Sleep-related movement disorders
Introduction Nocturnal sleep disturbances, excessive daytime sleepiness, sleep-related breathing disorders, and sleep-related movement disorders are major non-motor key features of many movement disorders. Most research has focussed on Parkinson’s disease, but there is also a substantial knowledge that has been generated for other movement disorders such as atypical Parkinson syndromes, dystonias, heredoataxias, and choreatic disorders. In addition to providing an understanding of the sleep disturbances associated with these disorders, there is increasing evidence that studies of sleep may provide a unique early window into neurodegenerative disorders. For example, research over the last decade demonstrated that REM sleep behavior disorder (RBD) – a complex parasomnia characterized by dream enactment and loss of physiological REM atonia – is often the first non-motor symptom of a neurodegenerative disease. Up to 80 percent of patients initially diagnosed as idiopathic RBD will develop parkinsonism within a twenty-year observational period. In this chapter we will provide an overview of specifically sleep-related movement disorders and start with movement disorders during sleep over motor phenomena in parasomnias to restless legs syndrome (RLS) which presents as a circadian sensorimotor movement disorder.
