title: Selective familiarity deficits in otherwise cognitively intact aging individuals with genetic risk for Alzheimer's disease.
abstract: BACKGROUND
  Familiarity has been associated with integrity of the rhinal cortex. Thus, impairment in familiarity is expected in very early stages of Alzheimer's disease (AD). The apolipoprotein E (APOE) ε4 allele is a major risk factor for AD. Here, we investigated the effect of the APOE ε4 status on familiarity in cognitively normal aging individuals.
  
  
  METHODS
  Eighty-one individuals aged between 55 and 80 years, 21 carriers and 60 noncarriers, were used in these analyses. A cognitive evaluation was performed on all participants to document the absence of objective cognitive deficits. The effect of APOE ε4 status on familiarity was tested using independent sample t test and an analysis of covariance controlling for age, gender, and education.
  
  
  RESULTS
  The groups did not differ in term of age, education, and male/female ratio. APOE ε4 carriers showed a significant reduction in familiarity. No other cognitive deficit was observed in the group of ε4 carriers, relative to noncarriers.
  
  
  CONCLUSIONS
  APOE ε4 is associated with a reduction in familiarity in the absence of other cognitive deficits. These results suggest that performance in familiarity could represent an early cognitive marker for individuals at risk of AD.
authors.affiliation: McGill Centre for Studies in Aging, McGill University, Montreal, QC, Canada; Douglas Hospital Research Centre, Montreal, QC, Canada.
authors.forename: Dorothee
authors.initials: D
authors.lastname: Schoemaker
authors.affiliation: Douglas Hospital Research Centre, Montreal, QC, Canada.
authors.forename: Judes
authors.initials: J
authors.lastname: Poirier
authors.affiliation: Douglas Hospital Research Centre, Montreal, QC, Canada.
authors.forename: Sophia
authors.initials: S
authors.lastname: Escobar
authors.affiliation: McGill Centre for Studies in Aging, McGill University, Montreal, QC, Canada.
authors.forename: Serge
authors.initials: S
authors.lastname: Gauthier
authors.affiliation: McGill Centre for Studies in Aging, McGill University, Montreal, QC, Canada; Douglas Hospital Research Centre, Montreal, QC, Canada.
authors.forename: Jens
authors.initials: J
authors.lastname: Pruessner
keywords: Aging; Alzheimer's disease; Apolipoprotein E; Cognitive marker; Familiarity; Recollection