Autism, Pervasive Development Disorder (PDD), Attention Deficit Hyperactive Disorder (ADHD), and Obsessive and Compulsive Disorder (OCD) involve significant frontal and temporal lobe dysfunction. This conclusion is based on NeuroSPECT work now in progress on children afflicted with these disorders. We have been using NeuroSPECT to image cerebral abnormalities of perfusion/function in Autism, ADHD, OCD, and other neuro-cognitive disorders.
With the increased focus and presentation of children labeled Autistic Syndrome / PDD, has come a greater need to understand and define the dysfunction in these children by objective "functional" quantification, now possible with new imaging technology such as NeuroSPECT.
The children have been evaluated by means of Xe133 for SPECT, expressing the results three-dimensionally and rCBF quantitatively in ml/min/100g; and qualitatively by means of Tc-99 HMPAO. The correlation of cerebral perfusion with brain function has been established, as NeuroSPECT is a useful tool for cerebral function assessment.
In this review paper, we will discuss our clinical observation and our rCBF findings for Autism and these related disorders.
The new definition of autism
Autism as classically defined was a severely incapacitating disability that was relatively rare. Its onset was in early childhood. This disorder was characterized by delays in language development, marked social deficits and a limited range of stereotyped repetitive behaviors. It occurred in approximately 1-2 out of every 10,000 births. Boys were afflicted more frequently than girls at a 3:1 ratio.
In this severe form of "Classic Autism" effective speech was absent. It could include symptoms of repetitive, highly unusual, aggressive and self-injurious behavior. Those afflicted had extremely abnormal ways of relating to people, objects, or events. Parents noticed that something was "not right" in the first three to six months of life.
Autistic infants did not demand attention, they did not enjoy being picked up, nor did they cuddle or cling when someone held them. They rarely smiled at other people or looked directly at them. In fact, they often appeared happiest when left alone. They resisted affection and did not interact normally. Mothers of autistic children often noted an understandable lessened pleasure in their maternal efforts. They complained that they felt they were caring for an "object" rather than a person.
In the last decade, another type of autism has surfaced that is often referred to as "Autistic Syndrome." Children suffering from this disorder appear normal in the first 15-18 months of life. They do not present signs or symptoms pediatricians or neurologists would find atypical. These children create an inconsistency with previous held beliefs that 70-80% of autistic children are mentally retarded. They crawl, sit up, walk, and usually hit normal motor milestones on schedule. Up until the age of onset, they are affectionate and appear to have above average intelligence.
Children with autistic syndrome may begin to develop some speech but then, without warning, they cease to progress, or begin to regress. Suddenly, these children become withdrawn. They are quiet sometimes and hyper at other times. Often self-stimulatory behaviors (i.e. arm flapping, rocking, spinning, or head banging) develop.
These children begin to display various abnormal behaviors in the preschool years often including:
- A need to preserve sameness
- Marked language abnormalities
- Indexes of developmental disorder - strange body movements, posturing and "soft" signs of neurological impairment
In time, some manifest symptoms that are both similar and atypical to children previously diagnosed as "classically autistic." What was once a relatively rare disorder is now twenty times more likely to occur.
In the past, autism was considered a "psychiatric" disorder. We now know that autism is a "medical condition," not a mental disorder. Perhaps one of the reasons no one has come up with an answer for autism is the way we have thought of it (or rather did not think of it in medicine).
Most researchers did not look for the answers to autism because they felt this was a disorder that was untreatable medically. Treatment for this affliction was primarily left in the hands of psychologists and a few psychiatrists.
Even though children with classic autism might be helped medically as our knowledge of the brain’s physiology expands, for now it might be helpful to separate children afflicted with autistic syndrome from those with classic autism. As children with autistic syndrome increasingly become categorized as a "medical" problem, separating them from the many negative connotations and hopelessness associated with "classic" autism could be advantageous to promoting research and funding to help these children. The differences between the two groups may be summarized as follows:
- A rare disorder affecting 1-2 children / 10,000
- Some/many individuals may have early signs of neurologic injury
- Some may have "physiologic/immune" factors / variables, "treatable" medically by current and future immune medicines
- Generally "abnormal" early (i.e. 3 - 6 months of age)
- "Classic" Autistic symptoms / presentation
- Presumed "static" / unchangeable
- An increasing population of children with "Autistic/ PDD" behavioral characteristics.
- Atypical symptoms
- Landau Kleffner’s
- ADHD / ADD variant
- Current estimate 20-40 children / 10,000 (incidence may be as high as 1-5%)
- Does NOT have "objective" physical signs of neurologic damage
- Majority (possibly all) are immune mediated, appropriately looked upon as a medical dysfunction - open to potential medical therapy
- Generally "normal" early (usually until 15 - 18 months of age)
- Potentially progressive disorder (if not treated / corrected) which may explain the origin of many cases of Landau-Kleffner syndrome
While the cause of autism is speculative, different theories that have surfaced in the past include:
- Brain injury
- Constitutional vulnerability
- Developmental aphasia
- Deficits in the reticular activating system
- An unfortunate interplay between psychogenic and neurodevelopmental factors
- Structural cerebellar changes
With the relatively new thinking that autism has medical origins have come several other theories. Some doctors believe autism is a result of a metabolic, enzyme, or genetic defect. Although a few children may suffer a built-in genetic or functional defect present since early gestation, our clinical observation and our rCBF findings for Autism do not support these theories for the majority of children afflicted. These theories do not fit or began to explain the large increase in the number of children diagnosed with autism today.