Harriet Akre

• Ueland, Thor; Traaen, Gunn Marit; Hunt, Tove Elizabeth Frances; Aakerøy, Lars; Øverland, Britt & Bendz, Christina [Show all 14 contributors for this article] (2025). High levels of the adipokines leptin and metrnl in patients with paroxysmal atrial fibrillation and obstructive sleep apnea are not associated with the severity of sleep apnea or the burden of atrial fibrillation. Sleep Medicine. ISSN 1389-9457. 136. doi: 10.1016/j.sleep.2025.106862. Full text in Research Archive
• Hunt, Tove Elizabeth Frances; Traaen, Gunn Marit; Aakerøy, Lars; Øverland, Britt; Bendz, Christina & Michelsen, Annika Elisabet [Show all 15 contributors for this article] (2025). Systemic markers of inflammation and immune activation in patients with obstructive sleep apnea and paroxysmal atrial fibrillation. European journal of internal medicine. ISSN 0953-6205. 139. doi: 10.1016/j.ejim.2025.05.028. Full text in Research Archive Show summary

  Background Atrial fibrillation (AF) and obstructive sleep apnea (OSA) frequently coexist, contributing to cardiovascular risk, possibly through shared inflammatory pathways. The specific role of inflammatory markers in patients with AF and OSA is not well established. Aim This study aimed to determine whether markers of inflammation and immune activation are elevated in patients with paroxysmal AF and OSA, assess the effects of continuous positive airway pressure (CPAP) and pulmonary vein isolation (PVI) on these markers, and evaluate their association with clinical outcomes, such as AF recurrence and thromboembolic risk. Methods We studied 143 patients with paroxysmal AF and moderate to severe OSA (apnea-hypopnea index ≥15). Of these, 99 were randomised to receive CPAP plus standard care (n = 51) or standard care alone (n = 48). A comparison group of 19 patients with paroxysmal AF and mild/no OSA (AHI <15) and 22 healthy controls were also included. Inflammatory markers related to leukocyte activation, vascular inflammation, and extracellular matrix remodelling were assessed at baseline, 6 months and 12 months follow-up. Results Patients with OSA and paroxysmal AF had higher levels of NGAL, PTX-3, GDF-15, MMP-9, VCAM1 and ANGP2 than healthy controls. These markers correlated poorly with AF and OSA severity. There was no modifying effect of CPAP on any marker. PTX3 was associated with AF recurrence and a high-risk score for thromboembolic stroke. Conclusion Moderate to severe OSA and AF are associated with elevated inflammatory markers. However, CPAP therapy did not significantly affect these levels. PTX-3 may hold prognostic value for AF recurrence and thromboembolic risk.

• Dheyauldeen, Sinan Ahmed Dheyauldeen; Heimdal, Ketil Riddervold; Osnes, Terje; Akre, Harriet & Olsson, Lars H. (2024). Choanal atresia: A review of surgical outcomes in a tertiary medical center. World Journal of Otorhinolaryngology - Head and Neck Surgery (WJOHNS). ISSN 2095-8811. doi: 10.1002/wjo2.196. Full text in Research Archive Show summary

  Introduction Choanal atresia (CA) is a congenital narrowing or obliteration of the posterior nasal aperture. The condition is rare with an incidence of approximately 1 in 5000 to 9000 live births. Objective The aim of this work was to assess the results of treating this condition at the Otolaryngology Department in Oslo University Hospital-Rikshospitalet. Methods Retrospective review of patients treated at Oslo University Hospital-Rikshospitalet between 2005 and 2015 were performed. The review consisted of surgical techniques and outcomes, types of atresia, uses of stent and mitomycin C, age at operation, laterality of atresia, and associated anomalies. Results Thirty-one patients with CA were referred to Oslo University Hospital-Rikshospitalet during the mentioned observation period. Nine (29%) of the cases had bilateral CA and 22 (71%) had unilateral CA. Ten patients (32%) had bony atresia, 12 (39%) had membranous and eight (26%) had mixed type of atresia. Twenty-one patients (68%) needed revision surgery because of complete or partial restenosis after primary surgery. Stents were applied in 16 cases (52%) of patients and Mitomycin C was only used in the primary surgery of three patients. In the bilateral group, eight of the nine patients were operated on within the first 9 days of life. Sixteen patients (45%) had associated anomalies. Conclusions According to the observations in our sample, the restenosis problem is expected more and may need more revisions in bilateral CA than the unilateral type. The presence of other anomalies is associated with higher incidence of restenosis. Stenting is not essential in preventing restenosis. Key point Risk factors of restenosis in choanal atresia.

• Lopez, Marta Quemada; Plagemann, Thomas Peter; Goebel, Vera Hermine; Adams, Jonathan; Hui, David & Øverland, Britt [Show all 8 contributors for this article] (2024). Requirements Analysis for Responsible Explainable AI for Pediatric Sleep Apnea Diagnosis. In Pesch, Dirk (Eds.), Proceeding IEEE International Conference on Smart Computing 2024. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9798350349948. p. 362–367. doi: 10.1109/SMARTCOMP61445.2024.00082. Full text in Research Archive Show summary

  This paper presents a novel approach to requirements engineering for responsible explainable AI (rexAI) that pays attention to the broad range of explanation aspects and enforces the consideration of computer science, ethical, legal, and medical requirements. The medical use-case we are investigating is pediatric sleep apnea diagnosis. We analyze the non-functional and functional requirements and explore the multiple relationships and dependencies between the rexAI requirements and principles.

• Hunt, Tove Elizabeth Frances; Traaen, Gunn Marit; Aakerøy, Lars; Massey, Richard; Bendz, Christina & Øverland, Britt [Show all 17 contributors for this article] (2024). Cardiac remodelling in patients with atrial fibrillation and obstructive sleep apnoea. Open heart. 11(2). doi: 10.1136/openhrt-2024-002718. Full text in Research Archive Show summary

  Background Obstructive sleep apnoea (OSA) can cause left atrial (LA) and left ventricular (LV) remodelling, which is linked to atrial fibrillation (AF). Whether continuous positive airway pressure (CPAP) can reverse LA and LV remodelling in patients with OSA and paroxysmal AF (PAF) has yet to be studied. We assessed the impact of CPAP treatment on LA and LV size and function in patients with OSA and PAF before and after catheter ablation. Methods In a randomised controlled trial, we screened patients with PAF for OSA. We enrolled patients with an Apnoea–Hypopnoea Index ≥15/hour. The burden of AF was monitored by an implantable loop recorder in all patients. Patients were then randomised to CPAP treatment or standard care. Transthoracic echocardiography was performed at baseline and after 6 and 12 months to assess LV and LA function and remodelling with advanced echocardiographic imaging techniques. Results We enrolled 109 patients (63±7 years, body mass index 29.6±4.3, 76% men). 83 patients were scheduled for pulmonary vein isolation (PVI) and 26 for clinical follow-up only. 55 patients were randomised to CPAP and 54 to standard care. The burden of AF decreased significantly in patients who underwent PVI irrespective of treatment with CPAP (p for difference ≤0.001). Patients in the study group had LV ejection fraction (LVEF) and LV global longitudinal strain (GLS) within the normal range, increased LA Volume Index (LAVI), LA volume (by speckle tracking) and decreased LA reservoir strain at baseline. We did not observe any improvement in LVEF, GLS, LAVI, LA volume or LA reservoir strain in either group during the 12 months of follow-up. Conclusions In patients with PAF and OSA, treatment with CPAP was not associated with reverse LA remodelling within 12 months of follow-up.

• Kristiansen, Stein; Nikolaidis, Konstantinos; Plagemann, Thomas Peter; Goebel, Vera Hermine; Traaen, Gunn Marit & Øverland, Britt [Show all 14 contributors for this article] (2023). A clinical evaluation of a low-cost strain gauge respiration belt and machine learning to detect sleep apnea. Smart Health. ISSN 2352-6483. 27. doi: 10.1016/j.smhl.2023.100373. Full text in Research Archive Show summary

  Sleep apnea is a common and severe sleep-related respiratory disorder. Since the symptoms of sleep apnea are often ambiguous, it is difficult for a physician to decide whether to prescribe a clinical diagnosis, i.e., polysomnography (PSG), which results in a large percentage of undiagnosed and very late diagnosed cases. To reduce the time to diagnosis we investigate whether sleep monitoring data collected with a low-cost strain gauge respiration belt (called Flow) and a smartphone can be used to estimate with machine learning (ML) the severity of a patient’s sleep apnea. The Flow belt and the Type III sleep monitor Nox T3 were used together by 29 patients for unattended sleep monitoring at home, resulting each in 235 hours of sleep data. Through experimental analysis, we found that Convolutional Neural Networks are best suited to analyze the Flow data, because they are most robust against the frequently occurring baseline issues and exhibit the best performance with an accuracy of 0.7609, sensitivity of 0.7833, and specificity of 0.7217. These results can be achieved even if the classifier is trained only on high-quality data from the Nox T3. Thus, there are good chances that future ML experiments with data from other low-cost respiration belts can benefit from existing open PSG datasets without new extensive data collection. On a low-end smartphone, the classifier needs approximately one second to analyze the sleep data from one night. The results demonstrate the potential of low-cost strain gauge belts, smartphones, and ML to enable large parts of the population to perform sleep apnea pre-screening at home.

• Nikolaidis, Konstantinos; Kristiansen, Stein; Plagemann, Thomas Peter; Goebel, Vera Hermine; Liestøl, Knut & Kankanhalli, Mohan [Show all 11 contributors for this article] (2022). Learning Realistic Patterns from Visually Unrealistic Stimuli: Generalization and Data Anonymization (Extended Abstract). In Raed, Luc de (Eds.), Proceedings of the Thirty-First International Joint Conference on Artificial Intelligence. AAAI Press. ISSN 9781956792003. p. 5762–5766. doi: 10.24963/ijcai.2022/806. Full text in Research Archive Show summary

  Good training data is a prerequisite to develop useful Machine Learning applications. However, in many domains existing data sets cannot be shared due to privacy regulations (e.g., from medical studies). This work investigates a simple yet unconventional approach for anonymized data synthesis to enable third parties to benefit from such anonymized data. We explore the feasibility of learning implicitly from visually unrealistic, task-relevant stimuli, which are synthesized by exciting the neurons of a trained deep neural network. As such, neuronal excitation can be used to generate synthetic stimuli. The stimuli data is used to train new classification models. Furthermore, we extend this framework to inhibit representations that are associated with specific individuals. Extensive comparative empirical investigation shows that different algorithms trained on the stimuli are able to generalize successfully on the same task as the original model.

• Hunt, Tove Elizabeth Frances; Traaen, Gunn Marit; Aakerøy, Lars; Bendz, Christina; Øverland, Britt & Akre, Harriet [Show all 15 contributors for this article] (2022). Effect of continuous positive airway pressure therapy on recurrence of atrial fibrillation after pulmonary vein isolation in patients with obstructive sleep apnea: A randomized controlled trial. Heart Rhythm. ISSN 1547-5271. 19(9), p. 1433–1441. doi: 10.1016/j.hrthm.2022.06.016. Full text in Research Archive Show summary

  Background Obstructive sleep apnea (OSA) is associated with atrial fibrillation (AF). Whether treatment with continuous positive airway pressure (CPAP) reduces AF recurrence after catheter ablation with pulmonary vein isolation (PVI) is unknown. Objective The purpose of this study was to assess the effect of CPAP treatment on the recurrence and burden of AF after PVI in patients with OSA. Methods We randomized patients with paroxysmal AF and an apnea-hypopnea index (AHI) ≥15 events/hour to treatment with CPAP or standard care. Heart rhythm was monitored by an implantable loop recorder. AF recurrence after PVI was defined as any episode of AF lasting >2 minutes after a 3-month blanking period. Results PVI was performed in 83 patients. Thirty-seven patients were randomized to CPAP treatment and 46 patients to standard care. The AHI was reduced from 26.7 ± 14 events/hour to 1.7 ± 1.3 events/hour at follow-up in the CPAP group (P = .001). A total of 57% of patients in both the CPAP group and the standard care group had at least 1 episode of AF 3–12 months after PVI (P for difference = 1). AF burden after ablation was reduced in both groups, with no between-group difference (P = .69). Conclusion In patients with paroxysmal AF and OSA, treatment with CPAP did not further reduce the risk of AF recurrence after ablation. PVI considerably reduced the burden of AF in OSA patients, without any difference between groups.

• Nikolaidis, Konstantinos; Kristiansen, Stein; Plagemann, Thomas Peter; Goebel, Vera Hermine; Liestøl, Knut & Kankanhalli, Mohan [Show all 11 contributors for this article] (2022). My Health Sensor, My Classifier - Adapting a Trained Classifier to Unlabeled End-User Data. ACM Transactions on Computing for Healthcare (HEALTH). ISSN 2691-1957. 3(4), p. 1–24. doi: 10.1145/3559767. Full text in Research Archive Show summary

  Sleep apnea is a common yet severely under-diagnosed sleep related disorder. Unattended sleep monitoring at home with low-cost sensors can be leveraged for condition detection, and Machine Learning offers a generalized solution for this task. However, patient characteristics, lack of sufficient training data, and other factors can imply a domain shift between training and end-user data; and reduced task performance. In this work, we address this issue with the aim to achieve personalization based on the patient’s needs. We present an unsupervised domain adaptation (UDA) solution with the constraint that labeled source data are not directly available. Instead, a classifier trained on the source data is provided. Our solution iteratively labels target data sub-regions based on classifier beliefs, and trains new classifiers from the expanding dataset. Experiments with sleep monitoring datasets and various sensors show that our solution outperforms the classifier trained on the source domain, with a kappa coefficient improvement from 0.012 to 0.242. Additionally, we apply our solution to digit classification DA between three well-established datasets, to investigate its generalizability, and allow for related work comparisons. Even without direct access to the source data, it outperforms several well-established UDA methods in these datasets.

• Kristiansen, Stein; Nikolaidis, Konstantinos; Plagemann, Thomas Peter; Goebel, Vera Hermine; Traaen, Gunn Marit & Øverland, Britt [Show all 14 contributors for this article] (2021). Machine learning for sleep apnea detection with unattended sleep monitoring at home. ACM Transactions on Computing for Healthcare (HEALTH). ISSN 2691-1957. 2(2). doi: 10.1145/3433987. Full text in Research Archive Show summary

  Sleep apnea is a common and strongly under-diagnosed severe sleep-related respiratory disorder with periods of disrupted or reduced breathing during sleep. To diagnose sleep apnea, sleep data are collected with either polysomnography or polygraphy and scored by a sleep expert. We investigate in this work the use of supervised machine learning to automate the analysis of polygraphy data from the A3 study containing more than 7,400 hours of sleep monitoring data from 579 patients. We conduct a systematic comparative study of classification performance and resource use with different combinations of 27 classifiers and four sleep signals. The classifiers achieve up to 0.8941 accuracy (kappa: 0.7877) when using all four signal types simultaneously and up to 0.8543 accuracy (kappa: 0.7080) with only one signal, i.e., oxygen saturation. Methods based on deep learning outperform other methods by a large margin. All deep learning methods achieve nearly the same maximum classification performance even when they have very different architectures and sizes. When jointly accounting for classification performance, resource consumption and the ability to achieve with less training data high classification performance, we find that convolutional neural networks substantially outperform the other classifiers.

• Kristiansen, Stein; Goebel, Vera Hermine; Andersen, Morten Hamborg; Plagemann, Thomas Peter; Traaen, Gunn Marit & Øverland, Britt [Show all 8 contributors for this article] (2021). Evaluating a Low-Cost Strain Gauge Breathing Sensor for Sleep Apnea Detection at Home. In Gedeon, Ibrahim (Eds.), 2021 IEEE International Conference on Communications Workshops (ICC Workshops). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781728194417. doi: 10.1109/ICCWorkshops50388.2021.9473597. Full text in Research Archive Show summary

  We report results and experience from a clinical evaluation of a low-cost strain gauge breathing sensor for sleep apnea detection. We collected from 34 individuals 57 nights of unattended sleep monitoring data at home with the certified Type 3 monitor Nox-T3 and the Flow strain gauge sensor from SweetZpot. The quality of the Flow data does not match the quality of the Nox-T3 data due to the much simpler build of the Flow sensor and issues during data acquisition. The Flow data can still be used to accurately discriminate between normal and disrupted breathing. With appropriate data pre-processing, we achieve a mean breath detection sensitivity of 97.2% and positive prediction value of 94.2%.

• Traaen, Gunn Marit; Aakerøy, Lars; Hunt, Tove Elizabeth Frances; Øverland, Britt; Bendz, Christina & Sande, Lars Øivind [Show all 16 contributors for this article] (2021). Effect of continuous positive airway pressure on arrhythmia in atrial fibrillation and sleep apnea a randomized controlled trial. American Journal of Respiratory and Critical Care Medicine. ISSN 1073-449X. 204(5), p. 573–582. doi: 10.1164/rccm.202011-4133OC. Full text in Research Archive Show summary

  Rationale: Sleep apnea (SA) is highly prevalent in patients with atrial fibrillation (AF), and both conditions are associated with adverse cardiovascular outcomes. Objectives: To determine the effect of continuous positive airway pressure (CPAP) on AF burden. Methods: This open-label, parallel-group, randomized controlled trial included patients with paroxysmal AF and moderate to severe SA (apnea–hypopnea index ⩾15). A computerized system randomized eligible patients (1:1) to 5 months’ treatment with CPAP plus usual care (CPAP, n = 55) or usual care alone (control, n = 54). The outcome assessment was blinded. The planned primary outcome was the difference between CPAP treatment and control groups in change of AF burden (percentage of time in AF) as measured by implantable loop recorder. Measurements and Main Results: A total of 579 patients with paroxysmal AF had respiratory polygraphy, of whom 244 (42%) had moderate to severe SA. Of these, 158 (65%) participated in the CPAP run-in period, of whom 39 (25%) patients did not tolerate the treatment. A total of 108 patients were available for the primary analysis. The mean time in AF decreased from 5.6% at baseline to 4.1% during the last 3 months of CPAP intervention and from 5.0% to 4.3% in the control group. The adjusted between-group difference at follow-up was −0.63 (95% confidence interval, −2.55 to 1.30) percentage points (P = 0.52). Seven serious adverse events (13%) occurred in the CPAP group, and two (4%) occurred in the control group. Conclusions: In patients with paroxysmal AF and SA, treatment with CPAP did not result in a statistically significant reduction in the burden of AF.Clinical trial registered with www.clinicaltrials.gov (NCT02727192).

• Øverland, Britt; Berdal, Hanne & Akre, Harriet (2021). Surgery for obstructive sleep apnea in young children: Outcome evaluated by polysomnograhy and quality of life. International Journal of Pediatric Otorhinolaryngology. ISSN 0165-5876. 142:110609, p. 1–6. doi: 10.1016/j.ijporl.2021.110609. Full text in Research Archive
• Nikolaidis, Konstantinos; Kristiansen, Stein; Plagemann, Thomas Peter; Goebel, Vera Hermine; Liestøl, Knut & Kankanhalli, Mohan [Show all 11 contributors for this article] (2021). Learning realistic patterns from visually unrealistic stimuli: Generalization and data anonymization. The journal of artificial intelligence research. ISSN 1076-9757. 72, p. 1163–1214. doi: 10.1613/JAIR.1.13252. Full text in Research Archive Show summary

  Good training data is a prerequisite to develop useful Machine Learning applications. However, in many domains existing data sets cannot be shared due to privacy regulations (e.g., from medical studies). This work investigates a simple yet unconventional approach for anonymized data synthesis to enable third parties to benefit from such anonymized data. We explore the feasibility of learning implicitly from visually unrealistic, task-relevant stimuli, which are synthesized by exciting the neurons of a trained deep neural network. As such, neuronal excitation can be used to generate synthetic stimuli. The stimuli data is used to train new classification models. Furthermore, we extend this framework to inhibit representations that are associated with specific individuals. We use sleep monitoring data from both an open and a large closed clinical study, and Electroencephalogram sleep stage classification data, to evaluate whether (1) end-users can create and successfully use customized classification models, and (2) the identity of participants in the study is protected. Extensive comparative empirical investigation shows that different algorithms trained on the stimuli are able to generalize successfully on the same task as the original model. Architectural and algorithmic similarity between new and original models play an important role in performance. For similar architectures, the performance is close to that of using the original data (e.g., Accuracy difference of 0.56%-3.82%, Kappa coefficient difference of 0.02-0.08). Further experiments show that the stimuli can provide state-ofthe-art resilience against adversarial association and membership inference attacks.

• Kristiansen, Stein; Traaen, Gunn Marit; Øverland, Britt; Plagemann, Thomas Peter; Gullestad, Lars & Akre, Harriet [Show all 14 contributors for this article] (2020). Comparing manual and automatic scoring of sleep monitoring data from portable polygraphy. Journal of Sleep Research. ISSN 0962-1105. doi: 10.1111/jsr.13036. Full text in Research Archive Show summary

  We used sleep monitoring data from a study that investigated the prevalence, characteristics, risk factors and type of sleep apnea (SA) in 579 patients with paroxysmal atrial fibrillation. Most patients were screened for two nights, resulting in 1,043 sleep recordings that each contained data from one night. SA was diagnosed using the Nox T3 portable sleep monitor. An experienced sleep specialist scored the recordings manually using Noxturnal software. A total of 157 women (27%) and 422 men (73%) were examined; 477 (82.7%) had an apnea–hypopnea index (AHI) ≥ 5/hr, whereas moderate to severe SA (AHI ≥ 15/hr) was diagnosed in 243 patients (42.1%). The AHI derived from automatic and manual scoring showed a good agreement (Pearson's r coefficient of 0.96). The median difference in AHI was very small (i.e., 0.72 [mean difference, 1.06]), but was statistically significant (p < .0001). Automatic scoring classified sleep recordings with more than 90% accuracy into SA categories of mild (AHI ≥ 5/hr), moderate (AHI ≥ 15/hr) and severe (AHI ≥ 30/hr). We found a minor (11%–21%) mis‐estimation of the number of recordings right above and below the boundary separating mild and moderate SA. The accuracy of automatic scoring differed from recording to recording, especially regarding the sensitivity of detecting disrupted breathing events. We found low to moderate agreement for the duration of disrupted breathing events (r = .53), for which the automatic scoring led to a statistically significant overestimation by 5.22 s (p < .0001).

• Øverland, Britt; Berdal, Hanne & Akre, Harriet (2020). Correlations between disease-specific quality of life and polysomnographic findings in children with obstructive sleep apnea. International Journal of Pediatric Otorhinolaryngology. ISSN 0165-5876. 134. doi: 10.1016/j.ijporl.2020.110077. Full text in Research Archive
• Hui, David; Johansen, Edvard; Akre, Harriet; Osnes, Terje & Dheyauldeen, Sinan (2020). Øre-nese-hals-leger og sars-CoV-2-viruset. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 140(10). doi: 10.4045/tidsskr.20.0423. Full text in Research Archive
• Traaen, Gunn Marit; Øverland, Britt; Aakerøy, Lars; Hunt, Tove Elizabeth Frances; Bendz, Christina & Magne, Sande Leif [Show all 13 contributors for this article] (2019). Prevalence, risk factors, and type of sleep apnea in patients with paroxysmal atrial fibrillation. International journal of cardiology: Heart and Vasculature (IJCHA). doi: 10.1016/j.ijcha.2019.100447. Full text in Research Archive Show summary

  Background Recent studies have suggested an association between sleep apnea (SA) and atrial fibrillation (AF). We aimed to study the prevalence, characteristics, risk factors and type of sleep apnea (SA) in ablation candidates with paroxysmal AF. Methods/Results We prospectively studied 579 patients with paroxysmal AF, including 157 women (27.1%) and 422 men (72.9%). Mean age was 59.9 ± 9.6 years and mean body mass index (BMI) 28.5 ± 4.5 kg/m2. SA was diagnosed using polygraphy for two nights at home. The Epworth Sleepiness Scale (ESS), STOP-Bang Questionnaire, and Berlin Questionnaire (BQ) assessed the degree of SA symptoms. A total of 479 (82.7%) patients had an apnea-hypopnea index (AHI) ≥ 5, whereas moderate-severe SA (AHI ≥ 15) was diagnosed in 244 patients (42.1%). The type of SA was predominantly obstructive, with a median AHI of 12.1 (6.7–20.6) (range 0.4–85.8). The median central apnea index was 0.3 (0.1–0.7). AHI increased with age, BMI, waist and neck circumference, body and visceral fat. Using the Atrial Fibrillation Severity Scale and the SF-36, patients with more severe SA had a higher AF burden, severity and symptom score and a lower Physical-Component Summary score. Age, male gender, BMI, duration of AF, and habitual snoring were independent risk factors in multivariate analysis (AHI ≥ 15). We found no association between ESS and AHI (R2 = 0.003, p = 0.367). Conclusions In our AF population, SA was highly prevalent and predominantly obstructive. The high prevalence of SA detected in this study may indicate that SA is under-recognized in patients with AF. None of the screening questionnaires predicted SA reliably.

• Øverland, Britt; Berdal, Hanne & Akre, Harriet (2019). Obstructive sleep apnea in 2–6 year old children referred for adenotonsillectomy. European Archives of Oto-Rhino-Laryngology. ISSN 0937-4477. 276(7), p. 2097–2104. doi: 10.1007/s00405-019-05362-3. Full text in Research Archive
• Traaen, Gunn Marit; Aakerøy, Lars; Hunt, Tove Elisabeth F.; Øverland, Britt; Lyseggen, Erik & Aukrust, Pål [Show all 16 contributors for this article] (2018). Treatment of sleep apnea in patients with paroxysmal atrial fibrillation: design and rationale of a randomized controlled trial. Scandinavian Cardiovascular Journal. ISSN 1401-7431. 52(6), p. 372–377. doi: 10.1080/14017431.2019.1567933. Full text in Research Archive Show summary

  Rationale. Atrial fibrillation is associated with increased mortality as well as morbidity. There is strong evidence for an association between atrial fibrillation and sleep apnea. It is not known whether treatment of sleep apnea with continuous positive airway pressure (CPAP) will reduce the burden of atrial fibrillation. Objective. The Treatment of Sleep Apnea in Patients with Paroxysmal Atrial Fibrillation study will investigate the effects of CPAP in patients with paroxysmal atrial fibrillation and sleep apnea. Design: The trial has a dual center, randomized, controlled, open-label, parallel design. Methods. Two centers will enroll a total of 100 patients with both paroxysmal atrial fibrillation and sleep apnea (apnea-hypopnea index [AHI] 15 events/h) who are scheduled for catheter ablation. Patients will be randomized in a 1:1 ratio to CPAP or control group (50 patients in each arm). The effects of CPAP treatment on atrial fibrillation will be determined using an implanted loop recorder (Reveal LINQTM, Medtronic) that detects all arrhythmia episodes. The primary endpoint is a reduction of the total burden of atrial fibrillation in the intervention group, after 5 months’ follow-up (preablation). Reduction in the arrhythmia recurrence rate after ablation is the main secondary endpoint. All patients will be followed up for 12 months after ablation. Conclusion. This study is the first randomized controlled trial that will provide data on the effects of CPAP therapy in patients with paroxysmal atrial fibrillation and sleep apnea. The results are expected to improve our understanding of the interaction between paroxysmal atrial fibrillation and sleep apnea.

• Austeng, Marit Erna; Øverland, Britt; Kvaerner, Kari Jorunn; Andersson, Els-Marie; Axelsson, Stefan & Abdelnoor, Michael [Show all 7 contributors for this article] (2014). Obstructive sleep apnea in younger school children with Down syndrome. International Journal of Pediatric Otorhinolaryngology. ISSN 0165-5876. 78(7), p. 1026–1029. doi: 10.1016/j.ijporl.2014.03.030. Full text in Research Archive
• Omland, Turid; Akre, Harriet; Lie, Kathrine; Jebsen, Peter Wilhelm; Sandvik, Leiv & Brøndbo, Kjell (2014). Risk factors for aggressive recurrent respiratory papillomatosis in adults and juveniles. PLOS ONE. 9(11). doi: 10.1371/journal.pone.0113584. Full text in Research Archive
• Herrscher, Tobias Erik; Akre, Harriet; Øverland, Britt; Sandvik, Leiv & Westheim, Arne (2014). Clinical predictors of sleep apnoea in heart failure outpatients. International Journal of Clinical Practice. ISSN 1368-5031. 68(6), p. 725–730. doi: 10.1111/ijcp.12396. Full text in Research Archive
• Omland, Turid; Lie, Kathrine; Akre, Harriet; Sandlie, Lars Eriks; Jebsen, Peter Wilhelm & Sandvik, Leiv [Show all 10 contributors for this article] (2014). Recurrent respiratory papillomatosis: HPV genotypes and risk of high-grade laryngeal neoplasia. PLOS ONE. 9(6). doi: 10.1371/journal.pone.0099114. Full text in Research Archive
• Åsten, Pamela; Akre, Harriet & Persson, Christina (2014). Associations between speach features and phenotypic severity in Treacher Collins syndrome. BMC Medical Genetics. 15:47. doi: 10.1186/1471-2350-15-47. Full text in Research Archive
• Herrscher, Tobias Erik; Øverland, Britt; Sandvik, Leiv; Westheim, Arne & Akre, Harriet (2014). High cardiovascular risk profile in patients with sleep apnea. The Laryngoscope. ISSN 0023-852X. 124(1), p. 306–310. doi: 10.1002/lary.24304. Full text in Research Archive
• Andersson, Els-Marie; Axelsson, Stefan; Austeng, Marit Erna; Øverland, Britt; Valen, Ingrid Ekroll & Jensen, Terese Agustin [Show all 7 contributors for this article] (2014). Bilateral hypodontia is more common than unilateral hypodontia in children with Down syndrome: A prospective population-based study. European Journal of Orthodontics. ISSN 0141-5387. 36(4), p. 414–418. doi: 10.1093/ejo/cjt063. Full text in Research Archive
• Åsten, Pamela; Skogedal, Nina; Nordgarden, Hilde; Axelsson, Stefan; Akre, Harriet & Sjogren, Lotta (2013). Orofacial functions and oral health associated with Treacher Collins syndrome. Acta Odontologica Scandinavica. ISSN 0001-6357. 71(3-4), p. 616–625. doi: 10.3109/00016357.2012.700065. Full text in Research Archive
• Austeng, Marit Erna; Akre, Harriet; Øverland, Britt; Abdelnoor, Michael; Falkenberg, Eva-Signe & Kvaerner, Kari Jorunn (2013). Otitis media with effusion in children with in Down syndrome. International Journal of Pediatric Otorhinolaryngology. ISSN 0165-5876. 77(8), p. 1329–1332. doi: 10.1016/j.ijporl.2013.05.027. Full text in Research Archive
• Geirdal, Amy Østertun; Øverland, Britt; Heimdal, Ketil Riddervold; Storhaug, Kari; Åsten, Pamela & Akre, Harriet (2013). Association between obstructive sleep apnea and health-related quality of life in individuals affected with Treacher Collins syndrome. European Archives of Oto-Rhino-Laryngology. ISSN 0937-4477. 270(11), p. 2879–2884. doi: 10.1007/s00405-013-2409-0. Full text in Research Archive
• Austeng, Marit Erna; Akre, Harriet; Falkenberg, Eva-Signe; Øverland, Britt; Abdelnoor, Michael & Kvaerner, Kari Jorunn (2013). Hearing level in children with Down syndrome at the age of eight. Research in Developmental Disabilities. ISSN 0891-4222. 34(7). doi: 10.1016/j.ridd.2013.04.006. Full text in Research Archive
• Østerhus, Ingvild; Skogedal, Nina; Akre, Harriet; Johnsen, Ulf; Nordgarden, Hilde & Åsten, Pamela (2012). Salivary gland pathology as a new finding in Treacher Collins syndrome. American Journal of Medical Genetics. Part A. ISSN 1552-4825. 158A(6), p. 1320–1325. doi: 10.1002/ajmg.a.35331. Full text in Research Archive
• Akre, Harriet; Øverland, Britt; Åsten, Pamela; Heimdal, Ketil Riddervold & Skogedal, Nina (2012). Obstructive sleep apnea in Treacher Collins syndrome. European Archives of Oto-Rhino-Laryngology. ISSN 0937-4477. 269(1), p. 331–337. doi: 10.1007/s00405-011-1649-0. Full text in Research Archive
• Kristiansen, Håvard Anton; Kvaerner, Kari Jorunn; Akre, Harriet; Øverland, Britt; Sandvik, Leiv & Russell, Michael Bjørn (2012). Sleep apnoea headache in the general population. Cephalalgia. ISSN 0333-1024. 32(6), p. 451–458. doi: 10.1177/0333102411431900. Full text in Research Archive
• Omland, Turid; Akre, Harriet; Vårdal, Mari H & Brøndbo, Kjell (2012). Epidemiological aspects of recurrent respiratory papillomatosis: A population-based study. The Laryngoscope. ISSN 0023-852X. 122(7), p. 1595–1599. doi: 10.1002/lary.23327. Full text in Research Archive
• Øverland, Britt; Akre, Harriet; Berdal, Hanne & Skatvedt, Olav (2012). Sleep-relating groaning: Prevalence and characteristics in a cohort of patients with suspected obstructive sleep apnea. Acta Oto-Laryngologica. ISSN 0001-6489. 132(1), p. 90–95. doi: 10.3109/00016489.2011.624119. Full text in Research Archive
• Kristiansen, Håvard Anton; Kvaerner, Kari Jorunn; Akre, Harriet; Øverland, Britt & Russell, Michael Bjørn (2011). Migraine and sleep apnea in the general population. The Journal of Headache and Pain. ISSN 1129-2369. 12(1), p. 55–61. doi: 10.1007/s10194-010-0268-2. Full text in Research Archive Show summary

  Objective is to investigate the relationship between migraine and obstructive sleep apnea in the general population. A cross-sectional population-based study. A random age and gender stratified sample of 40,000 persons aged 20–80 years residing in Akershus, Hedmark or Oppland County, Norway, were drawn by the National Population Register. A postal questionnaire containing the Berlin Questionnaire was used to classify respondents to be of either high or low risk of obstructive sleep apnea. 376 persons with high risk and 157 persons with low risk of sleep apnea aged 30–65 years were included for further investigations. They underwent an extensive clinical interview, a physical and a neurological examination by physicians, and in-hospital polysomnography. Those with apnea hypopnoea index (AHI) ≥5 were classified with obstructive sleep apnea. Migraine without aura (MO) and migraine with aura (MA) was diagnosed according to the International Classification of Headache Disorders. MO and MA occurred in 12.5 and 6.8% of the participants with obstructive sleep apnea. The logistic regression analyses showed no relationship between the two types of migraine and obstructive sleep apnea, with adjusted odds ratios for MO 1.15 (0.65–2.06) and MA 1.15 (0.95–2.39). Further, estimates using cutoff of moderate (AHI ≥ 15) and severe (AHI ≥ 30) obstructive sleep apnea, did not reveal any significant relationship between migraine and the AHI. Migraine and obstructive sleep apnea are unrelated in the general population. This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.

• Kristiansen, Håvard Anton; Kvaerner, Kari Jorunn; Akre, Harriet; Øverland, Britt & Russell, Michael Bjørn (2011). Tension-type headache and sleep apnea in the general population. The Journal of Headache and Pain. ISSN 1129-2369. 12(1), p. 63–69. doi: 10.1007/s10194-010-0265-5. Full text in Research Archive Show summary

  The main objective of this study is to investigate the relationship between tension-type headache and obstructive sleep apnea in the general population. The method involves a cross-sectional population-based study. A random age and gender stratified sample of 40,000 persons aged 20–80 years residing in Akershus, Hedmark or Oppland County, Norway were drawn by the National Population Register. A postal questionnaire containing the Berlin Questionnaire was used to classify respondents to be of either high or low risk of obstructive sleep apnea. Included in this study were 297 persons with high risk and 134 persons with low risk of sleep apnea, aged 30–65 years. They underwent an extensive clinical interview, a physical and a neurological examination by physicians, and in-hospital polysomnography. Those with apnea hypopnoea index (AHI) ≥5 were classified with obstructive sleep apnea. Tension-type headache was diagnosed according to the International Classification of Headache Disorders. Results showed the prevalence of frequent and chronic tension-type headache was 18.7 and 2.1% in the participants with obstructive sleep apnea. The logistic regression analyses showed no significant relationship between tension-type headache and obstructive sleep apnea, with adjusted odds ratios for frequent tension-type headache of 0.95 (0.55–1.62) and chronic tension-type headache of 1.91 (0.37–9.85). The results did not change when using cut-off of moderate (AHI ≥15) and severe (AHI ≥30) obstructive sleep apnea. Thus, we did not find any significant relationship between tension-type headache and the AHI. The presence and severity of sleep apneas seem not to influence presence and attack-frequency of tension-type headache in the general population. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.

• Herrscher, Tobias Erik; Akre, Harriet; Øverland, Britt; Sandvik, Leiv & Westheim, Arne (2011). High Prevalence of Sleep Apnea in Heart Failure Outpatients: Even in Patients With Preserved Systolic Function. Journal of Cardiac Failure. ISSN 1071-9164. 17(5), p. 420–425. doi: 10.1016/j.cardfail.2011.01.013. Full text in Research Archive
• Kristiansen, Håvard Anton; Kvaerner, Kari Jorunn; Akre, Harriet; Øverland, Britt & Russell, Michael Bjørn (2010). Migraine and sleep apnea in the general population. The Journal of Headache and Pain. ISSN 1129-2369. doi: 10.1007/s10194-010-0268-2. Full text in Research Archive
• Kristiansen, Håvard Anton; Kvaerner, Kari Jorunn; Akre, Harriet; Øverland, Britt & Russell, Michael Bjørn (2010). Tension-type headache and sleep apnea in the general population. The Journal of Headache and Pain. ISSN 1129-2369. doi: 10.1007/s10194-010-0265-5. Full text in Research Archive
• Akre, Harriet; Øverland, Britt & Skatvedt, Olav (2009). Respirasjonsforstyrrelser under søvn. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 129(17), p. 1762–1765. doi: 10.4045/tidsskr.08.0497. Full text in Research Archive

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• Hui, David; Akre, Harriet; Goebel, Vera Hermine; Plagemann, Thomas Peter & Arnesen, Lars Andre Strøm (2025). Bruk av KI-verktøy på fastlegekontoret. doi: 10.4045/tidsskr.25.0432. Full text in Research Archive
• Hui, David; Akre, Harriet; Goebel, Vera Hermine; Plagemann, Thomas Peter & Arnesen, Lars Andre Strøm (2025). Use of AI in general practice. 145. doi: 10.4045/tidsskr.25.0432. Full text in Research Archive
• Melteig, Elina; Plagemann, Thomas Peter; Goebel, Vera Hermine; Akre, Harriet; Øverland, Britt & Hui, David (2025). Noen barn slutter å puste om natten. Ofte har barnet sovet dårlig i flere år. Titan.uio.no. doi: https:/www.titan.uio.no/innovasjon/2025/noen-barn-slutter-a-puste-om-natten.html. Full text in Research Archive
• Lopez, Marta Quemada; Plagemann, Thomas Peter; Goebel, Vera Hermine; Adams, Jonathan; Hui, David & Øverland, Britt [Show all 8 contributors for this article] (2024). Requirements Analysis for Responsible Explainable AI for Pediatric Sleep Apnea Diagnosis. Full text in Research Archive
• Traaen, Gunn Marit; Akre, Harriet; Loennechen, Jan Pål & Gullestad, Lars (2022). Reply to Lalonde et al. American Journal of Respiratory and Critical Care Medicine. ISSN 1073-449X. 205(9), p. 1129–1130. doi: 10.1164/rccm.202112-2738LE. Full text in Research Archive
• Øverland, Britt; Berdal, Hanne & Akre, Harriet (2018). High prevalence of OSA in children referred for adenotonsillectomy. Full text in Research Archive
• Russell, Michael Bjørn; Kvaerner, Kari Jorunn; Akre, Harriet; Øverland, Britt & Kristiansen, Håvard Anton (2009). A population-based study of tension-type headache in obstructive sleep apnea. The Akershus sleep apnea project. Cephalalgia. ISSN 0333-1024. 29, p. 159–159. Full text in Research Archive

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