Discrimination of Healthy Aging and Very Mild Dementia of the Alzheimer’s Type

The present study explored the ability to control familiarity-based information in a memory exclusion paradigm in healthy young, older adults, and early stage DAT individuals. The authors compared the predictive power of memory exclusion performance to standard psychometric performance in discrim-inating between healthy aging and the earliest detectable form of DAT and between APOe4-present and APOe4-absent genotype in healthy control individuals. Participants responded “yes ” to words that were previously semantically encoded, and “no ” to other words. The number of targets and distractors on the read “distractor ” list was manipulated to investigate the degree to which aging and DAT influence the ability to recollect specific details of study episodes in the face of distractor familiarity because of repetition. Memory exclusion performance (as reflected by d) decreased across participant groups (young healthy old control very mild DAT). Logistic regression analyses showed that d increased the discriminative power for healthy older adults versus very mild DAT individuals above and beyond standard psychometric measures. Memory exclusion d was also lower for healthy control individuals with APOe4 allele, compared to those without the APOe4 allele after partialing out baseline psycho-metric performance. Discussion focuses on the importance of attentional control systems in memory retrieval and the utility of the opposition paradigm for early discrimination between healthy and pathological aging