Relationships Between Auditory Brainstem Responses and Early Language in Typically-Developing Children and Children with Autism Spectrum Disorders

Background: The neurological underpinnings of language in Autism Spectrum Disorders (ASD) have long been sought, both to shed light on possible causes of its complex and multi-faceted behavioral presentation, and to identify targets for intervention. Our project explores whether abnormalities in language development can be attributed to disruptions at an early stage of auditory processing, namely the auditory brainstem. Recent research has suggested that

instability in the nervous system’s response to sound, as revealed by comparisons between initial and later test trials of the auditory brainstem response (ABR), and earlier ABR latencies, might be characteristic of children with lower language skills (Hornickel et al., 2013; Skoe et al.,

2013).

Objectives: We collect ABRs in school-age children with ASD and typically developing (TD) children, whose early language development has been documented in rich detail (Tek et al., 2014; Naigles & Chin, 2015). We investigate the relationship between the ABRs and earlier language measures.

Methods: Fifteen children (one girl) were tested for ABRs; seven had been diagnosed with ASD (MAge=11.25) and eight were TD (MAge=11.14). At their most recent assessment, group average NVIQs were 74.00(ASD) and 102.75(TD); TACL-Q language scores were 73.71(ASD) and 123.63(TD), and ADOS Calibrated Severity Scores were 6.43(ASD) and 1(TD). The children had participated in four mother-child play sessions when they were between 2 and 4 years; the language measures were drawn from their transcripts. ABRs were recorded from scalp electrodes in response to a click stimulus (31.1/sec, 2000 trials) and a 40 millisecond “da” stimulus (10.9/sec, 6000 trials) presented at 80 dB SPL to the right ear. The latency of Wave V (the most robust peak within the ABR), plus Click and /da/ response stability (Fisher transformed Pearson’s r-values), served as the primary dependent measures of sound encoding.

Results: Although the TD children showed numerically faster Wave V latencies than the children with ASD, t-tests revealed no significant differences between the groups on any ABR measure. Bivariate correlations including both groups revealed that children who had produced a higher proportion of utterances with nouns during early language development displayed more consistent ABRs, to both the click and /da/ stimuli (rs > .54, ps < .05), even when age was covaried (see Figure 1). Moreover, children who had produced a higher proportion of utterances with the progressive –ing in their earliest language sample also displayed more consistent ABRs to the click stimulus (r = .525, p = .045). Finally, children’s TACL scores were significantly and independently predicted by their ADOS scores (β=-.681, p =.001) and their /da/ consistency (β= .352, p = .039).

Conclusions: Our procedures for collecting ABR data at home from school-age children with ASD yielded waveforms that resembled those collected in lab settings. Although group differences were not observed in this small sample, significant correlations across the entire dataset revealed that children who had displayed more advanced language early in development showed more stable neural responses to sound during school age, supporting links between early lexical and grammatical development and sound processing in the auditory brainstem.