This will be a long post as it seems that researchers can find numerous parts of the ADHD brain that seem dysfunctional. A major flaw in virtually all of this research is that they use very small groups that cannot depict the vast spectrum brain variability among the human species. This published research confuses many people as it seems the brains of those with ADHD are smaller, have damage in the basal ganglia, putamen, frontal lobes, cerebellum, and brain stem. This amounts to little more than neophrenology.
“It’s strong support for a very strong biological contribution to what causes ADHD.” Dr. Judith Rapoport, National Institute of Mental Health
(AP) Hyperactive children and teens have slightly smaller brains than those without the disorder, a study shows.
Exactly why this is so is not clear, but the researchers said the smaller brain volume does not appear to be related to the use of hyperactivity drugs such as Ritalin, as some parents had feared.
The finding could be reassuring to parents in another respect as well: It suggests that hyperactivity is biological in origin, not a product of bad parenting.
The researchers said it appears that that the brains of hyperactive children develop at a normal pace but never entirely catch up in size with the brains of other youngsters. However, they said that people with smaller brains are not necessarily less intelligent.
The findings were reported in Wednesday’s Journal of the American Medical Association.
Other studies also have suggested biological differences in the brains of people with attention deficit hyperactivity disorder.
“It’s strong support for a very strong biological contribution to what causes ADHD,” said one of the researchers, Dr. Judith Rapoport, chief of child psychiatry at the National Institute of Mental Health in Bethesda, Md.
The 10-year study used MRIs to look at 152 patients ages 5 to 18 who had the disorder, and 139 people in about the same age range who did not. It also compared patients who were on medication and those who were not.
The study found the disorder is associated with about a 3 percent to 4 percent decrease in volume throughout the brain. The smaller their brains, the greater their symptoms.
“The first thought people have is that this is a product of bad parenting” or that it is environmental, said Dr. Daniel Coury, a professor of clinical pediatrics at the Ohio State University College of Medicine who was not involved in the research. “Having clear biological findings that this is something beyond the control of parents or the child themselves helps to remove that stigma.”
Dr. Bennett Leventhal, professor of psychiatry and pediatrics at the University of Chicago, said the findings regarding the effects of medication “should be reassuring to parents that you can treat your kids and not hurt their brains.”
The research was conducted between 1991 and 2001 at the National Institute of Mental Health, which funded it.
ADHD is one of the most common childhood psychiatric disorders. Its symptoms include short attention span, impulsive behavior, difficulty focusing and fidgetiness. The American Academy of Pediatrics estimates 4 percent to 12 percent of school-age children are affected.
Bad Basal Ganglia
Reading and attention disorders both seem to stem from the same primitive part of the brain that governs thinking and muscle control, Yale researchers have found.
A study of 27 people ages 18 to 24 revealed that participants with attention deficit and hyperactivity disorder, and those with reading disorders, displayed low activity in their basal ganglia.
The study, which was published in the November issue of the American Journal of Psychiatry, is the first to use sophisticated functional magnetic resonance imaging to identify the neural circuits involved with ADHD.
When both groups were given the drug methyl-phenidate (brand name Ritalin) activity in the basal ganglia was normal, said Keith Shafritz, lead author.
Shafritz performed the work as a Yale graduate student and is now a research associate at the Duke University Medical Center.
Shafritz said the results suggest that Ritalin does not produce a unique effect in people with ADHD and that ADHD and reading disorders are in some way equivalent.
Nationally about 5 percent of children have reading disorders, characterized by reading at a lower level than expected.
About 3 to 5 percent of children show symptoms of ADHD. These include inattention, impulsiveness, and hyperactivity.
Participants were placed in a functional magnetic resonance imaging unit where they saw and heard a mixture of real and nonsense words.
The normal control group was about 80 percent accurate. People with ADHD and people with reading disorders both scored about 70 percent, Shafritz said.
Basal ganglia activity was higher in the control group.
When participants with ADHD or reading disorders were given methylphenidate and repeated the test their basal ganglia function rose to normal levels.
Shafritz said the basal ganglion is an inhibitory organ that can also activate areas of the brain. The neurotransmitter dopamine regulates the basal ganglion.
Ritalin apparently increases the inhibitory effect, dropping people with ADHD to a calmer and more attentive state.
The drug blocks the dopamine transporter, a system that clears away dopamine. With the transporter turned down dopamine accumulates.
“One driving question was, ‘Were the effects of Ritalin on the brain unique to kids with ADHD?’” Shafritz said. “The results suggest that Ritalin has similar effects in ADHD and other conditions. The idea that Ritalin is acting in a certain way in ADHD appears not to be the case.”
“The study also suggests that ADHD brains are not that different from everyone else’s brains,” Shafritz said.
Shafritz said the study was not designed to measure classroom behavior or reading skills. Also, medical ethics prevented giving Ritalin to the control group.
An inverse index of regional cerebral blood flow, T2 relaxometry (an fMRI procedure), was used to indirectly assess blood volume in the striatum (caudate and putamen) of boys ages 6 to 12 in steady-state conditions (Teicher et al., 2000). Boys with ADHD had higher T2 relaxation times bilaterally in the putamen than controls. Relaxation times strongly correlated with both the individual’s capacity to sit still and error performance on an attentional task. Daily treatment with methylphenidate significantly changed T2 relaxation times in the putamen of boys with ADHD, although the magnitude and direction of the effect was strongly dependent on unmedicated baseline activity.
Investigators at UCLA used magnetic resonance imaging (MRI) to compare the brains of 27 children with ADHD to those of 46 children without the disorder. They found that the region of the brain associated with attention and impulse control, located on the bottom of the frontal lobes of the brain, was smaller in the ADHD kids than in the other children.
“We would expect that the abnormalities would be in this region, and this is what we found,” lead investigator Elizabeth Sowell, PhD, tells WebMD.
The researchers also found that children with ADHD had larger areas of the outer layers of the brain.
Previous research has indicated that the differences were limited to the right side of the brain, but Sowell and colleagues found that they occurred on both sides.
Symptoms of ADHD in adults may include reading difficulties, poor concentration, clumsiness, and low self-esteem. Our research has shown that a medical condition we refer to as Cerebellar Developmental Delay (CDD) is a likely culprit of ADHD in adults. In CDD, the cerebellum is under-developed and not able to process information going to and coming from the cerebrum (often known as the “thinking brain”) efficiently. DORE has developed specific exercises that stimulate the cerebellum, thus allowing it to process information faster.
U.S. researchers reported brain scans of children with attention deficit hyperactivity disorder show anatomical abnormalities beyond a chemical imbalance.
The study by North Shore-Long Island Jewish Health Center was presented at the annual meeting of the Radiological Society of North America.
A second study by the same authors showed stimulant medications prescribed to balance brain chemistry appear to normalize some of these brain irregularities.
“We found abnormality of the fiber pathways in the frontal cortex, basal ganglia, brain stem and cerebellum,” said lead author Manzar Ashtari.
“These areas are involved in the processes that regulate attention, impulsive behavior, motor activity and inhibition – the key symptoms in ADHD children.”
The study used diffusion tensor imaging to compare 18 children with diagnosed ADHD with 15 control children to evaluate the brain’s white-matter fiber development. Researchers found differences in the brain fiber pathways that transmit and receive information among brain areas.
Usefulness of QEEG neurometrics in a clinical setting.
Chabot and colleagues found that generalized or focal theta/alpha excess was present in 76.2% of their sample of ADD, ADHD, and children with attentional problems. These theta and alpha excess children can be divided into two distinct neurophysiological subgroups .
The first and most common group consisting of 46.4% of the sample was characterised by theta and/or alpha excess, mostly at frontal and/or central regions with normal alpha mean frequency.
Excessively high output of thalamocortical alpha generators can result from (a) overactivation of the thalamus. The primary dopamine pathways originate in the substantia nigra in the brainstem and innervate the caudate nucleus and putamen and are largely responsible for sensorimotor integration. Down-regulation of nigrostriatal dopaminergic neurons results in overstimulation of the midbrain reticular formation and the production of excess alpha (b) underactivation of the prefrontal cortex resulting from disinhibition from nucleus reticularis.
The authors report a study to compare regional brain volumes at initial scan and their change over time in medicated and previously unmedicated male and female patients with ADHD and healthy controls. The case-control study was conducted from 1991-2001 at the National Institute of Mental Health, Bethesda, Md, of 152 children and adolescents with ADHD (age range, 5-18 years) and 139 age- and sex-matched controls (age range, 4.5-19 years) recruited from the local community, who contributed 544 anatomic magnetic resonance images. Using completely automated methods, the main outcome measures were initial volumes and prospective age-related changes of total cerebrum, cerebellum, gray and white matter for the 4 major lobes, and caudate nucleus of the brain were compared in patients and controls.
It’s both significant and tragic to note that one can use a search engine and type in ‘ADHD’ and virtually any particular portion of the brain and find clinically controlled research that indicates related brain damage or abnormality.
Brain scans and QEEG are relatively nascent technologies that are currently more art than science when used to determine the source of ADHD. Obviously, the publishing of data on small groups may assist researchers in garnering grant funds. It may even help them retain their position at university in a publish or perish world. However, publishing of such data is not only unethical, it is also highly misleading if it does not explicitly define itself as highly preliminary. Even then it is questionable.
Publication of this neophrenology allows media to portray ADHD individuals as irreparably brain damaged which is both harmful and flagrantly untrue.