Diffusion tensor imaging, white matter lesions, the corpus callosum, and gait in the elderly.

BACKGROUND AND PURPOSE Gait impairment is common in the elderly, especially those with stroke and white matter hyperintensities on conventional brain MRI. Diffusion tensor imaging (DTI) is more sensitive to white matter damage than conventional MRI. The relationship between DTI measures and gait has not been previously evaluated. Our purpose was to investigate the relationship between the integrity of white matter in the corpus callosum as determined by DTI and quantitative measures of gait in the elderly. METHODS One hundred seventy-three participants of a community-dwelling elderly cohort had neurological and neuropsychological examinations and brain MRI. Gait function was measured by Tinetti gait (0 to 12), balance (0 to 16) and total (0 to 28) scores. DTI assessed fractional anisotropy in the genu and splenium of the corpus callosum. Conventional MRI was used to evaluate for brain infarcts and white matter hyperintensity volume. RESULTS Participants with abnormal gait had low fractional anisotropy in the genu of the corpus callosum but not the splenium. Multiple regressions analyses showed an independent association between these genu abnormalities and all 3 Tinetti scores (P<0.001). This association remained significant after adding MRI infarcts and white matter hyperintensity volume to the analysis. CONCLUSIONS The independent association between quantitative measures of gait function and DTI findings shows that white matter integrity in the genu of corpus callosum is an important marker of gait in the elderly. DTI analyses of white matter tracts in the brain and spinal cord may improve knowledge about the pathophysiology of gait impairment and help target clinical interventions.