Sleep-related non epileptic motor disorders.

Sleep-related non epileptic motor disorders represent a frequent but often neglected or trivialized source of neurological disability. In recent decades, the widespread adoption of videopolygraphic techniques has better characterized already known nosographic entities and described a bewildering variety of previously unrecognized clinical entities (such as REM sleep behaviour disorder, sleep-related eating disorder, benign neonatal sleep myoclonus, facio-mandibular myoclonus during sleep, fragmentary hypnic myoclonus, propriospinal myoclonus at the wake-sleep transition, rhythmic feet movements during sleep, etc). The scope of the neurophysiological investigations of sleep related disorders has therefore been much expanded. However, advances in the semeiology and clinical description of sleep-related movement disorders has rarely been matched by adequate understanding of the underlying pathophysiological mechanisms, or by major advances in treatment. The main sleep-related motor disorders are described here, following the only classification currently available, e. g. that offered by the International Sleep Disorders Classification of the American Sleep Disorders Association, which is more a classification of diseases of sleep than of movement disorders. The increasing use of functional neuroimaging in vivo and of updated neurophysiological and molecular techniques in man and in the experimental animal will hopefully lead to a better understanding of these disorders in terms of pathophysiology of disordered motor control.