Sleep problems are important to recognize in Parkinson’s Disease (PD) because they are common, often overlooked and inadequately managed.

Sleep disruption in PD is often multifactorial. Sleep disturbance may be part of the neurodegenerative process disrupting neural pathways important in the regulation of sleep, including dopaminergic, serotonergic, cholinergic and noradrenergic systems. In addition psychological factors, physical discomfort, excessive involuntary movements, medication effects and underlying sleep disorders which have been associated with PD can contribute to the reduced amount and quality of sleep that is seen in this population. Various abnormalities in sleep patterns of PD patients have been described, including sleep fragmentation, increased arousals, decreased sleep efficiency and abnormal muscle tone during REM sleep.

Depression and anxiety in PD patients can cause insomnia, which typically presents with difficulty falling or staying asleep, and early morning awakenings. Nocturia, rigidity causing difficulty turning over in bed, painful leg cramps, nocturnal tremor, dystonic spasms and dyskinesias also affect sleep. Medication can be sedating or stimulating. Dopaminergic agents at lower doses may cause sleepiness, while higher doses induce wakefulness.

PD has been associated with several sleep disorders, including REM behaviour disorder, Restless Legs Syndrome with Periodic Limb Movements of Sleep, nightmares and obstructive sleep apnoea. Patients suspected of having sleep disordered breathing or parasomnias may need a sleep study for further evaluation.

Sleep evaluation should be a routine part of assessment of PD patients. Accurate diagnosis and effective management of sleep disorders can greatly improve the quality of life of these patients.