Effects of alcohol on myoclonus and somatosensory evoked potentials in dyssynergia cerebellaris myoclonica.

Three brothers with dyssynergia cerebellaris myoclonica received alcohol to study the correlation between improvement of myoclonus and alteration in somatosensory evoked potentials (SEPs). Alcohol considerably improved myoclonus for about six hours in two patients (cases 1 and 2) but had only a mild effect in one (case 3). All three patients had giant cortical SEPs. The amplitudes of median N20-P25 and P25-N35 components and tibial N30-P40 and P40-N50 components were considerably decreased after alcohol ingestion in two patients (cases 1 and 2) but unchanged or slightly decreased in one (case 3). The peak latencies of those components were not affected by alcohol. There was thus a good correlation between the suppression of myoclonus and the decrease in giant SEP amplitude.