Background:
The presence of white matter hyperinten-sities (WMHs) on magnetic resonance imaging (MRI) scans is associated with age. However, their functional significance is controversial with some studies reporting significant associations of WMHs volume with cognitive decline, while others have not found such an association. Because the human brain is anatomically and functionally lateralized, one potential confound in this area of research is an effect of WMHs lateralization in the left and right cerebral hemispheres and their varying intra- and interhemispheric transfer consequences. The present study investigated the relationship between WMHs lateralization and corpus callosum (CC) measures and fine motor and cognitive performance.
Methods:
A subsample of 478 individuals aged 60-64 years from a larger community sample were assessed for fine motor control (Purdue Pegboard), global cognitive function, episodic memory and working memory. Subjects also underwent brain MRI scans. WMHs on T2-weighted FLAIR MRI scans were assessed using an automated procedure. CC areas were hand traced.
Results:
WMHs were significantly more lateralized to the left in the frontal, temporal and parietal lobes, and lateralized to the right in the occipital lobe. Periven-tricular and whole hemisphere WMHs were not lateral-ized. WMHs lateralization was significantly associated with CC areas, hippocampal laterlization and fine motor control. These associations were modulated by the location of WMHs in each hemisphere and by sex.
Conclusion:
The lateralization of WMHs is an important factor to consider in the interpretation of their association with callosal structure and behavioural measures of motor control and cognition.
