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The Scientific World Journal
Volume 2013, Article ID 350623, 16 pages
Research Article

Cognitive Intraindividual Variability and White Matter Integrity in Aging

1FPSE, University of Geneva, Boul du Pont d’Arve 40, 1211 Geneva 4, Switzerland
2Clinical Neurological Sciences, Western University, 339 Windermere Road, London, ON, Canada N6A 5A5
3Electrical and Computer Engineering, Western University, 1151 Richmond Street, London, ON, Canada N6A 3K7
4CIGEV, University of Geneva, Boul du Pont d’Arve 40, 1211 Geneva 4, Switzerland

Received 24 May 2013; Accepted 3 July 2013

Academic Editors: A. Bayer, D. Dykiert, J. Kremláček, P. McLaughlin, and A. Tales

Copyright © 2013 Nathalie Mella et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The intraindividual variability (IIV) of cognitive performance has been shown to increase with aging. While brain research has generally focused on mean performance, little is known about neural correlates of cognitive IIV. Nevertheless, some studies suggest that IIV relates more strongly than mean level of performance to the quality of white matter (WM). Our study aims to explore the relation between WM integrity and cognitive IIV by combining functional (fMRI) and structural (diffusion tensor imaging, DTI) imaging. Twelve young adults (aged 18–30 years) and thirteen older adults (61–82 years) underwent a battery of neuropsychological tasks, along with fMRI and DTI imaging. Their behavioral data were analyzed and correlated with the imaging data at WM regions of interest defined on the basis of (1) the fMRI-activated areas and (2) the Johns Hopkins University (JHU) WM tractography atlas. For both methods, fractional anisotropy, along with the mean, radial, and axial diffusivity parameters, was computed. In accord with previous studies, our results showed that the DTI parameters were more related to IIV than to mean performance. Results also indicated that age differences in the DTI parameters were more pronounced in the regions activated primarily by young adults during a choice reaction-time task than in those also activated in older adults.