title: Cognitive activity, cognitive function, and brain diffusion characteristics in old age.
abstract: The objective of this work was to test the hypotheses that a) more frequent cognitive activity in late life is associated with higher brain diffusion anisotropy and lower trace of the diffusion tensor, and b) brain diffusion characteristics partially mediate the association of late life cognitive activity with cognition. As part of a longitudinal cohort study, 379 older people without dementia rated their frequency of participation in cognitive activities, completed a battery of cognitive function tests, and underwent diffusion tensor imaging. We used tract-based spatial statistics to test the association between late life cognitive activity and brain diffusion characteristics. Clusters with statistically significant findings defined regions of interest in which we tested the hypothesis that diffusion characteristics partially mediate the association of late life cognitive activity with cognition. More frequent cognitive activity in late life was associated with higher level of global cognition after adjustment for age, sex, education, and indicators of early life cognitive enrichment (p = 0.001). More frequent cognitive activity was also related to higher fractional anisotropy in the left superior and inferior longitudinal fasciculi, left fornix, and corpus callosum, and lower trace in the thalamus (p < 0.05, FWE-corrected). After controlling for fractional anisotropy or trace from these regions, the regression coefficient for the association of late life cognitive activity with cognition was reduced by as much as 26 %. These findings suggest that the association of late life cognitive activity with cognition may be partially mediated by brain diffusion characteristics.
authors.affiliation: Department of Biomedical Engineering, Medical Imaging Research Center, M-102, Illinois Institute of Technology, 3440 South Dearborn St., Chicago, IL, 60616, USA. arfanakis@iit.edu.|Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA. arfanakis@iit.edu.|Department of Diagnostic Radiology and Nuclear Medicine, Rush University Medical Center, Chicago, IL, USA. arfanakis@iit.edu.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Arfanakis
authors.affiliation: Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA.|Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA.|Department of Behavioral Sciences, Rush University Medical Center, Chicago, IL, USA.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Wilson
authors.affiliation: Department of Biomedical Engineering, Medical Imaging Research Center, M-102, Illinois Institute of Technology, 3440 South Dearborn St., Chicago, IL, 60616, USA.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Barth
authors.affiliation: Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA.|Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA.
authors.forename: Ana W
authors.initials: AW
authors.lastname: Capuano
authors.affiliation: Department of Biomedical Engineering, Medical Imaging Research Center, M-102, Illinois Institute of Technology, 3440 South Dearborn St., Chicago, IL, 60616, USA.
authors.forename: Anil
authors.initials: A
authors.lastname: Vasireddi
authors.affiliation: Department of Biomedical Engineering, Medical Imaging Research Center, M-102, Illinois Institute of Technology, 3440 South Dearborn St., Chicago, IL, 60616, USA.
authors.forename: Shengwei
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA.|Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA.|Department of Behavioral Sciences, Rush University Medical Center, Chicago, IL, USA.
authors.forename: Debra A
authors.initials: DA
authors.lastname: Fleischman
authors.affiliation: Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA.|Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Bennett
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D016880:Anisotropy; D001921:Brain / Q000473:pathology*; D003071:Cognition / Q000502:physiology*; D003072:Cognition Disorders; D000066492:Cognitive Aging / Q000502:physiology*; D015331:Cohort Studies; D056324:Diffusion Tensor Imaging / Q000379:methods; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests
keywords: Cognition; Cognitive activity; DTI; Diffusion tensor imaging; MRI; Magnetic resonance imaging