Evaluating self- and informant-reported complaints as predictors of cognitive progression in subjective cognitive...

BackgroundSubjective cognitive complaints (SCCs) in cognitively normal older adults are associated with increased dementia risk. However, it remains uncertain which complaints best predict cognitive decline and whether predictive value differs between patient and informant reports.ObjectiveTo examine associations between self- and informant-reported total scores and individual items from the Questionnaire of Cognitive Complaints (QPC) and longitudinal cognitive decline in individuals with subjective cognitive decline (SCD).Methods261 individuals with SCD from the prospective Czech Brain Aging Study were followed longitudinally (mean 4.2-year follow-up). Linear mixed-effects models (random intercepts), adjusted for age, sex, and education, were estimated separately for self- and informant-reported QPC-total scores and for individual QPC-items to examine associations with change over time in global cognition, memory, and executive function/processing speed cognitive composites.ResultsHigher QPC-total scores predicted steeper decline across all cognitive composites in both self- and informant-reports, with modest effects. At the item level, after Bonferroni correction, informant-reported impressions of memory change and worse memory compared with peers were associated with a more pronounced decline across all cognitive composites exceeding the predictive value of the QPC-total score. Several other memory- and non-memory-related complaints showed associations in the same direction but did not consistently remain significant after correction.ConclusionsIn older adults with SCD, focusing on specific SCCs, particularly informant-reported memory complaints, rather than relying solely on global SCC score, allows more targeted identification of individuals whose complaints are most consistently associated with longitudinal cognitive decline. Structured assessments integrating informant perspective may improve early risk stratification.