The Role of Dyads in Subjective Reporting and Prediction of Cognitive Worsening in Cognitively Unimpaired Individuals and Individuals with Subjective Cognitive Decline: Results of the CompAS Longitudinal Study

Abstract

Objective: The main aim was to examine the value of agreement on subjective cognitive complaints (SCCs) reported by study participants and informants in predicting worsening cognitive function over time in cognitively unimpaired (CU) and subjective cognitive decline (SCD) participants. Methods: The sample consisted of 175 participants from the CompAS study (CU = 139; SCD = 36), who were followed up three times along a period from 17 to 76 months after the start of the study. Levels of agreement on the "Dyadic SCCs" were categorized according to whether informant and participant scores at baseline on the short version of the "Questionnaire d'Autoevaluation de la Mémoire" were above or below a cut-off point accounting for age-related normative complaints. Two categories of agreement were identified: (a) participant scores above the cut-off and informant scores below the cut-off ("Self-over-reporting"); (b) both participant and informant scores above the cut-off point ("Agreement on presence"). We performed Cox proportional hazards regression model adjusted for sex, age, and years of education. Results: The tested model yielded statistical significant findings and acceptable model fit parameters. "Dyadic SCCs" significantly predicted cognitive worsening over time, with "Self-over-reporting" acting as a better indicator of the risk than "Agreement on presence" in both CU and SCD groups. Conclusions: The data showed that the "Self-overreporting," compared to "Agreement on presence," increases the risk of worsening per time unit. The findings may be explained by greater awareness of one's own difficulties (hypernosognosia) in preclinical stages of cognitive decline.