Sleep disorders in Parkinson's disease: facts and new perspectives

Abstract

Awareness of the clinical and pathophysiological importance of sleep disorders in Parkinson's disease (PD) has been growing in recent years. Sleep disorders are now regarded as important among non-motor symptoms in PD and as a significant variable of PD-related quality of life. Furthermore, some sleep disorders, namely REM behaviour disorder (RBD), has been hypothesised to herald PD by years. Subjective reports of disrupted nocturnal sleep and daytime sleepiness appear to be supported by descriptions of several sleep alterations at nocturnal polysomnographic investigation and Multiple Sleep Latency Test findings. Sleep alterations in PD are to be viewed from the multifactorial perspective of a framework of reciprocally interacting factors: pathophysiology of the disease itself, sleep-related motor symptoms, dopaminergic treatments, ageing, depression, restless legs, periodic limb movements (PMLs) and sleep-disordered breathing. Ad hoc questionnaires and scales such as the Parkinson's Disease Sleep Scale and the Short and Practical (SCOPA) Sleep Scale are now available for the evaluation of disordered sleep in PD patients and have been proved to be useful for preliminary screening of sleep disorders in PD. However in a few cases a video-polysomnography (V-PSG) is needed in order to confirm a diagnosis of sleep disorder in PD, particularly in diagnosing RBD. As for treatment of sleep disorders, combined pharmacological and non-pharmacological protocols appear to be particularly suitable in their treatment in PD.