Neuropsychological Profiles of Older Adults with Superior versus Average Episodic Memory: The Northwestern "SuperAger" Cohort.

ABSTRACT

OBJECTIVE: SuperAgers are adults over the age of 80 with superior episodic memory performance and at least average-for-age performance in non-episodic memory domains. This study further characterized the neuropsychological profile of SuperAgers compared to average-for-age episodic memory peers to determine potential cognitive mechanisms contributing to their superior episodic memory performance. METHOD: Retrospective analysis of neuropsychological test data from 56 SuperAgers and 23 similar-age peers with average episodic memory was conducted. Independent sample t-tests evaluated between-group differences in neuropsychological scores. Multiple linear regression determined the influence of non-episodic memory function on episodic memory scores across participants. RESULTS: As a group, SuperAgers had better scores than their average memory peers on measures of attention, working memory, naming, and speeded set shifting. Scores on tests of processing speed, visuospatial function, verbal fluency, response inhibition, and abstract reasoning did not differ. On an individual level, there was variability among SuperAgers with regard to non-episodic memory performance, with some performing above average-for-age across cognitive domains while others performed in the average-for-age range on non-memory tests. Across all participants, attention and executive function scores explained 20.4% of the variance in episodic memory scores. CONCLUSIONS: As a group, SuperAgers outperformed their average memory peers in multiple cognitive domains, however, there was considerable intragroup variability suggesting that SuperAgers' episodic memory strength is not simply related to globally superior cognitive functioning. Attention and executive function performance explained approximately one-fifth of the variance in episodic memory and maybe areas to target with cognitive interventions.