Increased regional fractional anisotropy in highly screened attention-deficit hyperactivity disorder (ADHD)

Abstract

Diffusion tensor imaging data were collected at 3.0 Tesla from 16 children with attention-deficit hyperactivity disorder (ADHD) and 16 typically developing controls, ages 9 to 14 years. Fractional anisotropy images were calculated and normalized by linear transformation. Voxel-wise and atlas-based region-of-interest analyses were performed. Using voxel-wise analysis, fractional anisotropy was found to be significantly increased in the attention-deficit hyperactivity disorder group in the right superior frontal gyrus and posterior thalamic radiation, and left dorsal posterior cingulate gyrus, lingual gyrus, and parahippocampal gyrus. No regions showed significantly decreased fractional anisotropy in attention-deficit hyperactivity disorder. Region-of-interest analysis revealed increased fractional anisotropy in the left sagittal stratum, that is, white matter that connects the temporal lobe to distant cortical regions. Only fractional anisotropy in the left sagittal stratum was significantly associated with attention-deficit hyperactivity disorder symptom severity. Several recent studies have reported pathological increases in fractional anisotropy in other conditions, highlighting the relevance of diffusion tensor imaging in identifying atypical white matter structure associated with neurodevelopmental processes.

Figure 1

Increased fractional anisotropy in children with attention-deficit hyperactivity disorder compared to controls from voxel-wise analysis.

Figure 2

The Johns Hopkins University Diffusion Weighted Image Atlas sagittal stratum region of interest overlaid on the average fractional anisotropy image, with the region of increase from the voxel-wise analysis. There is an overlapping region of significant fractional anisotropy increase near the junction of the left parahippocampal gyrus (Brodmann area 19) and the left sagittal stratum. Figure appears in color online at jcn.sagepub.com

Figure 3

Box plot of fractional anisotropy increase in the left sagittal stratum among participants with attention-deficit hyperactivity disorder, compared to control participants.