Frontal lobe function in Korsakoff and non-Korsakoff alcoholics: planning and spatial working memory.

Groups of Korsakoff (KS) and non-Korsakoff alcoholics (ALC) and a group of normal volunteers, matched for age and verbal IQ, were tested on traditional neuropsychological tests of frontal lobe function and on computerized tests of planning (the Tower of London task) and spatial working memory. KS demonstrated deficits on the planning task which could not be explained by abnormalities of memory, including spatial span, or by visuoperceptive disturbances. KS were also impaired on the spatial working memory task, in part because of the failure to adopt an organized strategy. ALC exhibited fewer impairments which could not be attributed to deficits in either planning or spatial working memory. On Nelson's modified Wisconsin Card Sorting Task, KS and ALC achieved fewer categories than controls but only KS made perseverative errors. The data suggest that in the alcoholic Korsakoff's syndrome there is a specific disturbance of frontal-lobe function in addition to amnesia. The impairment seen in chronic alcoholics without Korsakoff's syndrome, on the other hand, do not reflect specific frontal dysfunction.