Examination of the metacognitive errors that contribute to anosognosia in Alzheimer's disease

Disordered awareness of memory loss (i.e., anosognosia) is a frequent and clinically relevant symptom of Alzheimer's disease (AD). The metacognitive errors which characterize anosognosia in AD, however, have not been fully articulated. The current study examined metamemory performance as a function of clinically defined awareness groups using different task conditions to examine the extent to which specific metacognitive deficits (i.e., detecting, integrating, or being explicitly aware of errors) contribute to anosognosia in AD (n = 49). In the prospective condition of the metamemory task, analyses examining the association between awareness group, confidence (i.e., FOK) ratings, and memory performance demonstrated an interaction effect F (1, 43) = 5.16, p = .028 with only the aware group (n = 22) providing higher FOK ratings for correct responses compared to incorrect responses (p < .001). The unaware group (n = 27) did not show this dissociation (p = .167), and also made higher FOK ratings for incorrect responses than the aware group (p = .048). There was no main effect of task condition on FOK [F (2, 66) = 1.51, p = .228] with all participants providing comparable FOK ratings for memory performance whether ratings were made prospectively, retrospectively, or in the context of examiner feedback. The overall pattern of performance in the unaware group, whereby individuals did not sufficiently lower confidence ratings in the context of memory errors, and did not benefit from either retrospective assessment or examiner feedback, appears most consistent with a primary anosognosia in which memory failures are not available in explicit awareness.