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Neuropsychological functioning in Parkinson's disease: Differential relationships with self-reported sleep-wake disturbances

Authors

  • Sharon L. Naismith BA Hons, MClinNpsych, DPsych, MAPS, CCN,

    1. Parkinson's Disease Research Clinic, Ageing Brain Centre, Brain & Mind Research Institute, University of Sydney, Camperdown, Australia
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  • Zoë Terpening BPsych Hons, MSc, DClinNeuropsych, MAPS, CCN,

    1. Parkinson's Disease Research Clinic, Ageing Brain Centre, Brain & Mind Research Institute, University of Sydney, Camperdown, Australia
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  • James M. Shine BSc, MBBS,

    1. Parkinson's Disease Research Clinic, Ageing Brain Centre, Brain & Mind Research Institute, University of Sydney, Camperdown, Australia
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  • Simon J.G. Lewis MBBCh, BSc, MRCP, FRACP, MD

    Corresponding author
    1. Parkinson's Disease Research Clinic, Ageing Brain Centre, Brain & Mind Research Institute, University of Sydney, Camperdown, Australia
    • Director, Parkinson's Disease Research Clinic, Brain & Mind Research Institute, 94 Mallett Street, Camperdown NSW, Australia
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  • Relevant conflicts of interest/financial disclosures: This study was supported by NHMRC Project Grant 632689. Dr. Lewis is supported by a University of Sydney Rolf Edgar Lake Postdoctoral Fellowship. Full financial disclosure and author roles can be found in the online version of this article.

Abstract

Background:

Sleep disturbance may represent a risk factor for the development of dementia in Parkinson's disease. However, prior studies exploring the association between specific sleep–wake disturbances and neuropsychological functions have been limited.

Methods:

In this study, 101 patients with idiopathic Parkinson's disease were assessed neurologically, underwent neuropsychological testing, and completed self-report questionnaires covering nocturnal disturbance, excessive daytime sleepiness, and symptoms of rapid eye movement sleep behavior disorder.

Results:

Univariate correlations revealed differential patterns of neuropsychological performance in relation to nocturnal sleep disturbance, excessive daytime sleepiness, and rapid eye movement sleep behavior disorder. After controlling for potential confounders, excessive daytime sleepiness remained a significant predictor of slowed processing speed, and rapid eye movement sleep behavior disorder predicted working memory and verbal fluency performance. The relationships between nocturnal sleep disturbance and memory appeared to be mediated by education.

Conclusions:

These findings highlight the critical role that specific sleep–wake disturbances in Parkinson's disease might have on neuropsychological functioning, which may reflect common neural underpinnings. © 2011 Movement Disorder Society

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