Wemicke-Korsakoff syndrome is due:

(Thiamine deficiency): Ref: 403-4-H (169,442-HI7th)* Alcoholic patients with chronic thiamine deficiency may also have CNS manifestations known as Wernicke's encephalopathy (consisting of horizontal nystagmus, ophthalmoplegia, cerebellar ataxis, and mental impairment, when there is an additional loss of memory and a confabulatory psychosis, the syndrome is known as Wernicke Korsakoff syndrome.