Behavioral and electrophysiological characteristics of auditory atypicalities in children with autism spectrum disorder

Sensory atypicalities, particularly auditory, are highly prevalent in children with autism spectrum disorder (ASD). Objective electrophysiological indices for characterizing these differences are lacking. Mismatch Negativity (MMN) reflects automatic auditory processing at the pre-attentive stage and may help explore auditory processing heterogeneity in ASD. We assessed 353 children with ASD (322 males, 31 females, mean age of 6.37 ± 1.47 years) and 576 typically developing (TD) children (511 males and 65 females, mean age of 6.22 ± 1.51 years) using the Sensory Processing and Self-Regulation Checklist (SPSRC). Based on auditory status, children were categorized into four groups: ASD with auditory atypicalities (ASD-AA, n = 114), ASD without auditory atypicalities (ASD-noAA, n = 239), TD with auditory atypicalities (TD-AA, n = 118), and TD without auditory atypicalities (TD-noAA, n = 458). Clinical symptoms were evaluated using the ADOS-2, SRS, CARS, and CNBS-R 2016. ERPs were recorded using a passive auditory oddball paradigm with duration, frequency, and dual deviant stimuli in 122 children with ASD (111 males, 11 females, mean age of 7.18 ± 2.08 years) and 67 TD children (47 males, 20 females, mean age of 6.86 ± 2.07 years). Parameters were set as standard tone 1000 Hz, 50 ms; frequency deviant 1200 Hz; duration deviant 100 ms; dual deviant 1200 Hz/100 ms, 80 dB SPL, ISI 800 ms, percentage of each trial type. MMN mean amplitude was extracted from the Fz electrode, and group differences and correlations with clinical measures were analyzed. 52.36% of children with ASD exhibited at least one sensory atypicality, with auditory atypicalities (32.29%) more prevalent than in TD children (20.49%). The ASD-AA group showed significantly higher scores across all SRS domains and total scores, as well as higher RBS-R total scores, compared to the ASD-noAA group, with no differences in IQ or developmental quotient. While no overall MMN difference was found between ASD and TD children, a significant deviant type × group interaction emerged after stratification by auditory status: the ASD-AA group exhibited significantly larger MMN amplitudes to duration deviant compared to both the ASD-noAA and TD-AA groups, with no such differences for frequency-deviant or dual deviant. More negative MMN amplitudes correlated with higher ADOS-2 social-affective and total scores, and lower adaptive behavior, language, personal-society, and overall developmental levels. Children with ASD presenting auditory atypicalities represent a distinct subgroup with specific clinical and neuroelectrophysiological features. Enhanced MMN responses to sound duration changes, accompanied by more severe social deficits and lower developmental levels, suggest that duration deviant MMN may serve as an objective biomarker for auditory processing atypicality in ASD with clinical subtyping value.