A study published in August 2006, led by Stephen Dager at the University of Washington School of Medicine, reported on research that examined the brains of children ages 3 and 4. The researchers used magnetic resonance imaging to discover that the brains of autistic children are about 10% larger than those of normally developing children. While the brains of autistic children are larger, they seem to be delayed in neuronal development.
These findings challenge a study that previously held that brain abnormalities in autistic children resulted from their brain’s faster development.
The technique used in this study measured the water properties of brain tissue. In the normally developing brain, water is incorporated into neurons rapidly for the first 6 months of life, and then slows for the next 18 months. The University of Washington study found that, in the autistic brain, water was more mobile. This finding suggests a delay in the development of neurons, specifically at the grey matter at the brain’s surface.
Dager suggests delays could be caused by inflammation: “If you’ve got inflammation, it can affect connectivity at a critical stage of brain development.” This inflammation during the first year of life could lead to learning problems. “For example,” Dager states, “a child has certain key developmental stages for learning language and if you miss those it can be harder to learn that language.”
This early inflammation, Dager suggest, may be due to a particular gene. Research into genetic links to autism is ongoing, but Matthew Belmonte, senior research associate at the Autism Research Center at the University of Cambridge asserts that “Until we know exactly what it is that causes the abnormal development of grey matter we cannot develop drug treatments.” Belmonte suggests that “One might look at genes that cause a susceptibility to inflammation instead [of brain changes].”
Whatever the focus of the research, learning more about the causes of this complex disorder can only help researchers to develop more, and more effective, treatment and intervention possibilities.