Increased memory confidence and delusions in Alzheimer's disease: a preliminary study.

Abstract

There is uncertainty about whether delusion formation in Alzheimer's disease (AD) can be explained by false memories. "Metamemory," the ability to self-evaluate memory and identify memory errors, is impaired in people with delusions in schizophrenia. Our objective was to investigate whether false memory and metamemory were associated with delusions in AD. Participants with mild AD, with and without delusions, completed a computerized word recognition task and a metamemory measure. Group differences were compared using independent-samples t-tests or Mann Whitney tests. Significant findings were explored through binary logistic regression modeling. Participants with delusions (n = 10) gave more high confidence responses, significantly so for correct responses; percentage of high confidence correct responses for those with delusions (mean (SD)) was 69.7% (31.0%) and for those without (n = 14) was 43.5% (29.9%); t₂₂ = -2.09, p = .049. This remained significant when sex was included in regression modeling; for each 1.0% increase in high confidence correct responses, participants were 5.4% more likely to have delusions (Exp(β) 1.054, 95% CI 1.007-1.105, p = .025). Findings provide tentative support for a link between metamemory and delusions in AD. This should be explored in a larger sample as it has potential implications for treatment.