Spouse‐appraised memory functioning predicts memory decline better than subjective memory complaints in non‐demented older adults

Authors: Youssef Bellaali, Bernard J. Hanseeuw, John L. Woodard, Adrian Ivanoiu

Published: 2020-12-07

Abstract

AbstractBackgroundAlzheimer's disease (AD) begins with subtle memory decline, years before dementia onset. The presence of subjective memory complaints (SMC) has been proposed as a marker of preclinical AD. However, recent evidence has demonstrated early and progressive loss of awareness of memory difficulties in non‐demented older adults harboring AD pathology. We investigated the respective contributions of SMC and spouse‐appraised memory functioning (SAM) to predict memory decline in a large cohort of non‐demented older adults.MethodThe Wisconsin Longitudinal Study collected cognitive data from a community‐based cohort of 3607 participants in both 2005 and 2011. The participant and the participant’s spouse were each asked to rate the participant’s memory functioning using a Likert scale. We predicted change in objective episodic memory performance (immediate and delayed recall of 10 words) with models including baseline SMC, baseline SAM, or both SMC and SAM, adjusting for age, sex, and education. We also evaluated an awareness index (SAM minus SMC). We then tested the interaction between APOE4 carrier status and SMC/SAM to evaluate whether the effects were driven by the individuals at‐risk for AD pathology.ResultIn separate models, SMC (Figure 1A: ‐0.081±0.036, p=0.025) and SAM (Figure 1B ‐0.084±0.028, p=0.003) were both associated with memory decline over approximately six years, but the awareness index was not (‐0.028±0.025, p=0.25). When tested in the same model, only SAM (‐0.074±0.028, p=0.009) was associated with memory decline, while SMC was not significant (‐0.061±0.037, p=0.10). The association between SAM and memory decline was stronger in the APOE4 carriers than in the non‐carriers (Figure 2B: APOE‐by‐SAM interaction: F= 6.07; p= 0.002), demonstrating that SAM was particularly predictive for individuals at‐risk for AD pathology. The association between SMC and memory decline was not driven by APOE4 carriers (Figure 2A: APOE‐by‐SMC interaction: F=2.29; p= 0.13).ConclusionSpouse‐appraised memory functioning was more predictive of memory decline than SMC or an awareness index, particularly for APOE4 carriers, who are at increased risk for AD pathology.