepoints (up to three years) using a linear mixed effects model. To provide context, we explored the independent influence of LVV in relation to National Institutes of Health Stroke Scale (NIHSS), modified Rankin Scale (mRS), and Global Deterioration Scale (GDS). Results: The sample of N = 547 participants were 74 ± 12 years (range: 35-97 years) and 54% female. Log-transformed LVV was inversely associated with longitudinal MoCA scores (t=-3.75, p < 0.001). This relationship was consistent across cross-sectional analyses at individual time points. Secondary analyses revealed significant LVV associations with NIHSS, mRS, and GDS scores (all p < 0.05). Conclusion: LVV was independently associated with lower MoCA scores across the three-year follow-up after stroke. Specifically, a patient with twice the initial LVV scored 0.7 points lower on the MoCA across three years of follow-up. These findings reveal that CT obtained at stroke admission may yield prognostic information about long-term cognitive outcomes, supporting the case for automated LVV estimation.

• Aamodt, Eva Birgitte; Røvang, Martin Soria; Beyer, Mona Kristiansen; Borei, Karim; Vahidy, Farhaan S. & Potter, Thomas B.H. (2026). A binational study of the association between white matter hyperintensities and functional outcome in stroke patients. Frontiers in Neurology. 17. doi: 10.3389/fneur.2026.1712109. Full text in Research Archive
• Ihle-Hansen, Håkon; Walle-Hansen, Marte; Berge, Trygve; Ihle-Hansen, Hege Beate; Rønningen, Peter Selmer & Omland, Torbjørn [Show all 16 contributors for this article] (2026). Burden of atherosclerosis, cardiovascular risk factors and atrial fibrillation in individuals with covert brain infarcts in late midlife: the Akershus Cardiac Examination 1950 Study. BMJ Open. 16(3). doi: 10.1136/bmjopen-2025-114232. Full text in Research Archive Show summary

  Background Current expert consensus statements generally suggest cardiovascular risk assessment, including atrial fibrillation (AF) screening, on detection of covert brain infarctions (CBIs). However, evidence to guide management of CBI remains limited. In the absence of randomised clinical trials specifically targeting CBI populations, observational studies comparing individuals with and without CBI can provide insights into the prevalence and burden of cardiovascular risk factors. Objectives We aimed to compare the burden of atherosclerosis and cardiovascular risk factors in participants with CBI to those without, and to explore the yield of AF screening in individuals with CBI. Design A prospective population-based birth cohort study including men and women born in 1950 and resident in Akershus County, Norway. Setting The two hospitals serving the population of Akershus county, Norway. Participants Participants included in the Akershus Cardiac Examination (ACE) 1950 study who also underwent a subsequent MRI examination were eligible for this study. Outcome measures Cardiovascular risk assessment was performed at study inclusion (2012–2015). Carotid ultrasound was used to quantify atherosclerosis through a carotid plaque score, and CHA₂DS₂-VA and Systematic COronary Risk Evaluation 2 (SCORE2) scores were calculated to estimate cardiovascular risk. Brain MRI was performed in a randomly selected, blood pressure-stratified subset of participants (2016–2024). CBI was defined as focal lesions consistent with ischaemia in the absence of clinical stroke. Participants with CBI were offered 72-hour ambulatory ECG monitoring for AF detection. Results MRI was performed in 414 of 3706 (11%) participants in the ACE 1950 Study. The mean age at the time of the MRI examination was 70.2±2.3 years, and 165 (41%) were women. CBI was identified in 54 participants (13%), of whom 45 (83%) completed 72-hour ambulatory ECG monitoring. There were no differences in mean carotid plaque score, SCORE2 or CHA₂DS₂-VA score between participants with CBI compared with those with normal MRI findings. AF was detected in one (2%) participant with CBI. Conclusions In this community-based cohort of individuals in late midlife, individuals with CBI did not have an increased cardiovascular risk compared with those without, as indicated by SCORE2, CHA₂DS₂-VA score, age-appropriate carotid plaque burden and a low prevalence of AF. Trial registration number URL: https://www.clinicaltrials.gov . Unique identifier: NCT01555411 .

• Helland, Gisle Berg; Ihle-Hansen, Håkon; Aamodt, Anne Hege; Leonardsen, Esten Høyland; Kaufmann, Tobias Herbert & Enriquez, Brian Anthony [Show all 13 contributors for this article] (2026). Brain age trajectories and cognition after stroke in two longitudinal cohorts. Brain Communications. 8(1). doi: 10.1093/braincomms/fcaf509. Full text in Research Archive Show summary

  Brain age is a promising neuroimaging biomarker, reflecting biological aging, but long-term trajectories and predictive value for cognitive outcomes post-stroke remains unclear. This study aimed to characterize brain aging trajectories over 8 years following a first-ever stroke and to evaluate the predictive value of brain age estimates for long-term cognitive outcomes. We analysed data from working-age (&lt;65 years) ischaemic stroke patients with small- and medium-sized strokes (lesion volumes &lt;70 ml), using two longitudinal stroke cohorts. T1-weighted MRI was acquired in the acute phase and at multiple time points up to 8 years post-stroke. Montreal cognitive assessment (MoCA) was assessed at follow-up sessions. Brain age was estimated using a state-of-the-art deep learning model. Brain-predicted age difference (Brain-PAD) was calculated as estimated brain age minus chronological age and corrected by regressing on age, age² and sex. Linear mixed-effects models examined Brain-PAD over multiple time points (whole-brain, ipsilesional and contralesional). Normalized brain volume was derived from FreeSurfer and included in the whole-brain analysis. Linear regression models evaluated whether brain age was associated with cognitive performance (MoCA) at long-term follow-up. We included 120 patients [n = 50 (42%) female, mean ± SD age at discharge was 54.9 ± 9 and National Institutes of Health Stroke Scale was 3.7 ± 6.4], with a mean follow-up of 3.4 ± 2.5 years. The mean MoCA score at follow-up was 24.7 ± 3.7. Brain-PAD increased significantly over time in the whole-brain analysis (β = 0.6/year, P &lt; 0.01), indicating 60% acceleration in brain aging after stroke, with the association remaining significant after adjusting for normalized brain volume (β = 0.5/year, P &lt; 0.01). Accelerated brain aging was observed in the ipsilesional hemisphere (β = 0.7/year, P &lt; 0.01), but not the contralesional hemisphere (β = 0.3/year, P = 0.12). Higher brain age in the acute phase of stroke predicted lower MoCA scores at follow-up (β = −0.12, P &lt; 0.05), whereas chronological age was not a significant predictor (P = 0.12). The association between brain age estimations and cognitive performance remained significant after adjusting for age, sex and education (β = −0.42, P &lt; 0.01). In this longitudinal study, we found accelerated brain aging following stroke. Furthermore, brain age was associated with cognitive outcomes several years later, highlighting its potential as an early biomarker for long-term cognitive prognosis.

• Walle-Hansen, Marte; Hagberg, Guri; Myrstad, Marius; Berge, Trygve; Vigen, Thea & Ihle-Hansen, Hege Beate [Show all 14 contributors for this article] (2025). Blood pressure at age 40 and key features of cerebral small vessel disease at age 70: data from the ACE 1950 Study. BMC Cardiovascular Disorders. 25(1). doi: 10.1186/s12872-025-05140-6. Full text in Research Archive Show summary

  Background The separate effects of systolic (SBP) and diastolic blood pressure (DBP) on cerebral small vessel disease (cSVD) development needs elucidation. We investigated the association between SBP and DBP at age 40 and two selected brain magnetic resonance imaging (MRI) features of cSVD (lacunes and white matter hyperintensities [WMHs]) at age 70 in a general Norwegian population cohort. Methods We included individuals from the Akershus Cardiac Examination (ACE) 1950 Study (2012–2015) who had previously participated in the Age 40 Program (1990–1993). A random subset of participants with SBP in the categories of non-elevated (< 120 mmHg), high elevated (130–139 mmHg) or hypertension (≥ 140 mmHg) at age 40 were invited to perform brain MRI for assessment of cSVD (lacunes and WMHs) at age 70 (2016–2024). DBP was categorized as non-elevated (< 70 mmHg), low elevated (70–79 mmHg), high elevated (80–89 mmHg) and hypertension (≥ 90 mmHg). Logistic and ordinal regressions assessed the association between SBP and DBP and lacunes and severity of WMHs (measured with Fazekas scale), adjusting for sex, total cholesterol, smoking, physical activity, diabetes, education, and age at MRI, with non-elevated BP as the reference category. Results A total of 414 participants (167 [40%] women) were included. Participants were 70.2 ± 2.3 years when undergoing brain MRI. Mean Fazekas scale was 1.3 ± 0.8, and 54 (13%) had lacunes. SBP and DPB were not associated with lacunes. DPB of 80–89 mmHg (adjusted OR [95% CI], 1.91 [1.01–3.62]) and ≥ 90 mmHg (2.11 [1.06–4.19]) at age 40 were associated with WMHs. Conclusions Elevated DBP (80–89 mmHg) and diastolic hypertension (> 90 mmHg) at age 40 were associated with WMH burden at age 70, suggesting a long-term association between midlife DBP and cerebrovascular health.

• Skattør, Thor Håkon; Bjørnerud, Atle; Nome, Terje; Bakke, Kine Mari; Enriquez, Brian Anthony & Digernes, Ingrid [Show all 10 contributors for this article] (2025). Predicting lesion reversal in acute cerebral ischaemia via apparent diffusion coefficient threshold on diffusion-weighted MRI. European Radiology. ISSN 0938-7994. p. 1–11. doi: 10.1007/s00330-025-12014-0. Full text in Research Archive Show summary

  Objectives Diffusion-weighted imaging (DWI) quickly detects early ischaemic changes, but does not necessarily signify irreversible tissue damage, as DWI lesion reversal (DWI-R) can occur. Apparent diffusion coefficient (ADC) thresholds have been proposed to distinguish salvageable from irreversibly damaged tissue. This study aimed to evaluate the predictive value of a single ADC threshold for DWI-R following rapid and successful recanalization with voxel-level methodology. Materials and methods In this cohort study, we retrospectively analysed consecutive patients examined with DWI before and the day after endovascular therapy, with successful recanalization within 120 min of baseline MRI. DWI-R was assessed voxel-wise for ADC values between 200 mm2/s and 760 × 10−6 mm2/s. Predictive accuracy of ADC thresholds was evaluated using receiver operating characteristic (ROC) analyses. Results Seventy-one patients with a mean baseline DWI lesion volume of 18.13 mL (IQR: 6.15, 26.25) were included. Median time from MRI to recanalization was 84.0 min (IQR: 72.0, 95.5). On average, 37.5% of voxels demonstrated reversal. The area under the curve for predicting reversal based on ADC was 0.708, and the optimal threshold was 555 × 10–6 mm2/s (sensitivity 73.8%, specificity 58.6%). The voxel-wise probability of reversal declined with lower ADC, but even low ADC values exhibited some degree of reversal. Conclusion This study reinforces existing concerns about using fixed ADC thresholds to define irreversible injury. A single ADC cut-off showed only modest sensitivity and poor specificity for predicting DWI-R. No definitive lower ADC boundary was identified across clinically relevant ranges below which the likelihood of DWI-R became negligible.

• Skattør, Thor Håkon; Offersen, Cecilie Mørck; Nome, Terje; Bakke, Kine Mari; Enriquez, Brian Anthony & Carlsen, Jonathan Frederik [Show all 9 contributors for this article] (2025). Mapping DWI signal reversal and long-term tissue outcomes following endovascular therapy in acute ischemic stroke. European Radiology. ISSN 0938-7994. p. 1–12. doi: 10.1007/s00330-025-11943-0. Full text in Research Archive Show summary

  Objectives Diffusion-weighted imaging lesion reversal (DWI-R) is commonly observed on MRI after treatment for acute ischemic stroke. However, its extent across different brain regions post-endovascular therapy (EVT) and its long-term tissue-specific consequences are inadequately described in the literature. This study evaluated DWI-R across brain regions and tissue types and assessed long-term changes after 1 month. Materials and methods This cohort study included acute ischemic stroke patients with MRI acquired before and 12 to 36 h after EVT. DWI lesions were segmented and co-registered to MNI space to generate probabilistic maps of DWI-R distribution. The probability of DWI-R was analyzed in relation to the involvement of white matter, cortical regions, and deep gray matter. Changes indicative of tissue damage were evaluated in a subgroup with follow-up imaging > 1 month post-EVT. Results Of 565 consecutive EVT patients in the period January 2017-March 2022, 303 were included. DWI-R was observed in all major vascular territories. White matter showed 1.95 times higher probability of DWI-R compared to deep gray matter (p < 0.001), with no significant difference compared to cortical regions. Among 62 DWI-R cases with follow-up imaging, 29 (47%) showed no signal changes in areas of the initial lesion, with no significant difference between white and gray matter. Conclusions Caution is advised when excluding patients from EVT based on restrictive diffusion, as both white and gray matter frequently responded to treatment in this study.

• Skattebøl, Lars; Nygaard, Gro Owren; Leonardsen, Esten Høyland; Kaufmann, Tobias Herbert; Moridi, Thomas & Stawiarz, Leszek [Show all 23 contributors for this article] (2025). Brain age in multiple sclerosis: a study with deep learning and traditional machine learning. Brain Communications. 7(3). doi: 10.1093/braincomms/fcaf152. Full text in Research Archive Show summary

  ‘Brain age’ is a numerical estimate of the biological age of the brain and an overall effort to measure neurodegeneration, regardless of disease type. In multiple sclerosis, accelerated brain ageing has been linked to disability accrual. Artificial intelligence has emerged as a promising tool for the assessment and quantification of the impact of neurodegenerative diseases. Despite the existence of numerous AI models, there is a noticeable lack of comparative imaging data for traditional machine learning versus deep learning in conditions such as multiple sclerosis. A retrospective observational study was initiated to analyse clinical and MRI data (4584 MRIs) from various scanners in a large longitudinal cohort (n = 1516) of people with multiple sclerosis collected from two institutions (Karolinska Institute and Oslo University Hospital) using a uniform data post-processing pipeline. We conducted a comparative assessment of brain age using a deep learning simple fully convolutional network and a well-established traditional machine learning model. This study was primarily aimed to validate the deep learning brain age model in multiple sclerosis. The correlation between estimated brain age and chronological age was stronger for the deep learning estimates (r = 0.90, P &lt; 0.001) than the traditional machine learning estimates (r = 0.75, P &lt; 0.001). An increase in brain age was significantly associated with higher expanded disability status scale scores (traditional machine learning: t = 5.3, P &lt; 0.001; deep learning: t = 3.7, P &lt; 0.001) and longer disease duration (traditional machine learning: t = 6.5, P &lt; 0.001; deep learning: t = 5.8, P &lt; 0.001). No significant inter-model difference in clinical correlation or effect measure was found, but significant differences for traditional machine learning-derived brain age estimates were found between several scanners. Our study suggests that the deep learning-derived brain age is significantly associated with clinical disability, performed equally well to the traditional machine learning-derived brain age measures, and may counteract scanner variability.

• Furevik, Liv; Lapina, Oksana; Lindland, Elisabeth Margrete Stokke; Høgestøl, Einar August; Geier, Oliver Marcel & Devik, Kristina [Show all 22 contributors for this article] (2025). Brain MRI findings in patients with post COVID-19 condition: frequency and longitudinal changes in a nationwide cohort study. Frontiers in Neurology. 16, p. 1–9. doi: 10.3389/fneur.2025.1662263. Full text in Research Archive Show summary

  Background Prolonged neurological symptoms following COVID-19 are common, yet few longitudinal studies describe brain MRI findings in this patient group. The use of contrast enhanced sequences is particularly lacking. We address this knowledge gap by reporting the frequency and longitudinal changes in brain MRI findings among patients with post COVID-19 condition exhibiting neurological symptoms. Methods This prospective multicenter study included 140 adult patients referred for persistent neurological symptoms following COVID-19. Brain MRI was performed at both 6 and 12 months after infection onset, reporting white matter hyperintensities, cerebral microbleeds, and additional pathological findings including contrast enhancement. White matter hyperintensities were compared with a healthy control group. Results The prevalence of white matter hyperintensities was comparable to healthy controls, and microbleeds were found at rates comparable to population studies, with longitudinal changes being infrequent. Lesions consistent with inflammation or demyelination were present in 4% (5/120) of patients at 6 months. Cranial nerve enhancement was found in 7% (7/94) of patients, persisting up to 12 months, predominantly affecting the oculomotor nerve. However, enhancement occurred without clinically detected ocular muscle paresis. Conclusion Our findings indicate that brain MRI primarily serves to exclude differential diagnoses in post COVID-19 condition, with limited clinical benefit of repeated imaging in the absence of new symptoms. However, signs of long-term inflammatory processes can be observed, and detection is improved by contrast enhanced sequences.

• Sannes, Ida; Harr, Marianne Efskind; Antal, Ellen-Ann; Beyer, Mona K. & Nordengen, Kaja (2025). Acute hemorrhagic leukoencephalitis with gradual symptom onset: Case Report and literature review. Frontiers in Neuroscience. ISSN 1662-4548. 19. doi: 10.3389/fnins.2025.1557046. Full text in Research Archive Show summary

  This report highlights an atypical case of acute hemorrhagic Leukoencephalitis (AHLE) in a 73-year-old male, contributing valuable insights into the disease’s progression in older adults. AHLE, a rare and often fatal central nervous system disorder typically affecting younger individuals, with a median age of 33. Our patient experienced atypical subacute symptoms over 3 months, the longest duration reported, and ultimately achieved a functional outcome with a modified Rankin Scale (mRS) score of 2. A comprehensive review of 152 cases available through PubMed, revealing a 58% mortality rate with a median survival of just 2 days, and a mean mRS of 4.3, though survivor exhibited a more favorable mean mRS of 1.8. Only 6% of cases had a subacute onset of 3 weeks or more.

• Høgestøl, Einar August; Rinker, Daniel Allen; Maximov, Ivan; Sowa, Piotr; Celius, Elisabeth Gulowsen & Hope, Tuva Roaldsdatter [Show all 26 contributors for this article] (2025). A cross-sectional multicentre study of multishell diffusion MRI in multiple sclerosis. Multiple Sclerosis and Related Disorders. ISSN 2211-0348. 98. doi: 10.1016/j.msard.2025.106435. Full text in Research Archive Show summary

  Background and objectives White matter (WM) microstructural properties from advanced multishell diffusion MRI (dMRI) have been linked to clinical disability in multiple sclerosis (MS). This multicentre study used multishell dMRI to compute WM metrics and test for differences between people with MS (pwMS) and healthy controls (HCs). Methods We included multishell dMRI data from 251 pwMS or clinically isolated syndrome (CIS) (mean age 40.7 years, 72.4 % women, 88.8 % relapsing remitting MS) at six MAGNIMS centres and 543 HCs. Eleven scalar metric maps were estimated from multishell dMRI sequences, based on diffusion tensor imaging (DTI) and restriction spectrum imaging (RSI). The maps were analysed using tract-based spatial statistics (TBSS). The diffusion output was submitted to paired sampled t-tests to test for case-control differences and linear regression models to test for associations with Expanded Disability Status Scale (EDSS) scores, while accounting for confounders. In a sub-sample from Oslo, we tested for correlations between EDSS and dMRI metrics within WM lesions. Results Significant group differences were found in nine out of eleven dMRI metrics. Linear regression models revealed significant correlations between EDSS and fractional anisotropy (FA) fast (β=-4.54, p = 0.01) and apparent diffusion coefficient (ADC) fast (β=10.92, p = 8.7 × 10−3). Conclusions Diffusion MRI based on clinically feasible multishell sequences uncovers WM group differences between pwMS and HCs, but only a selection of the advanced multishell parameters were sensitive to disability, and no statistically significant correlations with disability remained after Bonferroni correction.

• Ihle-Hansen, Håkon; Hagberg, Guri; Ihle-Hansen, Hege Beate; Munthe-Kaas, Ragnhild; Aam, Stina & Aamodt, Eva Birgitte [Show all 11 contributors for this article] (2025). Impact of Insufficient or Excessive Sleep Duration on Cognitive Function After Stroke: The Norwegian Cognitive Impairment After Stroke Study. Journal of the American Heart Association (JAHA). 14(8). doi: 10.1161/JAHA.124.038125. Full text in Research Archive Show summary

  Background The impact of sleep duration on cognition, particularly in the context of poststroke cognitive impairment, is not fully understood. Therefore, our objective was to investigate how sleep duration after stroke predicts poststroke cognitive impairment. Methods and Results Patients admitted with acute stroke between 2015 and 2017 were consecutively recruited to the Nor‐COAST (Norwegian Cognitive Impairment After Stroke) study and invited to follow‐up assessments at 3 and 18 months. Time in bed, used as a surrogate for sleep duration at 3 months post stroke, was measured using the activPAL thigh‐worn sensor over a 3‐day period. Sleep duration was categorized into 3 groups: <7 hours (insufficient), 7 to 9 hours (reference), and ≥9 hours (excessive). Cognitive impairment was assessed based on the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) criteria at 3‐ and 18‐month follow‐up. Out of the 815 patients, we included 443 (54%) prestroke cognitive healthy with valid activPAL registration in this analysis. Mean±SD age was 71.2±11.4 years, 185 (42%) were women, 363 (82%) had prestroke modified Rankin Scale score <2, and 345 (78%) suffered a minor stroke (National Institutes of Health Stroke Scale score ≤5). On average, participants spent 8.3±1.4 hours in bed each night, 17.2% had a sleep duration <7 hours, and 25% slept more than 9 hours. Insufficient (odds ratio [OR], 3.6 [95% CI, 1.3–10.2], and OR, 1.4 [95% CI, 0.5–3.8]) and excessive (OR, 2.8 [95% CI, 1.1–7.5], and OR, 3.3 [95% CI, 1.3–8.1]) sleep duration were associated with an increased risk of cognitive impairment at 3‐ and 18‐month follow‐up, respectively. Conclusions Insufficient or excessive sleep duration was associated with poststroke cognitive impairment.

• Enriquez, Brian Anthony; Skattør, Thor Håkon; Laugesen, Nicolaj Grønbæk; Truelsen, Thomas; Lund, Christian & Nome, Terje [Show all 9 contributors for this article] (2024). External validation of clinical risk prediction score for elderly treated with endovascular thrombectomy. Journal of Neurology. ISSN 0340-5354. 271, p. 5838–5845. doi: 10.1007/s00415-024-12535-6. Full text in Research Archive Show summary

  Background and aim: The thrombectomy in the elderly prediction score (TERPS) for functional outcome after anterior circulation endovascular therapy (EVT) in patients ≥ 80 years was recently developed. The aim of this study was to assess predictors of functional outcome in the elderly and validate the prediction model. Methods: Consecutive patients treated with EVT from the Oslo Acute Reperfusion Stroke Study were evaluated for inclusion. Clinical and radiological parameters were used to calculate the TERPS, and functional outcome were assessed at 3-month follow-up. Results: Out of 1028 patients who underwent EVT for acute ischemic stroke from January 2017 to July 2022, 218 (21.2%) patients ≥ 80 years with anterior ischemic stroke were included. Fair outcome, defined as modified Rankin scale ≤ 3 (mRS), was achieved in 117 (53.7%). In bivariate analyses, male sex (p 0.035), age (p 0.025), baseline National Institute of Health Stroke Scale (NIHSS, p < 0.001), pre-stroke mRS (p 0.002) and Alberta Stroke Program Early Computed Tomography score (ASPECTS, p 0.001) were associated with fair outcome. Significant predictors for fair outcome in regression analyses were lower pre-stroke mRS, adjusted odd ratio, (aOR) 0.67 (95% CI 0.50–0.91, p 0.01), NIHSS, aOR 0.92 (95% CI 0.87–0.97, p 0.002), and higher ASPECTS, aOR 1.22 (95% CI 1.03–1.44, p 0.023). The area under the curve (AUC) using TERPS was 0.74 (95% CI 0.67–0.80). Conclusions: The risk prediction score TERPS showed moderate performance in this external validation. Other variables may still be included to improve the model and validation using other cohorts is recommended. Trial registration: NCT06220981.

• Helland, Gisle Berg; Beyer, Mona K.; Enriquez, Brian Anthony; Ihle-Hansen, Hege Beate; Ihle-Hansen, Håkon & Andersson, Stein [Show all 13 contributors for this article] (2024). Lesion Volume as a Predictor for Return to Work After Endovascular Treatment: A 4‐Year Prospective Cohort Study. Stroke: Vascular and Interventional Neurology. 4(6). doi: 10.1161/SVIN.124.001494. Full text in Research Archive Show summary

  Background There are no known objective biomarkers for predicting return to work (RTW) in ischemic stroke survivors. This study aims to explore the predictive utility and defines a cutoff value of lesion volume on RTW after endovascular treatment. Methods We included patients aged <65 years undergoing endovascular treatment at Oslo University Hospital between January 2017 and May 2019. Employment status was obtained at both baseline and a 4‐year follow‐up. Stroke lesion volumes were segmented using magnetic resonance imaging scans 24 hours after endovascular treatment. Logistic regression models were conducted to assess the impact of lesion volume on RTW status at follow‐up, adjusted for patients’ characteristics, stroke‐related factors, and treatment. We calculated the receiver operating characteristic curve to determine the optimal lesion volume cutoff. Machine learning regression models were used to assess the predictive abilities of baseline clinical and imaging variables for RTW. Results Of the 109 individuals treated, 81 (74%) were employed at baseline. Among these, 60 completed 4‐year follow‐up with magnetic resonance imaging available for stroke lesion segmentation and were included in the analyses. Mean age at stroke onset was 51.8 years (range, 23.5–64.9 years), and 50% were female. Median lesion volume was 18 mL (interquartile ranges, 45—47 mL). After 4 years, 34 (57%) had successfully RTW. The odds for not RTW increased by 5% for every 1 mL increase in lesion volume (adjusted odds ratio, 1.05 [95% CI, 1.02–1.11]; P = 0.02). A lesion volume cutoff value of 29 cm3 yielded a sensitivity of 0.91 and specificity of 0.65 for predicting RTW. Notably, the most influential feature in the machine learning model for predicting RTW was lesion volume. Conclusion Lesion volume was the most robust predictor of RTW 4 years after endovascular treatment. Our findings suggest that a cutoff of 29 cm3 is suitable to distinguish between those with high and low chance of RTW.

• Frič, Radek; Beyer, Mona K. & Due-Tønnessen, Bernt Johan (2024). Regression of Chiari malformation type 2 following early postnatal meningomyelocele repair—a retrospective observation from an institutional series of patients. Child's Nervous System. ISSN 0256-7040. 40, p. 3641–3646. doi: 10.1007/s00381-024-06586-3. Full text in Research Archive
• Lindland, Elisabeth S.; Røvang, Martin S.; Solheim, Anne Marit; Andreassen, Silje; Skarstein, Ingerid & Dareez, Nazeer [Show all 17 contributors for this article] (2024). Are white matter hyperintensities associated with neuroborreliosis? The answer is twofold. Neuroradiology. ISSN 0028-3940. 67, p. 37–48. doi: 10.1007/s00234-024-03482-0. Full text in Research Archive Show summary

  Purpose Many consider white matter hyperintensities (WMHs) to be important imaging findings in neuroborreliosis. However, evidence regarding association with WMHs is of low quality. The objective was to investigate WMHs in neuroborreliosis visually and quantitatively. Materials and methods Patients underwent brain MRI within one month of diagnosis and six months after treatment. Healthy controls were recruited. WMHs were counted by visual rating and the volume was calculated from automatic segmentation. Biochemical markers and scores for clinical symptoms and findings were used to explore association with longitudinal volume change of WMHs. Results The study included 74 patients (37 males) with early neuroborreliosis and 65 controls (30 males). Mean age (standard deviation) was 57.4 (13.5) and 57.7 (12.9) years, respectively. Baseline WMH lesion count was zero in 14 patients/16 controls, < 10 in 36/31, 10–20 in 9/7 and > 20 in 13/11, with no difference between groups (p = 0.90). However, from baseline to follow-up the patients had a small reduction in WMH volume and the controls a small increase, median difference 0.136 (95% confidence interval 0.051–0.251) ml. In patients, volume change was not associated with biochemical or clinical markers, but with degree of WMHs (p values 0.002–0.01). Conclusion WMH lesions were not more numerous in patients with neuroborreliosis compared to healthy controls. However, there was a small reduction of WMH volume from baseline to follow-up among patients, which was associated with higher baseline WMH severity, but not with disease burden or outcome. Overall, non-specific WMHs should not be considered suggestive of neuroborreliosis.

• Enriquez, Brian Anthony; Nome, Terje; Nome, Cecilie; Tennøe, Bjørn; Lund, Christian & Beyer, Mona K. [Show all 8 contributors for this article] (2023). Predictors of outcome after endovascular treatment for tandem occlusions: a single center retrospective analysis. BMC Neurology. 23, p. 1–9. doi: 10.1186/s12883-023-03127-4. Full text in Research Archive Show summary

  Background The endovascular treatment procedure in tandem occlusions (TO) is complex compared to single occlusion (SO) and optimal management remains uncertain. The aim of this study was to identify clinical and procedural factors that may be associated to efficacy and safety in the management of TO and compare functional outcome in TO and SO stroke patients. Methods This is a retrospective single center study of medium (MeVO) and large vessel occlusion (LVO) of the anterior circulation. Clinical, imaging, and interventional data were analyzed to identify predictive factors for symptomatic intracranial hemorrhage (sICH) and functional outcome after endovascular treatment (EVT) in TO. Functional outcome in TO and SO patients was compared. Results Of 662 anterior circulation stroke patients with MeVO and LVO stroke, 90 (14%) had TO. Stenting was performed in 73 (81%) of TO patients. Stent thromboses occurred in 8 (11%) patients. Successful reperfusion with modified thrombolysis in cerebral infarction (mTICI) ≥ 2b was achieved in 82 (91%). SICH occurred in seven (8%). The strongest predictors for sICH were diabetes mellitus and number of stent retriever passes. Good functional clinical outcome (mRS ≤ 2) at 90-day follow up was similar in TO and SO patients (58% vs 59% respectively). General anesthesia (GA) was associated with good functional outcome whereas hemorrhage in the infarcted tissue, lower mTICI score and history of smoking were associated with poor outcome. Conclusions The risk of sICH was increased in patients with diabetes mellitus and those with extra stent-retriever attempts. Functional clinical outcomes in patients with TO were comparable to patients with SO.

• Hodel, Jérôme; Vernooij, Meike W.; Beyer, Mona K.; Severino, Mariasavina; Leclerc, Xavier & Créange, Alain [Show all 15 contributors for this article] (2023). Multiple sclerosis imaging in clinical practice: a European-wide survey of 428 centers and conclusions by the ESNR Working Group. European Radiology. ISSN 0938-7994. 33, p. 7025–7033. doi: 10.1007/s00330-023-09701-1. Full text in Research Archive
• Moltu, Sissel Jennifer; Nordvik, Tone; Rossholt, Madelaine; Wendel, Kristina; Chawla, Maninder Singh & Server, Andrés [Show all 18 contributors for this article] (2023). Arachidonic and docosahexaenoic acid supplementation and brain maturation in preterm infants; a double blind RCT. Clinical Nutrition. ISSN 0261-5614. 43(1), p. 176–186. doi: 10.1016/j.clnu.2023.11.037. Full text in Research Archive
• Lindland, Elisabeth Margrete Stokke; Solheim, Anne Marit; Andreassen, Silje; Bugge, Robin Antony Birkeland; Eikeland, Randi & Reiso, Harald [Show all 10 contributors for this article] (2023). Dynamic contrast-enhanced MRI shows altered blood–brain barrier function of deep gray matter structures in neuroborreliosis: a case–control study. European Radiology Experimental. 7(1). doi: 10.1186/s41747-023-00365-6. Full text in Research Archive Show summary

  Background Main aim was assessment of regional blood–brain barrier (BBB) function by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in patients with neuroborreliosis. Secondary aim was to study the correlation of BBB function with biochemical, clinical, and cognitive parameters. Methods Regional ethical committee approved this prospective single-center case–control study. Within 1 month after diagnosis of neuroborreliosis, 55 patients underwent DCE-MRI. The patient group consisted of 25 males and 30 females with mean age 58 years, and the controls were 8 males and 7 females with mean age 57 years. Pharmacokinetic compartment modelling with Patlak fit was applied, providing estimates for capillary leakage rate and blood volume fraction. Nine anatomical brain regions were sampled with auto-generated binary masks. Fatigue, severity of clinical symptoms and findings, and cognitive function were assessed in the acute phase and 6 months after treatment. Results Leakage rates and blood volume fractions were lower in patients compared to controls in the thalamus (p = 0.027 and p = 0.018, respectively), caudate nucleus (p = 0.009 for both), and hippocampus (p = 0.054 and p = 0.009). No correlation of leakage rates with fatigue, clinical disease severity or cognitive function was found. Conclusions In neuroborreliosis, leakage rate and blood volume fraction in the thalamus, caudate nucleus, and hippocampus were lower in patients compared to controls. DCE-MRI provided new insight to pathophysiology of neuroborreliosis, and can serve as biomarker of BBB function and regulatory mechanisms of the neurovascular unit in infection and inflammation. Relevance statement DCE-MRI provided new insight to pathophysiology of neuroborreliosis, and can serve as biomarker of blood–brain barrier function and regulatory mechanisms of the neurovascular unit in infection and inflammation.

• Nome, Terje; Enriquez, Brian Anthony; Nome, Cecilie; Tennøe, Bjørn; Lund, Christian & Skjelland, Mona [Show all 8 contributors for this article] (2023). Clinical outcome after thrombectomy in patients with MeVO stroke: importance of clinical and technical factors. Journal of Neurology. ISSN 0340-5354. 1(2), p. 877–886. doi: 10.1007/s00415-023-12025-1. Full text in Research Archive Show summary

  Background and aims Whereas high-level evidence has been proven for safety and efficacy of endovascular treatment (EVT) in large vessel occlusion (LVO) stroke, the evidence for EVT in medium vessel occlusion (MeVO) in both sexes and different age groupremains to be answered. The aim of this study was to evaluate the importance of clinical and technical parameters, focusing on sex, age and EVT procedural factors, on functional outcome in primary MeVO (pMeVO) strokes. Methods 144 patients with pMeVO in the MCA territory from the Oslo Acute Reperfusion Stroke Study (OSCAR) were included. Clinical and radiological data were collected including 90-day mRS follow-up. Results Successful reperfusion with modified thrombolysis in cerebral infarction (mTICI) ≥ 2b was achieved in 123 patients (84%). Good functional outcome (mRS ≤ 2) at 90-day follow-up was achieved in 84 patients (61.8%). Two or more passes with stent retriever was associated with increased risk of SAH, poor mTICI and poor functional outcome. In average, women had 62 min longer ictus to recanalization time compared to men. Age over 80 years was significantly associated with poor outcome and death. Conclusion In pMeVO patients, TICI score and number of passes with stent retriever were the main technical factors predicting mRS ≤ 2. Good clinical outcome occurred almost twice as often in patients under 80 years of age compared to patients over 80 years. Women with MeVO strokes had significant longer time from ictus to recanalization; however, this did not affect the clinical outcome.

• MacIntosh, Bradley; Liu, Qinghui; SCHELLHORN, TILL; Beyer, Mona K.; Groote, Inge Rasmus & Morberg, Pål [Show all 20 contributors for this article] (2023). Radiological features of brain hemorrhage through automated segmentation from computed tomography in stroke and traumatic brain injury. Frontiers in Neurology. 14. doi: 10.3389/fneur.2023.1244672. Full text in Research Archive Show summary

  Introduction Radiological assessment is necessary to diagnose spontaneous intracerebral hemorrhage (ICH) and traumatic brain injury intracranial hemorrhage (TBI-bleed). Artificial intelligence (AI) deep learning tools provide a means for decision support. This study evaluates the hemorrhage segmentations produced from three-dimensional deep learning AI model that was developed using non-contrast computed tomography (CT) imaging data external to the current study. Methods Non-contrast CT imaging data from 1263 patients were accessed across seven data sources (referred to as sites) in Norway and Sweden. Patients were included based on ICH, TBI-bleed, or mild TBI diagnosis. Initial non-contrast CT images were available for all participants. Hemorrhage location frequency maps were generated. The number of estimated haematoma clusters was correlated with the total haematoma volume. Ground truth expert annotations were available for one ICH site; hence, a comparison was made with the estimated haematoma volumes. Segmentation volume estimates were used in a receiver operator characteristics (ROC) analysis for all samples (i.e., bleed detected) and then specifically for one site with few TBI-bleed cases. Results The hemorrhage frequency maps showed spatial patterns of estimated lesions consistent with ICH or TBI-bleed presentations. There was a positive correlation between the estimated number of clusters and total haematoma volume for each site (correlation range: 0.45–0.74; each p -value &amp;lt; 0.01) and evidence of ICH between-site differences. Relative to hand-drawn annotations for one ICH site, the VIOLA-AI segmentation mask achieved a median Dice Similarity Coefficient of 0.82 (interquartile range: 0.78 and 0.83), resulting in a small overestimate in the haematoma volume by a median of 0.47 mL (interquartile range: 0.04 and 1.75 mL). The bleed detection ROC analysis for the whole sample gave a high area-under-the-curve (AUC) of 0.92 (with sensitivity and specificity of 83.28% and 95.41%); however, when considering only the mild head injury site, the TBI-bleed detection gave an AUC of 0.70. Discussion An open-source segmentation tool was used to visualize hemorrhage locations across multiple data sources and revealed quantitative hemorrhage site differences. The automated total hemorrhage volume estimate correlated with a per-participant hemorrhage cluster count. ROC results were moderate-to-high. The VIOLA-AI tool had promising results and might be useful for various types of intracranial hemorrhage.

• Sandvig, Heidi Vihovde; Aam, Stina; Alme, Katinka Nordheim; Askim, Torunn; Beyer, Mona K. & Ellekjær, Hanne [Show all 16 contributors for this article] (2023). Plasma Inflammatory Biomarkers Are Associated With Poststroke Cognitive Impairment: The Nor-COAST Study. Stroke. ISSN 0039-2499. 54(5), p. 1303–1311. doi: 10.1161/STROKEAHA.122.041965. Full text in Research Archive Show summary

  Background: Inflammation is proposed to be involved in the pathogenesis of poststroke cognitive impairment. The aim of this study was to investigate associations between concentrations of systemic inflammatory biomarkers after ischemic stroke and poststroke cognitive impairment. Methods: The Nor-COAST study (Norwegian Cognitive Impairment After Stroke) is a prospective observational multicenter cohort study, including patients hospitalized with acute stroke between 2015 and 2017. Inflammatory biomarkers, including the TCC (terminal C5b-9 complement complex) and 20 cytokines, were analyzed in plasma, collected at baseline, 3-, and 18 months poststroke, using ELISA and a multiplex assay. Global cognitive outcome was assessed with the Montreal Cognitive Assessment (MoCA) scale. We investigated the associations between plasma inflammatory biomarkers at baseline and MoCA score at 3-, 18-, and 36-month follow-ups; the associations between inflammatory biomarkers at 3 months and MoCA score at 18- and 36-month follow-ups; and the association between these biomarkers at 18 months and MoCA score at 36-month follow-up. We used mixed linear regression adjusted for age and sex. Results: We included 455 survivors of ischemic stroke. Higher concentrations of 7 baseline biomarkers were significantly associated with lower MoCA score at 36 months; TCC, IL (interleukin)-6, and MIP (macrophage inflammatory protein)-1α were associated with MoCA at 3, 18, and 36 months (P<0.01). No biomarker at 3 months was significantly associated with MoCA score at either 18 or 36 months, whereas higher concentrations of 3 biomarkers at 18 months were associated with lower MoCA score at 36 months (P<0.01). TCC at baseline and IL-6 and MIP-1α measured both at baseline and 18 months were particularly strongly associated with MoCA (P<0.01). Conclusions: Higher concentrations of plasma inflammatory biomarkers were associated with lower MoCA scores up to 36 months poststroke. This was most pronounced for inflammatory biomarkers measured in the acute phase following stroke.

• Andreassen, Silje; Lindland, Elisabeth Margrete Stokke; Beyer, Mona K.; Solheim, Anne Marit; Ljøstad, Unn & Mygland, Åse Daasvand [Show all 13 contributors for this article] (2022). Assessment of cognitive function, structural brain changes and fatigue 6 months after treatment of neuroborreliosis. Journal of Neurology. ISSN 0340-5354. doi: 10.1007/s00415-022-11463-7. Full text in Research Archive Show summary

  Background Complete recovery after adequately treated neuroborreliosis is common, but studies report that some patients experience persistent symptoms like self-reported cognitive problems and fatigue. Persisting symptoms are often termed post-Lyme disease syndrome, of which etiology is not clearly understood. The aim of this study was to investigate cognitive function, possible structural changes in brain regions and level of fatigue. We have not found previous studies on neuroborreliosis that use standardized neuropsychological tests and MRI with advanced image processing to investigate if there are subtle regional changes in cortical thickness and brain volumes after treatment. Methods We examined 68 patients treated for neuroborreliosis 6 months earlier and 66 healthy controls, with a comprehensive neuropsychological test protocol, quantitative structural MRI analysis of the brain and Fatigue Severity Scale. Results We found no differences between the groups in either cognitive function, cortical thickness or brain volumes. The patients had higher score on Fatigue Severity Scale 3.8 vs. 2.9 (p = 0.001), and more patients (25.4%) than controls (5%) had severe fatigue (p = 0.002), but neither mean score nor proportion of patients with severe fatigue differed from findings in the general Norwegian population. Conclusion The prognosis regarding cognitive function, brain MRI findings and fatigue after adequately treated neuroborreliosis is favorable.

• Rise, Henning Hoel; Brune, Synne; Chien, Claudia; Berge, Tone; Bos, Steffan Daniel & Andorrà, Magí [Show all 23 contributors for this article] (2022). Brain disconnectome mapping derived from white matter lesions and serum neurofilament light levels in multiple sclerosis: A longitudinal multicenter study. NeuroImage: Clinical. 35, p. 1–11. doi: 10.1016/j.nicl.2022.103099. Full text in Research Archive Show summary

  Background and Objectives Connectivity-based approaches incorporating the distribution and magnitude of the extended brain network aberrations caused by lesions may offer higher sensitivity for axonal damage in patients with multiple sclerosis (MS) than conventional lesion characteristics. Using individual brain disconnectome mapping, we tested the longitudinal associations between putative imaging-based brain network aberrations and levels of serum neurofilament light chain (NfL) as a neuroaxonal injury biomarker. Methods MS patients (n = 312, mean age 42.9 years, 71 % female) and healthy controls (HC) (n = 59, mean age 39.9 years, 78 % female) were prospectively enrolled at four European MS centres, and reassessed after two years (MS, n = 242; HC, n = 30). Post-processing of 3 Tesla (3 T) MRI data was performed at one centre using a harmonized pipeline, and disconnectome maps were calculated using BCBtoolkit based on individual lesion maps. Global disconnectivity (GD) was defined as the average disconnectome probability in each patient’s white matter. Serum NfL concentrations were measured by single molecule array (Simoa). Robust linear mixed models (rLMM) with GD or T2-lesion volume (T2LV) as dependent variables, patient as a random factor, serum NfL, age, sex, timepoint for visit, diagnosis, treatment, and center as fixed factors were run. Results rLMM revealed significant associations between GD and serum NfL (t = 2.94, p = 0.003), age (t = 4.21, p = 2.5 × 10−5), and longitudinal changes in NfL (t = -2.29, p = 0.02), but not for sex (t = 0.63, p = 0.53) or treatments (t = 0.80–0.83, p = 0.41–0.42). Voxel-wise analyses revealed significant associations between dysconnectivity in cerebellar and brainstem regions and serum NfL (t = 7.03, p < 0.001). Discussion In our prospective multi-site MS cohort, rLMMs demonstrated that the extent of global and regional brain disconnectivity is sensitive to a systemic biomarker of axonal damage, serum NfL, in patients with MS. These findings provide a neuroaxonal correlate of advanced disconnectome mapping and provide a platform for further investigations of the functional and potential clinical relevance of brain disconnectome mapping in patients with brain disorders.

• Aamodt, Eva Birgitte; Lydersen, Stian; Alnæs, Dag; SCHELLHORN, TILL; Saltvedt, Ingvild & Beyer, Mona K. [Show all 7 contributors for this article] (2022). Longitudinal Brain Changes After Stroke and the Association With Cognitive Decline. Frontiers in Neurology. 13, p. 1–13. doi: 10.3389/fneur.2022.856919. Full text in Research Archive Show summary

  Background: Cognitive impairment is common after stroke. So is cortical- and subcortical atrophy, with studies reporting more atrophy in the ipsilesional hemisphere than the contralesional hemisphere. The current study aimed to investigate the longitudinal associations between (I) lateralization of brain atrophy and stroke hemisphere, and (II) cognitive impairment and brain atrophy after stroke. We expected to find that (I) cortical thickness and hippocampal-, thalamic-, and caudate nucleus volumes declined more in the ipsilesional than the contralesional hemisphere up to 36 months after stroke. Furthermore, we predicted that (II) cognitive decline was associated with greater stroke volumes, and with greater cortical thickness and subcortical structural volume atrophy across the 36 months. Methods: Stroke survivors from five Norwegian hospitals were included from the multisite-prospective “Norwegian Cognitive Impairment After Stroke” (Nor-COAST) study. Analyses were run with clinical, neuropsychological and structural magnetic resonance imaging (MRI) data from baseline, 18- and 36 months. Cortical thicknesses and subcortical volumes were obtained via FreeSurfer segmentations and stroke lesion volumes were semi-automatically derived using ITK-SNAP. Cognition was measured using MoCA. Results: Findings from 244 stroke survivors [age = 72.2 (11.3) years, women = 55.7%, stroke severity NIHSS = 4.9 (5.0)] were included at baseline. Of these, 145 (59.4%) had an MRI scan at 18 months and 72 (49.7% of 18 months) at 36 months. Most cortices and subcortices showed a higher ipsi- compared to contralesional atrophy rate, with the effect being more prominent in the right hemisphere. Next, greater degrees of atrophy particularly in the medial temporal lobe after left-sided strokes and larger stroke lesion volumes after right-sided strokes were associated with cognitive decline over time. Conclusion: Atrophy in the ipsilesional hemisphere was greater than in the contralesional hemisphere over time. This effect was found to be more prominent in the right hemisphere, pointing to a possible higher resilience to stroke of the left hemisphere. Lastly, greater atrophy of the cortex and subcortex, as well as larger stroke volume, were associated with worse cognition over time and should be included in risk assessments of cognitive decline after stroke.

• Brune, Synne; Høgestøl, Einar August; Benavent, Sigrid Aune de Rodez; Berg-Hansen, Pål; Beyer, Mona K. & Leikfoss, Ingvild Sørum [Show all 23 contributors for this article] (2022). Serum neurofilament light chain concentration predicts disease worsening in multiple sclerosis. Multiple Sclerosis. ISSN 1352-4585. 28(12), p. 1859–1870. doi: 10.1177/13524585221097296. Full text in Research Archive Show summary

  Background: Serum neurofilament light (sNfL) chain is a promising biomarker reflecting neuro-axonal injury in multiple sclerosis (MS). However, the ability of sNfL to predict outcomes in real-world MS cohorts requires further validation. Objective: The aim of the study is to investigate the associations of sNfL concentration, magnetic resonance imaging (MRI) and retinal optical coherence tomography (OCT) markers with disease worsening in a longitudinal European multicentre MS cohort. Methods: MS patients ( n = 309) were prospectively enrolled at four centres and re-examined after 2 years ( n = 226). NfL concentration was measured by single molecule array assay in serum. The patients’ phenotypes were thoroughly characterized with clinical examination, retinal OCT and MRI brain scans. The primary outcome was disease worsening at median 2-year follow-up. Results: Patients with high sNfL concentrations (⩾8 pg/mL) at baseline had increased risk of disease worsening at median 2-year follow-up (odds ratio (95% confidence interval) = 2.8 (1.5–5.3), p = 0.001). We found no significant associations of MRI or OCT measures at baseline with risk of disease worsening. Conclusion: Serum NfL concentration was the only factor associated with disease worsening, indicating that sNfL is a useful biomarker in MS that might be relevant in a clinical setting.

• Lindland, Elisabeth Margrete Stokke; Solheim, Anne Marit; Dareez, Muhammad Nazeer; Eikeland, Randi; Ljøstad, Unn & Mygland, Åse Daasvand [Show all 10 contributors for this article] (2022). Enhancement of cranial nerves in Lyme neuroborreliosis: incidence and correlation with clinical symptoms and prognosis. Neuroradiology. ISSN 0028-3940. 64, p. 2323–2333. doi: 10.1007/s00234-022-02957-2. Full text in Research Archive Show summary

  Purpose Symptoms of cranial neuritis are a common presentation of Lyme neuroborreliosis (LNB). Imaging studies are scarce and report contradictory low prevalence of enhancement compared to clinical studies of cranial neuropathy. We hypothesized that MRI enhancement of cranial nerves in LNB is underreported, and aimed to assess the prevalence and clinical impact of cranial nerve enhancement in early LNB. Methods In this prospective, longitudinal cohort study, 69 patients with acute LNB were examined with MRI of the brain. Enhancement of cranial nerves III–XII was rated. MRI enhancement was correlated to clinical fndings of neuropathy in the acute phase and after 6 months. Results Thirty-nine of 69 patients (57%) had pathological cranial nerve enhancement. Facial and oculomotor nerves were most frequently afected. There was a strong correlation between enhancement in the distal internal auditory canal and parotid segments of the facial nerve and degree of facial palsy (gamma=0.95, p<.01, and gamma=0.93, p<.01), despite that 19/37 nerves with mild-moderate enhancement in the distal internal auditory canal segment showed no clinically evident palsy. Oculomotor and abducens nerve enhancement did not correlate with eye movement palsy (gamma=1.00 and 0.97, p=.31 for both). Sixteen of 17 patients with oculomotor and/or abducens nerve enhancement had no evident eye movement palsy. Conclusions MRI cranial nerve enhancement is common in LNB patients, but it can be clinically occult. Facial and oculomotor nerves are most often afected. Enhancement of the facial nerve distal internal auditory canal and parotid segments correlate with degree of facial palsy.

• Andreassen, Silje; Solheim, Anne Marit; Ljøstad, Unn; Mygland, Åse Daasvand; Lorentzen, Åslaug Rudjord & Reiso, Harald [Show all 10 contributors for this article] (2022). Cognitive function in patients with neuroborreliosis: A prospective cohort study from the acute phase to 12 months post treatment. Brain and Behavior. 12(6). doi: 10.1002/brb3.2608. Full text in Research Archive Show summary

  Background: Long-term cognitive problems after neuroborreliosis treatment remain a subject of debate. We have previously shown that cognitive problems are not present in the acute phase of neuroborreliosis, although fatigue is common. The aim of this study was to re-assess the same patient cohort and evaluate long-term outcomes. Methods: In this follow-up, we re-assessed 58 patients with well-characterized neuroborreliosis 12 months after completing treatment. The same protocol with eight subtests measuring attention and processing speed and the Fatigue Severity Scale (FSS) were used to compare the results from the acute phase to 12 months post treatment. Results: We found no changes in attention or processing speed but a reduction in the level of fatigue (median score on FSS: 4.9 vs. 3.9, p < .001) from the acute phase to 12 months post treatment. Conclusion: The patient group did not develop problems with attention or processing speed post treatment, while the level of fatigue decreased.

• Einstad, Marte Stine; SCHELLHORN, TILL; Thingstad, Pernille; Lydersen, Stian; Aamodt, Eva Birgitte & Beyer, Mona K. [Show all 8 contributors for this article] (2022). Neuroimaging markers of dual impairment in cognition and physical performance following stroke: The Nor-COAST study. Frontiers in Aging Neuroscience. 14, p. 1–12. doi: 10.3389/fnagi.2022.1037936. Full text in Research Archive Show summary

  Background: Cognitive decline and decline in physical performance are common after stroke. Concurrent impairments in the two domains are reported to give increased risk of dementia and functional decline. The concept of dual impairment of physical performance and cognition after stroke is poorly investigated. Clinically accessible imaging markers of stroke and pre-existing brain pathology might help identify patients at risk. Objective: The primary aim of this study was to investigate to which extent pre-stroke cerebral pathology was associated with dual impairment in cognition and physical performance at time of stroke. Secondary aims were to examine whether white matter hyperintensities, medial temporal lobe atrophy, and stroke lesion volume and location were associated with dual impairment. Methods: Participants from the Norwegian Cognitive Impairment After Stroke (Nor-COAST) study with available MRI data at baseline were included in this cross-sectional study. Logistic regression analyses were conducted, with impairment status (no impairment, impaired cognition, impaired physical performance, and dual impairment) as the dependent variable and MRI markers as covariates. Pre-existing brain pathologies were classified into neurodegenerative, cerebrovascular, or mixed pathology. In addition, white matter hyperintensities and medial temporal lobe atrophy were included as independent covariates. Stroke volume and location were also ascertained from study-specific MRI scans. Results: Participants’ (n = 348) mean (SD) age was 72.3 (11.3) years; 148 (42.5%) were women. Participants with dual impairment (n = 99) were significantly older, had experienced a more severe stroke, and had a higher comorbidity burden and poorer pre-stroke function. Stroke lesion volume (odds ratio 1.03, 95%, confidence interval 1.00 to 1.05, p = 0.035), but not stroke location or pre-existing brain pathology, was associated with dual impairment, after adjusting for age and sex. Conclusion: In this large cohort of stroke survivors having suffered mainly mild to moderate stroke, stroke lesion volume—but not pre-existing brain pathology—was associated with dual impairment early after stroke, confirming the role of stroke severity in functional decline.

• Aamodt, Eva Birgitte; Alnæs, Dag; Lange, Ann-Marie Glasø de; Aam, Stina; Schellhorn, Till & Saltvedt, Ingvild Tina [Show all 8 contributors for this article] (2022). Longitudinal brain age prediction and cognitive function after stroke. Neurobiology of Aging. ISSN 0197-4580. 122, p. 55–64. doi: 10.1016/j.neurobiolaging.2022.10.007. Full text in Research Archive Show summary

  Advanced age is associated with post-stroke cognitive decline. Machine learning based on brain scans can be used to estimate brain age of patients, and the corresponding difference from chronological age, the brain age gap (BAG), has been investigated in a range of clinical conditions, yet not thoroughly in post-stroke neurocognitive disorder (NCD). We aimed to investigate the association between BAG and post-stroke NCD over time. Lower BAG (younger appearing brain compared to chronological age) was found associated with lower risk of post-stroke NCD up to 36 months after stroke, even among those showing no evidence of impairments 3 months after hospital admission. For patients with no NCD at baseline, survival analysis suggested that higher baseline BAG was associated with higher risk of post-stroke NCD at 18 and 36 months. In conclusion, a younger appearing brain is associated with a lower risk of post-stroke NCD.

• Nes, Dragana; Berg-Hansen, Pål; Benavent, Sigrid Aune de Rodez; Høgestøl, Einar August; Beyer, Mona K. & Rinker, Daniel Allen [Show all 12 contributors for this article] (2022). Exploring Retinal Blood Vessel Diameters as Biomarkers in Multiple Sclerosis. Journal of Clinical Medicine. 11(11). doi: 10.3390/jcm11113109. Full text in Research Archive Show summary

  We aimed to determine whether retinal vessel diameters and retinal oxygen saturation in newly diagnosed patients with multiple sclerosis (pwMS) are different from those of a healthy population. Retinal blood vessel diameters were measured using imaging with a spectrophotometric non-invasive retinal oximeter. Twenty-three newly diagnosed untreated relapsing-remitting MS (RRMS) patients (mean age: 32.2 ± 7.5 years, age range = 18–50 years, 56.5% female) were measured and compared to 23 age- and sex-matched healthy controls (HCs) (mean age: 34.8 ± 8.1 years). Patients with Optic Neuritis were excluded. Retinal venular diameter (143.8 µm versus 157.8 µm: mean; p = 0.0013) and retinal arteriolar diameter (112.6 µm versus 120.6 µm: mean; p = 0.0089) were smaller in pwMS when compared with HCs, respectively. There was no significant difference in the oxygen saturation in retinal venules and arterioles in pwMS (mean: 60.0% and 93.7%; p = 0.5980) compared to HCs (mean: 59.3% and 91.5%; p = 0.8934), respectively. There was a significant difference in the median low contrast visual acuity (2.5% contrast) between the pwMS and the HC groups (p = 0.0143) Retinal arteriolar and venular diameter may have potential as objective biomarkers for MS.

• Lauvsnes, Maria Boge; Zetterberg, Henrik; Blennow, Kaj; Kvaløy, Jan Terje; Tjensvoll, Anne Bolette & Maroni, Stian [Show all 14 contributors for this article] (2021). Neurofilament light in plasma is a potential biomarker of central nervous system involvement in systemic lupus erythematosus. Journal of Neurology. ISSN 0340-5354. doi: 10.1007/s00415-021-10893-z. Full text in Research Archive
• Wendel, Kristina; Pfeiffer, Helle Cecilie; Fugelseth, Drude; Nestaas, Eirik; Domellöf, Magnus & Skålhegg, Bjørn Steen [Show all 42 contributors for this article] (2021). Effects of nutrition therapy on growth, inflammation and metabolism in immature infants: a study protocol of a double-blind randomized controlled trial (ImNuT). BMC Pediatrics. 21. doi: 10.1186/s12887-020-02425-x. Full text in Research Archive Show summary

  Background: Current nutritional management of infants born very preterm results in significant deficiency of the essential fatty acids (FAs) arachidonic acid (ARA) and docosahexaenoic acid (DHA). The impact of this deficit on brain maturation and inflammation mediated neonatal morbidities are unknown. The aim of this study is to determine whether early supply of ARA and DHA improves brain maturation and neonatal outcomes in infants born before 29 weeks of gestation. Methods: Infants born at Oslo University Hospital are eligible to participate in this double-blind randomized controlled trial. Study participants are randomized to receive an enteral FA supplement of either 0.4 ml/kg MCT-oil™ (medium chain triglycerides) or 0.4 ml/kg Formulaid™ (100 mg/kg of ARA and 50 mg/kg of DHA). The FA supplement is given from the second day of life to 36 weeks' postmenstrual age (PMA). The primary outcome is brain maturation assessed by Magnetic Resonance Imaging (MRI) at term equivalent age. Secondary outcomes include quality of growth, incidence of neonatal morbidities, cardiovascular health and neuro-development. Target sample size is 120 infants (60 per group), this will provide 80% power to detect a 0.04 difference in mean diffusivity (MD, mm2/sec) in major white matter tracts on MRI. Discussion: Supplementation of ARA and DHA has the potential to improve brain maturation and reduce inflammation related diseases. This study is expected to provide valuable information for future nutritional guidelines for preterm infants. Trial registration: Clinicaltrials.gov ID: NCT03555019 . Registered 4 October 2018- Retrospectively registered.

• Einstad, Marte Stine; Saltvedt, Ingvild; Lydersen, Stian; Ursin, Marie Helene; Munthe-Kaas, Ragnhild & Ihle-Hansen, Hege [Show all 13 contributors for this article] (2021). Associations between post-stroke motor and cognitive function: a cross-sectional study. BMC Geriatrics. 21(1), p. 1–10. doi: 10.1186/s12877-021-02055-7. Full text in Research Archive Show summary

  Background: Motor and cognitive impairments are frequently observed following stroke, but are often managed as distinct entities, and there is little evidence regarding how they are related. The aim of this study was to describe the prevalence of concurrent motor and cognitive impairments 3 months after stroke and to examine how motor performance was associated with memory, executive function and global cognition. Methods: The Norwegian Cognitive Impairment After Stroke (Nor-COAST) study is a prospective multicentre cohort study including patients hospitalized with acute stroke between May 2015 and March 2017. The National Institutes of Health Stroke Scale (NIHSS) was used to measure stroke severity at admission. Level of disability was assessed by the Modified Rankin Scale (mRS). Motor and cognitive functions were assessed 3 months post-stroke using the Montreal Cognitive Assessment (MoCA), Trail Making Test Part B (TMT-B), 10-Word List Recall (10WLR), Short Physical Performance Battery (SPPB), dual-task cost (DTC) and grip strength (Jamar®). Cut-offs were set according to current recommendations. Associations were examined using linear regression with cognitive tests as dependent variables and motor domains as covariates, adjusted for age, sex, education and stroke severity. Results: Of 567 participants included, 242 (43%) were women, mean (SD) age was 72.2 (11.7) years, 416 (75%) had an NIHSS score ≤ 4 and 475 (84%) had an mRS score of ≤2. Prevalence of concurrent motor and cognitive impairment ranged from 9.5% for DTC and 10WLR to 22.9% for grip strength and TMT-B. SPPB was associated with MoCA (regression coefficient B = 0.465, 95%CI [0.352, 0.578]), TMT-B (B = -9.494, 95%CI [− 11.726, − 7.925]) and 10WLR (B = 0.132, 95%CI [0.054, 0.211]). Grip strength was associated with MoCA (B = 0.075, 95%CI [0.039, 0.112]), TMT-B (B = -1.972, 95%CI [− 2.672, − 1.272]) and 10WLR (B = 0.041, 95%CI [0.016, 0.066]). Higher DTC was associated with more time needed to complete TMT-B (B = 0.475, 95%CI [0.075, 0.875]) but not with MoCA or 10WLR.

• Schellhorn, Till; Zucknick, Manuela; Askim, Torunn; Munthe-Kaas, Ragnhild; Ihle-Hansen, Hege & Seljeseth, Yngve Müller [Show all 13 contributors for this article] (2021). Pre-stroke cognitive impairment is associated with vascular imaging pathology: a prospective observational study. BMC Geriatrics. 21:362(362), p. 1–10. doi: 10.1186/s12877-021-02327-2. Full text in Research Archive Show summary

  Background: Chronic brain pathology and pre-stroke cognitive impairment (PCI) is predictive of post-stroke dementia. The aim of the current study was to measure pre-stroke neurodegenerative and vascular disease burden found on brain MRI and to assess the association between pre-stroke imaging pathology and PCI, whilst also looking for potential sex differences. Methods: This prospective brain MRI cohort is part of the multicentre Norwegian cognitive impairment after stroke (Nor-COAST) study. Patients hospitalized with acute ischemic or hemorrhagic stroke were included from five participating stroke units. Visual rating scales were used to categorize baseline MRIs (N = 410) as vascular, neurodegenerative, mixed, or normal, based on the presence of pathological imaging findings. Pre-stroke cognition was assessed by interviews of patients or caregivers using the Global Deterioration Scale (GDS). Stroke severity was assessed with the National Institute of Health Stroke Scale (NIHSS). Univariate and multiple logistic regression analyses were performed to investigate the association between imaging markers, PCI, and sex. Results: Patients’ (N = 410) mean (SD) age was 73.6 (±11) years; 182 (44%) participants were female, the mean (SD) NIHSS at admittance was 4.1 (±5). In 68% of the participants, at least one pathological imaging marker was found. Medial temporal lobe atrophy (MTA) was present in 30% of patients, white matter hyperintensities (WMH) in 38% of patients and lacunes in 35% of patients. PCI was found in 30% of the patients. PCI was associated with cerebrovascular pathology (OR 2.5; CI = 1.4 to 4.5, p = 0.001) and mixed pathology (OR 3.4; CI = 1.9 to 6.1, p = 0.001) but was not associated with neurodegeneration (OR 1.0; CI = 0.5 to 2.2; p = 0.973). Pathological MRI markers, including MTA and lacunes, were more prevalent among men, as was a history of clinical stroke prior to the index stroke. The OR of PCI for women was not significantly increased (OR 1.2; CI = 0.8 to 1.9; p = 0.3).

• Andreassen, Silje; Lindland, Elisabeth Margrete Stokke; Solheim, Anne Marit; Beyer, Mona K.; Ljøstad, Unn & Mygland, Åse Daasvand [Show all 11 contributors for this article] (2021). Cognitive function, fatigue and Fazekas score in patients with acute neuroborreliosis. Ticks and Tick-borne Diseases. ISSN 1877-959X. 12(3), p. 1–5. doi: 10.1016/j.ttbdis.2021.101678. Full text in Research Archive Show summary

  Long-term cognitive problems and fatigue after adequately treated neuroborreliosis has caused uncertainty and debate among patients and health care workers for years. Despite several studies, the prevalence, cause and severity of such complaints are still not clarified. More knowledge about cognitive function, fatigue and MRI findings in the acute phase of neuroborreliosis could possibly contribute to clarification. In the current study, we therefore aimed to address this. Patients with well-characterized acute neuroborreliosis (n = 72) and a matched control group (n = 68) were screened with eight subtests from three different neuropsychological test batteries assessing attention, working memory and processing speed, and with Fatigue Severity Scale. Fazekas score was used to grade white matter hyperintensities on MRI. We found no differences in mean scores on the neuropsychological tests between the groups. The patient group reported significantly higher level of fatigue (Fatigue Severity Scale: 4.8 vs. 2.9, p < .001). There was no significant difference in Fazekas score between the groups. Neuroborreliosis does not seem to affect cognitive functions in the acute state of the disease, while fatigue is common.

• Ihle-Hansen, Håkon; Ihle-Hansen, Hege; Fure, Brynjar; Thommessen, Bente; Helland, Gisle Berg & Øksengård, Anne Rita [Show all 10 contributors for this article] (2021). Carotid Atherosclerosis and Longitudinal Changes of MRI Visual Rating Measures in Stroke Survivors: A Seven-Year Follow-Up Study. Journal of Stroke & Cerebrovascular Diseases. ISSN 1052-3057. 30(10), p. 1–6. doi: 10.1016/j.jstrokecerebrovasdis.2021.106010. Full text in Research Archive Show summary

  Objectives We aimed to assess longitudinal changes in MRI measures of brain atrophy and white matter lesions in stroke and transient ischemic attack (TIA) survivors, and explore whether carotid stenosis predicts progression of these changes, assessed by visual rating scales. Materials and Methods All patients with a first-ever stroke or TIA admitted to Bærum Hospital, Norway, in 2007/2008, were invited in the acute phase and followed for seven years. Carotid ultrasound was performed during the hospital stay. Carotid stenosis was defined as ≥50% narrowing of lumen. MRI was performed one and seven years after the index event and analyzed according to the visual rating scales Fazekas scale (0-3), Medial Temporal Lobe Atrophy (MTLA) (0-4) score, and Global Cortical Atrophy (GCA) scale (0-3). Patients with MRI scans at both time points were included in this sub-study. Results Of 227 patients recruited, 76 had both MRI examinations. Mean age 73.9±10.6, 41% women, and 9% had ≥50% carotid stenosis. Mean Fazekas scale was 1.7±0.9 and 1.8±1.0, mean MTLA score 1.0 ±1.0 and 1.7±1.0, and mean GCA scale score 1.4±0.7 and 1.4±0.6 after one and seven years, respectively. 71% retained the same Fazekas scale score, while 21% showed progression. Deterioration in GCA scale was seen in 20% and increasing MTLA score in 57%. Carotid stenosis was not associated with progression on Fazekas score, MTLA score or GCA scale. Conclusions Three out of five showed progression on the MTLA score. Carotid stenosis was not associated with longitudinal change of visual rating scales.

• Schellhorn, Till; Aamodt, Eva Birgitte; Lydersen, Stian; Aam, Stina; Wyller, Torgeir Bruun & Saltvedt, Ingvild [Show all 7 contributors for this article] (2021). Clinically accessible neuroimaging predictors of post-stroke neurocognitive disorder: a prospective observational study. BMC Neurology. 21(1), p. 1–11. doi: 10.1186/s12883-021-02117-8. Full text in Research Archive Show summary

  Background Neurocognitive disorder (NCD) is common in stroke survivors. We aimed to identify clinically accessible imaging markers of stroke and chronic pathology that are associated with early post-stroke NCD. Methods We included 231 stroke survivors from the “Norwegian Cognitive Impairment after Stroke (Nor-COAST)” study who underwent a standardized cognitive assessment 3 months after the stroke. Any NCD (mild cognitive impairment and dementia) and major NCD (dementia) were diagnosed according to “Diagnostic and Statistical Manual of Mental Disorders (DSM-5)” criteria. Clinically accessible imaging findings were analyzed on study-specific brain MRIs in the early phase after stroke. Stroke lesion volumes were semi automatically quantified and strategic stroke locations were determined by an atlas based coregistration. White matter hyperintensities (WMH) and medial temporal lobe atrophy (MTA) were visually scored. Logistic regression was used to identify neuroimaging findings associated with major NCD and any NCD. Results Mean age was 71.8 years (SD 11.1), 101 (43.7%) were females, mean time from stroke to imaging was 8 (SD 16) days. At 3 months 63 (27.3%) had mild NCD and 65 (28.1%) had major NCD. Any NCD was significantly associated with WMH pathology (odds ratio (OR) = 2.73 [1.56 to 4.77], p = 0.001), MTA pathology (OR = 1.95 [1.12 to 3.41], p = 0.019), and left hemispheric stroke (OR = 1.8 [1.05 to 3.09], p = 0.032). Major NCD was significantly associated with WMH pathology (OR = 2.54 [1.33 to 4.84], p = 0.005) and stroke lesion volume (OR (per ml) =1.04 [1.01 to 1.06], p = 0.001). Conclusion WMH pathology, MTA pathology and left hemispheric stroke were associated with the development of any NCD. Stroke lesion volume and WMH pathology were associated with the development of major NCD 3 months after stroke. These imaging findings may be used in the routine clinical setting to identify patients at risk for early post-stroke NCD.

• Høgestøl, Einar August; Ghezzo, Samuele; Nygaard, Gro Owren; Espeseth, Thomas; Sowa, Piotr & Beyer, Mona K. [Show all 10 contributors for this article] (2021). Functional connectivity in multiple sclerosis modelled as connectome stability: A 5-year follow-up study. Multiple Sclerosis. ISSN 1352-4585. p. 1–9. doi: 10.1177/13524585211030212. Full text in Research Archive Show summary

  Background: Brain functional connectivity (FC) in multiple sclerosis (MS) is abnormal compared to healthy controls (HCs). More longitudinal studies in MS are needed to evaluate whether FC stability is clinically relevant. Objective: To compare functional magnetic resonance imaging (fMRI)-based FC between MS and HC, and to determine the relationship between longitudinal FC changes and structural brain damage, cognitive performance and physical disability. Methods: T1-weighted MPRAGE and resting-state fMRI (1.5T) were acquired from 70 relapsing-remitting MS patients and 94 matched HC at baseline (mean months since diagnosis 14.0 ± 11) and from 60 MS patients after 5 years. Independent component analysis and network modelling were used to measure longitudinal FC stability and cross-sectional comparisons with HC. Linear mixed models, adjusted for age and sex, were used to calculate correlations. Results: At baseline, patients with MS showed FC abnormalities both within networks and in single connections compared to HC. Longitudinal analyses revealed functional stability and no significant relationships with clinical disability, cognitive performance, lesion or brain volume. Conclusion: FC abnormalities occur already at the first decade of MS, yet we found no relevant clinical correlations for these network deviations. Future large-scale longitudinal fMRI studies across a range of MS subtypes and outcomes are required.

• Aamodt, Eva Birgitte; SCHELLHORN, TILL; Stage, Edwin; Sanjay, Apoorva Bharthur; Logan, Paige E. & Svaldi, Diana Otero [Show all 9 contributors for this article] (2021). Predicting the Emergence of Major Neurocognitive Disorder Within Three Months After a Stroke. Frontiers in Aging Neuroscience. 13, p. 1–13. doi: 10.3389/fnagi.2021.705889. Full text in Research Archive Show summary

  Background: Neurocognitive disorder (NCD) is common after stroke, with major NCD appearing in about 10% of survivors of a first-ever stroke. We aimed to classify clinical- and imaging factors related to rapid development of major NCD 3 months after a stroke, so as to examine the optimal composition of factors for predicting rapid development of the disorder. We hypothesized that the prediction would mainly be driven by neurodegenerative as opposed to vascular brain changes. Methods: Stroke survivors from five Norwegian hospitals were included from the “Norwegian COgnitive Impairment After STroke” (Nor-COAST) study. A support vector machine (SVM) classifier was trained to distinguish between patients who developed major NCD 3 months after the stroke and those who did not. Potential predictor factors were based on previous literature and included both vascular and neurodegenerative factors from clinical and structural magnetic resonance imaging findings. Cortical thickness was obtained via FreeSurfer segmentations, and volumes of white matter hyperintensities (WMH) and stroke lesions were semi-automatically gathered using FSL BIANCA and ITK-SNAP, respectively. The predictive value of the classifier was measured, compared between classifier models and cross-validated. Results: Findings from 227 stroke survivors [age = 71.7 (11.3), males = (56.4%), stroke severity NIHSS = 3.8 (4.8)] were included. The best predictive accuracy (AUC = 0.876) was achieved by an SVM classifier with 19 features. The model with the fewest number of features that achieved statistically comparable accuracy (AUC = 0.850) was the 8-feature model. These features ranked by their weighting were; stroke lesion volume, WMH volume, left occipital and temporal cortical thickness, right cingulate cortical thickness, stroke severity (NIHSS), antiplatelet medication intake, and education. Conclusion: The rapid (<3 months) development of major NCD after stroke is possible to predict with an 87.6% accuracy and seems dependent on both neurodegenerative and vascular factors, as well as aspects of the stroke itself. In contrast to previous literature, we also found that vascular changes are more important than neurodegenerative ones. Although possible to predict with relatively high accuracy, our findings indicate that the development of rapid onset post-stroke NCD may be more complex than earlier suggested.

• Gynnild, Mari Nordbø; Aakerøy, Rachel; Spigset, Olav; Askim, Torunn; Beyer, Mona Kristiansen & Ihle-Hansen, Hege [Show all 15 contributors for this article] (2020). Vascular risk factor control and adherence to secondary preventive medication after ischaemic stroke. Journal of Internal Medicine. ISSN 0954-6820. 289(3), p. 1–14. doi: 10.1111/joim.13161. Full text in Research Archive Show summary

  Background Studies regarding adequacy of secondary stroke prevention are limited. We report medication adherence, risk factor control and factors influencing vascular risk profile following ischaemic stroke. Methods A total of 664 home‐dwelling participants in the Norwegian Cognitive Impairment After Stroke study, a multicenter observational study, were evaluated 3 and 18 months poststroke. We assessed medication adherence by self‐reporting (4‐item Morisky Medication Adherence Scale) and medication persistence (defined as continuation of medication(s) prescribed at discharge), achievement of guideline‐defined targets of blood pressure (BP) (<140/90 mmHg), low‐density lipoprotein cholesterol (LDL‐C) (<2.0 mmol L−1) and haemoglobin A1c (HbA1c) (≤53 mmol mol−1) and determinants of risk factor control. Results At discharge, 97% were prescribed antithrombotics, 88% lipid‐lowering drugs, 68% antihypertensives and 12% antidiabetic drugs. Persistence of users declined to 99%, 88%, 93% and 95%, respectively, at 18 months. After 3 and 18 months, 80% and 73% reported high adherence. After 3 and 18 months, 40.7% and 47.0% gained BP control, 48.4% and 44.6% achieved LDL‐C control, and 69.2% and 69.5% of diabetic patients achieved HbA1c control. Advanced age was associated with increased LDL‐C control (OR 1.03, 95% CI 1.01 to 1.06) and reduced BP control (OR 0.98, 0.96 to 0.99). Women had poorer LDL‐C control (OR 0.60, 0.37 to 0.98). Polypharmacy was associated with increased LDL‐C control (OR 1.29, 1.18 to 1.41) and reduced HbA1c control (OR 0.76, 0.60 to 0.98). Conclusion Risk factor control is suboptimal despite high medication persistence and adherence. Improved understanding of this complex clinical setting is needed for optimization of secondary preventive strategies.

• Brune, Synne; Høgestøl, Einar August; Cengija, Vanja; Berg-Hansen, Pål; Sowa, Piotr & Nygaard, Gro Owren [Show all 8 contributors for this article] (2020). LesionQuant for assessment of MRI in multiple sclerosis—A promising supplement to the visual scan inspection. Frontiers in Neurology. 11:546744, p. 1–10. doi: 10.3389/fneur.2020.546744. Full text in Research Archive Show summary

  Background and Goals: Multiple sclerosis (MS) is a central nervous system inflammatory disease where magnetic resonance imaging (MRI) is an important tool for diagnosis and disease monitoring. Quantitative measurements of lesion volume, lesion count, distribution of lesions, and brain atrophy have a potentially significant value for evaluating disease progression. We hypothesize that utilizing software designed for evaluating MRI data in MS will provide more accurate and detailed analyses compared to the visual neuro-radiological evaluation. Methods: A group of 56 MS patients (mean age 35 years, 70% females and 96% relapsing-remitting MS) was examined with brain MRI one and 5 years after diagnosis. The T1 and FLAIR brain MRI sequences for all patients were analyzed using the LesionQuant (LQ) software. These data were compared with data from structured visual evaluations of the MRI scans performed by neuro-radiologists, including assessments of atrophy, and lesion count. The data from LQ were also compared with data from other validated research methods for brain segmentation, including assessments of whole brain volume and lesion volume. Correlations with clinical tests like the timed 25-foot walk test (T25FT) were performed to explore additional value of LQ analyses. Results: Lesion count assessments by LQ and by the neuro-radiologist were significantly correlated one year (cor = 0.92, p = 2.2 × 10 −16 ) and 5 years (cor = 0.84, p = 2.7 × 10 −16 ) after diagnosis. Analyzes of the intra- and interrater variability also correlated significantly (cor = 0.96, p &amp;lt; 0.001, cor = 0.97, p &amp;lt; 0.001). Significant positive correlation was found between lesion volume measured by LQ and by the software Cascade (cor = 0.7, p &amp;lt; 0.001. LQ detected a reduction in whole brain percentile &amp;gt;10 in 10 patients across the time-points, whereas the neuro-radiologist assessment identified six of these. The neuro-radiologist additionally identified five patients with increased atrophy in the follow-up period, all of them displayed decreasing low whole brain percentiles (median 11, range 8–28) in the LQ analysis. Significant positive correlation was identified between lesion volume measured by LQ and test performance on the T25FT both at 1 and 5 years after diagnosis. Conclusion: For the number of MS lesions at both time-points, we demonstrated strong correlations between the assessments done by LQ and the neuro-radiologist. Lesion volume evaluated with LQ correlated with T25FT performance. LQ-analyses classified more patients to have brain atrophy than the visual neuro-radiological evaluation. In conclusion, LQ seems like a promising supplement to the evaluation performed by neuro-radiologists, providing an automated tool for evaluating lesions in MS patients and also detecting early signs of atrophy in both a longitudinal and cross-sectional setting.

• Hagberg, Guri; Ihle-Hansen, Hege; Fure, Brynjar; Thommessen, Bente; Ihle-Hansen, Håkon & Øksengård, Anne Rita [Show all 11 contributors for this article] (2020). No evidence for amyloid pathology as a key mediator of neurodegeneration post-stroke - A seven-year follow-up study. BMC Neurology. 20, p. 1–11. doi: 10.1186/s12883-020-01753-w. Full text in Research Archive Show summary

  Background Cognitive impairment (CI) with mixed vascular and neurodegenerative pathologies after stroke is common. The role of amyloid pathology in post-stroke CI is unclear. We hypothesize that amyloid deposition, measured with Flutemetamol (18F-Flut) positron emission tomography (PET), is common in seven-year stroke survivors diagnosed with CI and, further, that quantitatively assessed 18F-Flut-PET uptake after 7 years correlates with amyloid-β peptide (Aβ42) levels in cerebrospinal fluid (CSF) at 1 year, and with measures of neurodegeneration and cognition at 7 years post-stroke. Methods 208 patients with first-ever stroke or transient Ischemic Attack (TIA) without pre-existing CI were included during 2007 and 2008. At one- and seven-years post-stroke, cognitive status was assessed, and categorized into dementia, mild cognitive impairment or normal. Etiologic sub-classification was based on magnetic resonance imaging (MRI) findings, CSF biomarkers and clinical cognitive profile. At 7 years, patients were offered 18F-Flut-PET, and amyloid-positivity was assessed visually and semi-quantitatively. The associations between 18F-Flut-PET standardized uptake value ratios (SUVr) and measures of neurodegeneration (medial temporal lobe atrophy (MTLA), global cortical atrophy (GCA)) and cognition (Mini-Mental State Exam (MMSE), Trail-making test A (TMT-A)) and CSF Aβ42 levels were assessed using linear regression. Results In total, 111 patients completed 7-year follow-up, and 26 patients agreed to PET imaging, of whom 13 had CSF biomarkers from 1 year. Thirteen out of 26 patients were diagnosed with CI 7 years post-stroke, but only one had visually assessed amyloid positivity. CSF Aβ42 levels at 1 year, MTA grade, GCA scale, MMSE score or TMT-A at 7 years did not correlate with 18F-Flut-PET SUVr in this cohort. Conclusions Amyloid binding was not common in 7-year stroke survivors diagnosed with CI. Quantitatively assessed, cortical amyloid deposition did not correlate with other measures related to neurodegeneration or cognition. Therefore, amyloid pathology may not be a key mediator of neurodegeneration 7 years post-stroke. Trial registration Clinicaltrials.gov (NCT00506818). July 23, 2007. Inclusion from February 2007, randomization and intervention from May 2007 and trial registration in July 2007.

• Tjensvoll, Anne Bolette; Lauvsnes, Maria Boge; Zetterberg, Henrik; Kvaløy, Jan Terje; Kvivik, Ingeborg & Maroni, Stian [Show all 15 contributors for this article] (2020). Neurofilament light is a biomarker of brain involvement in lupus and primary Sjögren’s syndrome. Journal of Neurology. ISSN 0340-5354. 268. doi: 10.1007/s00415-020-10290-y. Full text in Research Archive Show summary

  Background To test the hypothesis that neurofilament light (NfL) in CSF is a biomarker of CNS involvement in patients with systemic lupus erythematosus (SLE) and primary Sjögren’s syndrome (pSS), we measured NfL in CSF from 52 patients with lupus and 54 with pSS and explored associations with clinical, structural, immunological and biochemical abnormalities. Methods In CSF, we measured NfL, anti-P antibodies, protein S100B and TWEAK by ELISA and anti-NR2 antibodies by electrochemiluminescence. Anti-phospholipid antibodies and routine immunological tests were performed in blood. IgG and albumin were measured in CSF and serum for assessment of the blood–brain barrier function (Q-albumin) and intrathecal IgG production (IgG index). Cerebral MRI and neuropsychological testing were performed. Results A multivariable regression model showed that increasing CSF anti-NR2 antibody levels were associated with increasing NfL levels in patients with SLE (B 1.27, 95% CI 0.88–1.65, p < 0.001). Age contributed significantly in the model (B 0.04, 95% CI 0.03–0.05, p < 0.001). Similar findings were observed in the pSS group. Adjusted for age and sex, no associations were found between NfL levels and any MRI data. In SLE patients, higher NfL concentrations were associated with impairments in psychomotor speed and motor function, and in pSS with motor dysfunction. These associations remained in multivariable regression models. Conclusions Increased concentration of NfL in CSF is a marker of cerebral involvement in patients with SLE and pSS, is strongly associated with the presence of anti-NR2 antibodies, and correlates with cognitive impairment in several domains.

• Munthe-Kaas, Ragnhild; Aam, Stina; Ihle-Hansen, Hege; Lydersen, Stian; Knapskog, Anne Brita & Wyller, Torgeir Bruun [Show all 15 contributors for this article] (2020). Impact of different methods defining post-stroke neurocognitive disorder: The Nor-COAST study. Alzheimer's and Dementia: Translational Research and Clinical Interventions. 6:e12000(1), p. 1–9. doi: 10.1002/trc2.12000. Full text in Research Archive Show summary

  Introduction Post‐stroke neurocognitive disorder (NCD) is common; prevalence varies between studies, partially related to lack of consensus on how to identify cases. The aim was to compare the prevalence of post‐stroke NCD using only cognitive assessment (model A), DSM‐5 criteria (model B), and the Global Deterioration Scale (model C) and to determine agreement among the three models. Methods In the Norwegian Cognitive Impairment After Stroke study, 599 patients were assessed 3 months after suffering a stroke. Results The prevalence of mild NCD varied from 174 (29%) in model B to 83 (14%) in model C; prevalence of major NCD varied from 249 (42%) in model A to 68 (11%) in model C. Cohen's kappa and Cohen's quadratic weighted kappa showed fair to very good agreement among models; the poorest agreement was found for identification of mild NCD. Discussion The findings indicate a need for international harmonization to classify post‐stroke NCD.

• Alme, Katinka Nordheim; Knapskog, Anne Brita; Næss, Halvor; Naik, Mala; Beyer, Mona K. & Ellekjær, Hanne [Show all 15 contributors for this article] (2020). Is long-bout sedentary behaviour associated with long-Term glucose levels 3 months after acute ischaemic stroke? A prospective observational cohort study. BMJ Open. 10(11), p. 1–9. doi: 10.1136/bmjopen-2020-037475. Full text in Research Archive Show summary

  Background and purpose Sedentary behaviour is a risk factor for vascular disease and stroke patients are more sedentary than their age-matched peers. The association with glucose levels, as a potential mediator, is unclear, and we have investigated the association between long-bout sedentary behaviour and long-term glucose levels in stroke survivors. Methods This study uses data from the Norwegian Cognitive Impairment After Stroke study, a multicentre cohort study. The patients were recruited at hospital admission for acute stroke, and the follow-up was done at the outpatient clinic. Sedentary behaviour—being in a sitting or reclining position—was registered 3 months after stroke using position transition data from the body-worn sensor activPAL attached to the unaffected thigh. A MATLAB script was developed to extract activity data from 08:00 to 10:00 for 4 days and to categorise the data into four bout-length categories. The primary outcome was glycated haemoglobin (HbA1c), analysed at 3 months. Regression models were used to analyse the association between HbA1c and sedentary behaviour in the whole population and stratified based on a diagnosis of diabetes mellitus (DM). Age, body mass index and the use of antidiabetic drugs were added as covariates into the models. Results From a total of 815 included patients, 379 patients fulfilled the inclusion criteria for this study. We found no association between time in sedentary behaviour and HbA1c in the whole stroke population. We found time in sedentary behaviour in bouts of ≥90 min to be associated with a higher HbA1c in patients with DM. Conclusion Long-bout sedentary time is associated with a higher HbA1c in patients with DM 3 months after ischaemic stroke. Future research should investigate the benefit of breaking up sedentary time as a secondary preventive measure. Trial registration number NCT02650531, https://clinicaltrials.gov/ct2/show/NCT02650531

• Elvsåshagen, Torbjørn; Bahrami, Shahram; Meer, Dennis van der; Agartz, Ingrid; Alnæs, Dag & Barch, Deanna M. [Show all 76 contributors for this article] (2020). The genetic architecture of human brainstem structures and their involvement in common brain disorders. Nature Communications. 11. doi: 10.1038/s41467-020-17376-1. Full text in Research Archive Show summary

  Brainstem regions support vital bodily functions, yet their genetic architectures and involvement in common brain disorders remain understudied. Here, using imaging-genetics data from a discovery sample of 27,034 individuals, we identify 45 brainstem-associated genetic loci, including the first linked to midbrain, pons, and medulla oblongata volumes, and map them to 305 genes. In a replication sample of 7432 participants most of the loci show the same effect direction and are significant at a nominal threshold. We detect genetic overlap between brainstem volumes and eight psychiatric and neurological disorders. In additional clinical data from 5062 individuals with common brain disorders and 11,257 healthy controls, we observe differential volume alterations in schizophrenia, bipolar disorder, multiple sclerosis, mild cognitive impairment, dementia, and Parkinson’s disease, supporting the relevance of brainstem regions and their genetic architectures in common brain disorders.

• Høgestøl, Einar August; Kaufmann, Tobias; Nygaard, Gro Owren; Beyer, Mona K.; Sowa, Piotr & Nordvik, Jan Egil [Show all 11 contributors for this article] (2019). Cross-sectional and longitudinal MRI brain scans reveal accelerated brain aging in multiple sclerosis. Frontiers in Neurology. 10:450, p. 1–9. doi: 10.3389/fneur.2019.00450. Full text in Research Archive Show summary

  Multiple sclerosis (MS) is an inflammatory disorder of the central nervous system. By combining longitudinal MRI-based brain morphometry and brain age estimation using machine learning, we tested the hypothesis that MS patients have higher brain age relative to chronological age than healthy controls (HC) and that longitudinal rate of brain aging in MS patients is associated with clinical course and severity. Seventy-six MS patients [71% females, mean age 34.8 years (range 21–49) at inclusion] were examined with brain MRI at three time points with a mean total follow up period of 4.4 years (±0.4 years). We used additional cross-sectional MRI data from 235 HC for case-control comparison. We applied a machine learning model trained on an independent set of 3,208 HC to estimate individual brain age and to calculate the difference between estimated and chronological age, termed brain age gap (BAG). We also assessed the longitudinal change rate in BAG in individuals with MS. MS patients showed significantly higher BAG (4.4 ± 6.6 years) compared to HC (Cohen's D = 0.69, p = 4.0 × 10−6). Longitudinal estimates of BAG in MS patients showed high reliability and suggested an accelerated rate of brain aging corresponding to an annual increase of 0.41 (SE = 0.15) years compared to chronological aging (p = 0.008). Multiple regression analyses revealed higher rate of brain aging in patients with more brain atrophy (Cohen's D = 0.86, p = 4.3 × 10−15) and increased white matter lesion load (WMLL) (Cohen's D = 0.55, p = 0.015). On average, patients with MS had significantly higher BAG compared to HC. Progressive brain aging in patients with MS was related to brain atrophy and increased WMLL. No significant clinical associations were found in our sample, future studies are warranted on this matter. Brain age estimation is a promising method for evaluation of subtle brain changes in MS, which is important for predicting clinical outcome and guide choice of intervention.

• Kaufmann, Tobias; Meer, Dennis van der; Doan, Nhat Trung; Schwarz, Emanuel; Lund, Martina Jonette & Agartz, Ingrid [Show all 84 contributors for this article] (2019). Common brain disorders are associated with heritable patterns of apparent aging of the brain. Nature Neuroscience. ISSN 1097-6256. 22(10), p. 1617–1623. doi: 10.1038/s41593-019-0471-7. Full text in Research Archive Show summary

  Common risk factors for psychiatric and other brain disorders are likely to converge on biological pathways influencing the development and maintenance of brain structure and function across life. Using structural MRI data from 45,615 individuals aged 3–96 years, we demonstrate distinct patterns of apparent brain aging in several brain disorders and reveal genetic pleiotropy between apparent brain aging in healthy individuals and common brain disorders.

• Høgestøl, Einar August; Nygaard, Gro Owren; Alnæs, Dag; Beyer, Mona K.; Westlye, Lars Tjelta & Harbo, Hanne Flinstad (2019). Symptoms of fatigue and depression is reflected in altered default mode network connectivity in multiple sclerosis. PLOS ONE. 14(4). doi: 10.1371/journal.pone.0210375. Full text in Research Archive Show summary

  Background Fatigue and depression are frequent and often co-occurring symptoms in multiple sclerosis (MS). Resting-state functional magnetic resonance imaging (rs-fMRI) represents a promising tool for disentangling differential associations between depression and fatigue and brain network function and connectivity. In this study we tested for associations between symptoms of fatigue and depression and DMN connectivity in patients with MS. Materials and methods Seventy-four MS patients were included on average 14 months after diagnosis. They underwent MRI scanning of the brain including rs-fMRI, and symptoms of fatigue and depression were assessed with Fatigue Severity Scale (FSS) and Beck Depression Inventory II (BDI). A principal component analysis (PCA) on FSS and BDI scores was performed, and the component scores were analysed using linear regression models to test for associations with default mode network (DMN) connectivity. Results We observed higher DMN connectivity with higher scores on the primary principal component reflecting common symptom burden for fatigue and depression (Cohen’s f2 = 0.075, t = 2.17, p = 0.03). The secondary principal component reflecting a pattern of low fatigue scores with high scores of depression was associated with lower DMN connectivity (Cohen’s f2 = 0.067, t = -2.1, p = 0.04). Using continuous mean scores of FSS we also observed higher DMN connectivity with higher symptom burden (t = 3.1, p = 0.003), but no significant associations between continuous sum scores of BDI and DMN connectivity (t = 0.8, p = 0.4). Conclusion Multivariate decomposition of FSS and BDI data supported both overlapping and unique manifestation of fatigue and depression in MS patients. Rs-fMRI analyses showed that symptoms of fatigue and depression were reflected in altered DMN connectivity, and that higher DMN activity was seen in MS patients with fatigue even with low depression scores.

• Hagberg, Guri; Fure, Brynjar; Thommessen, Bente; Ihle-Hansen, Håkon; Øksengård, Anne Rita & Nygård, Ståle [Show all 10 contributors for this article] (2019). Predictors for Favorable Cognitive Outcome Post-Stroke: A-Seven-Year Follow-Up Study. Dementia and Geriatric Cognitive Disorders. ISSN 1420-8008. p. 1–11. doi: 10.1159/000501850. Full text in Research Archive
• Lindland, Elisabeth Margrete Stokke; Solheim, Anne Marit; Andreassen, Silje; Paulsen, Else Quist; Eikeland, Randi & Ljøstad, Unn [Show all 12 contributors for this article] (2018). Imaging in Lyme neuroborreliosis. Insights into Imaging. 9(5), p. 833–844. doi: 10.1007/s13244-018-0646-x. Full text in Research Archive Show summary

  Lyme neuroborreliosis (LNB) is a tick-borne spirochetal infection with a broad spectrum of imaging pathology. For individuals who live in or have travelled to areas where ticks reside, LNB should be considered among differential diagnoses when clinical manifestations from the nervous system occur. Radiculitis, meningitis and facial palsy are commonly encountered, while peripheral neuropathy, myelitis, meningoencephalitis and cerebral vasculitis are rarer manifestations of LNB. Cerebrospinal fluid (CSF) analysis and serology are key investigations in patient workup. The primary role of imaging is to rule out other reasons for the neurological symptoms. It is therefore important to know the diversity of possible imaging findings from the infection itself. There may be no imaging abnormality, or findings suggestive of neuritis, meningitis, myelitis, encephalitis or vasculitis. White matter lesions are not a prominent feature of LNB. Insight into LNB clinical presentation, laboratory test methods and spectrum of imaging pathology will aid in the multidisciplinary interaction that often is imperative to achieve an efficient patient workup and arrive at a correct diagnosis. This article can educate those engaged in imaging of the nervous system and serve as a comprehensive tool in clinical cases.

• Sowa, Piotr; Harbo, Hanne Flinstad; White, Nathan S.; Celius, Elisabeth Gulowsen; Bartsch, Hauke & Berg-Hansen, Pål [Show all 12 contributors for this article] (2018). Restriction spectrum imaging of white matter and its relation to neurological disability in multiple sclerosis. Multiple Sclerosis. ISSN 1352-4585. p. 1–12. doi: 10.1177/1352458518765671. Full text in Research Archive Show summary

  Background: Restriction spectrum imaging (RSI) is a recently introduced magnetic resonance imaging diffusion technique. The utility of RSI in multiple sclerosis (MS) is unknown. Objective: To investigate the association between RSI-derived parameters and neurological disability in MS. Methods: Seventy-seven relapsing-remitting MS patients were scanned with RSI on a 3-Tesla scanner. RSI-derived parameters: fast and slow apparent diffusion coefficient (sADC), fractional anisotropy, restricted fractional anisotropy, neurite density (ND), cellularity, extracellular water fraction and free water fraction were obtained in white matter lesions (WML) and normal appearing white matter (NAWM). Patients were divided into three groups according to their expanded disability status scale (EDSS): with minimal, low and substantial disability (<2.5, 2.5–3 and >3, respectively). Group comparisons and correlation analyses were performed. Results: All tested RSI-derived parameters differed between WML and NAWM (p<0.001 for all pairwise comparisons). The sADC in WML showed largest difference across disability subgroups (ANOVA: F=5.1, η2=0.12 p=0.008). ND in NAWM showed strongest correlation with disability (ϱ=-0.39, p<0.001). Conclusion: The strongest correlation with EDSS of ND obtained in NAWM indicates that processes outside lesions are important for disability in MS. Our study suggests that RSIderived parameters may help understand the “clinico-radiological paradox” and improve disease monitoring in MS.

• Beyer, Mona K.; Dalaker, Turi Olene; Greve, Ole Jacob; Pignatiello, Siv Elin & Agartz, Ingrid (2018). A population study of Norwegian psychiatric patients referred for clinical brain scanning. BJPsych Open. 4(3), p. 149–156. doi: 10.1192/bjo.2018.16. Full text in Research Archive Show summary

  Background Patients with psychiatric conditions are often referred for a brain scan during the course of their diagnostic workup. Aims The aim of our study is to determine frequency and type of organic brain pathology, the relationship to age, gender and psychiatric diagnosis. Method We investigated magnetic resonance imaging and computed tomography brain scans from consecutively referred patients over a 10-year period (January 2002-December 2011). The reasons for referral, estimated psychiatric diagnosis, and the pathology discovered for each patient were registered. Results A total of 34% of patients demonstrated organic brain pathology, of which 32.8% were considered clinically relevant. This represents a higher frequency of relevant pathology than reported in healthy subjects. Age (P < 0.001) and diagnosis (P = 0.016) were the most important determinants for frequency of pathological findings. Conclusions Brain imaging in clinical psychiatry resulted in approximately 30% positive findings mainly associated with increasing pathologies with age, but also with diagnosis. Declaration of interest Both T.O.D. and M.K.B. have received honorary from Novartis for scientific lectures about multiple sclerosis. M.K.B. also received honoraria from Biogen for scientific lectures. The other authors have no conflicts of interest.

• Thingstad, Pernille; Askim, Torunn; Beyer, Mona K.; Bråthen, Geir; Ellekjær, Hanne & Ihle-Hansen, Hege [Show all 13 contributors for this article] (2018). The Norwegian Cognitive impairment after stroke study (Nor-COAST): study protocol of a multicentre, prospective cohort study. BMC Neurology. 18:193(193). doi: 10.1186/s12883-018-1198-x. Full text in Research Archive Show summary

  Background Early and late onset post-stroke cognitive impairment (PCI) contributes substantially to disability following stroke, and is a high priority within stroke research. The aetiology for PCI is complex and related to the stroke itself, brain resilience, comorbid brain diseases, prestroke vulnerability and complications during the hospital stay. The aim of the Norwegian Cognitive Impairment After Stroke study (Nor-COAST) is to quantify and measure levels of cognitive impairments in a general Norwegian stroke population and to identify biological and clinical markers associated with prognosis for cognitive disorders following incident stroke. The study will be organised within five work packages: 1) Incidence and trajectories 2) Pathological mechanisms 3) Development of a risk score 4) Impact of physical activity and 5) Adherence to secondary prevention. Methods Nor-COAST is an ongoing multicentre (five participating hospitals), prospective, cohort study with consecutive inclusion during the acute phase and with follow-up at three and 18 months, and at three years. Inclusion criteria are stroke defined according to the WHO criteria. During the recruitment period from 18.05.2015 to 31.03.2017, 816 participants have been included. Cognitive impairment will be classified according to the DSM-5 criteria using a consensus group. Cognitive function is assessed by a standardised neuropsychological test battery, the Montreal Cognitive Assessment, Trail making A and B, ten-word immediate and delayed recall test, the Controlled Oral Word Association, Global Deterioration Scale and proxy based information by and the Ascertain Dementia 8 item informant questionnaire. Biomarkers include magnetic resonance imaging, routine blood samples and bio-banking. Clinical assessments include characteristics of the stroke, comorbidity, delirium, frailty and tests for cognitive and physical function, sensor based activity monitoring and adherence to secondary prophylaxis. Discussion Nor-COAST is the first Norwegian multicentre study to quantify burden of PCI that will provide reliable estimates in a general stroke population. A multidisciplinary approach aiming to identify biomarkers and clinical markers of overall prognosis will add new knowledge about risk profiles, including pre-stroke vulnerability and modifiable factors such as physical activity and secondary prophylaxis of relevance for clinical practice and later intervention studies.

• Hammonds, Solveig Kristina; Lauvsnes, Maria Boge; Dalen, Ingvild; Beyer, Mona K.; Kurz, Kathinka Dæhli & Greve, Ole Jacob [Show all 8 contributors for this article] (2017). No structural cerebral MRI changes related to fatigue in patients with primary Sjögren’s syndrome. Rheumatology - Advances in Practice (Rheumap). 1(1). doi: 10.1093/rap/rkx007. Full text in Research Archive Show summary

  Objective Whether or not chronic fatigue is reflected in structural changes in the brain is a matter of debate. Primary SS (pSS) is characterized by dryness of the mouth and eyes, migrating muscle and joint pain and prominent fatigue. We aimed to investigate whether the severity of fatigue in pSS was associated with cerebral MRI findings. Methods Fatigue was measured with the fatigue visual analog scale in 65 patients with pSS. Global grey matter (GM) and white matter volumes were estimated from magnetic resonance T1 images, and associations between fatigue and brain volumes were assessed in regression models. Voxel-based morphometric analyses of GM were performed to investigate possible associations between fatigue and GM volume changes in particular brain regions. Results The fatigue scores in the patient group were spread across a wide range. Global volume analyses showed no significant effect of GM volumes and white matter volumes on fatigue. Voxel-wise analyses of GM did not identify any particular brain region associated with fatigue. Conclusion Fatigue is a dominant phenomenon in pSS patients but is not reflected in structural abnormalities in the brain as visualized by conventional MRI. Our findings support the hypothesis of fatigue as a physiological phenomenon that does not lead to vascular changes or neuronal or glial death or damage.

• Sowa, Piotr; Nygaard, Gro Owren; Bjørnerud, Atle; Celius, Elisabeth Gulowsen; Harbo, Hanne Flinstad & Beyer, Mona K. (2017). Magnetic resonance imaging perfusion is associated with disease severity and activity in multiple sclerosis. Neuroradiology. ISSN 0028-3940. 59(7), p. 655–664. doi: 10.1007/s00234-017-1849-4. Full text in Research Archive Show summary

  Purpose The utility of perfusion-weighted imaging in multiple sclerosis (MS) is not well investigated. The purpose of this study was to compare baseline normalized perfusion measures in subgroups of newly diagnosed MS patients. We wanted to test the hypothesis that this method can differentiate between groups defined according to disease severity and disease activity at 1 year follow-up. Methods Baseline magnetic resonance imaging (MRI) including a dynamic susceptibility contrast perfusion sequence was performed on a 1.5-T scanner in 66 patients newly diagnosed with relapsing-remitting MS. From the baseline MRI, cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) maps were generated. Normalized (n) perfusion values were calculated by dividing each perfusion parameter obtained in white matter lesions by the same parameter obtained in normal-appearing white matter. Neurological examination was performed at baseline and at follow-up approximately 1 year later to establish the multiple sclerosis severity score (MSSS) and evidence of disease activity (EDA). Results Baseline normalized mean transit time (nMTT) was lower in patients with MSSS >3.79 (p = 0.016), in patients with EDA (p = 0.041), and in patients with both MSSS >3.79 and EDA (p = 0.032) at 1-year follow-up. Baseline normalized cerebral blood flow and normalized cerebral blood volume did not differ between these groups. Conclusion Lower baseline nMTT was associated with higher disease severity and with presence of disease activity 1 year later in newly diagnosed MS patients. Further longitudinal studies are needed to confirm whether baseline-normalized perfusion measures can differentiate between disease severity and disease activity subgroups over time.

• Brix, Maiken Kirkegaard; Ersland, Lars; Hugdahl, Kenneth; Dwyer, Gerard Eric; Grüner, Renate & Noeske, Ralph [Show all 8 contributors for this article] (2017). Within- and between-session reproducibility of GABA measurements with MR spectroscopy. Journal of Magnetic Resonance Imaging. ISSN 1053-1807. 46(2), p. 421–430. doi: 10.1002/jmri.25588. Full text in Research Archive
• Persson, Karin; Selbæk, Geir; Brækhus, Anne; Beyer, Mona K.; Barca, Maria Lage & Engedal, Knut (2017). Fully automated structural MRI of the brain in clinical dementia workup. Acta Radiologica. ISSN 0284-1851. 58(6), p. 740–747. doi: 10.1177/0284185116669874. Full text in Research Archive
• Lebedeva, Aleksandra K.; Westman, Eric; Borza, Tom; Beyer, Mona K.; Engedal, Knut & Aarsland, Dag [Show all 8 contributors for this article] (2017). MRI-based classification models in prediction of mild cognitive impairment and dementia in late-life depression. Frontiers in Aging Neuroscience. 9:13, p. 1–11. doi: 10.3389/fnagi.2017.00013. Full text in Research Archive Show summary

  Objective: Late-life depression (LLD) is associated with development of different types of dementia. Identification of LLD patients, who will develop cognitive decline, i.e., the early stage of dementia would help to implement interventions earlier. The purpose of this study was to assess whether structural brain magnetic resonance imaging (MRI) in LLD patients can predict mild cognitive impairment (MCI) or dementia 1 year prior to the diagnosis. Methods: LLD patients underwent brain MRI at baseline and repeated clinical assessment after 1-year. Structural brain measurements were obtained using Freesurfer software (v. 5.1) from the T1W brain MRI images. MRI-based Random Forest classifier was used to discriminate between LLD who developed MCI or dementia after 1-year follow-up and cognitively stable LLD. Additionally, a previously established Random Forest model trained on 185 patients with Alzheimer’s disease (AD) vs. 225 cognitively normal elderly from the Alzheimer’s disease Neuroimaging Initiative was tested on the LLD data set (ADNI model). Results: MCI and dementia diagnoses were predicted in LLD patients with 76%/68%/84% accuracy/sensitivity/specificity. Adding the baseline Mini-Mental State Examination (MMSE) scores to the models improved accuracy/sensitivity/specificity to 81%/75%/86%. The best model predicted MCI status alone using MRI and baseline MMSE scores with accuracy/sensitivity/specificity of 89%/85%/90%. The most important region for all the models was right ventral diencephalon, including hypothalamus. Its volume correlated negatively with the number of depressive episodes. ADNI model trained on AD vs. Controls using SV could predict MCI-DEM patients with 67% accuracy. Conclusion: LDD patients developing MCI and dementia can be discriminated from LLD patients remaining cognitively stable with good accuracy based on baseline structural MRI alone. Baseline MMSE score improves prediction accuracy. Ventral diencephalon, including the hypothalamus might play an important role in preservation of cognitive functions in LLD.

• Oppedal, Ketil; Engan, Kjersti; Eftestøl, Trygve Christian; Beyer, Mona K. & Aarsland, Dag (2017). Classifying Alzheimer's disease, Lewy body dementia, and normal controls using 3D texture analysis in magnetic resonance images. Biomedical Signal Processing and Control. ISSN 1746-8094. 33, p. 19–29. doi: 10.1016/j.bspc.2016.10.007. Full text in Research Archive Show summary

  Dementia is an evolving challenge in society and early intervention is important. The ability to distinguish between different dementia and non-dementia early in course may be essential for successful patient care. Magnetic resonance (MR) imaging may aid as a noninvasive method to increase prediction accuracy. In this work we explored the use of two different 3D local binary pattern (LBP) texture features extracted from T1 MR images of the brain combined with a random forest classifier in an attempt to discern patients with Alzheimer's disease (AD), Lewy body dementia (LBD), and normal controls (NC). Analysis were conducted in areas with white matter lesions (WML) and normal appearing white matter (NAWM). We also calculated correlations between texture features and cognition measured by mini mental state examination (MMSE) controlling for age. Additionally, two different methods for handling the imbalanced data problem were tested, namely cost-sensitive classification and resampling of the data using the synthetic minority oversampling technique (SMOTE). Four different classification tasks were extensively tested, a three-class problem: AD vs. LBD vs. NC, a two-class problem: NC vs. AD, a two-class problem NC vs. LBD, and a two-class problem: AD vs. LBD. Results from 10 folds nested cross validation are reported as mean accuracy, precision, and recall with standard deviation in brackets. The two-class problems NC vs. AD and NC vs. LBD, show encouraging results with total accuracy of 0.97 (0.07) and 0.97 (0.06) respectively. The three-class problem and the two-class problem AD vs. LBD are not equally encouraging but shows higher accuracy than clinical diagnosis with a total accuracy of 0.79 (0.07) and 0.79 (0.15) respectively. Possible explanations may be that the AD- and LBD group are too similar concerning LBP texture analysis and that the LBD group is too small. Most of the texture features calculated for the AD subjects in the NAWM region were significantly correlated with cognition. Together with the positive classification results from the NAWM region this may suggest that the NAWM region is an important area for studying AD. Both cost-sensitive classification and resampling using SMOTE proved useful and improved the results considerably in many of the tests.

• Brix, Maiken Kirkegaard; Westman, Eric; Simmons, Andrew; Ringstad, Geir; Eide, Per Kristian & Wagner-Larsen, Kari Strøno [Show all 9 contributors for this article] (2017). The Evans' Index revisited: New cut-off levels for use in radiological assessment of ventricular enlargement in the elderly. European Journal of Radiology. ISSN 0720-048X. 95, p. 28–32. doi: 10.1016/j.ejrad.2017.07.013. Full text in Research Archive
• Keshavan, Anisha; Paul, Friedemann; Beyer, Mona K.; Zhu, Alyssa H.; Papinutto, Nico & Shinohara, Russell T. [Show all 56 contributors for this article] (2016). Power estimation for non-standardized multisite studies. NeuroImage. ISSN 1053-8119. 134, p. 281–294. doi: 10.1016/j.neuroimage.2016.03.051. Full text in Research Archive
• Tjensvoll, Anne Bolette; Lauvsnes, Maria Boge; Hirohata, Shunsei; Beyer, Mona K.; Greve, Ole Jacob & Kvivik, Ingeborg [Show all 10 contributors for this article] (2016). Migraine in patients with systemic lupus erythematosus is associated with reduced cerebral grey matter volume but not with measures of glial activation or anti-NR2 or anti-P antibodies. European Journal of Neurology. ISSN 1351-5101. 23(4), p. 780–786. doi: 10.1111/ene.12946. Full text in Research Archive
• Brix, Maiken Kirkegaard; Ersland, Lars; Hugdahl, Kenneth; Grüner, Renate; Posserud, Maj-Britt Rocio & Hammar, Åsa [Show all 12 contributors for this article] (2015). Brain MR spectroscopy in autism spectrum disorder—the GABA excitatory/inhibitory imbalance theory revisited. Frontiers in Human Neuroscience. 9(365), p. 1–12. doi: 10.3389/fnhum.2015.00365. Full text in Research Archive Show summary

  Magnetic resonance spectroscopy (MRS) from voxels placed in the left anterior cingulate cortex (ACC) was measured from 14 boys with Autism Spectrum Disorder (ASD) and 24 gender and age-matched typically developing (TD) control group. Our main aims were to compare the concentration of γ-aminobutyric acid (GABA) between the two groups, and to investigate the relationship between brain metabolites and autism symptom severity in the ASD group. We did find a significant negative correlation in the ASD group between Autism Spectrum Screening Questionnaire (ASSQ) and GABA+/Cr, which may imply that severity of symptoms in ASD is associated with differences in the level of GABA in the brain, supporting the excitatory/inhibitory (E/I) imbalance theory. However we did not find a significant difference between the two groups in GABA levels.

• Nygaard, Gro Owren; Walhovd, Kristine B; Sowa, Piotr; Chepkoech, Joy-Loi; Bjørnerud, Atle & Due-Tønnessen, Paulina [Show all 14 contributors for this article] (2015). Cortical thickness and surface area relate to specific symptoms in early relapsing−remitting multiple sclerosis. Multiple Sclerosis. ISSN 1352-4585. 21(4), p. 402–414. doi: 10.1177/1352458514543811. Full text in Research Archive
• Sowa, Piotr; Bjørnerud, Atle; Nygaard, Gro Owren; Damangir, Soheil; Spulber, Gabriela & Celius, Elisabeth Gulowsen [Show all 9 contributors for this article] (2015). Reduced perfusion in white matter lesions in multiple sclerosis. European Journal of Radiology. ISSN 0720-048X. 84(12), p. 2605–2612. doi: 10.1016/j.ejrad.2015.09.007. Full text in Research Archive
• Oppedal, Ketil; Eftestøl, Trygve; Engan, Kjersti; Beyer, Mona K. & Aarsland, Dag (2015). Classifying dementia using local binary patterns from different regions in magnetic resonance images. International Journal of Biomedical Imaging. ISSN 1687-4188. 2015. doi: 10.1155/2015/572567. Full text in Research Archive Show summary

  Dementia is an evolving challenge in society, and no disease-modifying treatment exists. Diagnosis can be demanding and MR imaging may aid as a noninvasive method to increase prediction accuracy. We explored the use of 2D local binary pattern (LBP) extracted from FLAIR and T1 MR images of the brain combined with a Random Forest classifier in an attempt to discern patients with Alzheimer’s disease (AD), Lewy body dementia (LBD), and normal controls (NC). Analysis was conducted in areas with white matter lesions (WML) and all of white matter (WM). Results from 10-fold nested cross validation are reported as mean accuracy, precision, and recall with standard deviation in brackets.The best result we achieved was in the two-class problem NC versus AD + LBD with total accuracy of 0.98 (0.04). In the three-class problem AD versus LBD versus NC and the two-class problem AD versus LBD, we achieved 0.87 (0.08) and 0.74 (0.16), respectively. The performance using 3DT1 images was notably better than when using FLAIR images.Theresults fromtheWMregion gave similar results as in theWMLregion.Our study demonstrates that LBP texture analysis in brain MR images can be successfully used for computer based dementia diagnosis.

• Lebedeva, Aleksandra; Borza, Tom; Håberg, Asta; Idland, Ane-Victoria; Dalaker, Turi Olene & Aarsland, Dag [Show all 8 contributors for this article] (2015). Neuroanatomical correlates of late-life depression and associated cognitive changes. Neurobiology of Aging. ISSN 0197-4580. 36(11), p. 3090–3099. doi: 10.1016/j.neurobiolaging.2015.04.020. Full text in Research Archive
• Lebedev, Alexander; Beyer, Mona Kristiansen; Fritze, Friederike; Westman, Eric; Ballard, Clive & Aarsland, Dag (2014). Cortical Changes Associated with Depression and Antidepressant Use in Alzheimer and Lewy Body Dementia: An MRI Surface-based Morphometric Study. The American journal of geriatric psychiatry. ISSN 1064-7481. 22(1), p. 4–13. doi: 10.1016/j.jagp.2013.02.004. Full text in Research Archive
• Lauvsnes, Maria Boge; Beyer, Mona Kristiansen; Appenzeller, Simone; Greve, Ole Jacob; Harboe, Erna & Gøransson, Lasse G [Show all 8 contributors for this article] (2014). Loss of cerebral white matter in primary Sjögren's syndrome: a controlled volumetric magnetic resonance imaging study. European Journal of Neurology. ISSN 1351-5101. 21(10), p. 1324–1329. doi: 10.1111/ene.12486. Full text in Research Archive
• Lauvsnes, Maria Boge; Beyer, Mona Kristiansen; Kvaløy, Jan Terje; Greve, Ole Jacob; Appenzeller, Simone & Kvivik, Ingeborg [Show all 10 contributors for this article] (2014). Association of hippocampal atrophy with cerebrospinal fluid antibodies against the nr2 subtype of the N-methyl- D -aspartate receptor in patients with systemic lupus erythematosus and patients with primary Sjögren's syndrome. Arthritis and Rheumatism. ISSN 0004-3591. 66(12), p. 3387–3394. doi: 10.1002/art.38852. Full text in Research Archive
• Beyer, Mona Kristiansen; Alves, Guido; Hwang, Kristy S.; Babakchanian, Sona; Brønnick, Kolbjørn S & Chou, Yi-Yu [Show all 13 contributors for this article] (2013). Cerebrospinal fluid A levels correlate with structural brain changes in Parkinson's disease. Movement Disorders. ISSN 0885-3185. 28(3), p. 302–310. doi: 10.1002/mds.25282. Full text in Research Archive
• Alves, Guido; Pedersen, Kenn Freddy; Bloem, Bastiaan R.; Blennow, Kaj; Zetterberg, Henrik & Borm, George F. [Show all 14 contributors for this article] (2013). Cerebrospinal fluid amyloid-beta and phenotypic heterogeneity in de novo Parkinson's disease. Journal of Neurology, Neurosurgery and Psychiatry. ISSN 0022-3050. 84(5), p. 537–543. doi: 10.1136/jnnp-2012-303808. Full text in Research Archive
• Beyer, Mona Kristiansen; Brønnick, Kolbjørn S; Hwang, Kristy S.; Bergsland, Niels; Tysnes, Ole-Bjørn & Larsen, Jan Petter [Show all 9 contributors for this article] (2013). Verbal memory is associated with structural hippocampal changes in newly diagnosed Parkinson's disease. Journal of Neurology, Neurosurgery and Psychiatry. ISSN 0022-3050. 84(1), p. 23–28. doi: 10.1136/jnnp-2012-303054. Full text in Research Archive
• Boge, Maria; Maroni, Stian; Appenzeller, Simone; Beyer, Mona Kristiansen; Greve, Ole Jacob & Kvaløy, Jan Terje [Show all 10 contributors for this article] (2013). Memory dysfunction in Primary Sjögren’s Syndrome is associated with anti-NR2 antibodies. Arthritis and Rheumatism. ISSN 0004-3591. 65(12), p. 3209–3217. doi: 10.1002/art.38127. Full text in Research Archive
• Lebedev, Alexander; Westman, E.; Beyer, Mona Kristiansen; Kramberger, M.G.; Aguilar, C. & Pirtosek, Z. [Show all 7 contributors for this article] (2013). Multivariate classification of patients with Alzheimer's and dementia with Lewy bodies using high-dimensional cortical thickness measurements: an MRI surface-based morphometric study. Journal of Neurology. ISSN 0340-5354. 260(4), p. 1104–1115. doi: 10.1007/s00415-012-6768-z. Full text in Research Archive
• Tjensvoll, Anne Bolette; Harboe, Erna; Gøransson, Lasse G; Beyer, Mona Kristiansen; Greve, Ole Jacob & Kvaløy, Jan Terje [Show all 7 contributors for this article] (2013). Headache in primary Sjøgren's syndrome: a population-based retrospective cohort study. European Journal of Neurology. ISSN 1351-5101. 20(3), p. 558–563. doi: 10.1111/ene.12033. Full text in Research Archive

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• Vold, Victoria; Tingvoll, Stein-Helge; Beyer, Mona K. & Nordengen, Kaja (2025). Case report: Re-evaluating reversibility of cytotoxic lesions of the corpus callosum. Frontiers in neuroimaging. 4, p. 1–8. doi: 10.3389/fnimg.2025.1436931. Full text in Research Archive Show summary

  Cytotoxic lesions of the corpus callosum (CLOCC) are a clinicoradiological diagnosis, characterized by transient neurological symptoms and magnetic resonance imaging (MRI) changes in the splenium of the corpus callosum (SCC), which in most cases is completely reversible. However, the long-term pathophysiological trajectory and ultimate neurological outcomes of CLOCC remain largely unknown due to limited long-term follow-up data. We report an 11-year follow-up of a postpartum female with CLOCC, initially presenting with transient focal neurological symptoms and extensive diffusion-restricted white matter involvement including the SCC and surrounding area with diffusion restriction and low apparent diffusion coefficient values, indicative of cytotoxic edema. The edema regressed in days; over the years, she remained asymptomatic despite persistent white matter changes on MRI in the centrum semiovale. This case challenges the view of CLOCC as completely reversible and raises questions regarding the significance of lasting white matter changes. The enduring absence of neurological symptoms and stable radiological profile throughout the decade underscores the singular nature of CLOCC and the lasting, though isolated, impact on white matter. This report contributes a crucial perspective, suggesting that CLOCC may involve just an isolated episode without recurrent events or progressive neurological decline. By offering the first longitudinal analysis of a CLOCC episode with an extended follow-up of over a decade, our case enhances current knowledge about the long-term neurological and radiological landscape of this condition. It suggests a reevaluation of the conceptual understanding of CLOCC as an entirely reversible, non-relapsing disorder, highlighting the need for further research into its long-term impacts on cerebral white matter integrity.

• Lauvsnes, Maria Boge; Zetterberg, Henrik; Blennow, Kaj; Kvaløy, Jan Terje; Tjensvoll, Anne Bolette & Maroni, Stian [Show all 14 contributors for this article] (2024). Correction to: Neurofilament light in plasma is a potential biomarker of central nervous system involvement in systemic lupus erythematosus (Journal of Neurology, (2022), 269, 6, (3064-3074), 10.1007/s00415-021-10893-z). Journal of Neurology. ISSN 0340-5354. doi: 10.1007/s00415-024-12238-y. Full text in Research Archive
• Lindland, Elisabeth M.S.; Røvang, Martin Soria; Solheim, Anne Marit; Andreassen, Silje; Dareez, Muhammad Nazeer & Eikeland, Randi [Show all 7 contributors for this article] (2023). Brain White matter hyperintensities in neuroborreliosis. a case-control study. Full text in Research Archive
• Einstad, Marte Stine; SCHELLHORN, TILL; Thingstad, Pernille; Lydersen, Stian; Aamodt, Eva Birgitte & Beyer, Mona K. [Show all 8 contributors for this article] (2022). Neuroimaging Markers of Dual Impairment in Cognition and Physical Performance Following Stroke: The Norwegian Cognitive Impairment After Stroke (Nor-COAST) Study. Full text in Research Archive
• Kaufmann, Tobias; Meer, Dennis van der; Doan, Nhat Trung; Schwarz, Emanuel; Lund, Martina Jonette & Agartz, Ingrid [Show all 97 contributors for this article] (2020). Publisher Correction: Common brain disorders are associated with heritable patterns of apparent aging of the brain (Nature Neuroscience, (2019), 22, 10, (1617-1623), 10.1038/s41593-019-0471-7). Nature Neuroscience. ISSN 1097-6256. 23(2), p. 295–295. doi: 10.1038/s41593-019-0553-6. Full text in Research Archive
• Leikfoss, Ingvild Sørum; Bos, Steffan Daniel; Berg-Hansen, Pål; Berge, Tone; Beyer, Mona K. & Celius, Elisabeth Gulowsen [Show all 8 contributors for this article] (2018). The EU Horizon2020 Project MultipleMS: Improved Personalized Medicine for Multiple Sclerosis. Full text in Research Archive
• Munthe-Kaas, Ragnhild; Aam, Stina; Saltvedt, Ingvild; Thingstad, Pernille; Askim, Torunn & Beyer, Mona K. [Show all 14 contributors for this article] (2018). The burden of post-stroke cognitive impairments in a Norwegian stroke population (Nor-COAST). Full text in Research Archive
• Abildgaard, Andreas; Hopp, Einar; Sakinis, Tomas; Roterud, Håvard; Bjørnerud, Atle & Beyer, Mona K. [Show all 7 contributors for this article] (2018). Vil radiologer bli erstattet av kunstig intelligens? 138(17). doi: 10.4045/tidsskr.18.0587. Full text in Research Archive
• SCHELLHORN, TILL; Håberg, Asta; Nakken, Ingeborg Elise & Beyer, Mona K. (2017). MRI-reliability based on human phantom scans in "The Norwegian Cognitive impairment after stroke" (Nor-COAST) study. Full text in Research Archive
• SCHELLHORN, TILL; Thingstad, Pernille; Wyller, Torgeir Bruun; Saltvedt, Ingvild & Beyer, Mona K. (2017). Imaging in the NorCoast study: A multicentre, prospective cohort study on cognitive function following acute stroke. Full text in Research Archive
• Lebedeva, Aleksandra; Eric, Westman; Borza, Tom; Beyer, Mona K.; Engedal, Knut & Aarsland, Dag [Show all 8 contributors for this article] (2016). Early identification of patients who develop mild cognitive impairment and dementia among depressed elderly using structural brain measurements obtained one year prior. Full text in Research Archive
• Saltvedt, Ingvild; Askim, Torunn; Indredavik, Bent; Ihle-Hansen, Hege; Næss, Halvor & Thingstad, Pernille [Show all 9 contributors for this article] (2016). THE NORWEGIAN COGNITIVE IMPAIRMENT AFTER STROKE (Nor-COAST) STUDY. Full text in Research Archive
• Moen, Stine Marit; Harbo, Hanne Flinstad; Celius, Elisabeth Gulowsen; Sowa, Piotr; Nygaard, Gro Owren & Beyer, Mona K. (2016). S.M. Moen og medarbeidere svarer. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 136(20), p. 1702–1702. doi: 10.4045/tidsskr.16.0865. Full text in Research Archive
• Ellekjær, Hanne; Askim, Torunn; Indredavik, Bent; Thingstad, Pernille; Engstad, Torgeir & Næss, Halvor [Show all 10 contributors for this article] (2016). The Norwegian Cognitive impairement after stroke (Nor-COAST study. Full text in Research Archive
• Moen, Stine Marit; Harbo, Hanne Flinstad; Sowa, Piotr; Celius, Elisabeth Gulowsen; Nygaard, Gro Owren & Beyer, Mona K. (2016). MR-undersøkelser ved multippel sklerose. 136(16), p. 1373–1376. doi: 10.4045/tidsskr.15.1361. Full text in Research Archive
• Moen, Stine Marit; Harbo, Hanne Flinstad; Celius, Elisabeth Gulowsen; Sowa, Piotr; Nygaard, Gro Owren & Beyer, Mona K. (2016). S.M. Moen og medarbeidere svarer. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 136(19), p. 1608–1608. doi: 10.4045/tidsskr.16.0826. Full text in Research Archive
• Lauvsnes, Maria Boge; Greve, Ole Jacob; Kvivik, Ingeborg; Harboe, Erna; Tjensvoll, Anne Bolette & Beyer, Mona K. [Show all 10 contributors for this article] (2015). Reply. Arthritis & Rheumatology. ISSN 2326-5191. 67(6), p. 1683–1684. doi: 10.1002/art.39076. Full text in Research Archive
• Saltvedt, Ingvild; Askim, Torunn; Engstad, Torgeir; Fure, Brynjar; Ihle-Hansen, Hege & Næss, Halvor [Show all 8 contributors for this article] (2015). Norwegian Cognitive Impairment After Stroke Study (Nor-COAST). Full text in Research Archive
• Brix, Maiken Kirkegaard; Beyer, Mona K.; Ersland, Lars & Hugdahl, Kenneth (2018). Establishing reliable MR spectroscopy techniques for measuring GABA and Glutathione in the human brain. Universitetet i Bergen. ISSN 9788230837658. Full text in Research Archive Show summary

  Background: Proton MR spectroscopy (MRS) is a well-established method for measuring the relative concentration of a wide range of metabolites in the human brain noninvasively. Lately, more advanced spectroscopic techniques, such as MEGAPRESS, have emerged enabling us to measure low concentrated metabolites with complex peak splitting patterns. Examples of such metabolites are the main inhibitory brain neurotransmitter, g-aminobutyric acid (GABA), and the main brain antioxidant, glutathione (GSH). Impairment of both GABA and GSH have been implicated in the pathophysiology of several psychiatric and neurodegenerative disorders, including schizophrenia, bipolar disorder, autism spectrum disorder (ASD), multiple sclerosis, Alzheimer’s disease, amyotrophic lateral sclerosis and Parkinson disease. An accurate and reliable quantification of these metabolites in vivo is therefore of utmost interest and clinical relevance. The PhD started with an ASD focus, setting out to examine brain MRS measurable differences between boys with ASD and controls. The focus, however, soon shifted to the methodological aspect of MRS, with a desire to contribute in establishing reliable MRS techniques for measuring GABA and GSH in the human brain. Aims: The aim of the ASD study was to explore the excitatory/inhibitory hypothesis in children with ASD by looking for imbalances in brain metabolites in boys with ASD compared with typically developing controls with standard and advanced MRS techniques. Validating GABA and GSH edited MEGA-PRESS, and comparing these sequences to the standard single voxel measurements; short TE STEAM and PRESS sequence. Methods: Four different studies were performed, all on a 3.0 T GE MRI scanner. The ASD study: 14 boys with ASD and 24 age-matched controls were examined with both the GABA edited MEGA-PRESS and PRESS sequence. Autism symptom severity were reported by the Autism Spectrum Screening Questionnaire (ASSQ). The GABA reprod study: Two 20 min long GABA edited MEGA-PRESS acquisition were performed in 21 healthy young male volunteers. The participants were scanned twice with identical protocols. By applying a timewindowing approach, within-and between-session reproducibility was calculated. The “Christmas phantom” study: 122 GSH edited MEGA-PRESS and PRESS spectra of a phantom containing GSH were acquired over a time period of 11 days. The resulting decaying GSH curve (GSH oxidizes to GSSG) were modelled. A 1-year-after follow-up acquisition for both sequences was also performed. The GSH reprod study: GSH edited MEGA-PRESS and short TE STEAM and PRESS acquisitions were performed in 36 healthy volunteers. The participants were scanned twice with identical protocols, one week apart. The timewindowing approach was applied for within- and between-session reproducibility for GSH edited MEGA-PRESS. Differences between quantified GSH levels between males and females were examined, and the three different methods of measuring GSH were evaluated. Main Results: There was a significant negative correlation in the ASD group between ASSQ and GABA levels, however there was no significant difference between the ASD group and the control group in MEGA-PRESS measured GABA levels. Increasing the number of repetitions in GABA edited MEGA-PRESS showed improvements for within- and between-session reproducibility up to about 218 paired repetitions (scan length ~ 13 min). Gannet combined with LCModel proved the best method processing the GABA data. Both GSH edited MEGA-PRESS and PRESS were able to measure the degradation of GSH in the phantom, however the modelled GSH edited MEGA-PRESS degradation curve was more accurate than PRESS. Between-session variability of GSH edited MEGA-PRESS stabilised at around 128 paired repetitions (~8 min). There were no significant correlations between GSH measured with MEGA-PRESS, STEAM and PRESS, and no differences in measured GSH levels between males and females. Conclusion: In line with other studies, the ASD participants have GABA values that seem to change with their clinical severity although there was no group difference with healthy controls. For both GABA and GSH, it is possible to acquire reproducible MEGA-PRESS measurements. GSH edited MEGA-PRESS measurements have somewhat higher coefficient of variation (meaning lower reproducibility), but stabilises at a shorter scan length than GABA edited MEGA-PRESS. MEGA-PRESS is more accurate that both PRESS and STEAM in measuring GSH for in vivo measurements. This is also reflected in its in vitro quantification, where the PRESS measurements fit of GSH seem to include oxidised GSH.

• Oppedal, Ketil; Eftestøl, Trygve Christian; Engan, Kjersti; Aarsland, Dag & Beyer, Mona K. (2016). White Matter Lesions and Pattern Recognition in MRI of Neurodegenerative Dementia. Universitetet i Stavanger. ISSN 9788276446746. Full text in Research Archive Show summary

  Introduction Expected age is increasing globally and dementia is a common outcome for an increasing number of people. Dementia is a demanding syndrome for the patient and the environment as well as it is costly for society. Damaging changes to the cerebral blood flow also called white matter lesions (WML) are common in the elderly and is expected to increase as age advances. It has been reported that these types of lesions affect cognition in healthy elderly. They are also associated to Alzheimer’s disease but have not been much studied in DLB. Quantitative analysis and machine learning have a potential to contribute in understanding the disease process as well as aid in diagnosis. Methods Quantitative analysis of WML volumes were calculated using an automatic segmentation routine on magnetic resonance images (MRI) of subjects with Alzheimer’s disease (AD), Lewy body dementia (LBD), and normal controls (NC). Statistical tests were performed to compare groups as well as to investi- gate relations to cognition. Additionally, WML volumes were used as features in a machine learning (ML) environment to check whether WML volume were able to classify subjects with AD and LBD from NC. Texture analysis (TA) may be able to document changes at a microstructural level and was performed in WML an non-WML regions of the different types of MRI’s (FLAIR and T1). 2D- and 3D TA features were calculated and used in classification with the aim to serve as a tool for computer aided diagnosis (CAD) in dementia. The dataset used was imbalanced meaning that the number of subjects in each group were very different. Two methods for handling the imbalanced data were tested, namely upsampling and cost-sensitive classification. Results and conclusions Severity of WML did neither differ significantly between subjects with dementia and NC nor between mildly demented patients with AD and LBD. WML severity were associated with cognitive decline in AD, but not LBD suggesting that WML contributes to cognitive decline in AD, but not LBD. More studies of the potential clinical impact of WML in patients with LBD are needed. The best classification results obtained using WML volumes as features in an ML framework discerning subjects with dementia from healthy controls were an area under curve (AUC) of 0.73 and 95% confidence interval of 0.57 to 0.83. We experienced better classification results when using TA features compared to WML volumes in classification and better results when performing classifi- cation on TA features calculated from T1 MRI compared to FLAIR MRI. A total accuracy, reported as mean with standard deviation in brackets over cross validation folds, of 0.97(0.07) or higher was reported for the dementia vs. NC, AD vs. NC, and LBD vs. NC classification problems for both the 2D- and 3D texture analysis approaches. In the AD vs. LBD case a total accuracy of 0.73(0.16) was reported using the 2D TA approach slightly exceeded by the 3D TA approach were 0.79(0.15) was reported. It seems like the results do not differ much when performing analysis in different regions of the brain and that the results vary in an inconsistent way. Using upsampling increased classification accuracy to a large extent in the LBD class at the expense of total accuracy and the accuracy of the AD class. In both the two-class problems NC vs. AD and NC vs. LBD, adding cost- sensitivity increased classification performance in many of the tests, but upsam- pling increased accuracy even more in most of the tests. High classification performance was achieved when classifying dementia groups from NC’s. The classification performance reached when classifying AD from LBD did not reach the same level. Further research with the aim of developing methods with a higher sensitivity to the different brain changes going on in AD and LBD are needed.

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