Boys with regressive autism have bigger brains: Study

Boys suffering from a certain type
of autism have bigger brains than their peers without the
developmental disorder, a new study has found.
In the largest of its kind study, researchers from the
University of California found that children with regressive
autism -- which impinges speech and social skills -- had six
per cent greater brain volume than those of their non-autistic
counterparts.
The finding, they said, adds to a growing body of
evidence suggesting the incurable condition could be linked to
neurological growth and development, the Daily Mail reported.
Autism, which affects one in every 100 people, inhibits
the ability to communicate, recognise emotions and socialise,
and can take a mild or severe form.
For the study, published in the journal Proceedings of
the National Academy of Sciences Early Edition, the research
team used magnetic resonance imaging (MRI) scans to assess the
brains of 180 children, aged two to four.
Of those children, 61 had regressive autism, a form of
autism which becomes apparent when a child is aged 18 to 24
months, and affects language and social skills. And of the
remaining children, 53 had early onset autism and 66 did not
have autism at all.
Results showed that boys with regressive autism had six
per cent more brain volume than their peers who didn't have
autism, while the brains of boys with early onset autism were
similar in size to the brains of non-autistic children.
"The finding that boys with regressive autism show a
different form of neuropathology than boys with early onset
autism is novel," said Christine Wu Nordahl who led the study.
"Obtaining MRI scans in 3-year-old children without the
use of sedation may seem quite challenging. But, by working
closely with the parents, we actually were successful more
than 85 percent of the time," Nordahl said.
According to the researchers, accelerated head growth and
brain enlargement was consistently observed in the group of
children diagnosed with regressive autism.
However, all of the autistic girls in the study, even
those with regressive autism, showed no difference in brain
size than their non-autistic peers, suggesting that this
phenomenon could be gender-specific, they said.
"Moreover, when we evaluated girls with autism separately
from boys, we found that no girls -- regardless of whether
they had early onset or regressive autism --had abnormal brain
growth," Nordahl added.
The findings are now prompting scientists to investigate
how brain pathology varies within different subgroups of
autism. This will hopefully enable more effective treatments
to be developed, the researchers said.