A comparison of functional indexes, derived from screening tests, of chronic alcoholic neurotoxicity in the cerebral cortex, retina and peripheral nervous system.

Thirty abstinent alcoholics and 30 age-, education- and occupation-matched normal control subjects were tested with the Category test, the Lanthony-15 test of color discrimination and the Biothesiometer test of vibration detection threshold. Multivariate analysis of covariance revealed significant impairment of the alcoholics on these tasks (p < .007), but univariate analysis revealed that only the Category test yielded a significant difference (p < .001). Canonical correlation analysis, with age and education partialed out, was calculated on the alcoholics' data to determine whether duration, mean and maximum alcohol consumption, age of onset of alcoholism and duration of abstinence predicted performance on the tasks. The prediction was significant (p < .001). Multiple regression analysis revealed that vibration threshold, color preception and Category test performance were decreasingly predicted by the alcohol-related variables (p < .001, .006, .051, respectively). There was no higher incidence of hereditary dyschromatopsia in the alcoholic group than the control group. It was therefore concluded that all three functions (Category test performance, color discrimination, vibrotactile sensitivity) were impaired as a result of alcohol consumption.