Abnormal Brain Structures Observed in
Children with Attention Deficit Disorder and Learning Disabilities

University of South Florida Graduate Research Project - Special Education Department
Environmental Causes of Learning Disabilities and Attention Deficit Disorder
Information Compiled by Richard W. Pressinger, M.Ed.

There has been a growing amount of medical research identifying various types of brain damage in children with attention deficit disorder, hyperactivity and learning disabilities. The nationwide increases being observed in these child disorders is being explained by many scientists as resulting from environmental and chemical exposures during pregnancy.  These include the obvious culprits such as alcohol and cigarette use, but serious new concerns are being raised by government and university research showing many common household chemicals can also contribute to subtle damage to the developing brain during pregnancy. These include cleaning chemicals, home pesticide use, cosmetic chemicals, prescription medications, artificial food additives, chemicals in plastics, synthetic perfume and cologne ingredients, job chemicals, and the pesticide chlordane (found as a contaminant in the air of most U.S. homes built before 1988).

In a summary report entitled the Principles of Developmental Neurotoxicity, from the National Center for Toxicological Research (7), it was stated:

"According to the Congressional Office of Technology Assessment’s recent report on neurotoxicity, among the known or suspected causes of brain-related disorders are exposure to chemicals including pesticides, therapeutic drugs, food additives, foods, cosmetic ingredients and naturally occurring substances"

If we are to agree with this research that repeated exposure to certain consumer chemicals can weaken or damage brain growth and result in increases in mental retardation, learning disabilities or behavior disorders, then it is quite plausible to expect a corresponding subtle decrease in mental function of our above average students, but detecting such effects will be extremely difficult. Also, it is important to realize that a decrease in mental capacity is not strictly limited to academic function. The human brain is also responsible for all other mental functions including talent, personality, sense of humor, articulation skills and even conscience oriented behavior. Therefore, it is quite realistic to suspect the potential for these areas of the human brain to be compromised by the same compounds being found to cause learning disabilities and attention deficit disorder.

Many researchers now agree, as will be addressed in this paper, that subtle brain disorders can be the cause of learning disabilities, hyperactivity, attention deficit and even propensity toward behavior problems such as aggression and behavior "void of conscience." In fact, it has been only recently that abnormalities in brain structure have been found in people with learning disabilities and attention deficit disorders.

Damage to Brain Structure Found in Students
with Learning Disabilities and Attention Deficit Disorder

Comparison pictures of normal and Learning Disability brainExamples of visually detected brain damage in learning disability and attention deficit individuals are discussed in three different research projects below. One incident reported by Dr. Albert Galaburda at Harvard Medical School (9), investigated the unfortunate accidental death of an individual with known serious reading learning disabilities in school. At age 18 he had a reading level of fourth grade despite a 105 intelligence score on the Stanford- Binet test. Because of this discrepancy in intelligence and reading level, he was given the diagnosis of Developmental Dyslexia. He also had moderate math difficulties and mild difficulties with right-left orientation and finger recognition.

At age 20, six days after beginning his first paying job, the patient died suddenly as the result of an accidental fall from a great height. The cause of death was multiple internal injuries producing massive bleeding. An autopsy of the brain showed no evidence of trauma or other gross abnormalities according to the researchers. After receiving permission from the man’s parents, the physicians conducted a thorough examination of the man’s brain structure. The results are seen in the picture at left. The top photograph shows a normal brain with good column organization and larger cells. The bottom (learning disabilities) brain shows poor organization and smaller cells.

The researchers stated the area of the learning disability brain shows abnormalities also to a location in the brain called the "Wernicke’s Speech Area," and appears to play a particularly important role in language function. 

The researchers concluded by saying,

"The findings reported here lend support to the notion that language-relevant areas in the brains of patients with developmental dyslexia (a type of learning disability)may be small in the two cerebral hemispheres, a possibility which is also supported by findings of curtailed linguistic processing by both hemispheres in dyslexic patients."

Learning Disability & Attention Deficit Children Have
Lower Blood Flow in Some Brain Areas

A method for determining abnormalities in the brains of living learning disability (LD) and attention deficit disorder (ADD) children was used in a study of 13 LD and ADD children at the Department of Neurology, Kennedy Institute in Denmark (13). The study was conducted using a method called emission computed tomography which takes a picture of a "slice" of the brain after the child inhales a very small amount of a radioactive substance called xenon 133. The picture then allows the scientists to visually see how much blood is being used by different parts of the brain (a greater illumination in the picture represents increased blood flow). This also represents the level of metabolic activity in the brain areas. After comparing the photographs taken of all children the investigators stated,

"The cerebral blood flow distribution was abnormal in both hemispheres (both sides of the brains)in all patients, as compared with the mean cerebral blood flow distribution of nine normal children.... All 11 patients with attention deficit disorder (ADD) have hypoperfusion (low blood flow) in the mesial frontal lobes, in particular in the white matter.... Methylphenidate hydrochloride (Ritalin) increased perfusion (blood flow) in the central region, including the mesencephalon and the basal ganglia, and decreased perfusion of motor and primary sensory cortical areas.... Hypoperfusion and low metabolic activity may be due to subtle morphologic abnormalities not detectable with computed tomography but with important pathogenetic implications."

To bring this into perspective and without the multi-syllable medical terms, the investigators found lower levels of blood in Attention Deficit Disorder children in the area of the brain that is just behind the central forehead going in about an inch or two. When ritalin was given and measurements taken again, normal blood flow was created, thereby providing a biological explanation of why children improve after taking Ritalin.

Glucose Metabolism Defective in
Attention Deficit Hyperactive Disorder Syndrome

In a study of hyperactive students conducted at the National Institute of Mental Health, reported in the November 15, 1990 New England Journal of Medicine, researchers found the brain cells of these individuals were using lower levels of glucose than other non-hyperactive people (glucose is the primary fuel used by the brain cells which enables them to function).

In a study of hyperactive students conducted at the National Institute of Mental Health, reported in the November 15, 1990 New England Journal of Medicine, researchers found the brain cells of these individuals were using lower levels of glucose than other non-hyperactive people (glucose is the primary fuel used by the brain cells which enables them to function).

In conclusion, the investigators stated:

"Glucose metabolism, both global and regional, was reduced in adults who had been hyperactive since childhood. The largest reductions were in the pre-motor cortex and the superior prefrontal cortex - areas earlier shown to be involved in the control of attention and motor activity."

Since there is common agreement among researchers and medical professionals that learning disabilities and attention deficits can, in fact, result from subtle brain damage caused by a variety of common environmental chemical exposures in today's "modern" society, it is imperative to organize this information into an easy to read format.  This will give couples who desire to have children a far better chance of having a child that is neurologically healthy  without the complications accompanied by attention deficit disorder or learning disabilities.  This has been the goal of this research project.

An Interesting Observation
from an older Medical Journal

In the 1975 Canadian Psychiatric Association Journal, Dr. R. Denson discusses the increase society has observed in children with hyperactive disorders.

"The hyperkinetic syndrome is often encountered at the present time, although the textbooks of thirty years ago make scant reference to it. Henderson and Gillespie characterized hyperkinetic disease as one of the "very rare" psychoses of childhood (1), and Kanner, who devoted only five sentences to "the restless, fidgety, hyperkinetic child", omitted hyperactivity altogether when discussing the causes of scholastic problems (2). Recent estimates imply that persistent, disruptive hyperactivity occurs in from five to ten percent of North American elementary school children and Wender (5) who depicts hyperactivity as "the single most common behavioral disorder seen by child psychiatrists", has calculated that there are approximately five million hyperactive children in the United States, where more than 150,000 youngsters are receiving treatment with stimulant drugs for hyperkinesis and similar disorders."

For more information on how environmental exposures and
job occupations can increase Attention Deficit Hyperactive Disorder
and Learning Disabilities please visit..