The relationship between spoken language and speech and nonspeech processing in children with autism: a magnetic event-related field study

Design and methodology for a proof of mechanism study of individualized neuronavigated continuous Theta burst stimulation for auditory processing in adolescents with autism spectrum disorder

It has been suggested that aberrant excitation/inhibition (E/I) balance and dysfunctional structure and function of relevant brain networks may underlie the symptoms of autism spectrum disorder (ASD). However, the nomological network linking these constructs to quantifiable measures and mechanistically relating these constructs to behavioral symptoms of ASD is lacking. Herein we describe a within-subject, controlled, proof-of-mechanism study investigating the pathophysiology of auditory/language processing in adolescents with ASD. We utilize neurophysiological and neuroimaging techniques including magnetic resonance spectroscopy (MRS), diffusion-weighted imaging (DWI), functional magnetic resonance imaging (fMRI), and magnetoencephalography (MEG) metrics of language network structure and function. Additionally, we apply a single, individually targeted session of continuous theta burst stimulation (cTBS) as an experimental probe of the impact of perturbation of the system on these neurophysiological and neuroimaging outcomes. MRS, fMRI, and MEG measures are evaluated at baseline and immediately prior to and following cTBS over the posterior superior temporal cortex (pSTC), a region involved in auditory and language processing deficits in ASD. Also, behavioral measures of ASD and language processing and DWI measures of auditory/language network structures are obtained at baseline to characterize the relationship between the neuroimaging and neurophysiological measures and baseline symptom presentation. We hypothesize that local gamma-aminobutyric acid (GABA) and glutamate concentrations (measured with MRS), and structural and functional activity and network connectivity (measured with DWI and fMRI), will significantly predict MEG indices of auditory/language processing and behavioral deficits in ASD. Furthermore, a single session of cTBS over left pSTC is hypothesized to lead to significant, acute changes in local glutamate and GABA concentration, functional activity and network connectivity, and MEG indices of auditory/language processing. We have completed the pilot phase of the study (n=20 Healthy Volunteer adults) and have begun enrollment for the main phase with adolescents with ASD (n=86; age 14-17). If successful, this study will establish a nomological network linking local E/I balance measures to functional and structural connectivity within relevant brain networks, ultimately connecting them to ASD symptoms. Furthermore, this study will inform future therapeutic trials using cTBS to treat the symptoms of ASD.

Linear and Non-linear Analyses of EEG in a Group of ASD Children During Resting State Condition

This study analyses the spontaneous electroencephalogram (EEG) brain activity of 14 children diagnosed with Autism Spectrum Disorder (ASD) compared to 18 children with normal development, aged 5-11 years. (i) Power Spectral Density (PSD), (ii) variability across trials (coefficient of variation: CV), and (iii) complexity (multiscale entropy: MSE) of the brain signal analysis were computed on the resting state EEG. PSD (0.5-45 Hz) and CV were averaged over different frequency bands (low-delta, delta, theta, alpha, low-beta, high-beta and gamma). MSE were calculated with a coarse-grained procedure on 67 time scales and divided into fine, medium and coarse scales. In addition, significant neurophysiological variables were correlated with behavioral performance data (Kaufman Brief Intelligence Test (KBIT) and Autism Spectrum Quotient (AQ)). Results show increased PSD fast frequency bands (high-beta and gamma), higher variability (CV) and lower complexity (MSE) in children with ASD when compared to typically developed children. These results suggest a more variable, less complex and, probably, less adaptive neural networks with less capacity to generate optimal responses in ASD children.

Autism Spectrum Disorder and auditory sensory alterations: a systematic review on the integrity of cognitive and neuronal functions related to auditory processing

Autism Spectrum Disorder (ASD) is a neurodevelopmental condition with a wide spectrum of symptoms, mainly characterized by social, communication, and cognitive impairments. Latest diagnostic criteria according to DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, 2013) now include sensory issues among the four restricted/repetitive behavior features defined as "hyper- or hypo-reactivity to sensory input or unusual interest in sensory aspects of environment". Here, we review auditory sensory alterations in patients with ASD. Considering the updated diagnostic criteria for ASD, we examined research evidence (2015-2022) of the integrity of the cognitive function in auditory-related tasks, the integrity of the peripheral auditory system, and the integrity of the central nervous system in patients diagnosed with ASD. Taking into account the different approaches and experimental study designs, we reappraise the knowledge on auditory sensory alterations and reflect on how these might be linked with behavior symptomatology in ASD.

Specific Language Impairment, Autism Spectrum Disorders and Social (Pragmatic) Communication Disorders: Is There Overlap in Language Deficits? A Review

Analysing language characteristics and understanding their dynamics is the key for a successful intervention by speech and language therapists (SLT). Thus, this review aims to investigate a possible overlap in language development shared by autism spectrum disorders (ASD), specific language impairment (SLI) and social (pragmatic) communication disorder (SPCD). The sources of this work were the PubMed, PsycInfo and SciELO databases, as well as the Scientific Open Access Repositories of Portugal. The final selection included 18 studies, focused on several linguistic areas. Results suggest that when individuals are matched according to some language or cognitive skills, they will also show similar characteristics in other language domains. Future work should be done based on spontaneous speech.

Auditory Event Related Potentials in children with autism spectrum disorder

OBJECTIVE

To analyze auditory cortical processing in high functioning ASD individuals.

METHODS

Thirty individuals were included in the study (15 with Autism Spectrum Disorder and 15 with typical development), and their Auditory Event Related Potentials evaluation, elicited with tone burst and speech stimuli, were analyzed.

RESULTS

There were no significant differences between individuals with high-functioning Autism Spectrum Disorder without intellectual disability and those with typical development in the auditory Event-related Potentials elicited with tone bursts or speech stimuli.

CONCLUSIONS

The results of Auditory Event Related Potentials did not show any change at the cortical level in individuals with Autism Spectrum Disorder.

Delayed cortical processing of auditory stimuli in children with autism spectrum disorder: A meta-analysis of electrophysiological studies

Several researchers have hypothesised that individuals with Autism Spectrum Disorder (ASD) show encoding delays in their obligatory event-related potentials (ERPs)/ event-related fields (ERFs) for low-level auditory information compared to neurotypical (NT) samples. However, empirical research has yielded varied findings, such as low-level auditory processing in ASD samples being unimpaired, superior, or impaired compared to NT samples. Diverse outcomes have also been reported for studies investigating ASD-NT differences in functional lateralisation of delays. The lack of consistency across studies has prevented a comprehensive understanding of the overall effects in the autistic population. Therefore, this meta-analysis compared long-latency ERPs and ERFs produced by autistic and NT individuals to non-linguistic auditory stimuli to test, firstly, the robustness of auditory processing differences and, secondly, whether these differences are observed in one or both hemispheres. Nine articles meeting the inclusion criteria were included in the meta-analysis. Meta-analytic results indicated that autistic individuals demonstrate bilaterally delayed P1/ M50 peaks and lateralised delays in the right but not left hemisphere N1/ M100 peak. These results further inform our understanding of auditory processing and lateralisation across the autism spectrum.

Preference for speech in infancy differentially predicts language skills and autism-like behaviors

Early emerging biases for conspecific vocalizations are a hallmark of early development. Typically developing neonates listen to speech more than many other sounds, including non-biological non-speech sounds, but listen equally to speech and monkey calls. By 3 months of age, however, infants prefer speech over both non-biological non-speech sounds and monkey calls. We examined whether different listening preferences continue to develop along different developmental trajectories and whether listening preferences are related to developmental outcomes. Given the static preference for speech over non-biological non-speech sounds and the dynamic preference for speech over monkey calls between birth and 3 months, we examined whether 9-month-olds prefer speech over non-biological non-speech sounds (Experiment 1) and prefer speech over monkey calls (Experiment 2). We compared preferences for sounds in infants at low risk (SIBS-TD) and infants at high risk (SIBS-A) of autism spectrum disorder (ASD), a heterogeneous population who differ from typically developing infants in their preferences for speech, and examined whether listening preferences predict vocabulary and autism-like behaviors at 12 months for both groups. At 9 months, SIBS-TD listened longer to speech than to non-speech sounds and listened longer to monkey calls than to speech, whereas SIBS-A listened longer to speech than to non-speech sounds but listened equally to speech and monkey calls. SIBS-TD's preferences did not predict immediate developmental outcomes. In contrast, SIBS-A who preferred speech over non-speech or monkey calls had larger vocabularies and fewer markers of autism-like behaviors at 12 months, which could have positive developmental implications.

White Matter Tract Changes Associated with Clinical Improvement in an Open-Label Trial Assessing Autologous Umbilical Cord Blood for Treatment of Young Children with Autism

Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental disorder characterized by social communication deficits and the presence of restricted interests and repetitive behaviors. We have previously reported significant improvements in behavior, including increased social functioning, improved communication abilities, and decreased clinical symptoms in children with ASD, following treatment with a single infusion of autologous cord blood in a phase I open‐label trial. In the current study, we aimed to understand whether these improvements were associated with concurrent changes in brain structural connectivity. Twenty‐five 2‐ to 6‐year‐old children with ASD participated in this trial. Clinical outcome measures included the Vineland Adaptive Behavior Scales‐II Socialization Subscale, Expressive One‐Word Picture Vocabulary Test‐4, and the Clinical Global Impression‐Improvement Scale. Structural connectivity was measured at baseline and at 6 months in a subset of 19 children with 25‐direction diffusion tensor imaging and deterministic tractography. Behavioral improvements were associated with increased white matter connectivity in frontal, temporal, and subcortical regions (hippocampus and basal ganglia) that have been previously shown to show anatomical, connectivity, and functional abnormalities in ASD. The current results suggest that improvements in social communication skills and a reduction in symptoms in children with ASD following treatment with autologous cord blood infusion were associated with increased structural connectivity in brain networks supporting social, communication, and language abilities. stem cells translational medicine2019;8:138&10

Atypical auditory language processing in adolescents with autism spectrum disorder

OBJECTIVE

Individuals with autism spectrum disorder (ASD) often show characteristic differences in auditory processing. To clarify the mechanisms underlying communication impairment in ASD, we examined auditory language processing with both anatomical and functional methods.

METHODS

We assessed the language abilities of adolescents with ASD and typically developing (TD) adolescents, and analyzed the surface-based morphometric structure between the groups using magnetic resonance imaging. Furthermore, we measured cortical responses to an auditory word comprehension task with magnetoencephalography and performed network-based statistics using the phase locking values.

RESULTS

We observed no structural differences between the groups. However, the volume of the left ventral central sulcus (vCS) showed a significant correlation with linguistic scores in ASD. Moreover, adolescents with ASD showed weaker cortical activation in the left vCS and superior temporal sulcus. Furthermore, these regions showed differential correlations with linguistic scores between the groups. Moreover, the ASD group had an atypical gamma band (25-40 Hz) network centered on the left vCS.

CONCLUSIONS

Adolescents with ASD showed atypical responses on the auditory word comprehension task and functional brain differences.

SIGNIFICANCE

Our results suggest that phonological processing and gamma band cortical activity play a critical role in auditory language processing-related pathophysiology in adolescents with ASD.

Distinct ERP profiles for auditory processing in infants at-risk for autism and language impairment

Early identification of autism spectrum disorder (ASD) is crucial for the formulation of effective intervention programs. Language deficits may be a hallmark feature of ASD and language delay observed in ASD shows striking similarities to that observed in children with language impairment (LI). Auditory processing deficits are seen in both LI and ASD, however, they have not previously been compared directly using Event-Related Potentials (ERPs) in the two at-risk populations. This study aims to characterize infants at-risk for ASD (HR-ASD) at the electrophysiological level and to compare them with infants at-risk for LI (HR-LI) and controls, to find specific markers with predictive value. At 12-month-old, auditory processing in HR-ASD, HR-LI and controls was characterized via ERP oddball paradigm. All infants were then evaluated at 20 months, to investigate the associations between auditory processing and language/ASD-related outcomes. In both HR-ASD and HR-LI, mismatch response latency was delayed compared to controls, whereas only HR-ASD showed overall larger P3 amplitude compared to controls. Interestingly, these ERP measures correlated with later expressive vocabulary and M-CHAT critical items in the whole sample. These results may support the use of objective measurement of auditory processing to delineate pathophysiological mechanisms in ASD, as compared to LI.

Atypical speech versus non-speech detection and discrimination in 4- to 6- yr old children with autism spectrum disorder: An ERP study

Previous event-related potential (ERP) research utilizing oddball stimulus paradigms suggests diminished processing of speech versus non-speech sounds in children with an Autism Spectrum Disorder (ASD). However, brain mechanisms underlying these speech processing abnormalities, and to what extent they are related to poor language abilities in this population remain unknown. In the current study, we utilized a novel paired repetition paradigm in order to investigate ERP responses associated with the detection and discrimination of speech and non-speech sounds in 4- to 6-year old children with ASD, compared with gender and verbal age matched controls. ERPs were recorded while children passively listened to pairs of stimuli that were either both speech sounds, both non-speech sounds, speech followed by non-speech, or non-speech followed by speech. Control participants exhibited N330 match/mismatch responses measured from temporal electrodes, reflecting speech versus non-speech detection, bilaterally, whereas children with ASD exhibited this effect only over temporal electrodes in the left hemisphere. Furthermore, while the control groups exhibited match/mismatch effects at approximately 600 ms (central N600, temporal P600) when a non-speech sound was followed by a speech sound, these effects were absent in the ASD group. These findings suggest that children with ASD fail to activate right hemisphere mechanisms, likely associated with social or emotional aspects of speech detection, when distinguishing non-speech from speech stimuli. Together, these results demonstrate the presence of atypical speech versus non-speech processing in children with ASD when compared with typically developing children matched on verbal age.

Case study: auditory brain responses in a minimally verbal child with autism and cerebral palsy

An estimated 30% of individuals with autism spectrum disorders (ASD) remain minimally verbal into late childhood, but research on cognition and brain function in ASD focuses almost exclusively on those with good or only moderately impaired language. Here we present a case study investigating auditory processing of GM, a nonverbal child with ASD and cerebral palsy. At the age of 8 years, GM was tested using magnetoencephalography (MEG) whilst passively listening to speech sounds and complex tones. Where typically developing children and verbal autistic children all demonstrated similar brain responses to speech and nonspeech sounds, GM produced much stronger responses to nonspeech than speech, particularly in the 65-165 ms (M50/M100) time window post-stimulus onset. GM was retested aged 10 years using electroencephalography (EEG) whilst passively listening to pure tone stimuli. Consistent with her MEG response to complex tones, GM showed an unusually early and strong response to pure tones in her EEG responses. The consistency of the MEG and EEG data in this single case study demonstrate both the potential and the feasibility of these methods in the study of minimally verbal children with ASD. Further research is required to determine whether GM's atypical auditory responses are characteristic of other minimally verbal children with ASD or of other individuals with cerebral palsy.