Muscle twitch activity during REM sleep: Effect of sleep deprivation and relation with rapid eye movement activity

The present study assessed the effect of total sleep deprivation on muscle twitch (MT) frequency during the recovery night, as well as the intranight distribution of MTs and their correlation with rapid eye movements (REMs) in the baseline nights of a larger sample of subjects. Results showed that, in the recovery night, sleep deprivation determined an increase of slow-wave sleep amount and of sleep efficiency and a decrease of Stage 1, Stage 2, and intrasleep wake. In the same night, MT and REM frequency decreased, as compared with the baseline night. As regards intranight distribution, MT frequency showed a slight increase in the third and fourth cycles, as compared with the first one, whereas REM frequency sharply increased during the second, third, and fourth REM cycles, as compared with the first one. Finally, a weak but significant correlation between REMs and MTs was found only in the first REM cycle.