Head-shaking and Vibration-induced Nystagmus During and Between the Attacks of Unilateral Ménière's Disease.

OBJECTIVE: To aid in defining each phase of Ménière's disease (MD) and underlying vestibular pathophysiology by analyzing the evolving patterns of spontaneous, head-shaking (HSN), and vibration-induced nystagmus (VIN) during and between the attacks of MD. STUDY DESIGN: Retrospective case series review. METHODS: We analyzed the patterns of HSN and VIN during 123 attacks from 87 patients who had definite unilateral MD and underwent recording of eye movements both during and between the attacks using video-oculography. RESULTS: HSN tended to beat toward the lesion side during the irritative phase (80.0%) and toward the healthy side during the paretic phase (82.9%). In contrast, VIN was more commonly induced during the irritative phase (63.7%) and more likely beat toward the healthy side irrespective of the phases evaluated (84.3%). Directional dissociation may occur between HSN and VIN, especially during the irritative phase when HSN mostly beat to the lesion side, but VIN is toward the healthy side. CONCLUSION: The characteristic patterns of HSN and VIN during each phase of MD would aid in defining the acute phases of MD and understanding the underlying vestibular pathophysiology.

Combined peripheral and central vestibulopathy.

Diagnosis of central vestibulopathy remains a challenge when it is associated with peripheral vestibular dysfunction because neurotological findings from peripheral vestibulopathy may overshadow those from central vestibular involvements. To define the characteristics of disorders involving both peripheral and central vestibular structures, we classified the combined vestibulopathies into four types according to their vestibular manifestations, and describe a typical case in each subtype. Infarction involving the territory of anterior inferior cerebellar artery is the most common cause of acute unilateral cases, whereas tumors involving the cerebellopontine angle should be of prime suspicion in patients with chronic unilateral ones. Wernicke encephalopathy was most common in patients with acute bilateral combined vestibulopathy while degenerative disorders should be considered in chronic bilateral ones. Since the head impulse test (HIT) is mostly positive in combined vestibulopathy, signs of central vestibular dysfunction other than negative HIT should be sought carefully even in patients with obvious clinical or laboratory features of peripheral vestibulopathy.