Downbeat Nystagmus Is Abolished by Alcohol in Nonalcoholic Wernicke Encephalopathy.

BACKGROUND AND

OBJECTIVES

Lesions of the cerebellar flocculus cause enduring downbeat nystagmus (DBN) with unrelenting oscillopsia. Unlike most patients with DBN, the flocculus is structurally spared in nonalcoholic Wernicke encephalopathy (nWE) with chronic DBN. The objective was to study the effects of alcohol in nWE.

METHODS

We recorded eye movements of a unique patient with nWE under controlled alcohol consumption who said his oscillopsia disappeared with a few drinks of alcohol.

RESULTS

His DBN was markedly diminished by alcohol (by 77.4%), although he remained alert with normal saccades.

DISCUSSION: This striking observation may be caused by the differential effect of alcohol on the perihypoglossal complex and the paramedian tract neurons, which control the level of activity in the flocculus, with opposite (inhibition and excitation, respectively) effects. The finding suggests new ideas about the treatment and pathophysiology of DBN with a structurally intact cerebellum.