Association between memory complaints and incident Alzheimer's disease in elderly people with normal baseline cognition

Objective: Results of previous studies suggest that memory complaints may predict cognitive decline and dementia among elderly people in whom cognitive impairment is already apparent. However, cognitive decline is often a gradual process, and elderly people may notice that their memory deteriorates before mental status tests are able to detect any change in cognitive functioning. Therefore, the authors hypothesized that memory complaints would predict incident Alzheimer's disease in elderly subjects with no signs of cognitive impairment. Method: In the community-based Amsterdam Study of the Elderly, a sample of 3,778 nondemented persons, 65 to 84 years old, was selected and divided into two cognitive categories: normal (Mini-Mental State scores of 26-30) and borderline and impaired (Mini-Mental State scores less than 26). At baseline, the presence or absence of memory complaints was assessed. At follow-up, incident cases of Alzheimer's disease were diagnosed in a two-step procedure. Results: After an average of 3.2 years, 2,169 persons were reevaluated, of whom 77 had incident Alzheimer's disease. Multivariate logistic regression analyses showed that memory complaints were associated with incident Alzheimer's disease in subjects with normal baseline cognition but not in subjects with impaired baseline cognition. Conclusions: The findings of this study suggest that memory complaints are a relatively strong predictor of incident Alzheimer's disease in older persons in whom cognitive impairment is not yet apparent. Furthermore, they suggest that older persons may be aware of a decline in cognition at a time when mental status tests are still unable to detect a decline from premorbid functioning.