Multiple studies suggest that brain scans may detect autism in childrenby BMC Medicine, examiner.com
June 28th 2012
Three separate studies published this month suggest that a variety of brain scans may detect autism in children as young as 6 months of age, sparking hopes for earlier diagnosis and earlier intervention.
The first study published earlier this month in the American Journal of Psychiatry implemented a type of MRI called diffusion tensor imaging to study 92 at-risk infants, due to siblings diagnosed on the autism spectrum, and with follow-up behavioral assessments at 24 months. Out of the 92 participants, 28 were found to meet criteria for autism at 24 months, while the rest did not.
The researchers found that the organization of the white matter in the brain, labeled fractional anisotropy trajectories, differed significantly in the infants who developed autism. Their development was actually higher than the typical children early on but then sustained a sharp decrease, such that their values were lower at 24 months. This suggests that the atypical development of white matter pathways in infants precedes the onset of behavioral symptoms characteristic of autism. The scientists emphasized that longitudinal data (data that tracks participants over a length of time) is crucial in studies such as these.
The second study published this week in utilized a common EEG test on a much larger group of participants, 984 in total, 430 of whom were diagnosed with autism, aged 2 to 12. The researchers found that the children with autism all displayed similar patterns in their EEG scans, all of which displayed atypical connectivity between brain regions. Even more interesting was that there was reduced connectivity in the regions of the brain associated with the production and comprehension of language, located in the left hemisphere. They also found higher connectivity in other regions of the brain, which suggests a compensation for the lack of connectivity in the aforementioned areas.
In total, the researchers found 33 factors in the brain scans that distinguished the children diagnosed with autism from typical children. They took these results a step further beyond diagnosis, suggesting that they may be used to track progress of children enrolled in behavioral programs. If a program is successful, theoretically, more connections would be seen in areas that lacked connectivity prior.
Finally, in yet another study published in the Public Library of Science (PLoS) One Journal, last week researchers found that infants at high-risk for autism displayed fewer brain waves across a wide range of activities. This finding persisted when participants were seen at 24 and 36 months of age.
Each of these studies point to atypical neural development that occurs very early on in life, such as the neuronal connections detected in the EEG studies and the white matter development in the MRI study. And yet, one of the most fascinating aspects of this research is the suggestion that progress in early intervention and behavioral programs can potentially be tracked using these tests. That is in addition to the invaluable tool of earlier diagnosis, leading to more promising outcomes for children diagnosed on the autism spectrum.
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