Linking auditory brain responses to cortical microstructure and sensory behaviors in autism spectrum disorder: a preliminary study

Introduction – Atypical auditory processing is a core characteristic of autism spectrum disorder (ASD), potentially stemming from disrupted thalamocortical circuits and frontal modulation. This study investigated whether individual differences in cortical microstructure, as measured by neurite orientation dispersion and density imaging, are associated with auditory brainstem responses (ABR) and whether these ABR measures are associated with autism traits and atypical sensory processing. Methods – We recruited 15 adults with ASD (9 males, 6 females; mean age 26.9 ± 6.7 years) and 12 typically developing controls (12 males; mean age 37.1 ± 8.0 years) and assessed microstructural properties in the thalamus, temporal cortex, and orbitofrontal cortex (OFC). Auditory processing was evaluated via ABR recorded under forward-masking conditions. Results – In this preliminary, exploratory analysis, mediation models suggested that the amplitude of wave PVII mediated the association between the orientation dispersion index in the temporal cortex and autism traits, as measured by the Autism-Spectrum Quotient. Similarly, the ΔVI amplitude (peak-to-peak potential between NVI and PVI) mediated the relationship between the neurite density index in the OFC and atypical sensory behaviors, assessed using the Adolescent/Adult Sensory Profile. In the ASD group, reduced PVII amplitude was linked to difficulties in attention switching and imagination, while increased ΔVI amplitude was associated with sensory avoidance. Discussion/conclusion – Our preliminary and exploratory findings tentatively suggest that microstructural variability in the temporal cortex and OFC may relate to auditory neural responses and to sensory and cognitive features of ASD. However, given the small and demographically imbalanced sample, these results should be regarded as hypothesis-generating rather than confirmatory. These candidate brain–behavior pathways should be tested in larger, demographically matched cohorts before any mechanistic interpretation regarding sensory dysfunction in autism can be drawn.