Asperger’s syndrome came to our awareness in the late 1980s and 1990s. These were children who were very articulate and had very keen and focused interests and topics. They could speak to you and tell you about esoteric information about whatever was the focus of their interest at the time. In the 1980s we also became aware of a condition called Rett’s syndrome. This is a much rarer condition with an identified genetic disorder on the X chromosome. While the other conditions on the autism spectrum are much more common in boys, Rett’s syndrome affects mainly girls.
Explore This IssueOctober 2008
Thus, although the prevalence of autism spectrum disorders has increased, Dr. Rubin suggested that the increase occurred because we have now included the diagnoses of pervasive developmental disorder and Asperger’s syndrome in the autism spectrum; thus we have increased our diagnostic range. In many medical fields, we often identify the most dramatic presentation of a disease, disorder, or condition first and then, over the course of time, we expand our criteria and then we may realize that we are not be dealing with just one entity, but with multiple entities with common features.
Link Between Autism and Immunization?
Dr. Rubin also considered the controversy surrounding immunization and a possible link to autism. The hallmark of autism is delay and unusual pattern of speech development. Dr. Rubin said in many cases a child may have normal speech development, may start to say some words at the usual time, and then at about 18 months, the child stops speaking. Coincidentally, in the 1980s when MMR [the measles-mumps-rubella vaccine] was introduced, it was given at 18 months. In my opinion, the putative link between immunizations and autism began at that time and has branched out to implicate thimerosal, the mercury-containing preservative. Interestingly, despite the removal of thimerosal from the vaccines, the prevalence continued to rise. Eighteen months seems to be a turning point, whether or not children have immunizations at that time, he said.
Dr. Rubin said he subscribes to a theory that states, Infants are born with billions and billions of brain cells and there are phases of apoptosis-periods of mass destruction of brain cells-a kind of pruning process, he said. Those periods of cell destruction rid the brain of cells that are no longer useful-perhaps due to adaptation of the child’s brain to the immediate environment and particular language acquisition.
One of the theories on the neuropathology of autism is that there is a major phase of apoptosis that is supposed to occur around 18 months, but does not occur in some children with autism, which creates a kind of neural traffic jam, he said. It takes another six to 18 months for the brain to find uncrowded neural side roads to create new pathways, he suggested. He said that when these children start speaking again, they very often repeat words and phrases. I believe that the children on the autism spectrum learn to speak as if they are developing new neural pathways and are, in fact, learning a complete new language, rather than the intuitive process of language acquisition that typically occurs in infancy, he said.