Dr. Qiyong Gong
New imaging technique reveals info about ADHD
April 30, 2014
by Lauren Dubinsky, Senior Reporter
A new study published in the journal Radiology found disrupted connections between different areas of the brain in children and adolescents with attention deficit hyperactivity disorder (ADHD) using a relatively new technique called resting-state functional magnetic resonance imaging (rfMRI).
ADHD is a characterized by difficulty focusing and paying attention, lack of willpower and hyperactivity. These findings indict that rfMRI may provide an accurate and early diagnosis of this disorder that affects about 5 percent of children and adolescents around the world.
Previous studies used functional MRI (fMRI), which measures the patient's brain activity when they are focused on a particular task, and have indicated the frontostriatal circuit part of the brain, that helps control behavior. But the specific brain physiology that causes ADHD is still not well understood.
For the new study, the researchers decided to take a different approach and use rfMRI. "Compared with the fMRI technique, in which the patient has to perform certain tasks relevant to the brain functions to be examined, the rfMRI has no such requirement, and patients are just lying in the scanner bed doing nothing, similar to a conventional brain scan," Dr. Qiyong Gong, one of the researchers, wrote to DOTmed News in an email. "It is relatively easy to be implemented in a clinical setting and more comfortably accepted by patients."
The researchers performed rfMRI on 33 boys from ages six to 16 with ADHD and on 32 similarly aged boys without ADHD. They then compared the MRI findings with results from executive function tests that evaluate the mental processes involved in planning, organizing, time management, regulating emotions, etc.
The results show that the patients with ADHD had altered structure and function in areas of the brain including the orbitofrontal cortex, the area of the brain that deals with cognitive processing of strategic planning, and the globus pallidus, which is involved with executive inhibitory control.
The study suggests that the structural and functional abnormalities in those brain regions may be the reason for inattention and hyperactivity in patients with ADHD, according to Gong.
The researchers also discovered that there are defects in the connections between resting-state brain networks associated with executive dysfunction. "Although there has been much debate about what core deficit of brain function might cause the impairments of ADHD, our findings of several brain regions involved in ADHD related to the executive dysfunction, suggest that there exist widespread functional connectivity alterations," wrote Gong.
Gong wrote that the functional connectivity abnormalities in the large-scale neural system of ADHD may provide potential biomarkers to identify ADHD patients. Also, after the patients take medication, the rfMRI may evaluate the treatment effects on ADHD and measure whether the altered functional connectivity returns to normal.
The results look promising, but Gong points out that larger studies are need to validate the results. Going forward, the researchers plan to study the connectivity changes over time in ADHD patients, and also investigate the possible differences of functional connectivity between the clinical subtypes of ADHD such as inattentiveness and hyperactivity.
They plan to study connectivity changes by arranging before and after MRI examinations for those children who undergo medical treatment in order to detect the pharmacological effects on the neural system of ADHD. For the patients that don't receive medical treatment, the researchers will conduct three MRI exams at the baseline and then after two and four weeks in order to measure the neural changes in the natural course of the disease for comparison.
The study is part of a larger project that Gong's group at Huaxi Research Center of the West China Hospital is conducting to explore MRI's diagnostic and prognostic potential in other psychiatric disorders including schizophrenia, mood disorders, obsessive compulsive disorders, anxiety and post-traumatic stress disorder.
ADHD is a characterized by difficulty focusing and paying attention, lack of willpower and hyperactivity. These findings indict that rfMRI may provide an accurate and early diagnosis of this disorder that affects about 5 percent of children and adolescents around the world.
Previous studies used functional MRI (fMRI), which measures the patient's brain activity when they are focused on a particular task, and have indicated the frontostriatal circuit part of the brain, that helps control behavior. But the specific brain physiology that causes ADHD is still not well understood.
For the new study, the researchers decided to take a different approach and use rfMRI. "Compared with the fMRI technique, in which the patient has to perform certain tasks relevant to the brain functions to be examined, the rfMRI has no such requirement, and patients are just lying in the scanner bed doing nothing, similar to a conventional brain scan," Dr. Qiyong Gong, one of the researchers, wrote to DOTmed News in an email. "It is relatively easy to be implemented in a clinical setting and more comfortably accepted by patients."
The researchers performed rfMRI on 33 boys from ages six to 16 with ADHD and on 32 similarly aged boys without ADHD. They then compared the MRI findings with results from executive function tests that evaluate the mental processes involved in planning, organizing, time management, regulating emotions, etc.
The results show that the patients with ADHD had altered structure and function in areas of the brain including the orbitofrontal cortex, the area of the brain that deals with cognitive processing of strategic planning, and the globus pallidus, which is involved with executive inhibitory control.
The study suggests that the structural and functional abnormalities in those brain regions may be the reason for inattention and hyperactivity in patients with ADHD, according to Gong.
The researchers also discovered that there are defects in the connections between resting-state brain networks associated with executive dysfunction. "Although there has been much debate about what core deficit of brain function might cause the impairments of ADHD, our findings of several brain regions involved in ADHD related to the executive dysfunction, suggest that there exist widespread functional connectivity alterations," wrote Gong.
Gong wrote that the functional connectivity abnormalities in the large-scale neural system of ADHD may provide potential biomarkers to identify ADHD patients. Also, after the patients take medication, the rfMRI may evaluate the treatment effects on ADHD and measure whether the altered functional connectivity returns to normal.
The results look promising, but Gong points out that larger studies are need to validate the results. Going forward, the researchers plan to study the connectivity changes over time in ADHD patients, and also investigate the possible differences of functional connectivity between the clinical subtypes of ADHD such as inattentiveness and hyperactivity.
They plan to study connectivity changes by arranging before and after MRI examinations for those children who undergo medical treatment in order to detect the pharmacological effects on the neural system of ADHD. For the patients that don't receive medical treatment, the researchers will conduct three MRI exams at the baseline and then after two and four weeks in order to measure the neural changes in the natural course of the disease for comparison.
The study is part of a larger project that Gong's group at Huaxi Research Center of the West China Hospital is conducting to explore MRI's diagnostic and prognostic potential in other psychiatric disorders including schizophrenia, mood disorders, obsessive compulsive disorders, anxiety and post-traumatic stress disorder.