This post was contributed by Guy Collender, of Birkbeck’s Department of External Relations.

Professor Michael Thomas shared the latest autism research during Science Week. Photo: Harish Patel

The media spotlight never seems to be far away from autism, and interest in the developmental disorder has been reignited by the measles outbreak in Swansea. The discredited research linking the MMR vaccine and autism is in the news again, and other debates about autism abound – what causes it?, how early can it be diagnosed?, and how can it be treated?

In light of these controversies and unanswered questions, it was not surprising that a packed lecture theatre awaited the thoughts of Professor Michael Thomas when he delivered his talk about autism on 17 April during Birkbeck’s Science Week. Grabbing the last seat on the back row, I joined the audience and found it refreshing to hear a considered and comprehensive assessment of the spectrum disorder that affects how a person communicates with, and relates to, other people. The talk helped separate fact from fiction and explored an interesting new hypothesis about the cause of autism too.

Professor Thomas, of Birkbeck’s Department of Psychological Sciences, explored the different causal explanations of autism. He described how genes play the major role, but that most cases involve a mixture of common variants (not mutations) and that genetic explanations do not tell the whole story. For example, Professor Thomas said that an identical twin has a 60-90 per cent chance of developing autism if the other twin is affected by the disorder. Therefore, environmental factors must play a role in determining whether a child develops autism as if genes were wholly responsible the figure would be 100 per cent. He also highlighted how the severe deprivation experienced by children in Romanian orphanages caused around 10 per cent of these children to show quasi-autism.

Birkbeck research
Referring to recent Birkbeck research, Professor Thomas explained that changes in brain activity among babies can be detected and are able to predict whether a child will develop autism. Ongoing work at Birkbeck as part of the British Autism Study of Infant Siblings (BASIS) Network is investigating these early months, and early behavioural indicators of autism are being identified at 12 months.

Professor Thomas mentioned screening for autism, but indicated that this isn’t yet a realistic prospect because of the costs involved, concerns about the accuracy of the diagnosis, and what happens after diagnosis. For instance, if autism can be diagnosed, but effective interventions do not exist, then how helpful is a test? Earlier in the lecture, he referred to interventions and stressed that where they are effective they need to be sustained and intense. Research has shown that the most promising approach is early intensive behavioural intervention, which needs to start before age two and be carried out for at least 40 hours per week over two years.

New hypothesis
Professor Thomas also set out a new hypothesis regarding the cause of autism. He explained how connections within the brain are ‘pruned’ in early and middle childhood as unused connections, which are expensive for the body to maintain, are cut away. The pruning hypothesis proposes that this natural process malfunctions in children with autism. Instead of just cutting unnecessary connections, exaggerated pruning means functional connections within the brain are cut. In some children this occurs slightly later, allowing normally looking early behaviour followed by the loss of acquired skills during the second year of life. In other children, exaggerated pruning in the first year leads to atypical development after the first few months of life. The hypothesis predicts that such pruning should affect the sensory and motor systems first, and home videos of infants with autism recorded at four or six months do show some anomalous movements.

The complexities of autism were clearly made throughout the presentation, but what was also clear is that more and more research is leading to a greater understanding of autism and is likely to lead to earlier and earlier diagnosis of the disorder.