Rain Man, Forrest Gump, What's
Eating Gilbert Grape
� it seems like autism has hit the big screen with a vengeance.
Despite all the hype, how much is really understood about
this condition and how we define it? Research published
October 11 in the Annals of Neurology suggested
autism is an arbitrary label given to an overlapping set
of symptoms that may be due to different causes. A group
led by Dr Gordon Harris of Massachusetts General Hospital
found that autistic children with language impairment
had a fundamentally different brain structure than non-autistic
children � or autistic children without language difficulties.
Specifically, the language-impaired
children had reversed asymmetry of the language-processing
regions of the brain, like Broca's area. Normally, Broca's
area is asymmetrical between the two hemispheres, being
larger in the side opposite the 'master' hand. Autistic
children with language difficulties tend to have reversed
asymmetry � thus the Broca's area of a right-handed
autistic child with language difficulties will likely
be larger in the right hemisphere.
In the latest research, investigators
compared 16 language-impaired right-handed autistic
boys to six autistic boys with normal language abilities,
11 non-autistic normal controls, and nine non-autistic
boys with Specific Language Impairment (SLI), a rare
neurodevelopmental disorder.
"This study is the first to show
a direct, brain-based link between autism, SLI and language
ability," claimed Dr Harris. "Both groups of boys with
language impairment � both the autism and SLI groups
� showed the reversal of language area asymmetry, while
both groups of language-normal boys � both the autism
and control language-normal groups � had typical asymmetry."
Dr Anne Foundas, a neurologist
at Tulane University, Florida, said the research suggested
there is potentially more than one etiology behind what
we call autism. "It's well known that individuals with
autism are often not responsive to treatment. Perhaps,
this lack of response is not that these treatments do
not work, but rather that these treatments only work
in a specific biological subgroup."
"This study represents a major
contribution to the field," added Dr Foundas. "Ultimately,
if we can subdivide individuals based on some objective
measures... we may be able to more selectively and effectively
treat people with debilitating neurodevelopmental disorders
like autism and SLI."
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