Brain Imaging Study Connects Brain Volume to ADHD Symptoms

A recent brain imaging study performed by researchers at the Kennedy Krieger Institute discovered a difference between the brains of children affected by Attention-Deficit/Hyperactivity Disorder (ADHD) and those of children unaffected by the disorder.

The developmental disorder, commonly characterized by inattentiveness, hyperactivity and impulsivity, affects roughly two million children; it is estimated that by the age of four, as many of 40% of children are affected by symptoms of ADHD.

As ADHD has the potential to present early, just as most children are begining their educational journey with preschool, experts stress the importance of noting possible symptoms in young children.

“Clinically, this abnormal brain development sets the stage for the symptoms of ADHD that contribute to cognitive challenges and problems in school,” said lead author Mark Mahone, Ph.D. “Earlier identification and treatment of children presenting with attention problems in the preschool years may minimize the impact of ADHD in the long-term.”

During the study, Mahone and his researchers analyzed the brain images of twenty-six preschoolers between the ages of four and five years old. Thirteen of the child-participants presented with ADHD symptoms, while the other thirteen did not. The researchers focused primarily on the volumes of the cortical and basal ganglia, as well as the size of these particular areas of the brain.

The researchers discovered differences in the caudate nucleus, a small structure in the subcortical region of the brain associated with cognitive and motor control.

The children with ADHD symptoms showed drastically reduced caudate volumes in comparison to the children who did not present with ADHD symptoms.

Furthermore, these caudate volumes were found to be correlated with parent ratings of hyperactive/impulsive symptoms. Cortical volumes, however, were not associated with symptom severity.

Mahone and his fellow researchers noted that differences in basal ganglia development, especially the caudate nucleus, seemed to play an important role among children presenting with early onset symptoms of ADHD.

Researchers reported that they plan to continue to follow the brain development of the child-participants in the effort of determining whether the abnormalities carry on or regress as the children get older.

The study has been published in the journal Clinical Neuropsychologist.