Sleep disorders in Parkinson's disease

Sleep disorders are commonly reported by patients with Parkinson's Disease (PD) both in early and in advanced stage of illness. Furthermore, some sleep disorders, namely REM Behaviour Disorders (RBD), have been hypothesized to herald PD. Awareness of the clinical and pathophysiological importance of sleep disorders in PD has been growing in recent years. Sleep disorders are now regarded as the most frequent and disabling non-motor complications of PD and as a significant variable of PD-related quality of life. The common subjective reports of disrupted nocturnal sleep and daytime sleepiness find confirmation in the objective findings of various sleep alterations at neurophysiological investigations. Sleep alterations in PD are to be viewed from the multifactorial perspective of a picture build up by interacting factors: involvement of dopaminergic, serotoninergic, noradrenergic and cholinergic neural networks, neuro-degeneration linked to the disease itself, chronic use of antiparkinsonian drugs, sleep-related motor symptoms, aging, cognitive and psychiatric alterations, Restless legs syndrome, Periodic Limb Movements (PMLs) and sleep-disordered breathing. The use of ad hoc questionnaires and scales is advisable for the evaluation of disordered sleep in PD patients for preliminary screening of sleep disorders in PD. In a few cases neurophysiological investigations (i.e. the video-polysomnography in primis) are needed in order to confirm a diagnosis of sleep disorder in PD. It is true particularly in diagnosing RBD. The correct diagnosis unlock the way to the correct treatment, and combined pharmacological and non-pharmacological protocols appear to be particularly suitable in the treatment of sleep disorders in PD.