and Mark Rutter in London showed that in 42 percent of the families surveyed, either a sibling or a parent of an autistic child had delayed speech or learning problems.
Genetics, however, does not completely control brain development. Studies of identical twins by Folstein and Rutter show that sometimes one twin is severely autistic and the other has only a few autistic traits. MRI (magnetic resonance imaging) brain scans of identical twin schizophrenics have shown that the more severely afflicted twin has greater brain abnormalities. The brain is so complex that genetics cannot tell every little developing neuron exactly where it should be connected. There is a 10 percent variation in brain anatomical structure that is not controlled by genetics. Brain scans of normal identical twins by Michael Gazzaniga, at the Dartmouth Medical School, showed an easily observable variation in brain structure, but twins' brains are more similar than the brains of unrelated people. Likewise, the personalities of identical twins are similar. Studies at the University of Minnesota by Thomas Bouchard and his colleagues of twins reared in different families show that basic traits such as mathematical ability, athletic ability, and temperament are highly inheritable. A summary of these studies concluded that roughly half of what a person becomes is determined by genetics and the other half is determined by environment and upbringing.
Other theories suggest that if a fetus is exposed to certain toxins and viruses, these may interact with genes to cause the abnormal brain development typical of autism. If either parent is exposed to chemical toxins that slightly damage his or her genetic material, that could increase the likelihood of autism or some other developmental disorder. Some parents suspect that an allergic reaction to early childhood vaccinations triggers autistic regression. If this is true it is likely that the vaccine interacts with genetic factors. Another possibility is immune system abnormalities which interfere with brain development. However, there is still too much that is not known, and neither parent should be held responsible for an autistic child. Scientific studies and interviews with families indicate that both the father's and the mother's side contribute genetically to autism.
The Autistic Continuum
Countless researchers have attempted to figure out what factors determine the difference between high- and low-functioning autism. High-functioning children with Kanner's or Asperger's syndrome usually develop good speech and often do well academically Low-functioning children are often unable to speak or can say only a few words. They also have trouble learning simple skills such as buttoning a shirt. At age three, both types have similar behaviors, but as they grow older the difference becomes more and more apparent.
When my speech therapist held my chin and directed me to look at her, it jerked me out of my private world, but for others forcing eye contact can cause the opposite reaction — brain overload and shutdown. For instance, Donna Williams, the author of Nobody Nowhere, explained that she could use only one sensory channel at a time. If a teacher had grabbed her chin and forced eye contact, she would have turned off her ears. Her descriptions of sensory jumbling provide an important bridge to understanding the difference between high-functioning and low- functioning autism, which I would describe as a sensory processing continuum. At one end of the continuum is a person with Asperger's or Kanner's autism who has mild sensory oversensitivity problems, and at the other end of the spectrum is the low-functioning person who receives jumbled, inaccurate information, both visually and aurally.
I was able to learn to speak because I could understand speech, but low-functioning autistics may never learn to speak because their brains cannot discriminate among speech sounds. Many of these people are mentally retarded, but a few individuals may have a near-normal brain trapped inside a sensory system that does not work. Those who escape the prison of low-functioning autism probably do so because just enough undistorted information gets through. They do not totally lose contact with the world around them.
Twenty years ago, Carl Delacato, a therapist who worked with autistic children, speculated that low- functioning individuals may have «white noise» in their sensory channels. In his book The Ultimate Stranger, he described three kinds of sensory processing problems: hyper, hypo, and white noise. Hyper means oversensitive, hypo means undersensitive, and white noise means internal interference.
In questioning many people with autism, I soon found that there was a continuum of sensory abnormalities that would provide insight into the world of nonverbal people with autism. I imagine that the extent of sensory jumbling they experience would be equivalent to taking Donna's sensory problems and multiplying them tenfold. I am lucky in that I responded well when my mother, teachers, and governess kept encouraging social interaction and play. I was seldom allowed to retreat into the soothing world of rocking or spinning objects. When I daydreamed, my teachers yanked me back to reality.
Almost half of all very young children with autism respond well to gently intrusive programs in which they are constantly encouraged to look at the teacher and interact. Brightly colored wall decorations made learning fun for me, but they may be too distracting for a child with sensory jumbling. The popular Lovaas program, developed at UCLA, is being used successfully there to mainstream nearly half of young autistic children into a normal kindergarten or first grade. The Lovaas method pairs words with objects, and the children are rewarded with praise and food when they correctly match a word with an object. While this program is wonderful for some kids, it is certain to be confusing and possibly painful for children with severe sensory jumbling and mixing problems.
These children require a different approach. Touch is often their most reliable sense, and they learn best if teachers use a tactile system. One mother taught her nonverbal daughter to draw a circle by holding her hand and guiding it to make a circle. Plastic letters that can be felt are often useful for teaching words. The more protected these children are from distracting sights and sounds, the more likely it is that their dysfunctional nervous system will be able to perceive speech accurately To help them hear better, teachers must protect them from visual stimuli that will cause sensory overload. They may hear best in a quiet, dimly illuminated room that is free of fluorescent lights and bright wall decorations. Sometimes hearing is enhanced if the teacher whispers or sings softly. Teachers need to speak slowly to accommodate a nervous system that processes information slowly. And sudden movements that will cause sensory confusion should also be avoided.
Children who are echolalic — who repeat what they hear— may be at a midpoint on the sensory processing continuum. Enough recognizable speech gets through for them to be able to repeat the words. Dr. Doris Allen, at the Albert Einstein Hospital in New York, emphasizes that echolalia should not be discouraged, so as not to inhibit speech. The child repeats what has been said to verify that he heard it correctly. Research by Laura Berk, at Illinois State University, has shown that normal children talk to themselves to help them control their behavior and learn new skills. Since autism is caused by immature brain development, it is likely that echolalia and self-talking, which occur in older autistic children, are the result of immature speech patterns.
Unlike normal children, who naturally connect language to the things in their lives at a remarkable rate, autistic children have to learn that objects have names. They have to learn that words communicate. All autistic children have problems with long strings of verbal information. Even very high-functioning people have difficulty following verbal instructions and find it easier to follow written instructions, since they are unable to remember the sequence of the information. My college math teacher once commented that I took excessive notes. He told me that I should pay attention and understand the concept. The problem was that it was impossible for me to remember the sequence of the problems without the notes. I learned to read with phonics and sounding out words, because I was able to understand speech by age three. Children with more severe auditory processing problems often learn to read before they can speak. They learn best if a written word is paired with an object, because many of them have very poor comprehension of spoken words.
As an adult my method for learning a foreign language may be similar to how a more severely impaired autistic child learns to understand language. I cannot pick words out of a conversation in a foreign language until I have seen them written first.
Two basic patterns of autistic symptoms can help identify which children will respond well to intensive, gently intrusive teaching methods, and which will not. The first kind of child may appear deaf at age two, but by age three he or she can understand speech. I was this kind. When adults spoke directly to me, I could understand them, but when they talked among themselves, it sounded like gibberish. The second kind of child appears to develop normally until one and a half or two and then loses speech. As the syndrome progresses, the ability to understand speech deteriorates and autistic symptoms worsen. A child that has been affectionate withdraws into autism as his sensory system becomes more and more scrambled. Eventually he may lose awareness of his surroundings,
