Abnormal white matter integrity in young children with autism

Abstract

This study investigated white matter integrity in young children with autism using diffusion tensor imaging (DTI). Twenty-two children with autism, mean age 3:2 years, and 32 controls, mean age 3:4 years, participated in the study. Tract-based spatial statistics (TBSS) revealed white matter abnormalities in several distinct clusters within the genu and body of the corpus callosum (CC), left superior longitudinal fasciculus (SLF) and right and left cingulum (Cg). TBSS-VOIs analysis was performed in the clusters where differences in fractional anisotropy (FA) were detected to investigate the relationship between changes in FA and diffusivity indices. In all VOIs, increase in FA was caused by a decrease in radial diffusivity (Dr), while no changes in axial diffusivity (Da) or mean diffusivity (MD) were observed. Tractography analysis was applied to further study the CC, SLF, and Cg. Witelson parcellation scheme was used for the CC. Significant increase in FA was seen in children with autism in the mid-body of the CC as well as in the left Cg. It is suggested that such abnormal white matter integrity in young children with autism may adversely affect connectivity between different brain regions and may be linked to some of the behavioral impairments apparent in autism.

Copyright © 2010 Wiley-Liss, Inc.

Figures

Figure 1

(a) Witelson segmentation‐schematic view, (b) Tractography of CC; w1‐yellow, w2‐orange, w3‐ green, w4‐ purple, and w5‐light blue.

Figure 2

Elevated FA in genu and body of the CC (a,b: P < 0.05, TFCE‐corrected), in the left SLF (c: P < 0.05, TFCE‐uncorrected for multiple comparisons) and in the right Cg (d: 0 < 0.05, TFCE‐uncorrected for multiple comparison) in children with autism vs. TD controls.

Figure 3

Distribution of FA and Dr relative to age of the children in the body of the CC (a,b), in the left SLF (c,d), and in the left Cg (e,f).