Washington: Scientists have found that children with autism spectrum disorders (ASDs) process sound and language a fraction of a second slower than those without ASDs.
And measuring magnetic signals depicting this delay may become a standardized way to diagnose autism, say researchers at The Children`s Hospital of Philadelphia.
"More work needs to be done before this can become a standard tool, but this pattern of delayed brain response may be refined into the first imaging biomarker for autism," said study leader Dr Timothy PL Roberts, vice chair of Radiology Research at Children`s Hospital.
ASDs are a group of childhood neurodevelopmental disorders that cause impairments in verbal communication, social interaction and behavior.
If researchers can develop imaging results into standardized diagnostic tests, they may be able to diagnose ASDs as early as infancy, which could lead to possible earlier intervention with treatments.
This could also enable them to differentiate types of ASDs (classic autism, Asperger`s syndrome or other types) in individual patients.
In the current study, the researchers used magnetoencephalography (MEG), which detects magnetic fields in the brain, similar to the way electroencephalography (EEG) detects electrical fields.
Using a helmet that surrounds the child`s head, the team presents a series of recorded beeps, vowels and sentences.
As the child`s brain responds to each sound, noninvasive detectors in the MEG machine analyze the brain`s changing magnetic fields.
The researchers compared 25 children with ASDs, having a mean age of 10 years, to 17 age-matched typically developing children.
The children with ASDs had an average delay of 11 milliseconds (about 1/100 of a second) in their brain responses to sounds, compared to the control children. Among the group with ASDs, the delays were similar, whether or not the children had language impairments.
"This delayed response suggests that the auditory system may be slower to develop and mature in children with ASDs," said Roberts.
In a previous study, the researchers showed that normal age-related development of greater myelination corresponds with faster auditory responses in the brain.
"The delayed auditory response that we find in children with ASDs may reflect delayed white matter development in these children," said Roberts.
Roberts said that in further studies, the researchers would seek to refine their imaging techniques to determine that their biomarker is specific to ASDs, and will investigate other MEG patterns found in children with ASDs in addition to auditory delays.
The study has been published in an online article in the journal Autism Research.