Article abstract Objective: The term "mild cognitive impairment" refers to cognitive deficits in the older age which exceed age-related cognitive decline but do not fullfill criteria of dementia. Affected subjects are assumed to be at higher risk for the development of dementia such as Alzheimer's disease (AD). However, little is known about the group of "young-old" subjects with respect to prevalence and natural course of cognitive decline. Methods : Within the population-based

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... y Longitudinal Study on Adult Development and Aging (ILSE), neuropsychological functioning was assessed in 500 community-dwelling "young-old" subjects (mean age at baseline: 62.4±2.4 years) of two German urban regions born between 1930 and 1932. Participants were carefully screened for physical and mental health and reexamined four years later. The concept of "aging-associated cognitive decline" (AACD) was applied. Results: At baseline, 13.4% of the subjects fulfilled the AACD criteria. Four years later, AACD prevalence rates rose to 24.1%. 52.3% of the subjects initially classified as AACD retained the diagnosis at follow-up. While AACD subjects showed a reduced performance in all neuropsychological domains addressed, a significant (p<0.05) decline was confined to delayed verbal memory test performance during the 4-year follow-up period when compared to the controls. AACD did not predict conversion to dementia during the follow-up intervall. Conclusions: In "young-old" community-dwelling individuals, AACD is a frequent condition with a high temporal stability. During a 4-year follow-up period, AACD subjects deteriorated specifically in measures of episodic memory underscoring the value of the respective deficits in characterizing "mild cognitive impairment".