Vaccinations and Increased Prevalence of Autism/ASD
Numerous parents have reported the onset of autistic features shortly after their child received an MMR vaccination. Repeated research has failed to support such a causal link.
Concern was raised about the impact of the mercury present in the vaccine as a possible cause. Again, research has not supported this view. However, there is continuing research into this hypothesis.
Another factor being considered is the possible coincidence of the timing of the vaccinations and the developmental delays being identified – with both occurring around the 18 to 24 month time frame.
As recently as 10 years ago, the accepted rate of autism/ASD was four to five in 10,000. Since then the recognition of ASD is such that it is now widely accepted as being present at a rate of one in 165 individuals. You will hear some variation in the rate, but that tends to depend on whether the whole spectrum is being included or just autism, the most classic interpretation of this set of disorders.
Although there is some debate about the reasons for the increased prevalence of ASD, it is clear that a combination of improved diagnostic tools, better trained physicians, a more attuned and persistent population of young parents and broader media exposure has contributed to an increased identification of individuals with ASD.
Researchers such as Christopher Gillberg have revisited earlier diagnostic/prevalence studies and reexamined the data using today’s diagnostic criteria. They report that the rate from those earlier studies would now match those of more recent studies using these new criteria. On this basis, the rate of incidence has not increased, but our ability to identify has.
There continue to be questions about whether there are other factors affecting an increased incidence rate, but there is no conclusive evidence to support other explanations.
Intensive Behavioural Intervention (IBI)
There is widespread evidence that intensive intervention, as early as possible, is the best possible approach to increasing the development of skills in children with autism/ASD. There are many ways to provide intensive intervention, with the most commonly practiced approaches including Discrete Trial Training and significant levels of one-to-one structured teaching.
All successful interventions are based on the principles of Applied Behavioural Analysis. This means that time is taken to analyze the antecedents of behaviours, to evaluate motivators or reinforcers for behaviours and then to develop a strategy to teach alternative, adaptive behaviours. Reinforcing or rewarding the desired behaviour is central to positive, structured behavioural teaching.
Some children are not identified as having an ASD in their earlier years. This in no ways means that it is too late for them to learn. Individuals with autism learn throughout their lifetime. The principles of ABA are used to develop an appropriate structured teaching strategy, which is both age-appropriate and suited to their abilities.
There are many other intervention strategies that have been used to assist individuals with ASD to learn and adapt to their surroundings. Although structured behavioural teaching has been seen to have the most universally positive impact, the idiosyncratic features of ASD also means that a variety of other interventions can be helpful. What is clear is that there is no single approach that works equally well with all individuals with ASD.
Geneva Centre for Autism strives to provide information in an unbiased manner so that families can make informed choices about the intervention strategies they wish to pursue.
Causes of Autism/ASD
At present there is no conclusive cause of autism/ASD. However there is considerable research which points to genetic roots. This seems to be the most enthusiastically pursued option for finding answers to the autism question.
Other causes under consideration, but unproven, include pre-natal or post-natal viral infection, or environmental assault to a compromised central nervous system. Research is also occurring in the study of brain structure abnormality.
Genetics of Autism/ASD
Research into the genetic links to autism/ASD has received very significant funding in recent years. The National Institutes of Health and the Autism Spectrum Disorders - Canadian-American Research Consortium are leading the way in this area.