New research using brain imaging has found a difference in brain development among very young preschool children with early symptoms of attention deficit hyperactivity disorder (ADHD).
ADHD is the most common pediatric behavioral diagnois, affecting approximately 2 million children. The disorder is characterized by inattentiveness, hyperactivity and impulsivity.
According to the researchers, by age 4, as many as 40 percent of children have sufficient problems with attention to be of concern to parents and preschool teachers. Specialists say this observation is important as children whose symptoms begin in early childhood are at high risk for academic failure and grade repetition.
Because of this risk, researchers believe identification of the disorder early in the course of the diagnosis will allow early intervention and aid long-term outcomes.
Previous magnetic resonance imaging (MRI) studies have provided some insights into brain differences associated with ADHD, but these were focused on children ages 7 and older.
In the current study, researchers examined brain images in preschoolers (ages 4 and 5) both with and without symptoms of ADHD, specifically looking at cortical and basal ganglia volumes and the size of these particular areas of the brain.
Researchers analyzed high resolution MRI brain images in 26 preschoolers, 13 presenting with ADHD symptoms and 13 without, and found differences in the caudate nucleus. This is a small structure in the subcortical region of the brain associated with cognitive and motor control.
In the review, researchers discovered children with ADHD symptoms had significantly reduced caudate volumes compared to the children who did not present with ADHD symptoms. Additionally, these caudate volumes were significantly correlated with parent ratings of hyperactive/impulsive symptoms. Cortical volumes, however, were not associated with symptom severity.
Researchers concluded that differences in basal ganglia development, particularly the caudate nucleus, appear to play an important role among children presenting with early onset symptoms of ADHD.
“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.”
Researchers will continue to follow the brain development of the targeted children to determine if abnormalities persist or regress with age.
Source: Kennedy Krieger Institute