Equivalent disruption of regional white matter microstructure in ageing healthy men and women

Abstract

Diffusion tensor imaging was used to measure regional differences in brain white matter microstructure (intravoxel coherence) and macrostructure (intervoxel coherence) and age-related differences between men and women. Neuropsychiatrically healthy men and women, spanning the adult age range, showed the same pattern of variation in regional white matter coherence. The greatest coherence measured was in corpus callosum, where commissural fibers have one primary orientation, lower in the centrum semiovale, where fibers cross from multiple axes, and lowest in pericallosal areas, where fibers weave and interstitial fluid commonly pools. Age-related declines in intravoxel coherence was equally strong and strikingly similar in men and women, with evidence for greater age-dependent deterioration in frontal than parietal regions. Degree of regional white matter coherence correlated with gait, balance, and interhemispheric transfer test scores.

Age-related changes in human and non-human primate white matter: from myelination disturbances to cognitive decline

“…Similar to the volumetric data, FA peaks in early middle age when myelination peaks (Kemper 1994) and then declines in the elderly at a rate that parallels or precedes WM volumetric loss (Hasan et al 2007;Hasan et al 2008;Hasan et al 2010;Lebel et al 2010;Westlye et al 2010). Regionally, age-related deficits of FA have been described in the genu of the CC centrum semiovale, frontal, and parietal pericallosal WM of men (Pfefferbaum et al 2000), with a similar pattern found in both sexes (Sullivan et al 2001). When corrected for partial voluming, FA still decreased in the CC and centrum semiovale with age (Pfefferbaum and Sullivan 2003).…”

“…The increase in WM diffusivity has been associated with age-related cognitive decline, especially in the anterior WM (O 'Sullivan et al 2001;). However, one study of slightly younger subjects (average age of 65 years) found no loss of FA in anterior and caudal fiber tracts (Madden et al 2004).…”

Diffusion tensor imaging and aging – a review

“…As one would expect from examination of these tissues, the highest measured FA was present in the regions with the most homogeneously oriented fibers systems, namely, the genu and splenium of the corpus callosum. Sullivan et al 4 adds evidence that the deterioration of regional white matter coherence occurs in both men and women, with evidence for steeper decline in frontal than parietal regions, a finding supported by Pfefferbaum et al 3 The declines in these measured anisotropic values (FA, RA, etc.) are most likely a reflection of the underlying microstructural changes found in normal aging, which include a loss of myelin and axonal fibers and an increase in extracellular space, suggested explanations corroborated by histological studies.…”

“…Several papers have now appeared on the topic of DTI and aging, [3][4][5] suggesting that DTI can significantly add to our knowledge of the aging brain. The importance of a full characterization of the patterns of white matter microstructure deterioration that occur in normal aging would lead to an understanding of the pathophysiology of normal cognitive decline and would be a proper background for interpreting observed changes in neurodegenerative diseases of the aged beyond those of normal aging.…”

“…In a related study using similar MRI and DTI techniques, Sullivan, et al 4 measured FA between a group of 31 neuropsychologically normal men vs a group of 18 women. Within five similar regions of interest, they found no significant gender or regional differences in the adult age ranges of 23-79 years (Figures 1 and 2).…”