title: The relationship between sleep and cognition in Parkinson's disease: A meta-analysis.
abstract: It is well established that sleep disorders have neuropsychological consequences in otherwise healthy people. Studies of night-time sleep problems and cognition in Parkinson's disease (PD), however, paint a mixed picture, with many reporting no relationship between sleep problems and neuropsychological performance. This review aimed to meta-analyse this research and to examine the factors underlying these mixed results. A literature search was conducted of published and unpublished studies, resulting in 16 papers that met inclusion criteria. Data were analysed in the domains of: global cognitive function; memory (general, long-term verbal recognition, long-term verbal recall); and executive function (general, shifting, updating, inhibition, generativity, fluid reasoning). There was a significant effect of sleep on global cognitive function, long-term verbal recall, long-term verbal recognition, shifting, updating, generativity, and fluid reasoning. Although there are effects on memory and executive function associated with poor sleep in PD, the effects were driven by a small number of studies. Numerous methodological issues were identified. Further studies are needed reliably to determine whether disturbed sleep impacts on cognition via mechanisms of hypoxia, hypercapnia, sleep fragmentation, chronic sleep debt or decreased REM and/or slow wave sleep in PD, as this may have important clinical implications.
authors.affiliation: School of Psychology, University of Western Australia, Australia; ParkC Collaborative, Western Australia, Australia.
authors.forename: Maria E
authors.initials: ME
authors.lastname: Pushpanathan
authors.affiliation: School of Psychology and Speech Pathology, Curtin University, Australia; ParkC Collaborative, Western Australia, Australia.
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Loftus
authors.affiliation: Experimental and Regenerative Neuroscience, School of Animal Biology, University of Western Australia, Australia; ParkC Collaborative, Western Australia, Australia; Parkinson's Centre, Vario Health Institute, Edith Cowan University, Australia.
authors.forename: Meghan G
authors.initials: MG
authors.lastname: Thomas
authors.affiliation: School of Psychology and Speech Pathology, Curtin University, Australia; ParkC Collaborative, Western Australia, Australia.
authors.forename: Natalie
authors.initials: N
authors.lastname: Gasson
authors.affiliation: School of Psychology, University of Western Australia, Australia; ParkC Collaborative, Western Australia, Australia. Electronic address: romola.bucks@uwa.edu.au.
authors.forename: Romola S
authors.initials: RS
authors.lastname: Bucks
mesh_terms: D003071:Cognition / Q000502:physiology; D006801:Humans; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications*; D012893:Sleep Wake Disorders / Q000209:etiology*
keywords: Cognition; Executive function; Memory; Neuropsychology; Parkinson's disease; REM sleep behaviour disorder; Review; Sleep disorder