For some time now, researchers have been aware that children and adults with autism tend to have different sensory systems to those without the condition. Now, researchers from the University of Miami and Harvard Medical School have found that hearing tests newborns receive shortly after birth may provide a proxy for autism diagnosis later on.
"The importance for diagnosing autism early during infant and child development, when interventions can have the most impact, cannot be overstated. Any additional tool that could clarify diagnostic clues would be invaluable in that regard." says Oren Miron, lead author of the study.
For the study, the researchers examined 140,000 auditory recordings from babies born in Florida and screened for hearing impairments with auditory brainstem response (ABR) tests, which measure how well a baby's inner ear and brain respond to sound. They then matched this data to records from the Florida Department of Education to understand correlations with later developmental disabilities.
In the end, the researchers found that newborn babies who were later diagnosed with autism tended to have slower brain responses to sounds during their ABR tests. From the recordings taken, this meant that 321 of the children who underwent ABR tests went on to be diagnosed with autism by the time they were in preschool.
The researchers now hope to add additional layers to conventional ABR tests so that doctors can use them both to understand a newborn's hearing abilities and their risk for autism. They also hope to adapt the test to screen for other issues such as language impairment and Sudden Infant Death Syndrome.
"We know autism spectrum disorder is connected to how children process sound, so even if the child's hearing is normal, it can still be processed differently," says Elizabeth Simpson, one of the study's authors. "With better understanding of how ABR testing can be used to identify at-risk babies, we can flag children who might be at risk."