A new analysis tool, large deformation diffeomorphic mapping (LDDMM), has revealed shape differences in the brains of children with ADHD, which could help pinpoint the specific neural circuits involved in the disorder, according to a study published Nov. 17 in the online advance edition of the American Journal of Psychiatry.
Researchers from the Kennedy Krieger Institute and the Johns Hopkins Center for Imaging Science, both in Baltimore, used LDDMM to examine the shape of the basal ganglia, allowing for precise examination of brain structures beyond what has been examined in previous MRI studies of ADHD.
"This study represents a major advancement in our ability to examine the neuroanatomic features of ADHD and other developmental disorders," said Stewart H. Mostofsky, MD, senior study author and a pediatric neurologist in the department of developmental cognitive neurology at Kennedy Krieger. "Using LDDMM, we can more accurately measure the impact of ADHD on brain development, which will not only bring us closer to unlocking the biological basis of the disorder, but help us better diagnose and treat patients."
Researchers used MRI scans to examine children, ages eight to 13, including: 47 children with ADHD and a control group of 66 typically developing children. They compared the LDDMM mappings of children with ADHD to their typically developing peers, and then went a step further by repeating the analysis separately for boys and girls.
Mostofsky and colleagues said that children with ADHD, who had a history of other neuropsychiatric diagnoses including conduct disorder, mood disorder, generalized anxiety disorder, separation anxiety disorder and/or obsessive-compulsive disorder, were excluded from the study. Additionally, none of the children with ADHD had a learning disability or a history of speech/language disorders.
The study found boys with ADHD had significant shape differences and decreases in overall volume of the basal ganglia compared to their typically developing peers. Girls with ADHD did not have volume or shape differences, suggesting sex strongly influences the disorder's expression.
According to researchers, the potential next steps include research that carefully examines whether the brain abnormalities found in this study can predict certain behavioral features of ADHD.
Future studies will also examine structural features associated with the ability to compensate and respond to therapy. The researchers said they also plan to use LDDMM analysis on children in a wider age range to see if changes in the basal ganglia occur over time.