Publications
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Greisiger, Ralf; O’Leary, Stephen; Bester, Christofer; Korslund, Hilde; Iftikhar, Ummul Muneera Bushra & Jablonski, Greg Eigner
(2025).
The effect of surgical complexity on hearing preservation during cochlear implantation with sheathed perimodiolar electrodes.
European Archives of Oto-Rhino-Laryngology.
ISSN 0937-4477.
283,
p. 9–18.
doi:
10.1007/s00405-025-09581-9.
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Purpose
The causes of residual hearing loss during cochlear implantation are generally poorly understood. This study sought to understand whether the complexity of this surgical approach related to a loss of residual hearing.
Method
Thirty-four adults underwent implantation with a sheathed perimodiolar electrode, via an extended round window approach. During implantation, there was simultaneous video fluoroscopy, electrocochleography (ECochG) and video from the operating microscope. Three investigators reviewed the data simultaneously. Surgery was classified as straightforward or complex, defined as difficulty with either introduction of the electrode/sheath, advancement of the electrode, or withdrawal of the sheath. ECochG signal amplitude was correlated to intracochlear electrode movements, as determined by video fluoroscopy. The primary outcome was relative hearing loss, at least six weeks after surgery. The impact of surgical complexity on relative hearing loss was assessed. A secondary outcome was the impact of surgical complexity or electrode movement on ECochG signal amplitude.
Results
Complex surgery was associated with significantly worse relative hearing preservation (p=0.011), as well as lower maximum ECochG amplitudes (Kruskal-Wallis, chi2 = 4.35, p= 0.037). After the electrode had been advanced out of the sheath, sudden fluctuations in ECochG amplitude were related to sudden changes in insertion depth. In non-complex surgeries, the residual hearing was independent of such fluctuations (Kruskal-Wallis, chi2=1.12,p=0.289).
Conclusion
These data suggest residual hearing is lost early during the implant procedure, following complex surgical events. The low ECochG amplitudes encountered in complex surgeries support this interpretation. ECochG amplitude fluctuations were not associated with poorer residual hearing.
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Myhrum, Marte; Heldahl, Mariann Gjervik; Rødvik, Arne Kirkhorn; Tvete, Ole & Jablonski, Greg Eigner
(2023).
Validation of the Norwegian Version of the Speech, Spatial and Qualities of Hearing Scale (SSQ).
Audiology & neuro-otology.
ISSN 1420-3030.
28(6).
doi:
10.1159/000534197.
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<b><i>Introduction:</i></b> The main objective of the study was to validate the Norwegian translation of the Speech, Spatial and Qualities of Hearing Scale (SSQ) and investigate the SSQ disability profiles in a cochlear implant (CI) user population. <b><i>Methods:</i></b> The study involved 152 adult CI users. The mean age at implantation was 55 (standard deviation [SD] = 16), and the mean CI experience was 5 years (SD = 4.8). The cohort was split into three groups depending on the hearing modality: bilateral CIs (BCIs), a unilateral CI (UCI), and bimodal (CI plus contralateral hearing aid; HCI). The SSQ disability profiles of each group were compared with those observed in similar studies using the English version and other translations of the SSQ. Standard values, internal consistency, sensitivity, and floor and ceiling effects were investigated, and the missing-response rates to specific questions were calculated. Relationships to speech perception were measured using monosyllabic word scores and the Norwegian Hearing in Noise Test scores. <b><i>Results:</i></b> In the BCI group, the average scores were around 5.0 for the speech and spatial sections and 7.0 for the qualities section (SD ∼2). The average scores of the UCI and HCI groups were about one point lower than those of the BCI group. The SSQ disability profiles were comparable to the profiles in similar studies. The slopes of the linear regression lines measuring the relationships between the SSQ speech and monosyllabic word scores were 0.8 per 10% increase in the monosyllabic word score for the BCI group (explaining 35% of the variation) and 0.4 for the UCI and HCI groups (explaining 22–23% of the variation). <b><i>Conclusion:</i></b> The Norwegian version of the SSQ measures hearing disability similar to the original English version, and the internal consistency is good. Differences in the recipients’ pre-implantation variables could explain some variations we observed in the SSQ responses, and such predictors should be investigated. Data aggregation will be possible using the SSQ as a routine clinical assessment in global CI populations. Moreover, pre-implantation variables should be systematically registered so that they can be used in mixed-effects models.
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Sijgers, Leanne; Sørensen, Torquil Macdonald; Soulby, Andrew; Boyle, Patrick; Dalbert, Adrian & Röösli, Christof
[Show all 12 contributors for this article]
(2023).
Classification of Acoustic Hearing Preservation After Cochlear Implantation Using Electrocochleography.
Trends in Hearing (Trends).
27.
doi:
10.1177/23312165231220997.
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The objective to preserve residual hearing during cochlear implantation has recently led to the use of intracochlear electrocochleography (ECochG) as an intraoperative monitoring tool. Currently, a decrease in the amplitude of the difference between responses to alternating-polarity stimuli (DIF response), predominantly reflecting the hair cell response, is used for providing feedback. Including other ECochG response components, such as phase changes and harmonic distortions, could improve the accuracy of surgical feedback. The objectives of the present study were (1) to compare simultaneously recorded stepwise intracochlear and extracochlear ECochG responses to 500 Hz tone bursts, (2) to explore patterns in features extracted from the intracochlear ECochG recordings relating to hearing preservation or hearing loss, and (3) to design support vector machine (SVM) and random forest (RF) classifiers of acoustic hearing preservation that treat each subject as a sample and use all intracochlear ECochG recordings made during electrode array insertion for classification. Forty subjects undergoing cochlear implant (CI) surgery at the Oslo University Hospital, St. Thomas’ Hearing Implant Centre, or the University Hospital of Zurich were prospectively enrolled. In this cohort, DIF response amplitude decreases did not relate to postoperative acoustic hearing preservation. Exploratory analysis of the feature set extracted from the ECochG responses and preoperative audiogram showed that the features were not discriminative between outcome classes. The SVM and RF classifiers that were trained on these features could not distinguish cases with hearing loss and hearing preservation. These findings suggest that hearing loss following CI surgery is not always reflected in intraoperative ECochG recordings.
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Heyning, Paul Van de; Roland, Peter; Lassaletta, Luis; Agrawal, Sumit; Atlas, Marcus & Baumgartner, Wolf-Dieter
[Show all 39 contributors for this article]
(2022).
Suitable electrode choice for robotic-assisted cochlear implant surgery: A systematic literature review of manual electrode insertion adverse events.
Frontiers in Surgery.
9,
p. 1–14.
doi:
10.3389/fsurg.2022.823219.
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Background and Objective The cochlear implant (CI) electrode insertion process is a key step in CI surgery. One of the aims of advances in robotic-assisted CI surgery (RACIS) is to realize better cochlear structure preservation and to precisely control insertion. The aim of this literature review is to gain insight into electrode selection for RACIS by acquiring a thorough knowledge of electrode insertion and related complications from classic CI surgery involving a manual electrode insertion process. Methods A systematic electronic search of the literature was carried out using PubMed, Scopus, Cochrane, and Web of Science to find relevant literature on electrode tip fold over (ETFO), electrode scalar deviation (ESD), and electrode migration (EM) from both pre-shaped and straight electrode types. Results A total of 82 studies that include 8,603 ears implanted with a CI, i.e., pre-shaped (4,869) and straight electrodes (3,734), were evaluated. The rate of ETFO (25 studies, 2,335 ears), ESD (39 studies, 3,073 ears), and EM (18 studies, 3,195 ears) was determined. An incidence rate (±95% CI) of 5.38% (4.4–6.6%) of ETFO, 28.6% (26.6–30.6%) of ESD, and 0.53% (0.2–1.1%) of EM is associated with pre-shaped electrodes, whereas with straight electrodes it was 0.51% (0.1–1.3%), 11% (9.2–13.0%), and 3.2% (2.5–3.95%), respectively. The differences between the pre-shaped and straight electrode types are highly significant ( p &lt; 0.001). Laboratory experiments show evidence that robotic insertions of electrodes are less traumatic than manual insertions. The influence of round window (RW) vs. cochleostomy (Coch) was not assessed. Conclusion Considering the current electrode designs available and the reported incidence of insertion complications, the use of straight electrodes in RACIS and conventional CI surgery (and manual insertion) appears to be less traumatic to intracochlear structures compared with pre-shaped electrodes. However, EM of straight electrodes should be anticipated. RACIS has the potential to reduce these complications.
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Greisiger, Ralf; Heldahl, Mariann Gjervik; Myhrum, Marte; Sørensen, Torquil Macdonald; Dammerud, Jens Jørgen & Rasmussen, Kjell
[Show all 9 contributors for this article]
(2022).
Effect of Proximity to the Modiolus for the Cochlear CI532 Slim Modiolar Electrode Array on Evoked Compound Action Potentials and Programming Levels.
Audiology & neuro-otology.
ISSN 1420-3030.
27(5),
p. 397–405.
doi:
10.1159/000524256.
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Background: The first surgeries with CI532 showed an effect of the proximity of the electrode to the modiolus on the Evoked Compound Action Potentials (ECAPs). Objectives: Objectives of the study were to investigate the effect of the “pullback” procedure on intraoperative ECAP responses in three different electrode array positions and additionally to compare behavioral thresholds with the thresholds obtained in a group of patients using the standard insertion. The hypothesis of this study is that pullback will cause lower ECAPs and behavioral thresholds. Patients: The study included 40 patients, 20 in the pullback insertion group and 20 in the standard insertion group (without pullback). Method: During insertion of the CI532 electrode array, ECAP was performed in three different positions for the pullback group: at initial insertion, at over-insertion, and after pullback. Insertion was monitored by fluoroscopy. In the standard group, ECAP was performed at the initial position, which is also the final position. ECAP thresholds (T-ECAPs) were compared within subjects at the initial and the final position in the pullback group and between groups in the final positions of the pullback and standard groups. Programming levels (C- and T-levels) were compared between the two groups 1 year after switch-on. Results: Intraoperative measurements pullback shows lower average T-ECAPs after pullback compared to thresholds in initial position. Comparison of intraoperative T-ECAPs at the final positions showed no statistically significant difference between the pullback group and the standard insertion group. Furthermore, 1 year after switch-on there was no statistically significant difference in C- and T-levels between the two groups. Conclusion: The pullback maneuver of the CI532 electrode array after an over-insertion gave significantly lower T-ECAPs compared to the thresholds at the initial position. However, the between-groups analysis of pullback and standard insertion showed neither significantly different T-ECAPs nor different programming levels. Because T-ECAPs and programming levels vary considerably between subjects, large groups are required to detect differences between groups. Additionally, the effect pullback technique to preserving the residual hearing is not known yet.
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Andersson, Helene; Jablonski, Greg Eigner; Nordahl, Stein Helge Glad; Nordfalk, Karl; Helseth, Eirik & Martens, Camilla
[Show all 8 contributors for this article]
(2021).
The Risk of Benign Paroxysmal Positional Vertigo After Head Trauma.
The Laryngoscope.
ISSN 0023-852X.
132(2),
p. 443–448.
doi:
10.1002/lary.29851.
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Objectives: Head trauma may cause dislodgement of otoconia and development of benign paroxysmal positional vertigo (BPPV). The risk of developing BPPV is expected to be highest shortly after the trauma, then decrease and approach the risk seen in the general population. The aim of this study was to estimate the risk-time curve of BPPV development after head trauma. Study Design: Prospective observational study. Methods: Patients with minimal, mild, or moderate head trauma treated at the Department of Neurosurgery or the Department of Orthopedic Emergency at Oslo University Hospital, were interviewed and examined for BPPV using the Dix-Hallpike and supine roll maneuvers. BPPV was diagnosed according to the International diagnostic criteria of the Bárány Society. Telephone interviews were conducted at 2, 6, and 12 weeks after the first examination. Results: Out of 117 patients, 21% developed traumatic BPPV within 3 months after the trauma. The corresponding numbers were 12% with minimal trauma, 24% with mild, and 40% with moderate trauma. The difference in prevalence between the groups was significant (P = .018). During the first 4 weeks after the trauma, it was observed 20, 3, 0, and 1 BPPV onsets, respectively. No BPPV cases were seen for the remainder of the 3-month follow-up. Conclusion: The risk of developing BPPV after minimal-to-moderate head trauma is considerable and related to trauma severity. Most cases occur within few days after the trauma, but any BPPV occurring within the first 2 weeks after head trauma are likely due to the traumatic event.
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Jablonski, Greg Eigner; Falkenberg-Jensen, Benedicte; Bunne, Marie; Iftikhar, Ummul Muneera Bushra; Greisiger, Ralf & Opheim, Leif Runar
[Show all 9 contributors for this article]
(2021).
Fusion of Technology in Cochlear Implantation Surgery: Investigation of Fluoroscopically Assisted Robotic Electrode Insertion.
Frontiers in Surgery.
8,
p. 1–7.
doi:
10.3389/fsurg.2021.741401.
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The HEARO cochlear implantation surgery aims to replace the conventional wide mastoidectomy approach with a minimally invasive direct cochlear access. The main advantage of the HEARO access would be that the trajectory accommodates the optimal and individualized insertion parameters such as type of cochlear access and trajectory angles into the cochlea. To investigate the quality of electrode insertion with the HEARO procedure, the insertion process was inspected under fluoroscopy in 16 human cadaver temporal bones. Prior to the insertion, the robotic middle and inner ear access were performed through the HEARO procedures. The status of the insertion was analyzed on the post-operative image with Siemens Artis Pheno (Siemens AG, Munich, Germany). The completion of the full HEARO procedure, including the robotic inner ear access and fluoroscopy electrode insertion, was possible in all 16 cases. It was possible to insert the electrode in all 16 cases through the drilled tunnel. However, one case in which the full cochlea was not visible on the post-operative image for analysis was excluded. The post-operative analysis of the electrode insertion showed an average insertion angle of 507°, which is equivalent to 1.4 turns of the cochlea, and minimal and maximal insertion angles were recorded as 373° (1 cochlear turn) and 645° (1.8 cochlear turn), respectively. The fluoroscopy inspection indicated no sign of complications during the insertion.
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Falkenberg-Jensen, Benedicte Margrethe; Jablonski, Greg; Silvola, Juha Tapio; Kristiansen, Joanna Fenn & Hopp, Einar
(2020).
CT imaging of the Eustachian tube using focal contrast medium administration: a feasibility study in humans.
Acta Radiologica Open.
9,
p. 1–6.
doi:
10.1177/2058460119900435.
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Background Several methods of imaging the Eustachian tube have been tested in the last century, although neither has led to an established method. The introduction of balloon Eustachian tuboplasty (BET) has revived the request for Eustachian tube (ET) visualization in patients with chronic Eustachian tube dysfunction. Many institutions perform preoperative computed tomography (CT) scans of the temporal bone and epipharynx before BET. Purpose We hypothesize that the injection of a contrast medium into the tympanic cavity is safe and feasible and can evolve the CT scan by visualizing the ET lumen and, potentially, the level of obstruction. This study is the initial feasibility study for such a human application. Material and Methods Ten minutes before a CT scan, diluted iodixanol was injected into the middle ear in 18 patients planned for BET due to otitis media with effusion. Five patients with Meniere’s disease were controls. Any immediate or delayed adverse events were recorded. Masking of adjacent bony structures in the middle ear on the CT images was evaluated and the most caudally visible contrast medium between the middle ear and epipharynx recorded. Results There were no serious adverse events. One patient reported transitory vertigo. The contrast medium did not mask middle ear structures, apart from the tympanic membrane. The level of contrast medium passage could be assessed. Conclusion Visualizing the ET lumen in humans using intratympanic contrast medium is feasible and safe and does not obscure other valuable image information in a preoperative CT scan.
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Skogseid, Inger Marie; Røsby, Oddveig; Konglund, Ane; Connelly, James Pattrick; Nedregaard, Bård & Jablonski, Greg Eigner
[Show all 9 contributors for this article]
(2018).
Dystonia-deafness syndrome caused by ACTB p.Arg183Trp heterozygosity shows striatal dopaminergic dysfunction and response to pallidal stimulation.
Journal of Neurodevelopmental Disorders.
10(17),
p. 1–8.
doi:
10.1186/s11689-018-9235-z.
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Background Dystonia-deafness syndrome is a well-known clinical entity, with sensorineural deafness typically manifesting earlier than dystonia. ACTB p.Arg183Trp heterozygosity has been reported in six patients to cause combined infant-onset deafness and dystonia manifesting in adolescence or young adulthood. Three of these have received beneficial pallidal stimulation. Brain imaging to assess striatal function has not been reported previously, however. Nor has a comprehensive hypothesis been presented for how the pleiotropic manifestations of this specific beta-actin gene mutation originate developmentally. Case presentation A 19-year-old girl with congenital mild dysmorphic facial features, cochlear implants for infant-onset deafness, and mild cognitive and emotional disability, presented with an adolescent-onset, severe generalized dystonia. Brain MRI and multiple single gene sequencing were inconclusive. Due to life-threatening dystonia, we implanted a neurostimulation device, targeting the postero-ventral internal pallidum bilaterally. The Burke-Fahn-Marsden Dystonia Rating Scale motor/disability scores improved from 87/25 to 21/13 at 2.5 months postoperatively, 26/14 at 3 years, and 30/14 at 4 years. Subsequent whole exome sequencing identified heterozygosity for the ACTB p.Arg183Trp variant. Brain imaging included 123I-ioflupane single photon emission computed tomography (Dopamine Transporter-SPECT), SPECT with 123I-epidepride (binds to dopamine type 2-receptors) and 18 Fluoro-Deoxy-Glucose (FDG)–PET. Both Epidepride-SPECT and FDG-PET showed reduced tracer uptake in the striatum bilaterally, particularly in the putamen. DaT-SPECT was slightly abnormal. Conclusions In this patient with dystonia-deafness syndrome caused by ACTB p.Arg183Trp heterozygosity, unprecedented brain imaging findings strongly indicate striatal neuronal/dopaminergic dysfunction as the underlying cause of the dystonia. Pallidal stimulation provided a substantial improvement of the severe generalized dystonia, which is largely sustained at 4-year follow-up, and we advise this treatment to be considered in such patients. We hypothesize that the pleiotropic manifestations of the dystonia-deafness syndrome caused by this mutation derive from diverse developmental functions of beta-actin in neural crest migration and proliferation (facial dysmorphogenesis), hair cell stereocilia function (infant-onset deafness), and altered synaptic activity patterns associated with pubertal changes in striatal function (adolescent-onset dystonia). The temporal differences in developmental onset are likely due to varying degrees of susceptibility and of compensatory upregulation of other actin variants in the affected structures.
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Falkenberg-Jensen, Benedicte; Heimdal, Ketil Riddervold; Høgevold, Hans Erik; Jablonski, Greg Eigner; Due-Tønnessen, Bernt Johan & Hopp, Einar
(2018).
Abnormally Wide Eustachian Tubes Involving the Sphenoid Bone: A Collection.
Laryngoscope Investigative Otolaryngology (LIO).
3(3),
p. 214–217.
doi:
10.1002/lio2.158.
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Objectives: To present nine patients with an abnormal widened bony Eustachian tube running anteriorly in the skull base through the sphenoid bone. Methods: Patients with a particular anomaly in the bony Eustachian tube incidentally found on CT examinations were registered consecutively over a period of four years. Results: Nine patients had the anomaly, eight unilaterally and one bilaterally. All our patients had additional anomalies involving the outer, middle, and/or inner ear. Conclusion: The consequences of this anomaly remain unknown, but the presence of the widened, bony ET should increase the awareness for complex temporal bone deformities and vice versa.
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Falkenberg-Jensen, Benedicte; Hopp, Einar; Jablonski, Greg Eigner; Pripp, Are Hugo & Silvola, Juha Tapio
(2018).
The cartilaginous Eustachian tube: Reliable CT measurement and impact of the length.
American Journal of Otolaryngology.
ISSN 0196-0709.
39(4),
p. 436–440.
doi:
10.1016/j.amjoto.2018.04.010.
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Purpose: Balloon dilation of the Eustachian tube is a treatment option for obstructive Eustachian tube dysfunction. The desired balloon position is in the cartilaginous portion. However, the balloon catheter may slide into the bony portion without the surgeon's knowledge. Knowing the length of the cartilaginous portion may improve catheter positioning, but there is no published research on measuring this portion selectively or on whether the length has an impact on development of disease or treatment outcome. To evaluate whether a measurement obtained from CT images is valuable and accurate, to standardize the manner of which the length is measured, and to compare our radiologic measurements to procedural findings, we designed a combined study. Further, we tested the length's influence on development of disease and treatment outcome. Methods: Anatomical end points of the cartilaginous part of the Eustachian tube were unambiguously defined. The length was retrospectively measured bilaterally in 29 CT examinations by two radiologists, and repeated by one after two weeks. New reformats and measurements were made after 18 months for 10 of the patients. Prospectively 10 patients were included in a study where the length measured on CT was compared to per-procedural measurements based on catheter insertion depth to isthmus. Various parameters including length and treatment outcome were measured in 69 patients and 34 controls. Results: Correlation was adequate to excellent in all comparisons. The length of the cartilaginous Eustachian tube did not predict treatment outcome or disease development. The lengths were significantly shorter in females. Conclusion: Measuring the cartilaginous portion of the Eustachian tube on CT images is precise and reproducible, and reflects the length measured intraoperatively. However, it does not seem have a prognostic value.
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Nordfalk, Karl Fredrik; Rasmussen, Kjell; Bunne, Marie & Jablonski, Greg
(2016).
Deep round window insertion versus standard approach in cochlear implant surgery.
European Archives of Oto-Rhino-Laryngology.
ISSN 0937-4477.
273(1),
p. 43–50.
doi:
10.1007/s00405-014-3451-2.
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Falkenberg-Jensen, Benedicte; Silvola, Juha Tapio; Laurvik, Helene; Lervik, Andreas; Kristiansen, Joanna & Jablonski, Greg
[Show all 7 contributors for this article]
(2016).
CT imaging of the eustachian tube using focal contrast medium administration: a feasibility study.
Laryngoscope Investigative Otolaryngology (LIO).
1(4),
p. 83–87.
doi:
10.1002/lio2.24.
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Objectives: We aim to develop an imaging technique for visualization of the Eustachian tube (ET) lumen. Study Design: A prospective, experimental study in an animal model and in human cadaver specimens. Methods: Applying iodixanol to the middle ear in two human temporal bone specimens, followed by computed tomography (CT) examinations, we optimized contrast dilution, CT algorithm, and head positioning for visualization of contrast passage through the ET. Myringotomy was performed on eight rabbits. Based on the cadaver study, a 20% iodixanol solution was applied to the middle ear, and subsequent CT scans were performed to observe iodixanol in the epipharynx. For some animals, the procedure was repeated on the contralateral ear. We performed the procedure twice on four subjects. Twenty examinations were included. Iodixanol appearance in the ET and the epipharyngeal orifice was assessed qualitatively on CT scans. The tympanic membrane was inspected after 1 or 2 weeks, and histopathological examination of six contrast-exposed temporal bones was performed. Results: The cadaver study provided information on imaging technique and contrast dosage. In rabbits, iodixanol passed through the ET in 19 of the 20 ears. Qualitatively, optimal visualization was seen after 9 to 12 minutes. Clinical inspection after 1 or 2 weeks revealed normal middle ear status. Histopathological samples showed no sign of inflammatory reaction in the tympanic membrane, middle ear, or ET. Conclusion: Iodixanol application to the middle ear is feasible, safe, and demonstrates patency of the ET
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Nordfalk, Karl Fredrik; Rasmussen, Kjell; Hopp, Einar; Bunne, Marie; Silvola, Juha Tapio & Jablonski, Greg
(2016).
Insertion Depth in Cochlear Implantation and Outcome
in Residual Hearing and Vestibular Function.
Ear and Hearing.
ISSN 0196-0202.
37(2),
p. e129–e137.
doi:
10.1097/AUD.0000000000000241.
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Greisiger, Ralf; Shallop, Jon K.; Hol, Per Kristian; Elle, Ole Jakob & Jablonski, Greg
(2015).
Cochlear implantees: Analysis of behavioral and objective measures for a clinical population of various age groups.
Cochlear Implants International (CII).
ISSN 1467-0100.
16(4),
p. 1–19.
doi:
10.1080/14670100.2015.1110372.
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Nordfalk, Karl Fredrik; Rasmussen, Kjell; Hopp, Einar; Greisiger, Ralf & Jablonski, Greg
(2014).
Scalar position in cochlear implant surgery and outcome in residual hearing and the vestibular system.
International Journal of Audiology.
ISSN 1499-2027.
53(2),
p. 121–127.
doi:
10.3109/14992027.2013.854413.
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Heimdal, Ketil Riddervold; Guixe, Monica Sanchez; Aukrust, Ingvild; Bollerslev, Jens; Bruland, Ove & Jablonski, Greg
[Show all 17 contributors for this article]
(2014).
STUB1 mutations in autosomal recessive ataxias - evidence for mutation-specific clinical heterogeneity.
Orphanet Journal of Rare Diseases.
9:146.
doi:
10.1186/s13023-014-0146-0.
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Background: A subset of hereditary cerebellar ataxias is inherited as autosomal recessive traits (ARCAs). Classification of recessive ataxias due to phenotypic differences in the cerebellum and cerebellar structures is constantly evolving due to new identified disease genes. Recently, reports have linked mutations in genes involved in ubiquitination (RNF216, OTUD4, STUB1) to ARCA with hypogonadism. Methods and results: With a combination of homozygozity mapping and exome sequencing, we identified three mutations in STUB1 in two families with ARCA and cognitive impairment; a homozygous missense variant (c.194A > G, p.Asn65Ser) that segregated in three affected siblings, and a missense change (c.82G > A, p.Glu28Lys) which was inherited in trans with a nonsense mutation (c.430A > T, p.Lys144Ter) in another patient. STUB1 encodes CHIP (C-terminus of Heat shock protein 70 – Interacting Protein), a dual function protein with a role in ubiquitination as a co-chaperone with heat shock proteins, and as an E3 ligase. We show that the p.Asn65Ser substitution impairs CHIP’s ability to ubiquitinate HSC70 in vitro, despite being able to self-ubiquitinate. These results are consistent with previous studies highlighting this as a critical residue for the interaction between CHIP and its co-chaperones. Furthermore, we show that the levels of CHIP are strongly reduced in vivo in patients’ fibroblasts compared to controls. Conclusions: These results suggest that STUB1 mutations might cause disease by impacting not only the E3 ligase function, but also its protein interaction properties and protein amount. Whether the clinical heterogeneity seen in STUB1 ARCA can be related to the location of the mutations remains to be understood, but interestingly, all siblings with the p.Asn65Ser substitution showed a marked appearance of accelerated aging not previously described in STUB1 related ARCA, none display hormonal aberrations/clinical hypogonadism while some affected family members had diabetes, alopecia, uveitis and ulcerative colitis, further refining the spectrum of STUB1 related disease.
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Bachmann-Harildstad, Gregor; Stenklev, Niels Chr.; Myrvoll, Elin Alise; Jablonski, Greg & Klingenberg, Olav
(2011).
Beta-Trace Protein as a Diagnostic Marker for Perilymphatic Fluid Fistula: A Prospective Controlled Pilot Study to Test a Sample Collection Technique.
Otology & Neurotology.
ISSN 1531-7129.
32(1),
p. 7–10.
doi:
10.1097/MAO.0b013e3181fc74d0.
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Greisiger, Ralf; Tvete, Ole; Shallop, Jon K.; Elle, Ole Jakob; Hol, Per Kristian & Jablonski, Greg
(2011).
Cochlear implant-evoked electrical auditory brainstem responses during surgery in patients with auditory neuropathy spectrum disorder.
Cochlear Implants International (CII).
ISSN 1467-0100.
12,
p. 58–60.
doi:
10.1179/146701011X13001035753137.
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Henriksen, K; Solheim, E.; Sønsterud, Hilda; Jablonski, Greg & Dietrichs, Espen
(2007).
Kan stamming kureres gjennom induksjon av plastiske forandringer i hjernen?
Norsk tidsskrift for logopedi.
ISSN 0332-7256.
p. 24–27.
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Jablonski, Greg; Klem, K. H.; Danielsen, C.C.; Mosekilde, Leif & Gordeladze, Jan Oxholm
(1996).
Aluminium-induced bone disease in uremic rats: effect of deferoxamine.
Bioscience Reports.
ISSN 0144-8463.
16,
p. 49–63.
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Gordeladze, Jan Oxholm; Lund, H. W.; Jablonski, Greg & Bruland, Øyvind
(1996).
Diverse expression of G-proteins in human sarcoma cell lines with different osteogenic potential: evidence for the involvement of Gi2 in cell proliferation.
Journal of Cellular Biochemistry.
ISSN 0730-2312.
60,
p. 95–106.
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Jablonski, Greg; Mortensen, Berit Marie; Klem, Knut Henning; Mosekilde, Lis; Danielsen, CC & Gordeladze, Jan Oxholm
(1995).
Vitamin D analogs and salmon calcitonin partially reverse the development of renal dystrophy in rats.
Calcified Tissue International.
ISSN 0171-967X.
57(5),
p. 385–391.
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Mortensen, Berit Marie; Lund, Hanne Wessel; Jablonski, Greg; Paulssen, Ruth H & Gordeladze, Jan Oxholm
(1995).
Direct effects of vitamin D3 analogues on G-protein mediated signalling systems in rat osteosarcoma cells and rat pituitary adenoma cells.
Bioscience Reports.
ISSN 0144-8463.
15(3),
p. 135–50.
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Jablonski, Greg; Danielsen, CC; Mosekilde, Lis & Gordeladze, Jan Oxholm
(1994).
Surgically induced uremia in rats. II: Osseous PTH-susceptible signaling systems as predictors of bone resorption.
Calcified Tissue International.
ISSN 0171-967X.
55(4),
p. 281–287.
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Jablonski, Greg; Nordahl, Knut P; Halse, Johan; Dahl, E; Aksnes, L & Gautvik, Kaare M
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(1993).
PTH-stimulated adenylate cyclase activity and bone histomorphometry in iliac crest biopsies in the evaluation of uremic patients: a pilot study with the use of artificial intelligence.
Mineral and Electrolyte Metabolism.
ISSN 0378-0392.
19(6),
p. 351–361.
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Klem, HK; Jablonski, Greg; Saether, O; Jarosz, G; Gautvik, Kaare M & Gordeladze, Jan Oxholm
(1990).
1,25-dihydroxyvitamin D-3 and 24,25-dihydroxyvitamin D-3 affect parathormone (PTH)-sensitive adenylate cyclase activity and alkaline phosphatase secretion of osteoblastic cells through different mechanisms of action.
Biochimica et Biophysica Acta.
ISSN 0006-3002.
1054(3),
p. 304–310.
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Situkho, Maksym; Ikezono, Tetsuo; Myhrum, Marte; Rødvik, Arne Kirkhorn; Maeda, Yukihide & Matsuda, Han
[Show all 8 contributors for this article]
(2024).
Accuracy of diagnostic tests for perilymphatic fistula: protocol for a systematic review.
Frontiers in Neurology.
15.
doi:
10.3389/fneur.2024.1500780.
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Objective: Perilymphatic fistula (PLF) is a challenging inner ear condition, characterized by the abnormal connection between inner and middle ear and subsequent leakage of inner ear liquid (perilymph) into the middle ear. Early surgical intervention for PLF might lead to favorable audiological and vestibular outcomes. The conventional reference standard of PLF detection is the intraoperative visualization of perilymph leakage during explorative tympanotomy or endoscopic inspection; the specificity and sensitivity of this method is unknown. Systematic reviews assessing the accuracy of diagnostic tests for PLF are not available. To systematically review the literature for qualitative evidence exploring the diagnostic tests for the PLF diagnosis. The proposed systematic review will answer the following question: What is the accuracy of diagnostic tests in detecting perilymphatic fistula in humans? Methods: Eligibility criteria: original peer-reviewed articles regarding studies on humans of any age containing data with diagnostic test accuracy estimation (sensitivity and specificity) for PLF diagnosis or in which diagnostic test accuracy could be calculated based on data provided, without language, study design or study date limits. MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, Scopus, and Web of Science will be searched for eligible articles. Additional manual searches will be performed. Covidence software will be used for title and abstract screening, full text review and data extraction. The risk of bias assessment will be conducted using the Quality Assessment of Diagnostic Test Accuracy 2 (QUADAS-2) tool. If two or more high-quality articles evaluating the same diagnostic test will be identified, their findings will be quantitatively synthesized; if a quantitative synthesis is not feasible, the results will be described in a narrative summary. Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) framework will be used to evaluate evidence strength. Study funded by Oslo University Hospital.
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Falkenberg-Jensen, Benedicte; Heimdal, Ketil Riddervold; Høgevold, Hans Erik; Due-Tønnessen, Bernt Johan; Jablonski, Greg Eigner & Hopp, Einar
(2017).
The Didgeridoo Eustachian tube.
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Published
Nov. 27, 2013 1:37 PM
- Last modified
June 1, 2016 11:07 AM
