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P3‐238: Age‐associated memory impairment increases risk of conversion to MCI and dementia
Author(s) -
Lee Grace,
Elashoff David,
Di Lijie,
Teng Edmond,
Melchor Stephanie,
Kim Johnny,
Lu PoHaong
Publication year - 2012
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2012.05.1460
Subject(s) - dementia , recall , cognition , cognitive decline , effects of sleep deprivation on cognitive performance , psychology , cognitive impairment , medicine , audiology , gerontology , psychiatry , disease , cognitive psychology
Background: Age-associated memory impairment (AAMI) was initially conceptualized to describe a feature of cognitive aging. It is defined as memory performance consistent with normal age-matched peers but significantly lower than younger adults. However, mounting evidence suggests that AAMI may represent a harbinger of future cognitive decline and dementia rather than simply normal cognitive aging. The objective of this study was to investigate whether a diagnosis of AAMI increases risk of cognitive decline and conversion to Mild Cognitive Impairment (MCI) or dementia. Methods: 1549 subjects (551males) from the National Alzheimer’s Coordinating Center (NACC) who were initially diagnosed with normal cognition at baseline and had at least 3 follow-up visits were included in the present study. Subjects ranged in age from 51 to 97 years (mean1⁄474.39, sd1⁄48.4). Baseline performance on the delayed recall of Logical Memory Story A was examined, and individuals scoring more than 1 standard deviation below themean of younger adults (mean age1⁄431.1 years, sd1⁄411.2) were classified as having AAMI. Survival analysis was performed using Cox regression to determine whether a diagnosis of AAMI predicted progression to MCI or dementia. Results: In the current sample, 486 subjects (31.4%) met criteria for AAMI while 1063 were considered normal (NC) compared to younger adults. The proportion of subjects who converted to MCI or dementia was significantly higher (x 2 1⁄428.65, P<.001) in the AAMI group (n1⁄4117, 24.1%) compared to the NC group (n1⁄4140, 13.2%). The average time to conversion in these subjects was 2.5 years (sd1⁄41.2). After adjusting for baseline age, gender, years of education, and APOE genotype, Cox regression analysis revealed that a classification of AAMI at baseline was significantly (P<.001) associated with increased risk of converting to MCI or dementia (HR1⁄41.93, 95% CI 1⁄4 1.44 2.58). Conclusions: Among individuals with normal cognition, those meeting criteria for AAMI had a higher risk of conversion to MCI or dementia. Thus, AAMI may represent an early stage of cognitive decline, even preceding MCI, and may be diagnostically useful in identifying individuals at risk for eventual development of dementia.