Age-associated memory impairment

In this issue of Neurology, Koivisto et al ^[1] present important epidemiologic data on the prevalence of age-associated memory impairment (AAMI). As originally defined, AAMI represents persons aged 50 or older who have a subjective sense of decline in memory relative to their younger adult years, perform at least 1 SD below the mean for young adults on standard measures of memory function, are not demented, and have no other medical or psychiatric condition that can account for this memory decline ^[2]. Koivisto et al ^[1] discuss other issues concerning this controversial diagnostic category that merit further discussion, particularly since a related modified diagnostic category, Age-Related Cognitive Decline, has been included in DSM-IV ^[3].

Previous reports on the epidemiology of AAMI have not employed the specific diagnostic criteria for AAMI and have utilized varying methodology ^[4,5] or have been based on archival data reported for age-associated normative data on standard memory tests ^[6]. Koivisto et al ^[1] are the first to apply the specific AAMI criteria in a random, large-scale epidemiologic study, and they report a prevalence rate for AAMI of 38.4%, which declined with age, based on 1,049 subjects aged 60 to 78 years.

Their study ^[1] addresses several issues concerning the concept of AAMI: its relation to normal aging and Alzheimer's disease (AD); whether it has value as a diagnostic entity; and the utility of the objective memory tests, subjective complaints, intellectual capacity testing, and dementia exclusion factors proposed in the original definition of AAMI ^[2].

Koivisto et al ^[1] view AAMI as a phenomenon of normal aging and rate their reported prevalence of 38.4% as high. However, the data in their table 3 show that 8.8% of 1,049 subjects, or 92, had dementia, as defined by a Mini-Mental State Examination (MMSE) score of …