title: Cognitive discrepancies versus APOE genotype as predictors of cognitive decline in normal-functioning elderly individuals: a longitudinal study.
abstract: OBJECTIVE
  Cognitive-discrepancy analysis has been shown to be a useful technique for detecting subtle cognitive deficits in normal-functioning elderly individuals who are genetically at-risk for Alzheimer disease (AD). However, studies that have used cognitive-discrepancy measures to date have used retrospective or cross-sectional designs, and the utility of this approach to predict cognitive decline has not been examined in a prospective investigation.
  
  
  METHODS
  Longitudinal study.
  
  
  METHODS
  San Diego, CA, Veterans Administration Hospital.
  
  
  METHODS
  Twenty-four normal-functioning elderly individuals participated in the study, with 16 subjects exhibiting no change in their Dementia Rating Scale (DRS) scores over an 1-year period (Stable Group), and 8 subjects exhibiting a decline in DRS scores over the 1-year period (Decline group).
  
  
  METHODS
  A cognitive-discrepancy measure isolating cognitive switching was computed that contrasted performance on a new higher-level task of executive functioning (a Stroop/Switching measure) relative to a composite measure of lower-level Stroop conditions.
  
  
  RESULTS
  a) In the year before their cognitive changes, the Decline group exhibited a significantly larger cognitive-discrepancy (Stroop/Switching versus lower-level Stroop conditions) score compared with a control (Stable) group; and b) the cognitive-discrepancy measure was superior to APOE genotype in predicting DRS decline.
  
  
  CONCLUSIONS
  Cognitive-discrepancy analysis isolating a component executive function ability not only seems to be a useful tool for identifying individuals at risk for cognitive deficits, but also shows promise in predicting individuals who may show subtle cognitive decline over time.
authors.affiliation: Veterans Affairs San Diego Healthcare System, San Diego, CA 92161, USA. efine@ucsd.com
authors.forename: Eric M
authors.initials: EM
authors.lastname: Fine
authors.forename: Dean C
authors.initials: DC
authors.lastname: Delis
authors.forename: Spencer R
authors.initials: SR
authors.lastname: Wetter
authors.forename: Mark W
authors.initials: MW
authors.lastname: Jacobson
authors.forename: Amy J
authors.initials: AJ
authors.lastname: Jak
authors.forename: Carrie R
authors.initials: CR
authors.lastname: McDonald
authors.forename: Jodessa C
authors.initials: JC
authors.lastname: Braga
authors.forename: Leon J
authors.initials: LJ
authors.lastname: Thal
authors.forename: David P
authors.initials: DP
authors.lastname: Salmon
authors.forename: Mark W
authors.initials: MW
authors.lastname: Bondi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000145:classification / Q000453:epidemiology; D001053:Apolipoproteins / Q000235:genetics*; D003071:Cognition; D003072:Cognition Disorders / Q000453:epidemiology* / Q000235:genetics*; D004522:Educational Status; D005260:Female; D005838:Genotype; D015577:Geriatric Assessment; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D011569:Psychiatric Status Rating Scales; D014888:Wechsler Scales
chemical_list: D001053:Apolipoproteins