title: A diffusion model analysis of episodic recognition in preclinical individuals with a family history for Alzheimer's disease: The adult children study.
abstract: OBJECTIVE
  A family history of Alzheimer's disease (AD) increases the risk of developing AD and can influence the accumulation of well-established AD biomarkers. There is some evidence that family history can influence episodic memory performance even in cognitively normal individuals. We attempted to replicate the effect of family history on episodic memory and used a specific computational model of binary decision making (the diffusion model) to understand precisely how family history influences cognition. Finally, we assessed the sensitivity of model parameters to family history controlling for standard neuropsychological test performance.
  
  
  METHODS
  Across 2 experiments, cognitively healthy participants from the Adult Children Study completed an episodic recognition test consisting of high- and low-frequency words. The diffusion model was applied to decompose accuracy and reaction time (RT) into latent parameters which were analyzed as a function of family history.
  
  
  RESULTS
  In both experiments, individuals with a family history of AD exhibited lower recognition accuracy and this occurred in the absence of an apolipoprotein E (APOE) ε4 allele. The diffusion model revealed this difference was due to changes in the quality of information accumulation (the drift rate) and not differences in response caution or other model parameters. This difference remained after controlling for several standard neuropsychological tests.
  
  
  CONCLUSIONS
  These results confirm that the presence of a family history of AD confers a subtle cognitive deficit in episodic memory as reflected by decreased drift rate that cannot be attributed to APOE. This measure may serve as a novel cognitive marker of preclinical AD.
authors.affiliation: Department of Psychology, Washington University in St. Louis.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Aschenbrenner
authors.affiliation: Department of Psychology, Washington University in St. Louis.
authors.forename: David A
authors.initials: DA
authors.lastname: Balota
authors.affiliation: Department of Radiology, Washington University in St. Louis.
authors.forename: Brian A
authors.initials: BA
authors.lastname: Gordon
authors.affiliation: Department of Psychology, The Ohio State University.
authors.forename: Roger
authors.initials: R
authors.lastname: Ratcliff
authors.affiliation: Department of Neurology, Washington University in St. Louis.
authors.forename: John C
authors.initials: JC
authors.lastname: Morris
mesh_terms: D000328:Adult; D032721:Adult Children / Q000523:psychology*; D000483:Alleles; D000544:Alzheimer Disease / Q000235:genetics / Q000523:psychology*; D053327:Apolipoprotein E4 / Q000235:genetics*; D001057:Apolipoproteins E / Q000235:genetics; D003071:Cognition; D003072:Cognition Disorders / Q000235:genetics / Q000523:psychology; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008297:Male; D061212:Memory, Episodic; D011930:Reaction Time; D012306:Risk
chemical_list: D053327:Apolipoprotein E4; D001057:Apolipoproteins E