Sleep and neurodegenerative disorders: A review

The coexistence of neurodegenerative diseases and sleep disorders is increasingly being recognized. While there is considerable evidence suggesting that such conditions are inherent to the neurodegenerative process, most occur as a result of concomitant intrinsic and extrinsic factors. Primary sleep disorders such as obstructive sleep apnea and restless legs syndrome increase in prevalence with age, and can result in unique clinical scenarios and diagnostic challenges when combined with neurodegenerative diseases. Rapid-eye movement sleep behavior disorder appears to exhibit a predilection for specific neurodegenerative entities, and may therefore have diagnostic utility, and ultimately prove to be a useful marker to identify those best suited for studies investigating preventative therapies. Identification of all factors impacting sleep disturbances is important, as sleep complaints significantly influence the rate of institutionalization in the elderly. This review highlights various pathophysiologic and clinical investigations pertaining to sleep findings in Alzheimer's disease, dementia with Lewy bodies, Parkinson's disease, multiple system atrophy, and fatal familial insomnia.