Insights from studying human sleep disorders

Problems with sleep are one of the commonest reasons for seeking medical attention. Knowledge gained from basic research into sleep in animals has led to marked advances in the understanding of human sleep, with important diagnostic and therapeutic implications. At the same time, research guided by human sleep disorders is leading to important basic sleep concepts. For example, sleep may not be a global, but rather a local, brain phenomenon. Furthermore, contrary to common assumptions, wakefulness, rapid eye movement (REM) and non-REM sleep are not mutually exclusive states. This striking realization explains a fascinating range of clinical phenomena. Blinking sleep Rapid eye movement sleep behaviour disorder (RBD) is an extreme example of what can go wrong with our sleep patterns. Sufferers act out dramatic or violent dreams during rapid eye movement sleep. Alison Abbott reports on the latest research on RBD, including a controversial suggestion that it is closely linked to Parkinson's disease. And in the Insight reviews section, Mahowald and Schenk show how the study of disorders such as RBD throws light on the nature and role of normal sleep.