[The influence of sleep on abnormal waking movements]

Sleep decreases considerably the abnormal movements seen during waking in the degenerative extra-pyramidal diseases. However, the electrophysiologic recordings reveal that muscular contractions are not completely abolished. This decrease parallels the reduction of the waking system which act likely as a non-specific system of amplification. One can notice that sleep modifies the characteristics of the parkinsonian tremor and that some palatal myoclonias persist during sleep.