Abnormal auditory mismatch fields are associated with communication impairment in both verbal and minimally verbal/nonverbal children who have autism spectrum disorder

Abstract

Abnormal auditory discrimination neural processes, indexed by mismatch fields (MMFs) recorded by magnetoencephalography (MEG), have been reported in verbal children with ASD. Association with clinical measures indicates that delayed MMF components are associated with poorer language and communication performance. At present, little is known about neural correlates of language and communication skills in extremely language impaired (minimally-verbal/non-verbal) children who have ASD: ASD-MVNV. It is hypothesized that MMF delays observed in language-impaired but nonetheless verbal children with ASD will be exacerbated in ASD-MVNV. The present study investigated this hypothesis, examining MMF responses bilaterally during an auditory oddball paradigm with vowel stimuli in ASD-MVNV, in a verbal ASD cohort without cognitive impairment and in typically developing (TD) children. The verbal ASD cohort without cognitive impairment was split into those demonstrating considerable language impairment (CELF core language index <85; "ASD-LI") versus those with less or no language impairment (CELF CLI >85; "ASD-V"). Eighty-four participants (8-12 years) were included in final analysis: ASD-MVNV: n = 9, 9.67 ± 1.41 years, ASD: n = 48, (ASD-V: n = 27, 10.55 ± 1.21 years, ASD-LI: n = 21, 10.67 ± 1.20 years) and TD: n = 27, 10.14 ± 1.38 years. Delayed MMF latencies were found bilaterally in ASD-MVNV compared to verbal ASD (both ASD-V and ASD-LI) and TD children. Delayed MMF responses were associated with diminished language and communication skills. Furthermore, whereas the TD children showed leftward lateralization of MMF amplitude, ASD-MVNV and verbal ASD (ASD-V and ASD-LI) showed abnormal rightward lateralization. Findings suggest delayed auditory discrimination processes and abnormal rightward laterality as objective markers of language/communication skills in both verbal and MVNV children who have ASD. Autism Res 2019, 12: 1225-1235. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Brain imaging showed abnormal auditory discrimination processes in minimally-verbal/non-verbal children (MVNV) who have autism spectrum disorder (ASD). Delays in auditory discrimination were associated with impaired language and communication skills. Findings suggest these auditory neural measures may be objective markers of language and communication skills in both verbal and, previously-understudied, MVNV children who have ASD.

Keywords: autism spectrum disorder; language and communication skill; magnetoencephalography; minimally verbal/non-verbal children; vowel mismatch fields.

Figure 1.

Source response waveforms from superior temporal gyrus in representative individuals from each group. Vertical lines on the waveform indicated stimulus onset (zero ms). Arrows indicate MMF latency in a representative TD child (182 ms), ASD-V (214 ms), ASD-LI (222 ms) and ASD-MVNV (270 ms). The solid gray line indicates the standard response, the dashed gray line indicates the deviant response and the solid black line indicates their subtraction to yield the difference wave.

Figure 2

A. Estimated marginal mean MMF latencies by group and hemisphere. Error bars represent one standard error of the marginal means. There was a significant main effect of group on MMF latency (p < .0001), which was evidenced in both hemispheres. Post-hoc t-tests revealed significant differences between all pairwise comparisons of ASD-MVNV, ASD-LI, ASD-V and TD in both hemispheres (all p’s<0.001), with ASD-MVNV>ASD-LI>ASD-V>TD. B. Estimated marginal means of LI by group. Error bars represent one standard error of the marginal means. There was a significant main effect of group on LI (p < .0001). ASD-MVNV (as well as ASD-LI and ASD-V) showed a rightward LI derived from hemispheric MMF amplitudes which was significantly different from the leftward LI observed in TD (all p’s<0.01).