Attention Deficit/Hyperactivity Disorder (ADHD) is a neurobiological condition that usually shows up in childhood. Symptoms include poor impulse control, inattention, and difficulty staying on task.
A new study funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development shows that children who have it, also have reduced cortical volume in the regions of the brain that control behavior and impulsiveness. The study is the first to look at brain tissue volume and how it relates to ADHD.
The study, conducted by researchers from the Kennedy Krieger Institute at Johns Hopkins looked at brain scans (high-res MRI scans were used) of children aged 4 to 5 years old. There wasn't one specific area of the brain that showed lower tissue volume, but rather several, including the frontal, parietal and temporal lobes. In all of these areas, the primary function is cognition and behavior, including the predictability of some actions and the level of impulse control.
E. Mark Mahone, Ph.D., ABPP is the lead study author and a research scientist at the Kennedy Krieger Institute. He explained the findings, saying what many parents have known for a while, "These findings confirm what parents have known for a while — even in very young children, ADHD is a real biological condition with pronounced physical and cognitive manifestations." Scanning children, even those who are neurotypical, can be challenging for the team at Kennedy Krieger figured out a way to get a better success rate. Dr. Mahone went on to state, "MRI research in children can be challenging—particularly so for young children with ADHD—as it requires them to lie still for periods up to 30-40 minutes. To address this challenge, we employed an individualized behavioral desensitization procedure using a mock scanner to help prepare the children for the scans, leading to a nearly 90 percent success rate."
The work is significant because ADHD remains a growing problem for parents, educators and healthcare professionals. The statistics on ADHD show that it's a problem for at least 1 in 20 people under the age of 18. Of that number, roughly two-thirds report that their symptoms persisted in adulthood. ADHD presents typically before the age of 7 years old, however, due to the negative stereotypes sometimes associated with it, many children are just labeled as behavioral problems or "difficult." Seeing what ADHD looks like in the brain, closer to onset, is critical to understanding the mechanisms behind the disorder.
The researchers plan to continue the study with this cohort of young children and follow through to adolescence and adulthood. They are hopeful that being able to see the disorder from its early stages through to the point where the brain is done developing, will reveal how it progresses and how age and maturity impact the symptoms. Treatments could also change as patients age because further phases of the study hope to look at how the brain of an adult ADHD patient differs from that on a young child right at first onset. Check out the video below for more information on ADHD and how it begins.
Sources: Kennedy Krieger Institute-Johns Hopkins, Atlanta Journal Constitution, Cambridge University Press
