title: Is fatigue associated with cognitive dysfunction in early Parkinson's disease?
abstract: Fatigue is a common and disabling symptom which may be seen in early Parkinson's disease (PD). Our understanding of the phenomenology and etiology of fatigue in PD is limited. The objective of this study was to determine whether fatigue was related to cognition in early PD patients.
  
  
  
  The study is part of the Norwegian ParkWest project, a population-based cohort study, comprising 184 de novo, drug-naïve patients with PD. PD was diagnosed according to the Gelb criteria. Fatigue was assessed by the Fatigue Severity Scale (FSS). Cognition was assessed by a battery of tests evaluating functions in the domains of verbal memory, processing speed, executive function and visuospatial abilities.
  
  
  
  107 of the cohort had moderate to severe fatigue (FSS ≥ 4). In univariate correlation analyses high fatigue score was correlated to disease severity, presence of sleep problems, depressive symptoms, apathy, reduced processing speed and reduced visuospatial abilities. In a multiple regression analysis only disease severity (measured by the UPDRS part 3), sleep problems, depressive symptoms and reduced visuospatial abilities contributed to the model.
  
  
  
  Fatigue is associated with visuospatial function in early PD patients. Further studies are needed to determine the pathophysiologic relevance of this association.
authors.affiliation: Department of Neurology, University of Colorado Anschutz Medical Campus, 12631 E 17thAvenue, Aurora, CO 80045, USA. Electronic address: benzi.kluger@ucdenver.edu.
authors.forename: Benzi M
authors.initials: BM
authors.lastname: Kluger
authors.affiliation: Department of Neurology, The Norwegian Centre for Movement Disorders, Stavanger University Hospital, Gerd-Ragna Bloch Thorsens gate 8, 4011 Stavanger, Norway.
authors.forename: Kenn Freddy
authors.initials: KF
authors.lastname: Pedersen
authors.affiliation: Department of Neurology, Haukeland University Hospital, Jonas Lies vei 65, 5021 Bergen, Norway.
authors.forename: Ole-Bjorn
authors.initials: OB
authors.lastname: Tysnes
authors.affiliation: Department of Neurology, Sorlandet Hospital, Sykehusveien 1, 4838 Arendal, Norway.
authors.forename: Solgunn O
authors.initials: SO
authors.lastname: Ongre
authors.affiliation: Department of Rehabilitation, Sorlandet Hospital, Sykehusveien 1, 4838 Arendal, Norway.
authors.forename: Bjørg
authors.initials: B
authors.lastname: Øygarden
authors.affiliation: Department of Neurology, Sorlandet Hospital, Sykehusveien 1, 4838 Arendal, Norway.
authors.forename: Karen
authors.initials: K
authors.lastname: Herlofson
mesh_terms: D000368:Aged; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology*; D015331:Cohort Studies; D004185:Disability Evaluation; D056344:Executive Function / Q000502:physiology; D005221:Fatigue / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D009664:Norway; D010300:Parkinson Disease / Q000150:complications*; D012720:Severity of Illness Index
keywords: Cognition; Fatigue; Neuropsychology; Parkinson's disease