Scientists claim best biologically based test for autism to date|
CAMBRIDGE, Massachusetts, USA: A foolproof test for autism in adults and children is "a major step" closer after scientists claim to have developed a brain scan that can detect the condition with almost 100 per cent accuracy.
The diagnosis, which uses scans to measure deviations in brain circuitry, could some day replace the current questionnaire tests now used to identify those with the disorder. It could also lead to a better understanding of autism and to earlier and better management and treatments of affected individuals.
Researchers at Harvard University's McLean Hospital and the University of Utah claim they have developed the best biologically based test for autism to date. The test was able to detect the disorder in individuals with 94 per cent accuracy – even in those that have a milder form of the disorder.
"This is not yet ready for prime time use in the clinic yet, but the findings are the most promising thus far," said Professor Nicholas Lange, a psychiatrist at Harvard Medical School."
The researchers used the test on two groups of subjects.One group consisted of individuals who had previously been diagnosed with so-called "high-functioning" autism using the standard subjective scoring system.That system is based on assessing patients and questioning their parents about their abilities at a variety of areas including language, social functioning and behaviour. The second group studied was a control group consisting of normally developing individuals.
The subjects were put in an MRI scanner that was programmed to measure microscopic features of the brain's circuitry.By measuring six aspects of the brain's circuitry, the test was able to correctly distinguish those who had previously been diagnosed with autism with 94 per cent accuracy.
"It provides pictures and measurements of the microscopic fibre structures of the brain that enable language, social and emotional functioning, which can reveal deviations that are not found in those without autism," Professor Lange said."There is less directional flow to and from brain regions where there should be more information exchange."
A repeat study using two different sets of subjects showed the same high level of performance.
Future studies will look at patients with high-severity autism, younger children, and patients with brain disorders such as developmental language disorders, attention-deficit hyperactivity disorder and obsessive-compulsive disorder, who do not have autism.
If the test demonstrates further success, it could someday replace the current subjective system of diagnosing autism, which is not biologically based.
"It could also someday lead to pinpointing how autism develops," said Dr Janet Lainhart at the University of Utah."We can gain a better understanding of how this disorder arises and changes over the lifetime of an individual, and derive more effective treatments."
The study is published in the journal Autism Research.
(Source: The Daily Telegraph, December 2, 2010)