THE NUCLEUS BASALIS (CH4) IN THE ALCOHOLIC WERNICKE-KORSAKOFF-SYNDROME - REDUCED CELL NUMBER IN BOTH AMNESIC AND NON-AMNESIC PATIENTS

Background - The cholinergic nucleus basalis (Ch4) is an exclusive sit e of neurofibrillary degeneration in alcoholic patients with Wernicke' s encephalopathy. Aim - To test the hypothesis that the loss of Ch4 ne urons contributes to the memory disorder, Korsakoffs psychosis, common ly seen in Wernicke's encephalopathy. Methods - Magnocellular basal fo rebrain neurons were quantified in alcoholic patients with Wernicke's encephalopathy, both with and without Korsakoffs psychosis, and neurol ogically asymptomatic alcoholic and non-alcoholic controls. Because am nesic and non-amnesic patients with Wernicke's encephalopathy share co mmon periventricular lesions, both thiamine deficient groups as well a s alcoholic patients with no neurological complications were included to determine the lesion specific to memory impairment. Results - Ch4 c ell number did not differ significantly between alcoholic and nonalcoh olic controls and there was no correlation between cell number and lif etime alcohol intake. However, Ch4 cell. number in all groups was sign ificantly correlated with the volume of its major projection target, t he cerebral cortex. Ch4 cell number in the non-amnesic Wernicke's ence phalopathy group was significantly below controls (24%), with cell num ber in patients with Korsakoffs psychosis 21% below controls. There wa s considerable overlap in cell number between groups. On discriminant analysis, there was significantly greater cell. loss in three non-amne sic patients with Wernicke's encephalopathy than in some patients with Korsakoffs psychosis. The non-amnesic patient with the greatest cell loss was impaired on attentional tasks. Conclusion - Whereas neurons i n the nucleus basalis are at risk in thiamine deficient alcoholic pati ents, cell loss is minor and does not account for the profound memory disorder.