JAMA Logo For long, autism has been seemingly linked with an increase in brain size. Now with the help of MRI, scientists found that the brains of children with autism spectrum disorder (ASD) are larger than those without autism. Brain growth apparently begins to slow down by the age of 2 itself.

The study included 59 children diagnosed with ASD and 38 without the condition. During the investigation, behavioral assessments were conducted and MRIs of the participants’ brains at age 2 were scrutinized. After almost two years, when the children were 4 to 5 years old, the steps were repeated among a smaller group available for follow-up. The investigation was now triggered on 36 children with an ASD diagnosis and 21 without. All the scans were assessed for the volume of gray and white matter in the brain as well as the thickness of the brain cortex.

Investigators quote, “Brain overgrowth had its onset in the latter part of the first year of life direct evidence of the timing of early brain volume overgrowth in autism will focus future studies on this narrow window of brain development. Identifying the timeframe when brain changes occur can help isolate “brain markers that may increase prediction of ASD risk.”

Kids suffering from ASD reportedly pointed out enlargement of the cerebral cortex volume at all ages. But the rate of brain growth appeared to the rate observed among children who did not have ASD. It was affirmed that cortical thickness can be very much alike both groups, yet the ASD group displayed a greater cortical surface area along with an elevation in white matter within the temporal lobe. Heather Cody Hazlett, Ph.D., of the University of North Carolina, Chapel Hill, and colleagues did not register any increase in the rate of cerebral cortical growth between age 2 and 4 to 5 years.

The study is published in the May issue of Archives of General Psychiatry, one of the JAMA/Archives journals.