The spectrum of acute vestibular neuropathy through modern vestibular testing: A descriptive analysis.

OBJECTIVE: Acute vestibular neuropathy (AVN), often referred to as vestibular neuritis, is a cranial neuropathy responsible for a significant proportion of cases of acute vertigo. This study describes the spectrum of lesion patterns in AVN as identified by video head impulse testing (vHIT) which assesses the high frequency vestibulo-ocular reflex function of the semicircular canals, and cervical and ocular vestibular evoked myogenic potentials (VEMPs) which assess otolith function. METHODS: We used vHIT and VEMPs to assess 35 patients with vestibular neuropathy in the acute stage. RESULTS: Unilateral superior division vestibular nerve involvement was the most common variant (57.1%), followed by unilateral superior and inferior division (28.5%), bilateral superior division (8.5%) and unilateral inferior division (5.7%). We observed a partial inverse correlation between the proportion of afferent fibers from an organelle, and the likelihood that the test of that organelle's function will be abnormal. CONCLUSION: vHIT and VEMPs provide more detailed characterization of lesion pattern in AVN than caloric testing. SIGNIFICANCE: Comparison of lesion patterns from neuro-physiological testing with what is known about the proportional distribution of afferent fibers from the vestibular end-organelles suggests a new, neuro-anatomically based insight regarding susceptibility of these pathways to AVN.

Square wave manoeuvre for apogeotropic variant of horizontal canal benign paroxysmal positional vertigo in neck restricted patients.

OBJECTIVE: We aimed to describe the clinical features of the apogeotropic variant of horizontal canal benign paroxysmal positional vertigo (HC BPPV-AG) in a cluster of patients with restrictive neck movement disorders and a new therapeutic manoeuvre for its management. METHODS: In a retrospective review of cases from an ambulatory tertiary referral center, patients with HC BPPV-AG in combination with neck movement restriction that prevented any classical manual repositioning procedure or who were refractory to canalith repositioning manoeuvres, were treated with a new manoeuvre comprised of sequential square-wave pattern of head and body supine rotations while nystagmus was being monitored, until either an apogeotropic to geotropic conversion or resolution of the nystagmus was observed. RESULTS: Fifteen patients were studied. All but one [14/15 cases] showed a positive therapeutic response to the repositioning procedure in a single session. In two cases, a direct relief of vertigo and elimination of nystagmus was observed without an intermediate geotropic phase. Although in three patients the affected ear was not initially identified, it was ultimately identified and successfully treated by the square wave manoeuvre in all of them. CONCLUSIONS: The square-wave manoeuvre is an alternative for HC BPPV-AG treatment in either cases with neck restriction, where the affected side is not well identified at the bedside or when other manoeuvres fail to resolve the HC BPPV-AG.

Benign Paroxysmal Positional Vertigo: Canal Switching Affecting All Canals During a Single Session.

: SDC Video Link:http://links.lww.com/MAO/B86.

Evidence of Large Vestibulo-Ocular Reflex Reduction in Patients With Menière Attacks.

OBJECTIVE: To examine the high frequency horizontal vestibular ocular-reflex (hVOR) during acute attacks of vertigo in Menière's disease (MD). STUDY DESIGN: Retrospective case series and literature review. SETTING: Tertiary academic medical center. PATIENTS: Patients with clinical diagnosis of unilateral "definite MD." INTERVENTION: Review of medical records. MAIN OUTCOME MEASURES: Spontaneous nystagmus and the dynamic hVOR gain change at different stages of an acute episode of MD attack. RESULTS: We studied 10 vertigo attacks during the unique stages of the episode. During the acme stage of the attack, lower hVOR gain was recorded on the affected side (mean 0.48 ±â€Š0.23), which was associated with a paralytic nystagmus (beating away from the affected ear). Additionally, the mean hVOR gain remained significantly (p < 0.05) reduced during each of the other stages of the attack as compared with the unaffected side and a control group. After the attack, mean hVOR gains normalized in the affected ear. Mean hVOR gain of the unaffected ear remained normal during all stages. CONCLUSION: Vestibular function during an attack of MD is a dynamic process associated with fluctuation of the dynamic (hVOR gain) and static (spontaneous nystagmus) processes, which exist in parallel with the perception of vertigo. Our data support vHIT monitoring during an episode to provide objective and accurate evidence of the ear with active disease. This would be particularly useful for those patients with MD presentations of unreliable hearing or assisting to identify the ear to be treated in the case of bilateral MD.

Is Cerebellar Ataxia, Neuropathy, and Vestibular Areflexia Syndrome (CANVAS) a Vestibular Ganglionopathy?

OBJECTIVES: CANVAS is an acronym for cerebellar ataxia, neuropathy and vestibular areflexia syndrome. Limited autopsy data has suggested that CANVAS is caused by a focal dorsal root ganglionopathy that damages Scarpa's (vestibular) ganglion, but spares the Spiral (hearing) ganglion. If the vestibular areflexia of CANVAS is in fact due to ganglionopathy, then there should be global reduction of all vestibular responses. MATERIALS AND METHODS: With this hypothesis in mind, a retrospective review of 5 subjects who met the clinical criteria for CANVAS was performed. Recent advances in vestibular testing have made it possible to quantify responses from all 5 vestibular end organs in the inner ear. Results of the Video head impulse test (VHIT), video oculography, caloric test and vestibular evoked myogenic potential (VEMP) were examined to determine if all 5 end organs are nonfunctional in CANVAS. RESULTS: Severe reduction of function of the six semicircular canals and ocular VEMPs were observed. Only the cervical VEMPs were present and reproducible, consistent with either partial sparing of the inferior vestibular ganglia, specific embryologic resistance of the saccule to the degeneration or a mechanism for cervical VEMPs that does not require an intact vestibular ganglion. CONCLUSION: Our results suggest that Scarpa´s ganglia dysfunction could be the mechanism for loss of semicircular canal and utricular function in CANVAS patients, but the preservation of the cervical VEMP response is unexplained.