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Cognitive reserve and cortical thickness in preclinical Alzheimer's disease

TitleCognitive reserve and cortical thickness in preclinical Alzheimer's disease
Publication TypeJournal Article
Year of Publication2017
AuthorsPettigrew, C, Soldan, A, Zhu, Y, Wang, MC, Brown, T, Miller, M, Albert, M
JournalBrain Imaging Behav
Volume11
Pagination357-367
Date PublishedApr
ISBN Number1931-7557
Accession Number27544202
KeywordsAlzheimer's disease, Cognitive reserve, Cortical thickness, Magnetic Resonance Imaging, Preclinical AD
Abstract

This study examined whether cognitive reserve (CR) alters the relationship between magnetic resonance imaging (MRI) measures of cortical thickness and risk of progression from normal cognition to the onset of clinical symptoms associated with mild cognitive impairment (MCI). The analyses included 232 participants from the BIOCARD study. Participants were cognitively normal and largely middle aged (M age = 56.5) at their baseline MRI scan. After an average of 11.8 years of longitudinal follow-up, 48 have developed clinical symptoms of MCI or dementia (M time from baseline to clinical symptom onset = 7.0 years). Mean thickness was measured over eight 'AD vulnerable' cortical regions, and cognitive reserve was indexed by a composite score consisting of years of education, reading, and vocabulary measures. Using Cox regression models, CR and cortical thickness were each independently associated with risk of clinical symptom onset within 7 years of baseline, suggesting that the neuronal injury occurring proximal to symptom onset has a direct association with clinical outcomes, regardless of CR. In contrast, there was a significant interaction between CR and mean cortical thickness for risk of progression more than 7 years from baseline, suggesting that individuals with high CR are better able to compensate for cortical thinning that is beginning to occur at the very earliest phase of AD.