Overview of sleep disturbances and their management in Parkinson plus disorders.

Sleep disturbance is one of the commonly reported non-motor symptoms in patients with Parkinson's disease (PD) as well as in Parkinson plus disorders such as multiple system atrophy (MSA), dementia with Lewy bodies (DLB), progressive supranuclear palsy (PSP), and corticobasal syndrome (CBS). Although there is a wealth of literature on sleep disturbances in PD, the same is not robust on the Parkinson plus disorders. This article aims to comprehensively review the sleep disturbances in Parkinson plus disorders. The literature review was as per the guidelines of the preferred reporting items for systematic reviews and meta-analyses (PRISMA). We searched PubMed and MEDLINE till December 2019 using a combination of words - "Sleep disturbance" with additional search terms such as: "synucleinopathy", "tauopathy", "multiple system atrophy", "dementia with Lewy bodies", "progressive supranuclear palsy", and "corticobasal syndrome". A wide range of sleep disorders that include insomnia, rapid eye movement (REM) sleep behaviour disorder (RBD), periodic limb movement disorder, excessive daytime sleepiness, and sleep apneas, may complicate the course of the Parkinson plus disorders. Pathophysiology of these sleep disorders remains elusive, thus making targeted pharmacotherapy challenging. We describe the cardinal features and the management options of these sleep disorders in the context of Parkinson plus disorders.