Increased subcortical neural responses to repeating auditory stimulation in children with autism spectrum disorder

Recent research has highlighted atypical reactivity to sensory stimulation as a core symptom in children with autism spectrum disorder (ASD). However, little is known about the dysfunctional neurological mechanisms underlying these aberrant sensitivities. Here we tested the hypothesis that the ability to filter out auditory repeated information is deficient in children with ASD already from subcortical levels, yielding to auditory sensitivities. We recorded the frequency-following response (FFR), a non-invasive measure of the neural tracking of the periodic characteristics of a sound in the subcortical auditory system, to compare repetition-related effects in children with ASD and typically developing children. Results revealed an increase of the FFR with stimulus repetition in children with ASD compared to their peers. Moreover, such defective early sensory encoding of stimulus redundancy was associated with sensory overload. These results highlight that auditory sensitivities in ASD emerge already at the level of the subcortical auditory system.