Interview with Dr Eric Courchesne

Dr ERIC COURCHESNE, of the University of California, is a leading expert on the neurobiological aspects of autism. At the first session of the inaugural World Autism Congress in Melbourne on November 11, 2002, he presented the findings of his latest study revealing brain overgrowth in infants later diagnosed with autism. Adam Feinstein talked to him in Melbourne

ADAM FEINSTEIN: I was fascinated by your brain growth research, which you presented here in Melbourne, and particularly excited by the idea of a possible tie-in with Karin Nelson’s discovery in 2000 of four specific proteins - including brain-derived neurotrophic factor, which stimulates new growth -  in the blood of children in California who were later diagnosed with autism. In your talk, you called autism a “transient post-natal encephalopathy.” Does the fact that you use the term “post-natal” negate research like the thalidomide study of Patricia Rodier indicating damage to the foetus in early pregnancy?

ERIC COURCHESNE:  No - they could both co-exist. The idea of “post-natal” has to do with the macro-encephalopathy. The phenomenon of pathological overgrowth of the brain is taking place after birth, in the first year of life in children with autism. So that is why I call it post-natal. It is transient, because the overgrowth occurs for only a short period of time, leading the brain to be larger than normal for only about three to five years. At that point, the growth tends to stop and the normal brain catches up and surpasses it. There is still a very interesting question about what is happening pre-natally. There is a good possibility that whatever is triggering the post-natal overgrowth might have some connection to what is happening pre-natally. I think this is a very important question:  whether pre-natal events are setting up this post-natal phenomenon?

ADAM FEINSTEIN:  One or two people have come up to me at this congress and said:  “Two months, four months, six months” (the timing of the beginning of the overgrowth in the brain) - what about vaccines, some of which are administered at these stages? What’s your view on this idea?

ERIC COURCHESNE:  Well, there’s always someone who wants to put the blame on vaccines. First it was the MMR  - but quite clearly, if this pathological overgrowth of the brain begins before the MMR vaccine is given, it cannot be implicated. So now people are interested in the earlier vaccines. I think that this is reaching for something without asking: where is the evidence? We really need some serious, sober science to be done looking at the possible triggers for the overgrowth. We should not come to any conclusion too rapidly as to what these triggers might be.

ADAM FEINSTEIN:  What about the cases of so-called “regressive autism,” like my son, who start to speak, then lose language and other skills? I think, in fact, that my son was autistic from birth, anyway, because he was using non-social language. But could your research still apply in these cases?

ERIC COURCHESNE:  Yes. I actually believe that one possibility is that, as the brain grows too large, it is growing more and more abnormalities in its circuits in more and more locations, until it finally reaches a level of such disorganisation that it cannot support previously acquired behavioural functions. Then you have the loss of these functions.

ADAM FEINSTEIN:  So that might explain the mysterious loss of language in many children with autism?

ERIC COURCHESNE:  It might be what is happening. I think it’s too early to know for sure. It is clearly an extremely important area of research.

ADAM FEINSTEIN:  Could you describe the precise therapeutic use to which your findings could lead, potentially?

ERIC COURCHESNE: To begin with, if our study is replicated and found to be consistently true, then it may become a useful early warning of possible autism. That, in turn, allows the development of additional tests to verify the possible diagnosis of autism. It opens up the opportunity for a whole new realm of treatments at a much earlier stage.

ADAM FEINSTEIN:  In your talk, you spoke of the simple method of a tape-measure around the head of very young children?

ERIC COURCHESNE:  Yes. This might turn out to be an amazingly useful tool in the early identification of children who are potentially at risk from autism. Once again, I have to emphasise that we must verify that this is true.

ADAM FEINSTEIN:  Are there more studies in the pipeline?

ERIC COURCHESNE:  We are currently doing one. We hope that other people will do the same. We caution those doing replications that they have to be conducted with great care. Firstly, children have to be diagnosed using the most rigorous contemporary research standards for diagnosis of autism. After all, that is what we did. If people are looking at individuals as young as two or three years of age, a firm diagnosis of autism is not really possible. Studies have shown that, with children who have autistic characteristics at the age of two or three, when followed up and looked at when they’re five or six years old,  only about 70 per cent retain the diagnosis of autism. So if people set out to try to repeat the study looking at two- or three-year-olds, and then do the head circumference measures, they could end up with a mixture of autistic and non-autistic patients and fail to replicate because they are not studying autism per se.

ADAM FEINSTEIN:  How does your research possibly link up with other brain studies like that on mini-columns by Dr Manuel Casanova in Atlanta, Georgia?

ERIC COURCHESNE: It’s very exciting. What Casanova found was that, in autism, the brain is developing too many mini-columns too rapidly and these are nor really developing maturely. Of course, he is looking at the adult brain. There’s a lot of water that passes under the bridge between 12 months and 30 years of age. So to try to make a direct connection will require a lot  more research. But in principle, it fits.

ADAM FEINSTEIN:  Do you share the optimism of Nancy Minshew at the University of Pittsburgh, who has also been doing research on brain size in autistic individuals? She said recently: “The hunt is on for a cure for autism. This will be found in the lifetime of children born today - not in mine but in theirs - if research like this continues its course.”

ERIC COURCHESNE:  I’m very optimistic that, in the the span of five to seven years,  researchers will have discovered major factors involved in this brain overgrowth, and once they do, I believe research will proceed at a tremendously fast pace.

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