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O3‐05‐02: Cognitive change across the life span: Recent insights
Author(s) -
Shatil Evelyn
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.2012.05.1165
Subject(s) - cognition , cognitive decline , psychology , cognitive training , effects of sleep deprivation on cognitive performance , working memory , life span , cognitive skill , cognitive psychology , developmental psychology , gerontology , medicine , neuroscience , dementia , disease , pathology
asymptomatic APOE e4 carriers during their 50’s demonstrating a genedose effect that we have previously shown is nearly coincident with the onset of accelerated decline on the long term memory (LTM) score of the auditory verbal learning test (AVLT). An NIA-sponsored workgroup has emphasized the need to identify sensitive neuropsychological markers to detect and characterize this preclinical stage of Alzheimer’s disease (AD). Methods: 813 cognitively normal members of the Arizona APOE and Alzheimer’s Disease Center (ADC) cohorts aged 21-97 years underwent neuropsychological testing every 1-2 years. We estimated the longitudinal effect of age on cognition using statistical models that simultaneously modeled cross sectional and longitudinal effects of age on neuropsychological test scores by APOE and the interaction between the two. We then compared the baseline scores of all e4 homozygotes age 50-65 years, comprising a high probability preclinical stage AD subset, with e4 noncarriers to see whether the same measures showing longitudinal decline could discriminate the two groups in the absence of longitudinal data. Results: Baseline comparisons of 59 APOE e4 homozygotes with 258 e4 noncarriers age 50-65 failed to show differences on any cognitive measures. In contrast, in longitudinal analyses, there was significant decline in both linear (P1⁄40.001) and quadratic (P1⁄40.009) models on the AVLT LTM score in carriers vs. noncarriers that showed a strong e4 gene dose effect (P1⁄40.005). Similarly robust decline was seen on the Selective Reminding Test (SRT) and Visual Retention Test (VRT), but less so on the Complex Figure Test (CFT). There were no consistent effects in executive, language, visuospatial, general, functional, or subjective measures, but a significant gene-dose effect was evident on the Dementia Rating Scale (DRS). Conclusions: Preclinical stage AD is neuropsychologically characterized most consistently by memory decline affecting verbal more than visual memory measures with inconsistent and limited decline in other domains. Single baseline comparisons, however, fail to disclose these differences. Strategies for neuropsychological testing in preclinical cohorts based on traditional measures should emphasize longitudinal design and memory sensitive measures.