title: The Relationships Between Poor Sleep Efficiency and Mild Cognitive Impairment in Parkinson Disease.
abstract: BACKGROUND
  Mild cognitive impairment (MCI) and sleep disturbances are common features in Parkinson disease (PD). This study sought to investigate whether patients with MCI in PD (PD-MCI) have more pronounced sleep disturbance compared to those without PD-MCI and whether phenotypic presentations differ according to the PD-MCI subtypes.
  
  
  METHODS
  A total of 95 patients with idiopathic PD (53 meeting criteria for PD-MCI and 42 who were not cognitively impaired) and 22 controls underwent neurological and neuropsychological examination. They wore actigraphy watches for 2 weeks, from which measures of nocturnal sleep efficiency were calculated.
  
  
  RESULTS
  Patients with PD-MCI has significantly poorer sleep efficiency compared to those without PD-MCI. This effect was particularly apparent in those with multiple-domain PD-MCI, compared to those with single-domain PD-MCI. Furthermore, patients in the PD-MCI group had significantly more nontremor features.
  
  
  CONCLUSIONS
  These data suggest that PD-MCI is associated with greater sleep disturbance and nontremor features of PD. This is further evidence for the potential role that sleep disturbance plays in the heterogeneity of PD.
authors.affiliation: Parkinson's Disease Research Clinic, Aging Brain Centre, Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales, Australia.
authors.forename: David G
authors.initials: DG
authors.lastname: Gunn
authors.affiliation: Parkinson's Disease Research Clinic, Aging Brain Centre, Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Naismith
authors.affiliation: Parkinson's Disease Research Clinic, Aging Brain Centre, Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Zoe
authors.initials: Z
authors.lastname: Terpening
authors.affiliation: Parkinson's Disease Research Clinic, Aging Brain Centre, Brain & Mind Research Institute, The University of Sydney, Sydney, New South Wales, Australia simonl@med.usyd.edu.au.
authors.forename: Simon J G
authors.initials: SJ
authors.lastname: Lewis
mesh_terms: D056044:Actigraphy; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D060825:Cognitive Dysfunction / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications / Q000503:physiopathology* / Q000523:psychology; D012890:Sleep / Q000502:physiology*; D012893:Sleep Wake Disorders / Q000209:etiology / Q000503:physiopathology*
keywords: Parkinson disease; actigraphy; cognition; mild cognitive impairment; sleep