Brain scans detecting a sound processing delay common in children with autism could lead to earlier diagnosis of the developmental disorder, researchers said Friday.

In a study of children with and without autism, researchers monitored brain activity while the children listened to various sounds. They found that it took children with autism an average of 11 milliseconds longer for their brains to respond, researchers report online Friday in the journal Autism Research.

“This delayed response suggests that the auditory system may be slower to develop and mature in children with ASDs,” said study leader Timothy Roberts of Children’s Hospital of Philadelphia. “An 11-millisecond delay is brief, but it means, for instance, that a child with ASD, on hearing the word ‘elephant’ is still processing the ‘el’ sound while other children have moved on.”

The finding is significant because it could lead to a single, measurable tool for diagnosing autism as early as infancy, researchers say. Currently autism is diagnosed using clinical observation and the disorder can take years to manifest. If diagnosed at younger ages, experts say treatment could be more effective.

“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,” Roberts said.

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