Acute and chronic alcohol consumption causes sleep disturbances, which may never resolve and may be a key factor in alcoholism relapse. Alcohol-related sleep deficits also become more pronounced with advancing age. The most consistently reported finding of altered sleep in alcoholics is a reduction in spontaneously occurring slow wave sleep (SWS), defined by the presence of delta EEG activity. Further, alcoholics with reduced baseline SWS have an increased likelihood of relapse. External stimulation during sleep can elicit K-complexes, which when averaged produce a large N550 component thought to have the same generator as SWS delta activity. Given the potential value of sleep markers in predicting relapse, it would be advantageous to employ a probe of the sleeping nervous system that can be under experimenter control rather than one that relies on the traditional observation of spontaneous sleep physiological indices. We have demonstrated that sleep-evoked N550 component amplitudes are smaller and K-complexes are produced on a smaller number of trials in elderly than young controls. Our preliminary study indicates that alcoholics have even smaller N550 than would be expected for their age. A candidate generator of the K-complex and N550 is frontal cortical gray matter, which is especially reduced in older alcoholics. Sex differences in brain structure and electrophysiological indices of sleep also occur in alcoholism and aging, and objective study of them may further contribute to our understanding of relevant mechanisms of alcoholism-related sleep disturbance. We propose to test the following hypotheses: Hypothesis 1: Recently detoxified, chronic alcoholics will have smaller N550 amplitudes, lower evoked K-complex proportions, lower SWS levels and delta EEG power compared to sex- and age-matched controls. Hypothesis 2: Low evoked K-complex production rates, small N550 amplitude, low SWS levels and delta EEG power will be associated with small prefrontal gray matter volume. Hypothesis 3: Alcoholic men will have greater sleep abnormalities than alcoholic women. Hypothesis 4: Small amplitude, production rate and power of sleep electrophysiological variables in recently detoxified alcoholics will predict early relapse.
