Semicircular canal biomechanics in health and disease

Rabbitt, Richard D.

doi:10.1152/jn.00708.2018

Cited by 59 publications

(56 citation statements)

References 260 publications

(381 reference statements)

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“…In our study, we described acceleration sensitivity severely affected by complete occlusion of the lumen in the SCC, which would only hold for low-frequency stimuli like calorics. Therefore, a follow-up study using vHIT to test higher-frequency responses would be interesting (20). Moreover, all our patients had a symptomatic P15S COCH mutation; thus, future research should investigate correlations between hearing loss, vestibular testing, and imaging in mutations other than P51S.…”

Section: Discussionmentioning

confidence: 98%

Correlations Between Vestibular Function and Imaging of the Semicircular Canals in DFNA9 Patients

et al. 2020

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Background and Purpose: Radiologic abnormalities on computed tomography (CT), including narrowing or sclerosis of the semicircular canals (SCCs), and T2-weighted magnetic resonance imaging (MRI), including signal loss in the SCC, have been reported as potential biomarkers in patients with P51S mutations in the COCH gene (i.e., DFNA9). The aim of our study was to correlate caloric responses through electronystagmography (ENG) data with imaging results in DFNA9 patients. Materials and Methods: A retrospective study was performed in 45 patients; therefore, 90 ears with P51S mutations in the COCH gene were tested. Caloric responses and CT and MRI data were analyzed from June 2003 until May 2014. More than half of patients (54%) were candidates for cochlear implantation. Results: In our population, 91% of tested ears had sclerotic lesions and/or narrowing in one or more SCCs on CT scan. All tested ears had narrowing or signal loss in at least one SCC on T2-weighted MRI. The lateral SCC was affected in 87% on CT scan and 92% on MRI. However, in 83% of tested ears, all three SCCs were affected on MRI. Furthermore, in 77% of tested ears, caloric responses were reduced bilaterally, while 11.5% showed unilateral hypofunction and the other 11.5% had normal caloric responses. CT abnormalities correlated with hypofunction of caloric responses. This statistically significant difference was present if abnormalities were observed in at least one of the SCCs as well as in ipsilateral lateral SCC function loss. MRI abnormalities in at least one of the SCCs correlated with ENG hypofunction, but there was no direct correlation between lateral SCC abnormalities on MRI and caloric responses of the investigated lateral canal. Conclusion: Our retrospective analysis confirms the presence of CT and MRI abnormalities in DFNA9 patients with the P51S mutation in the COCH gene. A correlation between these radiologic features and vestibular function (tested by means of caloric response) was found in this population.

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Section: Discussionmentioning

confidence: 98%

Correlations Between Vestibular Function and Imaging of the Semicircular Canals in DFNA9 Patients

et al. 2020

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“…In our computations we used anatomic 3D models from microCT reconstruction (Figure 1B), that have never before been used with this purpose in vestibular physiopathology research. In our model we considered the membranous labyrinth to consist of rigid walls, when really, they are elastic, and this elasticity could influence the endolymph flow during the head impulse test (20).…”

Section: Discussionmentioning

confidence: 99%

Computing Endolymph Hydrodynamics During Head Impulse Test on Normal and Hydropic Vestibular Labyrinth Models

Rey-Martínez¹,

Altuna²,

Cheng

et al. 2020

Front. Neurol.

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Hypothesis: Build a biologic geometry based computational model to test the hypothesis that, in some circumstances, endolymphatic hydrops can mechanically cause enhanced eye velocity responses during clinical conditions of the head impulse test. Background: Some recent clinical and experimental findings had suggested that enhanced eye velocity responses measured with the video head impulse test could not only be caused by recording artifacts or central disfunction but also could be directly caused by the mechanical effect of endolymphatic hydrops on horizontal semicircular canal receptor. Methods: Data from clinical video head impulse test was computed in three biologic-based geometry models governed by Navier-Stokes equations; six head impulses of incrementally increasing peak head velocity were computed in each one of the three different geometric models, depending on absence, canal or utricular hydrops. Results: For all computed head impulses an increased endolymphatic pressure was measured at the ampullar region of the horizontal semicircular canal on both canal and utricular hydrops models. The mean of aVOR gain was 1.01 ± 0.008 for the no-hydrops model, 1.14 ± 0.010 for the canal hydrops model was, and 1.10 ± 0.007 for the utricular hydrops model. Conclusion: The results of the physical computation models support-the hypothesis that in endolymphatic hydrops conditions, which are affecting horizontal semicircular canal and utricular region on moderate dilatations, the eye velocity responses output-by the aVOR will be enhanced by a 1.14 factor and aVOR gain values will be enhanced by over 1.1 for impulses to the right side.

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“…For example, big particles falling in a narrow canal will evoke a PN that is intense and shortlived, whereas small particles fall more slowly, causing a less intense and more lasting response. 25,26 The morphology of the membranous labyrinth, the spatial orientation and the radius of the curvature of the SCC, and the orientation of the cupula within the ampulla are also important variables.…”

Section: Pathophysiologymentioning

confidence: 99%

Benign Paroxysmal Positional Vertigo: What We Do and Do Not Know

2020

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Benign paroxysmal positional vertigo (BPPV) is common, sometimes terrifying, but rarely portends serious disease. It is usually easily diagnosed and treated, and both the patient and the physician are immediately gratified. While much has been learned about the pathogenesis of BPPV in the past decades, many of its features remain mysterious, and one must still be wary of the rare times it mimics a dangerous brain disorder. Here we review common, relatively well understood clinical features of BPPV but also emphasize what we do not know and when the physician must look deeper for a more ominous cause.

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Semicircular canal biomechanics in health and disease

Cited by 59 publications

References 260 publications

Correlations Between Vestibular Function and Imaging of the Semicircular Canals in DFNA9 Patients

Correlations Between Vestibular Function and Imaging of the Semicircular Canals in DFNA9 Patients

Computing Endolymph Hydrodynamics During Head Impulse Test on Normal and Hydropic Vestibular Labyrinth Models

Benign Paroxysmal Positional Vertigo: What We Do and Do Not Know

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