Changes in Average Evoked Responses during Abstention in Chronic Alcoholics

Abstract

This study investigated changes in the amplitude of auditory average evoked responses (AER) following a period of abstention in chronic alcohol abusers. The subjects were 11 normal controls and 11 alcoholic inpatients. AERs, elicited by speech sounds and tones, were obtained from frontal and parietal leads over both hemispheres. Subjects were tested on two occasions separated by about 20 days. On the first run the mean amplitude of the alcoholics' AERs was smaller than that of the controls. However, on the second run the alcoholics' parietal responses had improved and were comparable in amplitude to those of the controls, whereas the frontal AERs remained significantly smaller than those of the control subjects. These electrophysiological changes are consistent with neuroanatomical and neuropsychological evidence implicating the frontal aspects of the brain as a site of deficit in alcoholism. Hemispheric differences generally were not statistically significant in either group. The right hemispheric responses of the controls tended to be larger than those of the left hemisphere for both speech and tone stimuli, but the left side produced larger responses in the alcoholic group. The results of this study suggest that electrophysiological responses reflect a process of cerebral recovery which may be distinguishable from EEG changes associated with the withdrawal of a toxic agent.