Memory decline in healthy older people - Implications for identifying mildcognitive impairment

Background: Criteria for mild cognitive impairment require objective eviden ce of a memory deficit but do not require objective evidence of memory decl ine. Application of these criteria may therefore result in the misclassific ation of older patients with memory decline as normal because their neurops ychological test performance at a single point in time may be within normal limits. This study aimed to identify and characterize older people with me mory decline. Method: Word list delayed recall (WLDR) test performance was assessed on five occasions during a 2-year period in a cohort of healthy ol der individuals. Older people with declining (n = 35) and nondeclining (n = 66) WLDR scores were identified. Both subgroups were then compared on apoE genotype, Clinical Dementia Rating, and neuropsychological test performanc e at the fifth assessment. Results: Thirty-four percent of the group with d eclining memory recorded a Clinical Dementia Rating of 0.5, compared with 5 % of the nondeclining memory group. No between-group differences were obser ved in cognitive domains other than memory, self-reported cognitive failure s, or the proportion of each group carrying the apoE epsilon 4 allele. Conc lusions: A large proportion of healthy older individuals show memory declin e, which may represent the early stages of a potentially more severe cognit ive impairment. Further investigation is necessary to determine the relatio nship between apoE genotype, self-reported cognitive impairment, and memory decline in older people.