Magnetic resonance imaging determinants of intraindividual variability in the elderly: combined analysis of grey and white matter

Abstract Elderly individuals display a rapid age-related increase in intraindividual variability (IIV) of their performances. This phenomenon could reflect subtle changes in frontal lobe integrity. However, structural studies in this field are still missing. To address this issue, we computed an IIV...

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Bibliographic Details
Published in:Neuroscience 2011-07, Vol.186, p.88-93
Main Authors: Moy, G, Millet, P, Haller, S, Baudois, S, de Bilbao, F, Weber, K, Lövblad, K, Lazeyras, F, Giannakopoulos, P, Delaloye, C
Format: Article
Language:English
Subjects:
Adult
Aged
Aged, 80 and over
aging
Aging - pathology
Biological and medical sciences
Cognition Disorders - pathology
Cognition Disorders - psychology
Female
fractional anisotropy
Frontal Lobe - pathology
Frontal Lobe - physiopathology
Fundamental and applied biological sciences. Psychology
Humans
Individuality
intraindividual variability
Male
Memory Disorders - pathology
Memory Disorders - psychology
Middle Aged
Nerve Degeneration - pathology
Nerve Degeneration - psychology
Nerve Fibers, Myelinated - pathology
Neurology
Vertebrates: nervous system and sense organs
Young Adult
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Summary:Abstract Elderly individuals display a rapid age-related increase in intraindividual variability (IIV) of their performances. This phenomenon could reflect subtle changes in frontal lobe integrity. However, structural studies in this field are still missing. To address this issue, we computed an IIV index for a simple reaction time (RT) task and performed magnetic resonance imaging (MRI) including voxel based morphometry (VBM) and the tract based spatial statistics (TBSS) analysis of diffusion tensor imaging (DTI) in 61 adults aged from 22 to 88 years. The age-related IIV increase was associated with decreased fractional anisotropy (FA) as well as increased radial (RD) and mean (MD) diffusion in the main white matter (WM) fiber tracts. In contrast, axial diffusion (AD) and grey matter (GM) densities did not show any significant correlation with IIV. In multivariate models, only FA has an age-independent effect on IIV. These results revealed that WM but not GM changes partly mediated the age-related increase of IIV. They also revealed that the association between WM and IIV could not be only attributed to the damage of frontal lobe circuits but concerned the majority of interhemispheric and intrahemispheric corticocortical connections.
ISSN:0306-4522
1873-7544
DOI:10.1016/j.neuroscience.2011.04.028