The Brain That Changes Itself (2007)
By Norman Doidge
Page 11 of 16
Lauralee, an eight-year-old autistic girl, was diagnosed with moderate autism when she was three. Even as an eight-year-old she rarely used language. She didn’t answer to her name, and to her parents, it seemed she was not hearing it. Sometimes she would speak, but when she did, “she had her own language,” says her mother, “which was often unintelligible.” If she wanted juice, she didn’t ask for it. She would make gestures and pull her parents over to the cabinets to get things for her.
She had other autistic symptoms, among them the repetitive movements that autistic children use to try to contain their sense of being overwhelmed. According to her mother, Lauralee had “the whole works—the flapping of the hands, toe-walking, a lot of energy, biting. And she couldn’t tell me what she was feeling.”
She was very attached to trees. When her parents took her walking in the evening to burn off energy, she’d often stop, touch a tree, hug it, and speak to it.
Lauralee was unusually sensitive to sounds. “She had bionic ears,” says her mother. “When she was little, she would often cover her ears. She couldn’t tolerate certain music on the radio, like classical and slow music.” At her pediatrician’s office she heard sounds from the floor upstairs that others didn’t. At home she would go over to the sinks, fill them with water, then wrap herself around the pipes, hugging them, listening to the water drain through them.
Lauralee’s father is in the navy and served in the Iraq war in 2003. When the family was transferred to California, Lauralee was enrolled in a public school with a special-ed class that used Fast ForWord. The program took her about two hours a day for eight weeks to complete.
When she finished it, “she had an explosion in language,” says her mother, “and began to speak more and use complete sentences. She could tell me about her days at school. Before I would just say, ‘Did you have a good day or a bad day?’ Now she was able to say what she did, and she remembered details. If she got into a bad situation, she would be able to tell me, and I wouldn’t have to prompt her to get it out of her. She also found it easier to remember things.” Lauralee has always loved to read, but now she is reading longer books, nonfiction and the encyclopedia. “She is listening to quieter sounds now and can tolerate different sounds from the radio,” says her mother. “It was an awakening for her. And with the better communication, there was an awakening for all of us. It was a big blessing.”
Merzenich decided that to deepen his understanding of autism and its many developmental delays, he would have to go back to the lab. He thought the best way to go about it was first to produce an “autistic animal”—one that had multiple developmental delays, as autistic children do. Then he could study it and try to treat it.
As Merzenich began to think through what he calls the “infantile catastrophe” of autism, he had a hunch that something might be going wrong in infancy, when most critical periods occur, plasticity is at its height, and a massive amount of development should be occurring. But autism is largely an inherited condition. If one identical twin is autistic, there is an 80 to 90 percent chance the other twin will be as well. In cases of nonidentical twins, where one is autistic, the nonautistic twin will often have some language and social problems.
Yet the incidence of autism has been climbing at a staggering rate that can’t be explained by genetics alone. When the condition was first recognized over forty years ago, about one in 5,000 people had it. Now it is fifteen in 5,000. That number has risen partly because autism is more often diagnosed, and because some children are labeled mildly autistic to get public funding for treatment. “But,” says Merzenich, “even when all of the corrections are made by very hard-assed epidemiologists, it looks like it’s about a threefold increase over the last fifteen years. There is a world emergency that relates to risk factors for autism.”
He has come to think it likely that an environmental factor affects the neural circuits in these children, forcing the critical periods to shut down early, before the brain maps are fully differentiated. When we are born, our brain maps are often “rough drafts,” or sketches, lacking detail, undifferentiated. In the critical period, when the structure of our brain maps is literally getting shaped by our first worldly experiences, the rough draft normally becomes detailed and differentiated.
Merzenich and his team used micromapping to show how maps in newborn rats are formed in the critical period. Right after birth, at the beginning of the critical period, auditory maps were undifferentiated, with only two broad regions in the cortex. Half of the map responded to any high-frequency sound. The other half responded to any low-frequency sound.
When the animal was exposed to a particular frequency during the critical period, that simple organization changed. If the animal was repeatedly exposed to a high C, after a while only a few neurons would turn on, becoming selective for high C. The same would happen when the animal was exposed to a D, E, F, and so on. Now the map, instead of having two broad areas, had many different areas, each responding to different notes. It was now differentiated.
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