After one year of treatment, children diagnosed with attention deficit hyperactivity disorder (ADHD) showed positive behavioral changes that were accompanied by functional recovery in neuronal pathways, as evidenced by new research using diffusion tensor imaging (DTI), according to Pilar Dies Suarez, M.D., chief radiologist at the Hospital Infantil de México Federico Gómez.
These results are a follow-up to original research by a multidisciplinary team led by Dr. Dies Suarez that was presented at RSNA 2013. In that study, conducted between May 2012 and May 2013, Dr. Dies Suarez and colleagues performed DTI on 23 children ages 7 to 12, including 11 diagnosed with ADHD and 12 controls. Subjects included patients with symptoms consistent with one of two major subtypes of the disorder: impulsive ADHD and inattentive ADHD.
Children with impulsive ADHD exhibit typical hyperactivity without motor deficits and respond well to treatment with stimulants. Patients with inattentive ADHD are less hyperactive, have motor deficits and decreased muscle tone and respond better to behavioral therapy, Omega-3 fatty acids and atomoxetine therapies. Inattentive ADHD is the less well understood of the two disorders, Dr. Dies Suarez said.
“It has been widely described that the frontostriatal tracts are altered in patients with impulsive ADHD,” Dr. Dies Suarez said. “We hypothesized the involvement of a second neural tract, likely a frontocerebellar circuit, that may explain the inattentive clinical type of ADHD.”
In the initial research, Dr. Dies Suarez examined connectivity in the frontocerebellar tracts by conducting DTI studies on 11 children exhibiting symptoms of the attentive ADHD subtype.
Results showed that compared to healthy controls, the inattentive ADHD patients had fewer frontocerebellar tracts disporportionately on the left side, and increased fractional anisotropy (FA) values. Healthy controls exhibited a greater number of frontocerebellar tracts and normal FA values.
“These data reinforce that the dysfunction in ADHD patients is primarily on the right side of the brain,” Dr. Dies Suarez said.
“Along with methodology, I would add that a collaborative parent-medical physicist relationship is important,” Dr. Dies Suarez said. “Generally those kids are very kinetic, so trying to get them inside the magnet without head movement is challenging. Sedation isn’t recommended to avoid the risks implicit to anesthesia.”
The 11 patients diagnosed with inattentive ADHD were re-examined with DTI after one year of one or more of the following treatments: atomoxetine and metildifenidato drug therapies and Omega-3 supplements.
“Following one year of treatment, we found recovery of the frontocerebellar tracts, including both an increase in the number of tracts as well as normalized FA values in the ADHD patients,” she said. “This recovery of function corresponded with positive behavioral changes.”
The DTI study also enabled the research team to distinguish ADHD from other pathologies. “We believe children initially diagnosed with ADHD who did not respond to treatment are experiencing different kinds of problems,” she said. “DTI gives physicians and parents a quantitative tool for diagnosing ADHD and monitoring the effects of treatment.”
ADHD affects approximately 7 percent of the world population and is one of the most common childhood disorders.
Pilar Dies Suarez, M.D., discusses the impetus for her research on attention deficit hyperactivity disorder (ADHD) patients, including:
Mary Henderson is a writer based in Bloomington, Ind., specializing in health and medicine.
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