Bilateral loss of vestibular sensation can be disabling. Those afflicted suffer illusory visual field movement during head movements, chronic disequilibrium and postural instability due to failure vestibulo-ocular vestibulo-spinal reflexes. A neural prosthesis that emulates the normal transduction rotation by semicircular canals could significantly improve quality life for these patients. Like three in a ear, such device should at least transduce orthogonal (or linearly separable) components...

Objective To evaluate the validity of 2D video-oculography (VOG) compared with scleral search coils for horizontal AVOR gain estimation in older individuals. Study Design Cross-sectional validation study. Setting Tertiary care academic medical center. Patients Six individuals age 70 and older. Interventions Simultaneous eye movement recording coil (over right eye) EyeSeeCam VOG camera left during head impulses. Main Outcome Measures Best estimate gain, presence compensatory saccades using...

We report four patients with the syndrome of cerebellar ataxia bilateral vestibulopathy (CABV) and, using search coil oculography, we validate its characteristic clinical sign, namely impairment visually enhanced vestibulo‐ocular reflex (VVOR) or doll's head reflex. In our patients, CABV began in sixth decade life; they are still ambulant and self‐caring 8–20 years after onset. The cause is unknown. None has a family history vestibular disease; spinocerebellar (SCA) 1, 2, 3, 6, 7...

Objective: To characterize semicircular canal function before and after surgery for superior dehiscence (SCD) syndrome. Study Design: Prospective unblinded study of physiologic effect intervention. Setting: Tertiary referral center. Patients: Patients with SCD syndrome documented by history, sound- or pressure-evoked eye movements, vestibular-evoked myogenic potential testing, high-resolution multiplanar computed tomographic scans. Intervention: Nineteen subjects had quantitative...

Conclusions. Our findings suggest that canal function is substantially preserved in subjects with active vertigo attacks as a result of Ménière's disease (MD). In these subjects, the head-thrust test (HTT) may not be sensitive to dysfunction traditional caloric testing. MD differentially affect low-frequency sensitivity canals. Objective. Caloric tests have traditionally been used characterize semicircular vestibular disorders, including MD. The quantitative HTT provides an objective...

Objective: Determine the risk posed by cochlear implantation (CI) to labyrinth. Study Design: Prospective cohort study. Setting: Academic tertiary referral center. Patients: Thirty-six ears belonging 35 adult CI candidates (mean age, 46 yr; range, 23-69 yr). Intervention: Cochlear implantation. Main Outcome Measures: Vestibular function was assessed using quantitative 3-dimensional head impulse test (qHIT), clinical (cHIT), post-head shake nystagmus, caloric electronystagmography,...

Although anatomically well described, the functional role of mammalian efferent vestibular system (EVS) remains unclear. Unlike in fish and reptiles, EVS does not seem to play a modulation primary afferent activity anticipation active head movements. However, it could modulating long-term mechanisms requiring plasticity such as adaptation. We measured efficacy vestibuloocular reflex (VOR) adaptation α9-knockout mice. These mice carry missense mutation gene encoding α9 nicotinic acetylcholine...

Objective: Measure vestibular function using the head impulse test and assess change in due to unilateral cochlear implantation. Background: Cochlear implantation entails risks implanted ear. However, nature extent of this risk is not known. The uses physiologically relevant stimuli that allow detection subtle changes individual semicircular canals. Subjects: Sixteen adults (age, 28-65 years) were recruited for prospective study from Listening Center at Johns Hopkins. Eleven these subjects...

1) Determine the prevalence of vestibular hypofunction in immediate postoperative period after surgical treatment superior semicircular canal dehiscence syndrome. 2) Evaluate whether length is associated with risk hypofunction. 3) Compare prevalences and late hypofunction.Clinical review.Tertiary referral center.Subjects syndrome (n = 42) based on history, physiologic testing, computed tomography findings, who underwent middle fossa craniotomy plugging.Dehiscence was measured...

The head impulse test can be used to measure peripheral vestibular function of all six semicircular canals. Traditionally, vertical canal is measured by rotating the from a starting neutral position (forward facing) about diagonal plane that bisects sagittal and coronal planes. These types rotations elicit eye movements with large torsional (about line sight) angular velocity components. Three-dimensional (3D: horizontal, torsional) measurement techniques are needed these We wanted determine...

Hypothesis Unilateral vestibulo-ocular reflex (VOR) short-term adaptation training causes some increase toward the nonadapting side (∼30% of on adapting side). We conducted a pilot study to determine if could be reduced by providing visual stimulus during rotations side. Background vestibular is technique that ipsilesional VOR response patients with unilateral hypofunction. However, this results in increasing for (normal) side, which undesirable because will overcompensatory (causing...

The α9-nicotinic acetylcholine receptor (α9-nAChR) subunit is expressed in the vestibular and auditory periphery, its loss of function could compromise peripheral input from predominantly cholinergic efferent system (EVS). A recent study has shown that α9-nAChRs play an important role short-term vestibulo-ocular reflex (VOR) adaptation. We hypothesize also be for other forms plasticity, such as needed VOR recovery after organ injury. measured efficacy compensation α9 knockout mice. These...

The aim of this study was to determine how context and on-line sensory information are combined control posture in seated subjects submitted high-jerk, passive linear accelerations. Subjects were with eyes closed on a servo-controlled sled. They asked relax received brief accelerations either sideways or the fore-aft direction. stimuli had an abrupt onset, comparable jerk experienced during minor car collision. Rotation translation head body measured using Optotrak system. In some subjects,...

Patients who fail to compensate for bilateral loss of vestibular sensory function are disabled by disequilibrium and illusory movement the visual field during head movement. An implantable prosthesis that restores sensation could significantly improve quality life these patients. To be effective, such a device should encode rotation in all 3 dimensions. We describe 3-dimensional angular vestibulo-ocular reflex normal chinchillas vestibular-deficient undergoing functional electrical...

A novel training method known as incremental VOR adaptation (IVA) can improve the vestibulo‐ocular reflex (VOR) gain for both active and passive head rotation by coupling rotations with a laser‐projected target that moves in opposite direction of at fraction velocity. 51‐year‐old male bilateral vestibular hypofunction participated research protocol using portable IVA device 645 days. Passive gains improved 179% to 600%; standing posture gait also improved. Motor learning within system is...

The vestibulo-ocular reflex (VOR) is the only system that maintains stable vision during rapid head rotations. VOR gain (eye/head velocity) can be trained to increase using a vestibular-visual mismatch stimulus. We sought determine whether low-frequency (sinusoidal) rotation training leads changes in high-frequency testing, where more physiologically relevant. tested eight normal subjects over three sessions. For protocol 1, performed active sinusoidal rotations at 1.3 Hz while tracking...