EXCESSIVE FRAGMENTARY MYOCLONUS - TIME OF NIGHT AND SLEEP STAGE DISTRIBUTIONS

Excessive fragmentary myoclonus during sleep consists of high amounts of brief twitch-like movements occurring asynchronously and asymmetric ally in different body areas and has been reported to occur in associa tion with a number of sleep disorders. It was analyzed using a new tec hnique of quantification, the fragmentary myoclonus index (FMI). The F MI exhibited high rates in all stages of sleep but with a somewhat low er frequency in slow wave sleep explaining, as well, a significantly l ower rate in the first hour after sleep onset compared to later hours. There was no evidence for greater sleep fragmentation or lighter slee p compared to a matched patient group in whom it had not been noted.