Figure 1.

Reduced white matter water diffusivities in OSA revealed by TBSS DTI analysis. Reduced (a) MD, (b) RD, and (c) AD values in mild OSA were observed compared with controls in multiple white matter tracts, including multiple projection and association fibers as well as within commissural fibers. Reduced (d) AD value in moderate to severe OSA compared with controls was observed in the corpus callosum. Average values of clusters showing significant group differences were extracted for each participant and are presented by groups. The moderate to severe OSA group had intermediate levels of diffusivity between controls and mild OSA, which led to nonsignificant group differences in most white matter tracts for (a) MD, (b) RD, and (c) AD. Group differences were considered significant at FWE‐corrected p < .05, and BMI was included as a covariate. Green lines represent the mean white matter skeleton over which statistical analyses were performed. AD, axial diffusivity; BMI, body mass index; DTI, diffusion tensor imaging; FWE, family‐wise error; MD, mean diffusivity; OSA, obstructive sleep apnea; RD, radial diffusivity; TBSS, tract‐based spatial statistics