Fractional anisotropy in the supplementary motor area correlates with disease duration and severity of amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is progressive and fatal neurodegenerative disorder with upper and lower motor neuron signs. There are no biomarkers to track disease progression. To address this issue, we investigated regions in which fractional anisotropy (FA) values derived from diffusion weighted images correlated with both disease severity and duration in ALS patients. Fourteen patients with ALS were enrolled in this study. Voxel-based analysis revealed volume of interests (VOIs) showing significant correlation. Finally, Spearman rank correlation coefficient was assessed between FA value in each VOI and disease severity or duration. In the VOI of left supplementary motor area (SMA), FA value significantly correlated with disease severity and duration both (disease severity, rho = 0.59, p = 0.025; disease duration, rho = -0.69, p = 0.006). The present finding suggested the possibility that the abnormality in motor-related region including SMA could be a candidate for a biomarker to track disease progression.