Cognitive correlates of metamemory in Alzheimer's disease.

Abstract

Metamemory, or knowledge of one's memory abilities, is often impaired in individuals with Alzheimer's disease (AD), although the basis of this metacognitive deficit has not been fully articulated. Behavioral and imaging studies have produced conflicting evidence regarding the extent to which specific cognitive domains (i.e., executive function; memory) and brain regions contribute to memory awareness. The primary aim of this study was to disentangle the cognitive correlates of metamemory in AD by examining the relatedness of objective metamemory performance to cognitive tasks grouped by domain (executive function or memory) as well as by preferential hemispheric reliance defined by task modality (verbal or nonverbal). Eighty-nine participants with mild AD recruited at Columbia University Medical Center and the University of Pennsylvania underwent objective metamemory and cognitive testing. Partial correlations were used to assess the relationship between metamemory and four cognitive variables, adjusted for recruitment site. The significant correlates of metamemory included nonverbal fluency (r = .27, p = .02) and nonverbal memory (r = .24, p = .04). Our findings suggest that objectively measured metamemory in a large sample of individuals with mild AD is selectively related to a set of interdomain nonverbal tasks. The association between metamemory and the nonverbal tasks may implicate a shared reliance on a right-sided cognitive network that spans frontal and temporal regions.