Otolith Research Articles

The otolith vermis: A systems neuroscience theory of the Nodulus and Uvula.

The Nodulus and Uvula (NU) (lobules X and IX of the cerebellar vermis) form a prominent center of vestibular information processing. Over decades, fundamental and clinical research on the NU has uncovered many aspects of its function. Those include the resolution of a sensory ambiguity inherent to inertial sensors in the inner ear, the otolith organs; the use of gravity signals to sense head rotations; and the differential processing of self-generated and externally imposed head motion. Here, I review these works in the context of a theoretical framework of information processing called the internal model hypothesis. I propose that the NU implements a forward internal model to predict the activation of the otoliths, and outputs sensory predictions errors to correct internal estimates of self-motion or to drive learning. I show that a Kalman filter based on this framework accounts for various functions of the NU, neurophysiological findings, as well as the clinical consequences of NU lesions. This highlights the role of the NU in processing information from the otoliths and supports its denomination as the “otolith” vermis.

Vestibular and balance function in veterans with chronic dizziness associated with mild traumatic brain injury and blast exposure.

The purpose of this study was to examine vestibular and balance function in individuals with chronic dizziness associated with mTBI/blast. A prospective case-control study design was used to examine ocular motor, vestibular function, and postural stability in veterans with symptoms of dizziness and/or imbalance following an mTBI or blast exposure (n = 77) and a healthy control group (n = 32). Significant group differences were observed for saccadic accuracy, VOR gain during slow harmonic acceleration at 0.01 Hz, cervical vestibular evoked myogenic potentials asymmetry ratio, composite equilibrium score on the sensory organization test, total Dynamic Gait Index score, and gait. The frequency of test abnormalities in participants with mTBI/blast ranged from 0 to 70% across vestibular, ocular motor, and balance/gait testing, with the most frequent abnormalities occurring on tests of balance and gait function. Seventy-two percent of the mTBI/blast participants had abnormal findings on one or more of the balance and gait tests. Vestibular test abnormalities occurred in ~34% of the individuals with chronic dizziness and mTBI/blast, and abnormalities occurred more frequently for measures of otolith organ function (25% for cVEMP and 18% for oVEMP) than for measures of hSCC function (8% for SHA and 6% for caloric test). Abnormal ocular motor function occurred in 18% of the mTBI/blast group. These findings support the need for comprehensive vestibular and balance assessment in individuals with dizziness following mTBI/blast-related injury.

The use of vestibular evoked myogenic potentials (VEMP) in the diagnosis of otolithic dysfunction of patients with obstructive sleep apnea: a survey of awareness and recognition of otorhinolaryngology medical staffs.

To assess awareness and recognition of vestibular function tests in otorhinolaryngology medical staffs, especially the vestibular evoked myogenic potentials (VEMP) testing in patients with obstructive sleep apnea (OSA). A survey was delivered via either email or a social media app. The medical staffs of the Chinese Medical Association of Otolaryngology Head and Neck Surgery from various branches were enrolled. Study data were collected and managed with an online data collection tool. A total of 1781 emails and 623 social media messages were sent to 2404 otorhinolaryngology medical staffs. One hundred and fifty-seven of them participated in the survey, including 24 via emails and 133 via the social media app. Regarding the knowledge of VEMP, only 59 (37.6%) of them agreed that OSA could be related to vertigo/dizziness/imbalance and 28 (17.8%) believed that OSA could result in VEMP abnormalities and would factor this in diagnosing the impairment of the vestibular function of OSA patients. A total of 7.6% of the respondents had never heard of the VEMP tests. Responses regarding the minimum age at which VEMP are possible ranged from younger than 6months to greater than 18years of age. Beliefs regarding the utility and reliability of VEMP varied, with 'unsure' being the most frequent response. In addition, only 17.8% of otolaryngologists indicated some access to the VEMP test. Knowledge and beliefs about the role of VEMP in diagnosing otolithic organ dysfunction caused by OSA in otorhinolaryngology vary widely. It is important for otorhinolaryngology medical staffs to learn the latest literatures and updated knowledge through continuing education.

High frequency hearing loss may act as a screening index evaluating otolith function in vertigo patients with normal semi-circular canal function.

ObjectiveTo investigate whether otolith dysfunction is related to hearing impairment in vertigo patients with normal semicircular canal function, and to clarify the types of hearing impairment that may be related to otolith organ damage.MethodsThe demographic data, pure tone threshold audiometry (PTA) results (air-conduction), data of bithermal and video-head impulse test (vHIT), and vestibular evoked myogenic potential (VEMP) results (reaction threshold, P1–N1 amplitude) of patients with vertigo in outpatient clinic from April 2017 to January 2020 were collected. The clinical records of 51 vertigo patients with normal semicircular canal function were included in this study. Low-frequency, speech-frequency, high-frequency, full-frequency PTA were defined as the average of PTA in different frequency bands, respectively (low: 0.125, 0.25, 0.5 kHz; speech: 0.5, 1, 2 kHz, high: 4, 8 kHz, full 0.125–8 kHz). The correlations between hearing impairment in different frequency bands and otolith function impairment were analyzed.ResultsThe mean thresholds of 51 patients (102 ears) in low-PTA, speech-PTA, high-PTA, full-PTA were 20.95 ± 6.01, 21.92 ± 6.90, 40.12 ± 17.47, 26.97 ± 8.53 dB nHL, respectively. Among 102 ears, 87 ears (85.3%) could elicit c-VEMP waveforms and 65 ears (63.7%) had o-VEMP waveforms. The mean threshold and P1–N1 amplitude of c-VEMP were 83.10 ± 6.96 dB nHL and 176.79 ± 103.10 uV, while those of o-VEMP were 87.92 ± 5.99 dB nHL and 21.45 ± 32.22 uV. The mean threshold in high-PTA was significantly linearly correlated with c-VEMP threshold (P = 0.01) and P1–N1 amplitude (P = 0.028). There were not significant linear correlations between the mean threshold in each frequency band of PTA and o-VEMP threshold (low-PTA: P = 0.266, speech-PTA: P = 0.33, high-PTA: P = 0.311) or P1–N1 amplitude (low-PTA: P = 0.414, speech-PTA: P = 0.069, high-PTA: P = 0.08).ConclusionsThere is a positive linear correlation between saccule dysfunction and high-frequency hearing impairment in vertigo patients with normal semi-circular canal function. High frequency hearing loss can be expected in patients who have saccular damage. It suggests that high frequency hearing loss in PTA may act as a screening index that otolith organ function should be comprehensively evaluated.

The correlation between the body shape and otolithic function in patients with obstructive sleep apnea

ObjectiveTo identify the typical pattern of changes of vestibular-evoked myogenic potentials (VEMPs) and explore the relationship between VEMPs and the anthropometry factors in patients with obstructive sleep apnea (OSA). MethodsPatients diagnosed as OSA after overnight polysomnography (PSG) tests were enrolled as the study group. Healthy volunteers were recruited as the control group. Anthropometry data of the body shape and VEMPs results were collected completely. The correlation analysis was conducted among those parameters. ResultsForty-nine patients with OSA who were diagnosed in the Therapy Center of Sleep-disordered Breathing in our hospital and sex- and age-matched healthy controls as well. Significant changes in ocular and cervical VEMPs (oVEMP and cVEMP) in the study group were observed, which were reduced response rates, elevated thresholds, decreased amplitudes, and prolonged first wave latencies. In oVEMP, the first wave (n1) latency was significantly correlated with weight, body mass index (BMI), neck circumference, waist circumference, hip circumference, and apnea hypopnea index (AHI). In a tentative application, combined use of BMI and oVEMP n1 latency increased the detection rate during OSA screening prior to PSG. ConclusionOSA can negatively affect function of otolithic organs and their pathways. The first wave latency of the VEMPs waveform may be another important parameter to define peripheral nervous system lesions caused by systemic diseases as OSA.

Clinical characteristics of vestibular evoked myogenic potentials in children with recurrent vertigo of childhood

ObjectiveTo explore the possible pathogenesis of recurrent vertigo of childhood (RVC) and the clinical diagnosis value of vestibular-evoked myogenic potentials (VEMPs). MethodsThe clinical data of 19 children (5.95 ± 0.38 years) diagnosed with RVC and 17 normal children (5.35 ± 0.31 years) enrolled in the control (NC) group from April 2017 to February 2021 was collected and analyzed. All subjects were tested for both cervical VEMP (cVEMP) and ocular VEMP (oVEMP). The elicit rate, thresholds, N1 latency, P1 latency, interval, amplitude, and amplitude asymmetry ratio (AAR) of VEMPs were compared and analyzed between the two groups. Results(1) The elicit rates of cVEMP and oVEMP have no significant difference between the two groups (P > 0.05). (2) The thresholds of cVEMP and oVEMP in the RVC group were higher than that in the NC group (P < 0.05). (3) The N1 latency of cVEMP in the RVC group was longer than that in the NC group (P < 0.05). The P1 latency of cVEMP and latencies of oVEMP have no significant difference between the two groups (P > 0.05). (4) The interval of cVEMP in the RVC group was longer than that in the NC group (P < 0.05), while the interval of oVEMP has no significant difference between the two groups (P > 0.05). (5) The amplitude of cVEMP in the RVC group was higher than that in the NC group (P < 0.05), while the amplitude of oVEMP was similar in the two groups (P > 0.05). (6) The AAR values of oVEMP and cVEMP were similar in the two groups (P > 0.05). ConclusionsThe elicit rates of VEMPs in children with RVC did not differ from that of normal children, but the thresholds were all increased, suggesting reduced sensitivity of the otolith organ and vestibular nerve conduction pathways. The P1 latency of cVEMP was normal in children with RVC, but N1 latency and interval of cVEMP were increased, we finally reached a conclusion that there might be potential impairment in the inferior vestibular nerve and the subsequent nerve conduction pathway in RVC.

Response of toadfish (Opsanus tau) utricular afferents to multimodal inputs.

The inner ear of teleost fishes is composed of three paired multimodal otolithic end organs (saccule, utricle, and lagena), which encode auditory and vestibular inputs via the deflection of hair cells contained within the sensory epithelia of each organ. However, it remains unclear how the multimodal otolithic end organs of the teleost inner ear simultaneously integrate vestibular and auditory inputs. Therefore, microwire electrodes were chronically implanted using a 3-D printed micromanipulator into the utricular nerve of oyster toadfish (Opsanus tau) to determine how utricular afferents respond to conspecific mate vocalizations termed boatwhistles (180 Hz fundamental frequency) during movement. Utricular afferents were recorded while fish were passively moved using a sled system along an underwater track at variable speeds (velocity: 4.0-12.5 cm/s; acceleration: 0.2-2.6 cm/s2) and while fish freely swam (velocity: 3.5-18.6 cm/s; acceleration: 0.8-29.8 cm/s2). Afferent fiber activities (spikes/s) increased in response to the onset of passive and active movements; however, afferent fibers differentially adapted to sustained movements. In addition, utricular afferent fibers remained sensitive to playbacks of conspecific male boatwhistle vocalizations during both passive and active movements. Here, we demonstrate in alert toadfish that utricular afferents exhibit enhanced activity levels (spikes/s) in response to behaviorally relevant acoustic stimuli during swimming.NEW & NOTEWORTHY The inner ear of teleost fishes is composed of three paired multimodal otolithic end organs, which are sensitive to vestibular and auditory inputs. Previous studies investigating inner ear functions have primarily focused on the effects of unimodal stimuli; therefore, it remains unclear how otolithic end organs simultaneously encode multiple stimuli. Here, we show that utricular afferents remain sensitive to behaviorally relevant acoustic stimuli during swimming.

Low 25-Hydroxyvitamin D Levels Are Associated With Residual Dizziness After Successful Treatment of Benign Paroxysmal Positional Vertigo.

Objective:Vitamin D (Vit D) regulates calcium and phosphate metabolism and helps to maintain otolith organ function. Residual dizziness (RD) is one of the most common complications after the successful treatment of benign paroxysmal positional vertigo (BPPV). Various theories have been suggested to explain the cause of RD, and otolith organ disorder is the most evident cause of RD. This study aimed to investigate the association between serum levels of Vit D and the occurrence of RD after the successful treatment of BPPV.MethodsA prospective study including patients who were diagnosed with de novo posterior semicircular canal-type BPPV (PC-BPPV) was conducted at our institution from May 2017 to May 2019. All the patients underwent canalith repositioning procedures and were followed up. Univariate and multivariate analyses were performed to investigate the relationship between serum 25-hydroxy vitamin D (25(OH)D) levels and RD occurrence after successful BPPV treatment.ResultsIn total, 123 patients with PC-BPPV were enrolled, and 41.5% (51/123) experienced RD. The serum level of 25(OH)D was significantly lower in PC-BPPV patients with RD [median 16.2 ng/ml (IQR 12.9–22.1)] than in patients without RD [median 20.5 ng/ml (IQR 16.5–26.5)] (P = 0.001). In multivariate models comparing the prevalence of RD in the insufficient group [25(OH)D ≥ 20 to <30 ng/ml], deficient group [25(OH)D < 20 ng/ml] and normal group [25(OH)D ≥ 30 ng/ml], the 25(OH)D levels in the deficient group were associated with the occurrence of RD (odds ratio = 5.48, 95% confidence interval = 1.08–27.71; P = 0.04).ConclusionLow 25(OH)D levels are associated with the development of RD in patients with PC-BPPV after successful treatment. Further efforts to validate and elucidate the mechanism are needed.

A New Vestibular Stimulation Mode for Motion Sickness With Emphatic Analysis of Pica.

Motion sickness (MS) was frequently introduced for rodents in research work through passive motion that disturbed vestibular signals in the presence of visual and aleatory, proprioceptive inputs. Inducement of MS in this way causes conflicting signals that activate intermixed neural circuits representing multimodal stimulation. From reductionism, a lab setup to elicit rat MS via vestibular stimulation was configured in the present study for MS study in connection with dissection of the central vestibular component causally underlying MS. The individual animal was blinded to light with a custom-made restrainer, and positioned at an inclination of 30° for otolith organs to receive unusual actions by gravitoinertial vector. Following a 2-h double-axis (earth–vertical) rotation involving angular acceleration/deceleration, a suit of behaviors characterizing the MS was observed to be significantly changed including pica (eating non-nutritive substance like kaolin), conditioned taste avoidance and locomotion (p < 0.05). Notably, for the statistical hypothesis testing, the utility of net increased amount of kaolin consumption as independent variables in data processing was expounded. In addition, Fos-immunostained neurons in vestibular nucleus complex were significantly increased in number, suggesting the rotation-induced MS was closely related to the vestibular activation. In conclusion, our work indicated that the present setup could effectively elicit the MS by disturbing vestibular signals in rat in the context of well-controlled proprioceptive inputs and lack of visual afference.

Unraveling the labyrinth of our balance system: Visualizing bony otolith organ structure through novel 3D modeling

The organs of balance, the semicircular canals (SCCs) and otolith organs (utricle and saccule) of the inner ear labyrinth, are essential to basic human movement and function. While the SCCs (both external and internal structure) are well visualized and understood, the seemingly vague bony structure of the utricle and saccule remains largely unexplored. Consequently, relationships between this bony structure and the internal otolith organs themselves remain unknown. As a result, a comprehensive understanding of the morphology of our balance organs and relationships to function has eluded us.As a first step to understand the relationships of the utricle and saccule (that is the membranous otolith organs responsible for detecting linear motion) to their external bony coverings, we have developed a morphometrically‐based modelling system to visualize bony otolith organ structure. The indeterminate shape of this capsule has precluded a standard metric approach to capture such relationships. Our method combines osmium tetroxide contrast enhanced micro‐computed tomography (μCT) imaging of human temporal bones (n=13), digital visualizations, and landmark‐based 3D shape analyses of bony and membranous structure. This was done in order to: 1) test the hypothesis that the bony form surrounding the otolith organs covaries with internal membranous anatomy (including the utricle and saccule); and 2) pinpoint specific arrangements of landmarks on the bone that best reflect the internal structure of the utricle and saccule. This approach allows us to extract the bony otolith organ structure from an otherwise nebulous bony form.Tests of integration on 3D shape data between bony and membranous tissue demonstrate a significant association between the hard and soft tissues of the otolith organs (p&lt;0.05). Relative orientation of the otolith organs also significantly correlates with surrounding bony structure (p&lt;0.005). These data support our initial hypothesis and inform the creation of our 3D visualization of human otolith organ structure, establishing the configuration of the otolith organs to bony structure of the labyrinth. Furthermore, this model enhances our understanding of spatial relationships between the otolith organs and cranial structure and provides the foundation to assess the evolution of a prime sensory system essential for providing a gravitational frame of reference for all vertebrate life.

Differential Activation of Canal and Otolith Afferents by Acoustic Tone Bursts in Rats.

Vestibular evoked myogenic potentials (VEMPs) are routinely used to test otolith function, but which specific vestibular afferent neurons and central circuits are activated by auditory frequency VEMP stimuli remains unclear. To examine this question, we analyzed the sensitivity of individual vestibular afferents in adult Sprague-Dawley rats to tone bursts delivered at 9 frequencies (125-4000Hz) and 3 intensity levels (60, 70, 80dB SL re: acoustic brainstem response (ABR) threshold). Afferent neuron tone sensitivity was quantified by the cumulative probability of evoking a spike (CPE). Based on a threshold CPE of 0.1, acoustic stimuli in the present study evoked responses in 78.2 % (390/499) of otolith afferent neurons vs. 48.4 % (431/891) of canal afferent neurons. Organ-specific vestibular inputs to the central nervous system in response to tone bursts differ based on intensity and frequency content of the stimulus. At frequencies below 500Hz, tone bursts primarily activated both otolith afferents, even at the highest intensity tested (80dB SL re ABR threshold). At 1500Hz, however, tone bursts activated the canal and otolith afferents at the moderate and high intensities tested (70, 80dB SL), but activated only otolith afferents at the low intensity tested (60dB SL). Within an end organ, diversity of sensitivity between individual afferent neurons correlated with spontaneous discharge rate and regularity. Examination of inner ear fluid mechanics in silico suggests that the frequency response and preferential activation of the otolith organs likely arise from inner ear fluid motion trapped near the oval and round windows. These results provide insight into understanding the mechanisms of sound activation of the vestibular system and developing novel discriminative VEMP testing protocols and interpretative guidelines in humans.

Uneven Effects of Sleep Apnea on Semicircular Canals and Otolithic Organs.

ObjectiveThis study aimed to explore how obstructive sleep apnea (OSA) affects the function of each vestibular organ and to identify the correlations among them.MethodsA prospective study was conducted involving 32 healthy controls and 64 patients with OSA. The objective detection methods of the utricle and saccule are vestibular-evoked myogenic potentials (VEMPs). A combination of the caloric test and video head impulse test (vHIT) was used to comprehensively evaluate the objective function of semicircular canals.ResultsElevated thresholds (p < 0.001), decreased waveform amplitudes (p < 0.001), prolonged first wave latencies (p < 0.001), and shortened first interpeak latencies (p < 0.001) were observed in both ocular VEMP (oVEMP) and cervical VEMP (cVEMP). A significant difference was found in the caloric test comparison (χ2 = 4.030, p = 0.045) but not in the vHIT. The intergroup comparison of normal rates among the VEMPs, caloric test, and vHIT groups showed a significant difference (p < 0.001).ConclusionThe impairment of vestibular function in patients with OSA was uneven and biased. More attention should be given to vestibular dysfunction in the diagnosis and treatment of OSA.

Nonlinearity in bone-conducted amplitude-modulated cervical vestibular-evoked myogenic potentials: harmonic distortion products.

Otolith organs of the balance system, the saccule and utricle, encode linear acceleration. Integrity of the saccule is commonly assessed using cervical vestibular-evoked myogenic potentials (cVEMPs) arising from an inhibitory reflex along the vestibulospinal pathway. Conventional approaches to eliciting these responses use brief, transient sounds to elicit onset responses. Here we used long-duration amplitude-modulated (AM) tones to elicit cVEMPs (AMcVEMPs) and analyzed their spectral content for evidence of nonlinear processing consistent with known characteristics of vestibular hair cells. Twelve young adults (ages 21-25) with no hearing or vestibular pathologies participated in this study. AMcVEMPs were elicited by bone-conducted AM tones with a 500-Hz carrier frequency. Eighteen modulation frequencies were used between 7 and 403 Hz. All participants had robust distortion products at harmonics of the modulation frequency. Total harmonic distortion ranged from approximately 10 to 80%. AMcVEMPs contain harmonic distortion products consistent with vestibular hair cell nonlinearities, and this new approach to studying the otolith organs may provide a noninvasive, in vivo method to study nonlinearity of vestibular hair cells in humans.NEW & NOTEWORTHY The otolith balance organs of humans are assessed for basic science and clinical applications by using vestibular-evoked myogenic potentials (VEMPs). Traditionally, VEMPs are elicited with brief, transient sounds to study onset responses. We used long-duration sounds to elicit steady-state VEMPs. This allowed us to measure nonlinear distortion products, consistent with nonlinear processing in vestibular hair cells. This new approach may help to better understand links between otolith organs and balance function.

Anatomy and Physiology of Vestibular System

A comprehensive understanding of vestibular anatomy and physiology is essential to interpreting and treating vestibular disorders. The otolithic organs and semicircular canals are the major components of the vestibular system. Each contains hair cells, mechanosensory cells responsible for converting mechanical signals produced by the body into electrical signals. Each hair cell produces a resting discharge rate. This rate can be increased or decreased as a result of head motion, with the magnitude of change dependent on the direction and strength of the motion. These signals are sent to the vestibulocochlear nerve which interprets and integrates the information with input from other sensory organs. The main role of the vestibular system is to maintain balance and detect angular and linear acceleration. Angular acceleration is detected by the semicircular canal via interpretation of endolymph flow caused by head movement. Linear acceleration is detected by the otolith organs through gravity-dependent otoconia movement. This article serves as a review for the structure and function of the major vestibular organs. This review contains, 9 figures, 1 table, and 8 references Keywords: Vestibular physiology, Hair cells, Otolith organs, Macule, Semicircular canals, Ampulla, Crista, Vestibulocochlear nerve, Angular acceleration, Linear acceleration

Galvanic vestibular-evoked myogenic potentials in evaluating damaged sites of vestibular neuritis.

ObjectivesTo test the possibility of pure otolithic organ deficits and validate the histopathological evidence of retrovestibular neural impairment in vestibular neuritis (VN), the authors adopted a topographic survey combining cervical vestibular‐evoked myogenic potential (cVEMP) and ocular vestibular‐evoked myogenic potential (oVEMP) using various stimulation modes and caloric tests.MethodsForty patients with VN were enrolled in this study. All patients underwent pure tone audiometry, acoustic cVEMP, galvanic cVEMP, vibratory oVEMP, galvanic oVEMP, and caloric tests. Different combinations of vestibular tests were further compared and analyzed.ResultsAccording to vestibular test results in affected VN ears, the proportion (10%) of pure saccular dysfunction was significantly less than that (52.5%) of saccular nerve deficit. The proportion (2.5%) of pure utricular dysfunction was significantly less than that (37.5%) of utricular nerve deficit. The percentage (82.5%) of VN involving the ampullar vestibulo‐ocular reflex (VOR) pathway was significantly higher than that (40%) involving the utriculo‐ocular reflex (UOR) pathway. The superior, inferior, and total VN percentages were 37.5%, 17.5%, and 45%, respectively. The proportion of inferior VN was significantly less than that of VN involving the superior vestibular nerve.ConclusionThere were significantly fewer cases of pure otolithic organ dysfunction than vestibular nerve involvement in VN patients. The damage to the ampullar VOR pathway was more significant than that to the UOR pathway, and both pathways might be independent of each other. In addition, the incidence of isolated inferior VN was significantly less than that of VN involving the superior vestibular nerve.Level of EvidenceLevel 3.

Differential Involvement of Lateral Semicircular Canal and Otolith Organs in Common Vestibular Disorders.

Semicircular canal and otolith functions came to be evaluated recently, but comprehensive and comparative analysis of canal and otolith dysfunction in common vestibular disorders is lacking. We aimed to analyze the abnormal rates of canal and otolith function in common vestibular disorders. We enrolled 302 patients who were managed for 2 months in a dizziness clinic. Results of caloric, video head impulse test (vHIT), and cervical and ocular vestibular evoked myogenic potential (cVEMP and oVEMP) tests were analyzed and compared among various diagnoses. Vestibular disorders diagnosed included recurrent vestibulopathy (RV, 27%), vestibular migraine (VM, 21%), benign paroxysmal positional vertigo (BPPV, 17%), Meniere's disease (MD, 11%), vestibular neuritis (VN, 10%), orthostatic dizziness (7%), and central lesions (3%). Lateral canal dysfunction was found most in VN (100%) and less commonly in definite MD (75%), RV (46%) and definite VM (29%). Abnormal caloric results were more common than abnormal vHIT in all disorders. Otolith dysfunction was found more frequently than lateral canal dysfunction in most vestibular disorders except VN. An abnormal cVEMP was more frequent in definite MD than the other disorders. Isolated otolith dysfunction without lateral canal dysfunction was the most found in BPPV, followed by definite VM, RV, and definite MD in decreasing order. Various patterns of involvement in canal and otoliths were revealed in vestibular disorders, suggesting different pathogenesis.

Objective vestibular function changes in children following cochlear implantation.

BACKGROUND:To date, systematically objective evaluations of vestibular function in children with cochlear implantation (CI) have been conducted sparsely, especially in children with large vestibular aqueduct syndrome (LVAS).OBJECTIVE:Our goal was to investigate the function of all five vestibular end-organs pre- and post-cochlear implantation in children with LVAS and normal CT.METHODS:In this retrospective cohort study, 34 children (age 4–17 years) with bilateral profound sensorineural hearing loss (SNHL) undergoing unilateral CI were included. Participants included 18 (52.9%) children with LVAS. Objective modalities to evaluate vestibular function included the caloric test, cervical vestibular-evoked myogenic potentials (cVEMP), ocular vestibular-evoked myogenic potentials (oVEMP), and video head impulse test (vHIT). All measurements were performed before surgery and 9 months after surgery.RESULTS:Mean age at CI was 8.1±3.7 years. Caloric testing showed hypofunction in 38.2% of cases before implantation and in 50% after (p > 0.05). We found a significant increase of overall abnormality rate in cVEMP and oVEMP from pre- to post-CI (p < 0.05). In all three semicircular canals tested by vHIT, there were no statistically significant mean gain changes (p > 0.05). Higher deterioration rates in cVEMP (53.3%) and oVEMP (52.0%) after surgery were observed (p < 0.05). In children with LVAS, cVEMP revealed a higher deterioration rate than superior semicircular canal (SSC) and posterior semicircular canal (PSC) (p < 0.05). In children with normal CT, the deterioration rates in VEMPs were both higher than those in vHIT (p < 0.05).CONCLUSIONS:In general, the otolith organs were the most affected peripheral vestibular sensors in children after cochlear implantation. The variations in otolith function influenced by CI were different between children with LVAS and normal CT. We recommend the use of this vestibular function test battery for children with cochlear implantation.

Efficacy of the subjective visual vertical test performed using a mobile application to detect vestibular pathology.

The subjective visual vertical (SVV) test is a sensitive test of vestibular dysfunction that allows the evaluation of otolithic organs; however, with the current method, there are technical and logistical limitations that make the application of this test difficult in the conventional clinic. The objective of this study is to assess the effectiveness of detecting vestibular pathology using the SVV via a new screening method. A consecutive sample of 62 patients with suspected vestibular pathology was included in the study. The patients were clinically diagnosed according to the Barany Society criteria. An exploratory system was designed using a mobile application in Android that detects accelerometer oscillations and involves placing the smartphone on a rotating disk anchored to the wall. All patients underwent a SVV examination using the bucket method and the study test. A cut-off point of the ROC curve was calculated for each test, and its sensitivity, specificity, diagnostic accuracy and probability ratios for detecting vestibular pathology were analysed. The SVV results were compared using the bucket test and the study test. We observed significant differences in sensitivity between the two tests: 86.95% for the study test versus 67.4% for the bucket test (p < 0.01). In the ROC curve, an area under the curve of 0.90 was observed for the study test, with a cut-off of 2.43 for a sensitivity of 86.95% and a specificity of 93.75%. SVV testing using a smartphone placed on a rotating disk anchored to the wall offers greater diagnostic accuracy than SVV using the bucket test. Both methods are inexpensive, harmless and easily accepted by patients.

Vestibular function for children with insulin dependent diabetes using cervical vestibular evoked myogenic potentials testing.

BACKGROUNDHealthy vestibular system adjusts balance during static and dynamic conditions. This is important for normal development (standing up and walking). Vestipulopathies (central and peripheral) are common complications of diabetes in adult population. Related studies are scare in children with type 1 diabetes (T1D). AIMTo assess saccular function of otolith organ in children with T1D and predictors for its dysfunction.METHODSCervical vestibular evoked myogenic potential (cVEMP) was used for objective evaluation. RESULTSThe study included 40 patients (boys = 15; girls = 25). Patients had mean age of 13.63 ± 1.50 years, duration of diabetes of 5.62 ± 2.80 years, frequent attacks of diabetic ketoacidosis (55%) and hypoglycemia (30%), hyperlipidemia (20%), hypertension (12.5%) and peripheral neuropathy (40%). Dizziness was found in 10%. Compared to healthy children (n = 25), patients had prolonged cVEMP P1 and N1 latencies and reduced P1-N1 amplitude. Bilateral cVEMP abnormalities were found in 60% (vs 25% for unilateral abnormalities). Higher frequencies and severe vestibulopathies were found with chronic diabetes of > 5 years, hemoglobin A1c values > 7%, frequent diabetic ketoacidosis and hypoglycemic attacks and presence of dizziness. Regression analyses showed that predictors for prolonged P1 latencies and reduced P1-N1 amplitudes were only chronic diabetes (> 5 years) {odds ratio (OR) = 2.80 [95% confidence interval (CI): 1.80–5.33], P = 0.01; OR = 3.42 (95%CI: 2.82–6.81)} and its severity (hemoglobin A1c > 7%) [OR = 3.05 (95%CI: 2.55–6.82), P = 0.01; OR = 4.20 (95%CI: 3.55–8.50), P = 0.001]. CONCLUSIONDysfunction or injury of the saccular macula and its pathways is prevalent in children with T1D. Optimum glycemic control is important to prevent diabetes related vestipulopathies.

Clinical Results of Peripheral Vestibular Function in People With Diabetes Mellitus

Background and Aims Diabetes Mellitus (DM) is one of the most common chronic metabolic diseases and one of the significant public health concerns in the world. The vestibular defect is a common pathology in DM. It causes ischemia of the vestibular structures and changes in the metabolism of the inner ear fluids. The purpose of this study was to review the studies that have evaluated the vestibular system by clinical tests, including Vestibular Evoked Myogenic Potential (VEMP), Subjective Visual Vertical (SVV), video Head Impulse Test (vHIT), and caloric tests in DM patients. Methods This review investigates the results of related papers in Google Scholar, PubMed (Medline), Science Direct, and Persian databases, including SID and Magiran, from 2000 to January 2021. According to inclusion criteria, eighteen studies were selected. Results More studies have been performed on the effect of DM on the otolith organs in humans. Most of them have used cervical Vestibular Evoked Myogenic Potential (cVEMP). They have been performed in people with and without vestibular symptoms and diabetic neuropathy. In some of the Cervical and ocular vestibular evoked myogenic potential (c/oVEMP) evaluations, increased wave latency and decreased amplitude were reported in the DM group compared to the control group. The predominant finding of the SVV test is an increase in the amplitude of the dynamic deviation in DM patients. The vHIT test was performed in asymptomatic vestibular DM. Some have reported the decrease of the VOR gain average in different semicircular canals without mentioning the observation of catch-up saccades. A caloric test is often performed in DM patients who all or some of them have vestibular symptoms. Unilateral weakness in some of them was the predominant result. Noteworthy is the discrepancy among the results of these vestibular tests in DM. Conclusion The vestibular system’s function can be affected by DM complications with or without symptoms (subclinical). The influence of the results of clinical tests on this disease, characteristics, and measurement parameters are also highly dependent on individual factors. A single outcome cannot be found for how the vestibular system works in these patients.