Sleep in Parkinson's disease and dementia with lewy bodies

Sleep disturbance in Parkinson's disease (PD) and dementia with Lewy bodies (DLB) is common and can have a debilitating effect on quality of life due to the effects of daytime somnolence on cognition, motor function, potential for injury and capacity to manage activities of daily living. Sources of excessive daytime sleepiness in PD and DLB often include sleep fragmentation, side effects of medications, and sleep disorders that disrupt night-time sleep continuity. The parasomnia of REM sleep behavior disorder has also been shown to be an early feature of PD and DLB and a risk factor for dementia in PD. Dysfunction of the dopamine nigrostriatal and mesolimbic systems is involved in Lewy body disease, but several other neurotransmitter systems have Lewy body pathology and neuronal loss that may be responsible for abnormal sleepiness and REM sleep behavior disorder in these conditions.