Brain Imaging Technique May Help Diagnose Autism
Researchers at The Children’s Hospital of Philadelphia report that a brain imaging technique may help in the diagnosis of autism. The reason this is possible is that children with autism spectrum disorders (ASDs) process language and sound a fraction of a second slower than children who do not have autism, and magnetoencephalography (MEG) allows clinicians to detect this difference.
There has been a flurry of news recently about autism spectrum disorders, and among the reports are those indicating that the neurodevelopmental disorders are more common than originally thought. A study published in the November 2009 issue of Pediatrics, for example, notes that among children ages 3 to 17, slightly more than 1 percent have autism or a related disorder, which is significantly more than the one in 150 statistic that experts have been using since 2003. More recently, researchers found a cluster of higher autism prevalence in California that has yet to be explained.
In the new imaging study, Timothy P.L. Roberts, PhD, vice chair of Radiology Research at Children’s Hospital, and his colleagues used magnetoencephalography, which detects magnetic fields in the brain, to analyze changing magnetic fields in the brains of 25 children with autism spectrum disorders and 17 controls. The children wore a helmet, through which they were given a series of recorded beeps, vowels, and sentences. The MEG machine analyzed the changing magnetic fields in each child’s brain as he or she responded to each sound.
In response to sounds, the children with ASDs had an average delay of 11 milliseconds in their brain responses when compared with the control children. Among the children with ASD, all the delays were similar, regardless of whether the child had a language impairment.
The significance of this albeit slight delayed response, says Roberts, is that “the auditory system may be slower to develop and mature in children with ASDs.” The delay is enough, he continues so that “a child with ASD, on hearing the word ‘elephant’ is still processing the ‘el’ sound while other children have moved on.”
The investigators acknowledge that more research is needed before this brain imaging technique becomes a standard diagnostic tool for autism. Roberts notes that their discovery “may be refined into the first imaging biomarker for autism.”
The Children’s Hospital of Philadelphia
Kogan MD et al. Pediatrics 2009 Nov; 124(5): 1395-403
Van Meter KC et al. Autism Research 2010 Jan 4