Semicircular Canal Research Articles

The specialized inner ear labyrinth of worm-lizards (Amphisbaenia: Squamata).

High-resolution computed tomography (HRCT) has become a widely used tool for studying the inner ear morphology of vertebrates. Amphisbaenians are one of the most specialized groups of fossorial reptiles but are poorly understood relative to other squamate reptile. In this paper we survey the anatomy of the inner and middle ear of these fossorial reptiles using HRCT models and we describe qualitatively and quantitatively (using 3D morphometrics) the anatomy of the inner ear. Amphisbaenians are diverse in skull anatomy, especially in the configuration of the snout, which correlates with digging modes. We demonstrate that the ear also exhibits a diversity of configurations, which are independent of phylogenetic relationships. Results from morphological analyses also allow us to describe 11 new potentially informative phylogenetic characters including some that help to diagnose amphisbaenians, such as: 1) the globular vestibule, ii) semicircular canals arranged in a circular trajectory, and iii) an extensive area of interaction between the columella footplate and the lagenar recess. Among extant amphisbaenians, Rhineura floridana has the most unusual inner ear configuration, including a horizontal semicircular canal that is in the same orientation as the inclined snout. The new morphological information helps us to better understand the morphology of headfirst-burrowing fossorial reptiles and contributes new data for resolution of phylogenetic relationships among amphisbaenians.

Morphology of the human inner ear and vestibulocochlear nerve assessed using 7T MRI.

To optimize high-resolution 7T MRI of the cochlea and measure normal cochlea and the cochlear nerve morphometry in vivo. Eight volunteers with normal hearing were scanned at 7T using an optimized protocol. Two neuroradiologists independently scored image quality. The basal turn lumen diameter (BTLD), height, width, length and volume of the cochlear, long (LD) and short (SD) diameter the calculated cross-sectional area (CSA) of the cochlear nerve were measured. Intra and inter-observer reliability was assessed using intraclass correlation (ICC). 3D T2W DRIVE combined with dielectric pads, allowed acquisition of high-resolution images showing detailed structures, such as the crista ampullaris in the semicircular canals. The overall grading scores from neuroradiologists were excellent. In the left ear, averaging over all subjects gave BTLD of 2.6 ± 0.05mm, height of 4.9 ± 0.1mm, width of 4.4 ± 0.2mm, length of 36.5 ± 0.4mm, volume of 0.16 ± 0.02ml, LD of 1.31 ± 0.1mm, SD of 1.06 ± 0.1mm, and CSA of 1.1 ± 0.1 mm2. The right ear gave BTLD of 2.6 ± 0.04mm, height of 4.9 ± 0.1mm, width of 4.4 ± 0.3mm, length of 35.5 ± 0.4mm, volume of 0.16 ± 0.02ml, LD of 1.29 ± 0.1mm, SD of 1.07 ± 0.1mm, and CSA of 1.10 ± 0.2 mm2. No statistically significant difference was found between the sides of the head (p-value > 0.05). The intra-observer reliability was high (0.77-0.94), while the inter-observer reliability varied from moderate to high (0.55-0.81). 7T MRI can provide excellent visualization of the internal structure of the cochlear and of the vestibulocochlear nerve in vivo.

SURG-55. NOVEL IQ-DOME APPROACH FOR SUPERIOR SEMICIRCULAR CANAL DEHISCENCE REPAIR REDUCES REVISIONAL SURGERY RATE

Abstract Superior Semicircular Canal Dehiscence (SSCD) is characterized by a thinning of the bony ceiling of the superior semicircular canal, manifesting in auditory and vestibular deficits. Surgical repair is the standard treatment modality of SSCD, with conventional methods including plugging or recapping the defective canal with bone wax, bone chips, muscle, and others. Previous research has shown multiple complications with these conventional materials, including a high rate of failure of the primary repair and the need for revisional surgeries. To address this challenge, we investigated a novel surgical sealing technique using IQ-Dome, a titanium mesh plate overlying the arcuate eminence. We aim to assess the efficacy of IQ-Dome in the repair of SSCD compared to conventional material while evaluating outcome measures including postoperative symptom resolution, complication, and revisional surgery rates. We performed a retrospective analysis of patients undergoing SSCD repair via the middle cranial fossa approach at UCLA between 2017 and 2021. We compared demographics and post-operative outcomes between the application of IQ-Dome and conventional materials. A total of 160 patients undergoing SSCD repair were included in our study, with 80 patients receiving IQ-Dome and 80 patients receiving non-IQ-Dome approaches. 60% of patients in the IQ-Dome cohort and 66.7% of patients in the non-IQ-Dome cohort were female. The mean ages of patients were 45.7 years (range 13-78) in the IQ-Dome cohort and 48.9 years (range 17-69) in the non-IQ-Dome cohort. The surgical revision rates for the IQ-Dome and non-IQ-Dome cohorts were 5.7% and 8.5%, respectively. There was no significant difference in postoperative complications between groups. Thus, IQ-Dome is a safe approach for the surgical management of SSCD, decreasing failure and revision rate by nearly 3% in our patient population and offering an alternative surgical sealing repair intervention. Future studies with larger sample sizes are warranted to further assess the efficacy of IQ-Dome.

Surgical and dermatological management of asymptomatic congenital ear canal atresia in a male Wirehaired Pointing Griffon dog

AbstractA 1‐year‐old, male, entire Wirehaired Pointing Griffon was evaluated for asymptomatic right congenital ear canal atresia. Head computed tomography confirmed congenital ear canal atresia diagnosis. Surgical resection and anastomosis of the ear canal followed by video otoscopy was performed. An intact, but flaccid tympanic membrane, suspected from impacted ear canal debris, was identified. One week postoperatively, bilateral yeast otitis externa was diagnosed and successfully treated with topical anti‐fungal therapy. Five months postoperatively, the stoma remained patent, the dog was asymptomatic, and computed tomography with video otoscopy revealed a taut tympanic membrane bulging into the horizontal ear canal. Myringotomy, cytology, bacterial cultures, susceptibility testing, middle ear saline lavage and pre‐emptive topical antibiotic therapy were pursued. Cultures yielded no bacterial growth. Four weeks later, the tympanic membrane was visibly normal, and the stoma was unchanged. This case report is the first to describe interdisciplinary management of asymptomatic congenital ear canal atresia and might support early surgical intervention as a reasonable option.

Semicircular canal drug delivery safely targets the inner ear perilymphatic space.

Effective, reproducible, and safe delivery of therapeutics into the inner ear is required for the prevention and treatment of hearing loss. A commonly used delivery method is via the posterior semicircular canal (PSCC); however, its specific targeting within the cochlea remains unclear, impacting precision and reproducibility. To assess safety and target specificity, we conducted in vivo recordings of the pharmacological manipulations delivered through the PSCC. Measurements of auditory brainstem response (ABR), vibrometry, and vestibular behavioral and sensory-evoked potential (VsEP) revealed preserved hearing and vestibular functions after artificial perilymph injections. Injection of curare, a mechanoelectrical transducer (MET) channel blocker that affects hearing when in the endolymph, had no effect on ABR or VsEP thresholds. Conversely, injection of CNQX, an AMPA receptor blocker, or lidocaine, a Na+ channel blocker, which affects hearing when in the perilymph, significantly increased both thresholds, indicating that PSCC injections selectively target the perilymphatic space. In vivo tracking of gold nanoparticles confirmed their exclusive distribution in the perilymph during PSCC injection, supporting the pharmacological finding. Together, PSCC injection is a safe method for inner ear delivery, specifically targeting the perilymphatic space. Our findings will allow for precise delivery of therapeutics within the inner ear for therapeutic and research purposes.

EFFECTIVENESS OF EPLEY MANEUVER AND GANS REPOSITIONING MANEUVER ON DIZZINESS, BALANCE AND KINESIOPHOBIA IN PATIENTS WITH POSTERIOR CANAL BENIGN PAROXYSMAL POSITIONAL VERTIGO

Background: Benign paroxysmal positional vertigo (BPPV) is the most prevalent type of peripheral vestibular vertigo, typically affecting the posterior semi-circular canal. Objective: The objective of study was to compare the effectiveness of Epley maneuver and Gans repositioning maneuver on dizziness, balance and kinesiophobia in patients with posterior canal BPPV. Methods: 30 BPPV patients were selected and assigned into two groups based on the selection criteria. Group-A (N=15), received Epley maneuver and 15 were assigned to Group-B, undergone Gans repositioning maneuver, for 20 minutes per session, 3 session (alternate days) per week for 3 weeks. Cawthorne and Cooksey Exercises were given to both the group as common intervention. Dizziness, balance and kinesiophobia were assessed both before and after the 3-week intervention program using Dizziness Handicap Inventory (DHI) scale, Timed-Up and Go (TUG) test and Tampa Scale of Kinesiophobia (TSK), respectively. The collected data were subsequently tabulated and analyzed using appropriate statistical tools. Results: The unpaired ‘t’ test analysis of dizziness and balance revealed statistically significant scores in DHI(t=2.2259) and TUG(t=2.2547), respectively, at a 95% confidence interval. Consequently, Group A demonstrated significant reduction in dizziness and balance improvement in patients with posterior canal BPPV. The scores of Kinesiophobia for both the groups were (A, Mean=31.6; B, Mean= 32.2), which showed no significant difference(t=1.074), that means the group showed the improvement from baseline. Conclusion: The study concluded that a 3-week intervention combining the Epley maneuver with Cawthorne-Cooksey exercises was effective in treating dizziness, balance and kinesiophobia in patients with posterior canal BPPV. Implication: The Epley and Gans maneuvers effectively reduce dizziness and improve balance in patients with posterior canal BPPV. They also may alleviate kinesiophobia, enhancing patient confidence in movement. These interventions highlight the importance of targeted therapy in managing vestibular disorders, promoting functional recovery and quality of life.

Associations Between Vestibular Perception and Cognitive Performance in Healthy Adults.

A growing body of evidence has linked vestibular function to the higher-order cognitive ability in aging individuals. Past evidence has suggested unique links between vestibular function and cognition on the basis of end-organ involvement (i.e., otoliths versus canals). However, past studies have only assessed vestibular reflexes despite the diversity of vestibular pathways. Thus, this exploratory study aimed to assess associations between vestibular perception and cognition in aging adults to determine potential relationships. Fifty adults (21 to 84 years; mean = 52.9, SD = 19.8) were included in this cross-sectional study. All participants completed a vestibular perceptual threshold test battery designed to target perception predominantly mediated by each end-organ pair and intra-vestibular integration: 1 Hz y-translation (utricle), 1 Hz z-translation (saccule), 2 Hz yaw rotation (horizontal canals), 2 Hz right anterior, left posterior (RALP), and left anterior, right posterior (LARP) tilts (vertical canals), and 0.5 Hz roll tilt (canal-otolith integration). Participants also completed standard assessments of cognition and path integration: Digit Symbol Substitution Test (DSST), Trail Making Test (TMT), and the Gait Disorientation Test (GDT). Associations were assessed using Spearman rank correlation, and multivariable regression analyses. For correlation analyses, DSST correlated to RALP/LARP tilt, roll tilt, and z-translation. TMT-A only correlated to z-translation, and TMT-B correlated to roll tilt and z-translation after correcting for multiple comparisons. GDT correlated to RALP/LARP tilt and y-translation. In age-adjusted regression analyses, DSST and TMT-B were associated with z-translation thresholds and GDT was associated with y-translation thresholds. In this cross-sectional study, we identified associations between vestibular perceptual thresholds with otolith contributions and standard measures of cognition. These results are in line with past results suggesting unique associations between otolith function and cognitive performance.

Video Head Impulse Test Coherence Predicts Vertigo Recovery in Sudden Sensorineural Hearing Loss with Vertigo.

The labyrinthitis poses inferior quality of life with prolonged vestibular symptoms in patients with sudden sensorineural hearing loss with vertigo (SSNHLV). This study utilized a novel coherence analysis in video head impulse test (vHIT) to investigate vertigo outcomes in SSNHLV patients. A retrospective review included 48 SSNHLV patients completing high-dose steroid treatment between December 2016 and April 2023, and 38 healthy volunteers were prospectively enrolled between November 2022 and April 2023 in our academic tertiary referral center. Magnitude-squared wavelet coherence was measured between eye and head velocities in vHIT to represent the degree of correlation across different frequency bands. Vertigo recovery, assessed by visual analog scale equal to zero at 2 weeks and 2 months, was analyzed using a multivariable Cox regression model. The VAS among patients with SSNHLV was 5.73 ± 2.45 (mean ± standard deviation). Higher coherent frequencies in the horizontal semicircular canal (SCC), posterior SCC, mean, and minimal coherent frequencies of all three SCCs combined were significantly associated with early complete vertigo remission at two weeks post-treatment. In the multivariate analysis, the minimal coherent frequency among the three SCCs emerged as an independent factor (hazard ratio [HR] 2.040, 95% confidence interval [CI] 1.776-2.304). At two months post-treatment, in addition to the previously significant parameters, vestibulo-ocular reflex (VOR) abnormality in the posterior SCC, gains in the horizontal and posterior SCCs, total and overt saccades in the horizontal SCC, coherent frequency in the anterior SCC, and mean VOR gain of all three SCCs combined were also statistically significantly related to total vertigo relief. The greater minimal coherent frequency among the three SCCs was a strong factor contributing to earlier relief of vertigo in patients with SSNHLV. Coherence analysis in vHIT may be more sensitive than time series analysis for evaluating vertigo prognosis prediction.

Determination of Recovery by Total Restitution or Compensation Using Multifrequency Vestibular Tests and Subjective Functional Scales in a Human Model of Vestibular Neuritis

Background: Vestibular Neuritis (VN) can induce unilateral acute vestibular syndrome (AVS). This study aimed to identify predictive factors of recovery from vestibular neuritis considering total restitution and/or compensation. Methods: In this longitudinal study, 40 patients were included. The initial assessment, performed within 36 to 72 h from the onset (T0), included medical history taking (general and specific), including screening for cardiovascular risk factors (CVRFs), and a battery of diagnostic vestibular tests, comprising the bithermal caloric test (BCT), video head impulse test (VHIT), and skull vibration-induced nystagmus (SVIN) test. All patients also completed a Dizziness Handicap Inventory (DHI). All assessments were repeated 90 ± 15 days later (T3). Subjective compensation criteria were based on the DHI total score, and objective compensation criteria were based on laboratory test results. Four groups of patients (A, B, C, D) were delineated by combining patients with normal vs. abnormal vestibular tests and patients with normal vs. abnormal DHI. Results: CVRFs (but not age or body mass index (BMI)) were associated with a poorer recovery of symptoms. The BCT (lateral semicircular canal paresis %), VHIT (lateral semicircular canal gain), and SVINT (nystagmus slow phase velocity) recovered to normal values in 20%, 20%, and 27% of patients, respectively, at T3. Conclusions: Vascular risk factors (hypercholesterolemia) are correlated with patients who do not recover their symptoms via either total restitution or compensation. There was no significant difference between high- and low-frequency vestibular tests in patients recovering from their symptoms. Some patients with objective recovery may continue to have persistent subjective symptoms.

When the Jugular Bulb Contacts the Facial Nerve.

Dehiscences of the intrapetrous canal of the facial nerve (FN) and those of a high jugular bulb (HJB) have various incidences. However, the HJB-FN common dehiscent osseous wall is a scarce finding and rarely reported. Thus, this work aimed to study this peculiar intrapetrous morphology on computed tomograms (CTs). A batch of 60 archived CTs was used. In 28.33% of cases, no HJBs were found; in 51.67% of cases, there were unilateral HJBs, and in 20% of cases, bilateral HJBs were found. 83.87% of the unilateral HJBs were on the right side, and the rest on the left side. In 3 cases with right-sided HJBs, 1 male and 2 females, FNs were found directly contacting the HJB. Therefore, the contact HJB-FN occurred in 5% of cases and 2.5% of the petrous bones/sides. HJBs' dehiscences to the retrotympanum or the posterior cranial fossa were also found in those cases. A dehiscent posterior semicircular canal to the HJB was found in one of these. Incidences for the HJB and the HJB-FN contacts seem higher than in previous studies. However, as only a 60-case batch of study was used, an overestimation may have resulted. Although scarce, the HJB-FN contact could determine specific symptoms and must be documented before specific surgical procedures involving the mastoid, retrotympanum, and posterior cranial fossa.

Retrolabyrinthine approach to the lateral skull base: The value of preoperative temporal bone CT analysis

PurposeThe most used neurosurgical approach to reach cerebellar-pontine angle is the retrosigmoid route. This article describes the presigmoid approach which requires excellent knowledge of the labyrinthine block together with quantitative analysis of temporal bone CT. MethodsCT-based quantitative measurements were obtained in patients undergoing vestibular neurectomy with a presigmoid approach. Eighteen patients were enrolled, and five measures were taken: Trautmann’s area, the petro-clival angle, presigmoid dura length and its angle. The relationship between these measurements and hospitalization days, operating times, and complications was explored. ResultsThe posterior semicircilar canal (PSC)-sigmoid sinus (SS) distance, presigmoid dura- internal auditory canal (IAC)-PSC angle, and duration of surgery are predictors of complications. Specifically, a PSC-sigmoid sinus distance <11 mm, a dura presig-IAC-PSC angle <14 are associated with the highest risk of complications. ConclusionPreoperative temporal bone CT scan can guide the surgeon through the narrowest areas of the surgical approach. Trautmann’s triangle area and petro-clival angle reduction are challenging and can be faced with combined microscopic-endoscopic technique, and with optics angulation-rotation. The retrolabyrinthine approach can enable hearing preservation and minimal cerebellar retraction.

Endocranial morphology of three early-diverging ceratopsians and implications for the behavior and the evolution of the endocast in ceratopsians

Abstract Ceratopsian dinosaurs underwent great changes, including a shift of locomotion mode, enlarged horns and frills, and increased body size. These changes occur alongside the evolution of endocranial morphology and physiology such as the size and shape of the flocculus, hearing range, olfactory ratio, and the reptile encephalization quotient (REQ). However, the evolution of endocranial structures in early ceratopsians is still unclear because of a lack of information on the earliest ceratopsians. Here, we reconstructed the endocasts of three early-diverging ceratopsians including the Late Jurassic Yinlong, and the Early Cretaceous Liaoceratops and Psittacosaurus. These ceratopsians display obvious flocculi, large and separate olfactory bulbs, long and high anterior semicircular canals, and relatively long cochlear ducts. In the evolution of the earliest ceratopsians to early neoceratopsians, changes include the increasing size of the flocculus (which is reduced or absent in late-diverging ceratopsids), the attenuation of the semicircular canals, and the heightening of the anterior semicircular canal (which is shortened in late-diverging ceratopsids). The endocranial structures suggest early-diverging ceratopsians had a higher olfactory acuity and were adapted to hearing higher frequencies than late-diverging ceratopsians. Furthermore, the REQ suggests that Yinlong and Psittacosaurus were more highly encephalized than late-diverging ceratopsians and most extant reptiles. The angle of the lateral semicircular canal suggests that heads in ceratopsians display a transition from a forward posture to a more downward posture. Our new findings are significant for understanding the physiological changes during ceratopsian evolution and also have implications for the evolution of physiology in extant tetrapods.

Model of superior semicircular canal dehiscence: asymmetrical vestibular dysfunction induces reversible balance impairment.

Superior semicircular canal dehiscence (SSCD) is a vestibular-cochlear disorder in humans in which a pathological third mobile window of the otic capsule creates changes to the flow of sound pressure energy through the perilymph/endolymph. The primary symptoms include sound-induced dizziness/vertigo, inner ear conductive hearing loss, autophony, headaches, and visual problems. We have developed an animal model of this human condition in the Mongolian Gerbil that uses surgically created SSCD to induce the condition. A feature that is unique in this model is that spontaneous resurfacing of the dehiscence occurs via osteoneogenesis without a subsequent intervention. In this study, we completed our assessment of this model to include reversible asymmetrical vestibular impairments that interfere with balance. Adult Mongolian gerbils (N = 6) were trained to complete a balance beam task. They were also trained to perform a Rotarod task. After 10 days of training, preoperative ABR and c+VEMP testing was followed by a surgical fenestration of the left superior semicircular canal. Balance beam testing recommenced at postoperative day 6 and continued through postoperative day 15 at which point final ABR and c+VEMP testing was carried out. Behavioral comparison of preoperative and postoperative performance show a significant decrease in Rotarod performance, increased rates of falling, and an increase in time to cross the balance beam. Impairments were the most significant at postoperative day 7 with a return toward preoperative performance by postoperative day 14. This behavioral impairment was correlated with residual impairments to auditory thresholds and vestibular myogenic amplitudes at postoperative day 14. These results confirm that aberrant asymmetric vestibular output in our model of SSCD results in reversible balance impairments. The level of these behavioral impairments is directly correlated with severity of the vestibular dysfunction as we have previously reported for peripheral ear physiology and cognition.

Specific features of bilateral otolith manifestations in patients with vestibular balance disorder

Bilateral asymmetry in the function of the semicircular canals underlies dizziness and vestibular balance disorders. According to the traditional view, otolith dysfunction does not have a significant effect on the clinical picture in individuals with peripheral vestibular disorders. In recent years, interest in studying the contribution of vestibular function to the control of posture and movements has increased. However, we have not identified any studies addressing the reactivity of otolith organs in vestibular balance disorders in the available literature.Aim: To study bilateral otolith reactions in patients with vestibular balance disorders using the method of cervical vestibular evoked myogenic potentials (cVEMP) in patients with episodic and chronic vestibular disorders.Material and Methods. A clinical examination was carried out in 63 patients complaining of dizziness and balance problems. They were hospitalized on an emergency and planned basis in the neurological departments of the clinics of the Siberian State Medical University and the Medical and Sanitary Unit No 2 in Tomsk. From the total group, 28 patients (8 men and 20 women aged from 22 to 84 years) were selected for assessment of vestibular function; the average age was 63.87 ± 11.52 years and 57.2 ± 18.5 years for men and women respectively. They had chronic and episodic vestibular dysfunction unrelated to acute or progressive neurological disease and inflammatory pathology of the inner ear.Results. 27 patients (96.4%) complained of dizziness. Systemic dizziness, characterized by a feeling of objects rotating around the subject, was detected in 29.63% of patients; non-systemic dizziness, including a feeling of “failing” – in 81.48%. Both types of complaints appeared in 10.71% of those examined, which made it possible to identify 2 groups of patients: Group A – with chronic vestibular disorders (7 patients) and Group B – with episodic vestibular disorders (21 patients). During the study of the groups of patients, differences were found in the amplitudes of cVEMP latency P13 and the coefficient of vestibular asymmetry between Groups A and B, as well as the absence of a difference in amplitudes in Group A and the presence of a difference in Group B on the right.Conclusion. Despite the fact that patients presented with predominantly one complaint of dizziness, clinical and instrumental tests of vestibular dysfunction showed the presence of damage to both the semicircular canals and otolithic organs; asymmetry of vestibular reflexes and/or bilateral damage to the vestibular organs. The results of the study allow us to consider the cVEMP method as one of the methods for objectively assessing the condition of the otolithic apparatus in patients with impaired vestibular function. In this regard, it is recommended to use this method in routine neurological practice.

Revised Classification of Inner Ear Schwannomas.

Over the past two decades, there has been increasing interest in the diagnosis and management of schwannomas of the inner ear including hearing rehabilitation with cochlear implants. However, tumor nomenclature and classification within the literature have been variable and oftentimes cumbersome. The term "intralabyrinthine schwannoma" is in common use when describing these tumors but is a potential source of confusion given that people often use the term "labyrinth" or "labyrinthine" to refer to the vestibular component of the inner ear only (i.e., labyrinthectomy or the translabyrinthine approach).During the Ninth Quadrennial Conference on Vestibular Schwannoma and Other Cerebellopontine Angle Lesions in Bergen, Norway, in May 2023, a multidisciplinary group of conference participants met and discussed issues pertaining to current terminology and classifications to enhance clarity and to reflect recent advances in tumor management and hearing rehabilitation.Although a variety of terms have been previously used to describe inner ear schwannomas, consensus was achieved on the term "inner ear schwannoma (IES)" to describe eighth nerve schwannomas of the cochlea, vestibule, or semicircular canals. Subgroups under this term comprise intravestibular, intracochlear, or intravestibulocochlear inner ear schwannomas (low complexity tumors), inner ear schwannomas with transfundal extension into the internal auditory canal but without modiolar involvement (intermediate complexity tumors), and inner ear schwannomas with transfundal extension with modiolar involvement (high complexity tumors).The details of the recommendations for an updated and simplified tumor nomenclature centered around tumor control and hearing rehabilitation with cochlear implantation are presented.

Minor's Syndrome or Dehiscence of the Superior Semicircular Canal: A Case Report

Semicircular canal dehiscence is a congenital syndrome that mainly affects the superior and, less commonly, the posterior semicircular canal in the temporal bone. This syndrome was first reported by Minor et al. in 1998. The prevalence is about 0.5% in the general population. The most characteristic symptom is the Tullio phenomenon, predominantly vertigo and nystagmus. Hearing loss (in particular conductive loss) often completes overall clinical picture. The dehiscence may be completely asymptomatic, in which case it is seen as an incidental finding on radiological investigations. Audiological evaluation includes audiometry and vestibular evoked myogenic potentials (VEMPs). Clinical symptoms are based on the pathophysiological concept of a third mobile window within the inner ear. Diagnosis is confirmed by high resolution petrous temporal bone CT with multiplanar reconstructions (MPRs) in the plane of the canal (Pöschls’ plane for the superior semicircular canal) and 3-D surface reconstructions. MR findings are less sensitive for this entity. The most common differential diagnosis is otosclerosis. Clinical–radiological correlations have therapeutic applications even though the indication for surgery depends on the severity of the vestibular symptoms.

The Impact of Sleep Deprivation on Video Head Impulse Test Results.

To investigate the association between sleep deprivation and vestibular dysfunction by Video Head Impulse Test (vHIT). This prospective clinical trial explores the impact of acute sleep deprivation on the vestibular-ocular reflex (VOR) in medical residents. The study involved healthy physicians from diverse medical disciplines. Participants underwent vHIT assessments before and after a 26-h shift. The examinations focused solely on the right lateral semicircular canal. Participants further completed a demographics and fatigue questionnaire, including the Fatigue Severity Scale (FSS) questionnaire and a Visual Analog Fatigue Score (VAFS). The study involved 30 medical residents. Participants experienced a statistically significant decrease in VOR gain in the right horizontal semicircular canal during a 26-h shift (p < 0.01). While the FSS and VAFS questionnaires showed no significant difference before and after the shift, the analysis of ∆VOR gain indicated a statistically significant increase associated with decreased sleep time during the shift (p = 0.018, 95% Confidence Interval [0.08, 0.68]). The most substantial increase in ∆VOR occurred between 22-26 h of sleep deprivation. No significant differences were observed in ∆VOR between genders, ages, disciplines, department shifts versus emergency room shifts, or years of residency. vHIT can be used as an objective, reliable screening tool for severe sleep deprivation among physicians. The decrease in the VOR gain may indicate that vestibular function is influenced by sleep deprivation. The clinical significance of these findings is still questioned, more studies may help to assess this effect. 3 Laryngoscope, 2024.

Automated volumetric analysis of the inner ear fluid space from hydrops magnetic resonance imaging using 3D neural networks

Due to the development of magnetic resonance (MR) imaging processing technology, image-based identification of endolymphatic hydrops (EH) has played an important role in understanding inner ear illnesses, such as Meniere’s disease or fluctuating sensorineural hearing loss. We segmented the inner ear, consisting of the cochlea, vestibule, and semicircular canals, using a 3D-based deep neural network model for accurate and automated EH volume ratio calculations. We built a dataset of MR cisternography (MRC) and HYDROPS-Mi2 stacks labeled with the segmentation of the perilymph fluid space and endolymph fluid space of the inner ear to devise a 3D segmentation deep neural network model. End-to-end learning was used to segment the perilymph fluid and the endolymph fluid spaces simultaneously using aligned pair data of the MRC and HYDROPS-Mi2 stacks. Consequently, the segmentation performance of the total fluid space and endolymph fluid space had Dice similarity coefficients of 0.9574 and 0.9186, respectively. In addition, the EH volume ratio calculated by experienced otologists and the EH volume ratio value predicted by the proposed deep learning model showed high agreement according to the interclass correlation coefficient (ICC) and Bland–Altman plot analysis.

Benign paroxysmal positional vertigo: diagnosis, treatment, rehabilitation. Current concepts on the role of betahistine in the complex treatment of patients with benign paroxysmal positional vertigo

The treatment of patients with benign paroxysmal positional vertigo (BPPV) is an urgent issue in modern medicine.Expert Council on the diagnosis and treatment of BPPV was held in Moscow on June 1, 2024. Timely diagnosis and effective treatment play a key role in the management of patients with BPPV, reduce the risk of falls and related injuries, prevent the development of emotional disorders and impairment of daily activities. Accurate patient routing and selection of appropriate treatment can significantly reduce the duration of disability and the burden on the healthcare system. Relatively simple positional tests aimed at detecting involvement of various semicircular canals have been found to be of paramount importance in the diagnosis of BPPV. Repositioning maneuvers are of paramount importance in the treatment of patients with BPPV. They vary depending on the canal affected and aim to move the otoliths out of the semicircular canals to the vestibule of the labyrinth. If repositioning maneuvers can not be performed, effective methods of vestibular gymnastics can be used. When discussing drug therapy, it was found that the use of betahistine in addition to repositioning maneuvers or vestibular gymnastics increases the efficacy of therapy, accelerates the recovery process and prevents the development of residual non-positional vertigo.

Spike-based rotation detection using a self-powered triboelectric sensor with mimicry of a vestibular system

The biological vestibular system in semicircular canals detects head rotation with high energy efficiency through its unique spike-based processing. We propose a self-powered vestibular sensory neuron inspired by the biological vestibular system and utilizing a triboelectric nanogenerator (TENG) as a rotation sensor and a neuron transistor (neuristor) as a spiking neuron. This artificial vestibular neuron simultaneously detects the angular velocity and encodes it into spikes. When the angular velocity that is applied to the TENG increases, the spiking frequency increases, and this is a desired property of the vestibular neuron. Therefore, the vestibular neuron can serve as an input neuron in a spiking neural network (SNN). We also demonstrate a fully hardware-based neuromorphic system that is attractive for its improved energy efficiency to recognize rotation axes. Compared to a vestibular system based on conventional von-Neumann computing, that based on the proposed neuromorphic computing can effectively reduce power consumption by adopting spike transmission and employing the self-powered sensor. The proposed system is promising for applications related to rotation that demands high energy-efficiency.