White‐matter abnormalities in attention deficit hyperactivity disorder: A diffusion tensor imaging study

Abstract

Current evidence suggests that attention deficit hyperactivity disorder (ADHD) involves dysfunction in wide functional networks of brain areas associated with attention and cognition. This study examines the structural integrity of white-matter neural pathways, which underpin these functional networks, connecting fronto-striatal and fronto-parietal circuits, in children with ADHD. Fifteen right-handed 8 to 18-year-old males with ADHD-combined type and 15 right-handed, age, verbal, and performance IQ-matched, healthy males underwent diffusion tensor imaging. A recent method of tract-based spatial statistics was used to examine fractional anisotropy (FA) and mean diffusivity within major white-matter pathways throughout the whole-brain. White-matter abnormalities were found in several distinct clusters within left fronto-temporal regions and right parietal-occipital regions. Specifically, participants with ADHD showed greater FA in white-matter regions underlying inferior parietal, occipito-parietal, inferior frontal, and inferior temporal cortex. Secondly, eigenvalue analysis suggests that the difference in FA in ADHD may relate to a lesser degree of neural branching within key white-matter pathways. Tractography methods showed these regions to generally form part of white-matter pathways connecting prefrontal and parieto-occipital areas with the striatum and the cerebellum. Our findings demonstrate anomalous white-matter development in ADHD in distinct cortical regions that have previously been shown to be dysfunctional or hypoactive in fMRI studies of ADHD. These data add to an emerging picture of abnormal development within fronto-parietal cortical networks that may underpin the cognitive and attentional disturbances associated with ADHD.

Attention-Deficit/Hyperactivity Disorder and Attention Networks

“…Makris et al (2008) showed that abnormalities of the cingulum bundle and superior longitudinal fascicle IIFconnection pathways that subserve attention and executive functionsFare evident in adults with ADHD. Lower corticospinal tract and superior longitudinal fasciculus FA (Hamilton et al, 2008) similarly suggested disruption of motor and attention networks in ADHD children, whereas the study by Silk et al (2008) indicated that fronto-striatal and fronto-parietal circuitry abnormalities exist in children with ADHD. Finally, pediatric samples showed decreased FA in the anterior corona radiata and abnormalities across multiple white matter tracts in ADHD, including the cingulum bundle, the superior and inferior longitudinal fasciculi, and internal capsule (Pavuluri et al, 2009).…”

Radiologic Imaging in Psychiatric Disorders in the Light of Recent Developments

“…Tractography may reveal that these regions generally form a part of white-matter pathways connecting prefrontal and parieto-occipital areas with the striatum and cerebellum. Again, when the information both from fMRI and from DTI studies is evaluated together, it was found that in ADHD some cortical regions that have previously been shown is dysfunctional or hypoactive (Silk et al, 2009). In another study, it was suggested that alterations in brain white matter integrity occur in frontal and cerebellar regions in ADHD.…”

Is ADHD a Stress-Related Disorder? Why Meditation Can Help

“…Symptoms of stress closely match symptoms of ADHD Recent research sheds further light on the relationship between stress and ADHD. Vance, et al, demonstrated dysfunction of the right prefrontal regions of the brain in ADHD children [16]. This region is responsible for developing coping strategies, influencing the ability to handle stress.…”