Individual Differences in Neural Response to Own Name Heard in Noise across Minimally Verbal and Verbally Fluent Adolescents with Autism

Background: Failure to effectively process salient speech in noisy settings could be both a significant contributor to and a reflection of communication and auditory filtering processing issues observed in many individuals with autism. However, research on these issues has been limited by a lack of neuroimaging research on individuals at the minimally verbal end of the spectrum.

Objectives: We sought to measure, across the entire autism spectrum, neural EEG response to one of the most salient speech sounds – one's own name – when presented in multispeaker noise. For those on the autism spectrum, how does atypical response to own name in noise vary with the individual’s communication abilities? How do responses correlate with phenotypic descriptions of the individual’s success in filtering speech from noise in everyday settings?

Methods: 38 adolescents with autism (26 M), ages 13 to 22 years, with a range of communication abilities from minimally verbal to verbally fluent, participated. Autism diagnoses were confirmed with the ADOS-2 or Adapted ADOS (Lord et al., 2012; Hus et al., 2011). We additionally collected the Vineland-3 Receptive Communication Subscale and Short Sensory Profile Auditory Filtering Subscale (Sparrow et al., 2016; Tomcheck & Dunn, 2007). 22 typically developing (TD), age-matched adolescents (14 M) served as a reference group to determine the spatial and temporal regions of interest for our autism-specific EEG analyses. For the EEG experiment, each participant heard their own name and two other participants’ names as a part of an 8 dB signal to noise multispeaker scene. For analyses, we compared differential response to own name relative to one other name. Peripheral hearing was confirmed as intact using an auditory brainstem measure.

Results: TD participants had a negative differential response from 100 to 300 ms post stimulus along fronto-central electrodes and a positive differential response in a similar time window along left temporal electrodes. They also had a positive differential response from 500 to 600 ms along parietal-occipital electrodes. When we examined this neural response within these reference-defined spatial and temporal components in our autism group, we found that more typical neural response corresponded with better receptive communication and auditory filtering skills. Early fronto-central differential response negatively correlated with receptive communication (p=0.02), early left temporal differential response positively correlated with receptive communication (p=0.01), and late parietal-occipital response positively correlated with auditory filtering ability (p<0.001). Results were not significantly influenced by number of accepted EEG trials.

Conclusions: This study is the first to demonstrate reduced early stage encoding of salient speech and diminished late stage attentional orienting to salient speech in individuals on the autism spectrum who have been characterized phenotypically as having poor communication skills and auditory filtering abilities. This work lays a foundation for uncovering the neural underpinnings of communication and auditory filtering processing issues in autism. Our results highlight the importance of capturing brain-behavior interactions through the measurement of individual differences within a heterogeneous sample of people with autism.