Downbeat Nystagmus Is Abolished by Alcohol in Nonalcoholic Wernicke Encephalopathy

Abstract

ABSTRACTObjective:Lesions of the cerebellar flocculus cause enduring downbeat nystagmus (DBN) with unrelenting oscillopsia. Unlike most DBN patients, the flocculus is structurally spared in non-alcoholic Wernicke’s 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 alcohol.Results:His downbeat nystagmus was markedly diminished by alcohol (by 77.4%) though he remained alert with normal saccades.Conclusion: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.