title: Detecting subtle changes in visuospatial executive function and learning in the amnestic variant of mild cognitive impairment.
abstract: OBJECTIVE
  Amnestic mild cognitive impairment (aMCI) is a putative prodromal stage of Alzheimer's disease (AD) characterized by deficits in episodic verbal memory. Our goal in the present study was to determine whether executive dysfunction may also be detectable in individuals diagnosed with aMCI.
  
  
  METHODS
  This study used a hidden maze learning test to characterize component processes of visuospatial executive function and learning in a sample of 62 individuals with aMCI compared with 94 healthy controls.
  
  
  RESULTS
  Relative to controls, individuals with aMCI made more exploratory/learning errors (Cohen's d = .41). Comparison of learning curves revealed that the slope between the first two of five learning trials was four times as steep for controls than for individuals with aMCI (Cohen's d = .64). Individuals with aMCI also made a significantly greater number of rule-break/error monitoring errors across learning trials (Cohen's d = .21).
  
  
  CONCLUSIONS
  These results suggest that performance on a task of complex visuospatial executive function is compromised in individuals with aMCI, and likely explained by reductions in initial strategy formulation during early visual learning and "on-line" maintenance of task rules.
authors.affiliation: Department of Psychology, University of Connecticut, Storrs, Connecticut, United States of America.
authors.forename: Kathryn V
authors.initials: KV
authors.lastname: Papp
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Snyder
authors.forename: Paul
authors.initials: P
authors.lastname: Maruff
authors.forename: Jennifer
authors.initials: J
authors.lastname: Bartkowiak
authors.forename: Robert H
authors.initials: RH
authors.lastname: Pietrzak
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000503:physiopathology*; D000647:Amnesia / Q000503:physiopathology*; D003072:Cognition Disorders / Q000503:physiopathology*; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged