Rapid eye movements, muscle twitches and sawtooth waves in the sleep of narcoleptic patients and controls

Abstract

Seventeen unmedicated patients with narcolepsy-cataplexy and 17 age- and sex-matched controls were recorded polygraphically for 3 consecutive nights. Rapid eye movements (REMs), m. mentalis twitches and sawtooth waves in the EEG were visually scored. REM and twitch densities during REM sleep were significantly higher in the patients than in the controls. The distribution pattern of REMs and twitches was altered in the patients: twitch density peaked in the first REM period and density of REMs showed an even distribution across all the REM periods of the night. In the controls both REM and twitch density increased from the first to the second REM period. We therefore assume that in the narcoleptics phasic activity of REM sleep is disinhibited. Densities of REMs, twitches and sawtooth waves did not correlate with one another in patients and controls. They appear to be independently regulated. The REM periods of the patients contained 3 times as many waking epochs as those of the controls. This suggests that in narcolepsy the transition REM/waking is selectively facilitated. The REM/NREM ratio of twitch and sawtooth wave densities was the same in patients and controls.