Repetitive behavior in children with autism
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Repetitive behavior -- what's going on in the brain?
Repetitive and stereotyped behavior -- sometimes called stimming -- is one of the key features of autism.
Behaviour-based autism therapies, such as ABA therapy or Relationship Development Interuption (RDI), focus on trying to alter the behavior of the autistic child -- by distracting them, offering rewards for 'good' behavior and so on. For example, some therapists have suggested substituting full-blown stimming -- like hand-flapping -- with less obvious repetitive actions like tapping the fingers.
Healthcare providers who adopt the biomedical approach to autism, however, have always contended that repetitive behavior -- as well as other typical symptoms of autism -- have a biological basis. In other words, that there is something different in the physical function of the autistic child.
A new study published in the 15 May 2008 issue of the Journal of Biological Psychiatry lends further support to this viewpoint. It shows that autistic individuals with repetitive behavior have reduced brain activity in certain regions of the brain. The results of this study suggest that it would be helpful to correct these biological differences, rather than just attempt to modify the behavior of the child.
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Keith M. Shafritz, Gabriel S. Dichter, Grace T. Baranek, Aysenil Bslger
Journal of Biological Psychiatry Vol 63 (10) 974-980
15 May 2008
Background
Recent studies have suggested that the social and cognitive impairments in autism are associated with neural processing deficits in specific brain regions. However, these studies have primarily focused on neural systems responsible for face processing and social behaviours. Although repetitive, stereotyped behaviours are a hallmark of autism, little is known about the neural mechanisms underlying these behaviours in the disorder.
Methods
We used functional magnetic resonance imaging (fMRI) to investigate the neural correlates of shifts in behavioural response and cognitive set in 18 individuals with high-functioning autism and 15 neuro-typical control participants. Participants performed a target detection task specifically designed to distinguish shifts in response from shifts in cognitive set.
Results
Individuals with autism showed lower accuracy on response shifting trials, independent of whether those trials also required a shift in cognitive set. Compared with control subjects, participants with autism showed reduced activation in frontal, striatal, and parietal regions during these trials. In addition, within the autism group, the severity of restricted, repetitive behaviours was negatively correlated with activation in anterior cingulate and posterior parietal regions.
Conclusions
These results suggest that executive deficits and, by extension, repetitive behaviors associated with autism might reflect a core dysfunction within the brain's executive circuitry.
Lay Summary
The researchers found that autistic individuals who have repetitive behaviour showed reduced activity in brain regions normally responsible for attention and executive function.
Comments by John Yeo
We have always maintained that repetitive behavior in autism is, in part, due to a lack of inhibition of impulsive thoughts or actions.
Conventional behavioural approaches to autism, such as ABA or RDI, focus on distraction and substitute behavior.
We are suggesting that a more viable approach is to recover the executive functions by increasing blood flow to the specific brain regions. This can be achieved through hyperbaric oxygen therapy (HBOT), neurofeedback training and other biomedical approaches.
Increasing blood flow to the specific brain regions can help improve brain function. This, in turn, facilitates the ability to exert self-control in order to limit or eradicate repetitive behavior.
Click here to read about Vanessa's recovery from verbal stimming and other repetitive behavior.
John Yeo, MSc. RAc.
20 May 2008
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