The Impact of Awareness of and Concern About Memory Performance on the Prediction of Progression From Mild Cognitive Impairment to Alzheimer Disease Dementia

Abstract

Objective: To investigate the relationship of awareness of and concern about memory performance to progression from mild cognitive impairment (MCI) to Alzheimer disease (AD) dementia.

Methods: Participants (n = 33) had a diagnosis of MCI at baseline and a diagnosis of MCI or AD dementia at follow-up. Participants were categorized as "Stable-MCI" if they retained an MCI diagnosis at follow-up (mean follow-up = 18.0 months) or "Progressor-MCI" if they were diagnosed with AD dementia at follow-up (mean follow-up = 21.6 months). Awareness was measured using the residual from regressing a participant's objective memory score onto their subjective complaint score (i.e., residual<0 indicates overestimation of performance). Concern was assessed using a questionnaire examining the degree of concern when forgetting. Logistic regression was used to determine whether the presence of these syndromes could predict future diagnosis of AD dementia, and repeated measures analysis of covariance tests were used to examine longitudinal patterns of these syndromes.

Results: Baseline anosognosia was apparent in the Progressor-MCI group, whereas participants in the Stable-MCI group demonstrated relative awareness of their memory performance. Baseline awareness scores successfully predicted whether an individual would progress to AD-dementia. Neither group showed change in awareness of performance over time. Neither group showed differences in concern about memory performance at baseline or change in concern about performance over time.

Conclusion: These data suggest that anosognosia may appear prior to the onset of AD dementia, while anosodiaphoria likely does not appear until later in the AD continuum. Additionally, neither group showed significant changes in awareness or concern over time, suggesting that change in these variables may happen over longer periods.

Keywords: Alzheimer disease; awareness; clinical progression; mild cognitive impairment; subjective memory complaints.

FIGURE 1.

Longitudinal awareness index scores in Stable-MCI and Progressor-MCI. This graph demonstrates the awareness scores at baseline and follow-up for the Stable-MCI and Progressor-MCI groups. The awareness score is the residual obtained from regressing subjective memory ratings onto objective memory performance, such that an awareness score of 0 would indicate perfect awareness of one’s own performance. A higher awareness score indicates a participant is underestimating their own performance and a lower awareness score indicates that a participant is overestimating their own performance. A logistic regression model showed that baseline awareness index score reliably distinguished between those within the Progressor-MCI group and those within the Stable-MCI group (overall model: χ² = 11.85, p = 0.019, df = 4, Nagelkerke’s R² = 0.427, prediction success = 84.8%). A repeated measures ANCOVA indicated that awareness score did not significantly change over time for either group (F[1,27] = 0.150, Wilks’s lambda = 0.994, p = 0.702).

FIGURE 2.

Longitudinal concern scores in Stable-MCI and Progressor-MCI. This graph demonstrates the concern scores (i.e., ratings of concern about memory) for the Stable-MCI and Progressor-MCI groups at baseline and follow-up visits. A higher concern score indicates greater concern about memory performance. A logistic regression model using baseline concern scores to predict group was not significant (χ² = 3.502, p = 0.478, df = 4), indicating baseline ratings of concern about memory performance do not seem to reliably predict which individuals with MCI will progress to AD dementia. A repeated measures ANCOVA investigating the interaction between group and time on concern scores was significant, indicating differential change over time for one group compared to the other, although neither group individually showed change that was statistically significant.