title: Antisaccades and executive dysfunction in early drug-naive Parkinson's disease: The discovery study.
abstract: BACKGROUND
  Cognitive impairment is well recognized in Parkinson's disease (PD), but when it begins to develop is unclear. The aim of this study was to identify early signs of cognitive impairment along with abnormalities in saccadic behavior in newly diagnosed unmedicated PD patients.
  
  
  METHODS
  Nineteen drug-naive PD patients and 20 controls were examined using a battery of tests, including an antisaccade task, phonemic and semantic verbal fluencies, and a switching and rule finding task.
  
  
  RESULTS
  With simple tasks, no differences were found between the two groups. However, cognitive performance of the two groups diverged with more complex tasks, occurring independently of PD-related motor impairment. Patients exhibited higher antisaccadic error rates and switch costs in the task switching test, and performed significantly worse in the rule finding task.
  
  
  CONCLUSIONS
  Certain cognitive domains and saccadic parameters are already significantly impoverished in newly diagnosed Parkinson's patients, even before the initiation of medication.
authors.affiliation: Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, United Kingdom.
authors.forename: Chrystalina A
authors.initials: CA
authors.lastname: Antoniades
authors.affiliation: Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford, United Kingdom.
authors.forename: Nele
authors.initials: N
authors.lastname: Demeyere
authors.affiliation: Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, United Kingdom.
authors.forename: Christopher
authors.initials: C
authors.lastname: Kennard
authors.affiliation: Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford, United Kingdom.
authors.forename: Glyn W
authors.initials: GW
authors.lastname: Humphreys
authors.affiliation: Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, United Kingdom.|Oxford Parkinson's Disease Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, United Kingdom.
authors.forename: Michele T
authors.initials: MT
authors.lastname: Hu
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D003072:Cognition Disorders / Q000175:diagnosis* / Q000523:psychology; D042241:Early Diagnosis; D056344:Executive Function; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000503:physiopathology* / Q000523:psychology*; D011597:Psychomotor Performance; D012438:Saccades
keywords: Parkinson's disease; antisaccades; executive function; eye movements; task switching