Korsakoff's syndrome refers to a permanent form of Dementia associated with long-term alcohol use in which the person develops retrograde and anterograde amnesia, leading to an inability to remember recent events or learn new information.

Other definition:

Korsakoff 's syndrome is a type of brain damage caused by thiamine deficiency, characterized by apathy, confusion, and memory impairment. Korsakoff syndrome , moreover is a brain dysfunction found in some long-term heavy users of alcohol and resulting in both physiological and psychological impairment.