Subjective memory complaints: presence, severity and future outcome in normal older subjects

BACKGROUND/AIMS: Subjective memory complaint (SMC) in normal individuals may predict future cognitive decline. The goal of this study was to examine whether the probability of decline increases with growing intensity of complaint. METHODS: Normal subjects over the age of 50 years were included in a longitudinal retrospective study (mean follow-up time = 8 years). All subjects (n = 230) underwent cognitive and medical examination at baseline. The presence of SMC was determined based on Global Deterioration Scale staging. A subgroup of 83 participants also received baseline assessment for the intensity of SMC. Logistic regression was used to predict outcome from baseline variables. Three outcome groups were established at the final visit: nondeclining, declining and diagnostically unstable (i.e. the diagnosis changed over time: from normal to mild cognitive impairment, then back to normal). RESULTS: The presence of SMC was a predictor of future decline but also increased the likelihood of the unstable diagnosis. Increasing intensity of SMC did not further raise the risk for decline. High intensity of complaints and more pronounced affective symptoms predicted the unstable clinical diagnosis. CONCLUSIONS: The presence of SMC contributes to the risk of future decline, however, the increasing intensity of the perceived impairment does not further enhance the risk.