A Population-Based Study of Cognitive Function in Older People with Subjective Memory Complaints

Given the uncertain relationship between objective and subjective memory complaints (SMC), we conducted a study of cognitive function in older people with memory complaints in a large population-based elderly Spanish cohort (NEDICES). A total of 1,073 subjects with SMC and 1,073 matched controls free from dementia underwent a neuropsychological assessment, including tests of global cognitive performance, frontal executive function, verbal fluency, and memory. SMC were associated with a number of specific objective cognitive deficits including poor verbal fluency, and poor immediate and delayed recall. However, there was a limited association with global cognitive impairment despite a strong influence upon Pfeffer Functional Activities Questionnaire based daily function. In the full sample the strongest predictors of SMC were poor psychological well-being, depressive symptoms (including those taking antidepressants) and hearing impairment. Moderate predictors were age and gender. If individuals with mild cognitive impairment (MCI) were removed, then the strongest predictors were poor psychological well-being, depressive symptoms, hearing impairment, illiteracy, age, and gender. For those with MCI alone, the only significant predictor of memory complaints was poor psychological well-being. Predictors of SMC in those with depressive symptoms included poor psychological well-being and hearing impairment. With depressive symptoms excluded the strongest predictors were poor psychological well-being, hearing impairment, illiteracy, and gender. In this population-based sample, individuals with SMC had evidence of impairments on specific neuropsychological testing which might not be apparent on global measures. Predictors of SMC may differ in those with versus without MCI and those with versus without depressive symptoms.