What are subjective cognitive difficulties and do they matter?

Abstract

Background: Subjective cognitive difficulties (SCD) have been associated with a higher risk of developing dementia. However, there is large variation in the way SCD are assessed and in their associations with cognitive functioning. Objective: To compare the agreement of different SCD measures in identifying people with SCD and to investigate whether SCD are more strongly associated with cognitive functioning, mood, subjective-age or background variables. Methods: This cross-sectional study included 206 community-dwelling people aged ≥65. SCD were assessed with individual domain specific questions and a multiple-item scaled measure. Performance on tests of memory, attention, and executive function, and ratings of mood, subjective-age and demographic information were recorded. Results: There was some classification overlap between the five measures of SCD, however of the 64 people identified as having SCD, only one person appeared in all five measures of SCD and 34 people were classified by one measure only. There were limited associations between SCD and objective cognition, with more consistent associations with mood and subjective-age. Conclusions: The conflicting evidence regarding whether SCD are related to objective cognition and future risk of dementia may be due to different measures of SCD being employed. Careful consideration and standardisation is recommended regarding the cognitive domains and the reference groups for comparison, the response structure and the classification criteria. Longitudinal studies of SCD that include these considerations are needed to clarify the conceptual utility of SCD.