Autism rates have been rising dramatically for several decades. A recent report published by the CDC shows a 78 % increase over just 8 years, with autism now affecting 1 in every 88 children. (Prevalence in Autism Studies) Utah has the highest autism rate in the nation: In Utah the rate is estimated at 1 in 47 children. (Utah at High End for Autism) Current rates indicate a 1000% increase (ten-fold increase) in the last forty years. (Troubling CDC Report on Autism) Boys are 5 times more likely to develop autism than girls.
A variety of factors have been suggested as the cause of the increase, most of them based on correlational studies. Correlational studies suggest a relationship, but do not prove a cause of the disease. To prove causality, the causative agent must be shown to create the disease. Although it would be unethical to “prove” causality in humans, it can be done in animals. Recently a prominent neuroplasticity researcher, Dr. Michael Merzenich, has done just that.
After reviewing research showing that closer proximity to loud, erratic noise centers (airports, busy freeways) corresponded with decreases in the IQ of children, Dr. Merzenich began to suspect that early brain development could be overloaded and derailed by bombardment with “white noise” (noises that is disorganized and covers many frequencies). In laboratory experiments, Merzenich exposed baby rats to pulses of white noise. He found that the brain development of the rats was “devastated” by the exposure. The rats developed symptoms that paralleled human autistic spectrum disorders—including a high rate of seizure activity, which could be triggered just by exposure to normal human speech. (Progressive Degradation and Subsequent Refinement of Acoustic Representations in the Adult Auditory Cortex)
In a society where white noise intrudes upon much of our lives, in the form of car engines, vacuum cleaners, air conditioners, electronics and a host of other devices, noise appears to be a credible accomplice in the autism problem.
However, it is likely not the only part of the problem. Recent studies of fraternal and identical twins with autism indicate that autism is impacted by environmental conditions more than by genetics. (California Autism Twin Study). These environmental conditions can include conditions in the womb. Something that happens to the mother during pregnancy may have a significant impact on the development of autism in the baby.
Another study, published in the Archives of General Psychiatry in November 2011 shows that antidepressant use (specifically, SSRI antidepressants) by the mother during pregnancy more than doubles the risk of autism. If the antidepressant use occurs during the first trimester of pregnancy, the risk of autism increases nearly four-fold. (Antidepressant Use During Pregnancy) The depression itself is not the culprit. The research shows that depression and other mental health problems that are not treated with SSRIs produce no increase in autism risk.
This research dovetails very nicely with Dr. Merzenech’s research. He theorizes that excessively sensory bombardment through noise overwhelms the developing brain. This bombardment would be exaggerated even more by the presence of SSRIs, which increase the neurotransmitter dopamine and would thus be likely to “amplify” the effects of sensory bombardment.
Perhaps the most interesting development in autism research is Dr. Merzenich’s efforts to reverse the brain damage in his rat subjects. He attempted this by using sound training sequences that exposed the autistic rats to single clear tones, one at a time, slowly, in a way that allowed their brains to begin to differentiate normally. This work produced dramatic improvement in the rats. (Progressive Degradation and Subsequent Refinement of Acoustic Representations in the Adult Auditory Cortex)
Such an intervention draws attention to Dr. Merzenich’s “Fast ForWord” software, which was developed for helping children with auditory processing disorders. Similar to the intervention he used to help the rats, but broader in its applications, it is being explored as a potentially potent resource for helping autistic children. (Study on Improved Language Skills for Children with Developmental Delays)
It is interesting to note that a similar intervention was developed over thirty years ago by a French scientist, Dr. Guy Berard. His program, “Auditory Integration Training” was widely publicized in the early 90s through the book “The Sound of a Miracle” by Anabel Stehli in which she described her daughter’s dramatic recovery from autism using Berard’s technique. Berard’s techniques have since been the subject of 28 research studies, 22 of which found the technique to be helpful. (AIT research) Berard’s techniques have failed to gain the support of the medical community, perhaps in part because of the lack of a scientific, physiological evidence for the neurological mechanisms showing why they worked. Merzenich has now supplied that.
In addition, the neurofeedback community has done considerable work in studying and treating autism as a brain dysregulation disorder. Their research is another confirmation of Merzenich’s theoretical approach. A pilot study using neurofeedback for improving the function of autistic children showed very positive results.
Join us on Wednesday, March 4 for more information and details on new insights into autism.
The information on Michael Merzenich’s research is taken from the bestselling book, The Brain that Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science, by Norman Doidge.