A recent study published in Autism Research is stirring controversy over reports that a simple hearing test may help with early autism diagnosis. The test is the auditory stapedial reflex (ASR) test which measures how one of the two middle ear muscles called the stapedius contracts in response to loud sounds. According to the authors of the study an absent reflex would indicate an autism risk factor.
The reflex attenuates sudden loud sound to protect the delicate inner hair cells from damage. Without this sound dampening the auditory system is bombarded by sound which results in a number of behavioral responses such as covering of ears, running from the sound, aggression, and more. These are characteristically fight/flight behaviors seemingly in response to sound, in this case a stressor. Last year I published an article with Dr. Jay Lucker in Autism Science Digest identifying that in most cases the response is an emotional rather than auditory response that can be trained with music listening therapy and behavioral techniques and is not exclusive to people diagnosed with autism.
If you read the research abstract (link below) you’ll see the investigators are making an argument for absent reflexes as an autism biomarker. My concern is they tested children with autism compared to a smaller group which was “neurotypical” but not other neurodevelopmental disorders which based on my experience would very likely yield the same results… Auditory deficits are a common feature in autism chief among them hypersensitivity to sound in which the brain appears unable to filter out undesirable sound resulting in pain or discomfort. However this is also true of Sensory Processing Disorder, ADHD, Auditory Processing Disorder, etc.
I’m pleased to see the attention on the auditory system in the autism research field, but caution looking to the ASR as a reliable autism biomarker without further study. What are your thoughts?