Parasomnias. Things that go thump in the night

General practitioners are well versed with patients presenting to the surgery with sleep symptoms, however, the approach to evaluating these symptoms is often haphazard. Insomnia is the commonest presenting complaint. Sleep apnoea, although readily treatable, carries with it significant morbidity and mortality.

This article aims to highlight those disorders that occur infrequently during the night but which interrupt sleep--the parasomnias.

Knowledge of the spectrum of parasomnias and their symptoms usually allows a reasonably accurate clinical diagnosis and the assistance of a sleep physician or sleep laboratory is not often required. Parasomnias may be classified by the sleep phase during which they occur. Nonrapid eye movement (NREM) parasomnias are most likely to occur during the first episode of stages 3 and 4 of NREM sleep (slow wave sleep) which is approximately one hour after sleep onset. Rapid eye movement (REM) sleep density is usually greatest in the last few hours of sleep, therefore REM sleep parasomnias are most likely to occur during this time.