Auditory Discrimination in Autism Spectrum Disorder

Fitting parameters in children with cochlear implants and severe additional disabilities

PURPOSE

The aim of this study was to investigate whether the fitting data of children with Cochlear implants (CI) and severe additional disabilities (CAD) differ compared to children with CI but without additional disabilities (CnonAD).

METHODS

In this retrospective analysis, 76 CI cases (fitted ears) from CAD were included and matched with 76 cases from CnonAD. The subjective set values, such as pulse width (PW), threshold (T) and most comfortable (MC) levels were recorded. Additionally, the response threshold values by means of aided soundfield threshold (AST), the values of the intracochlear electrode impedances, the eCAP thresholds and the daily wearing time by using data logging were recorded and analysed.

RESULTS

The T and MC levels for the Medel implants were significantly lower in the sample than in the control group. A similar trend was evident for Cochlear® implants. The sample showed a positive correlation between the eCAP thresholds and the T level and MC level in case of the Cochlear implants. The CAD group showed a significantly higher aided soundfield threshold. In contrast to the CnonAD (0%), there was a total of 18% in the CAD with a reduced daily wearing time. When these were excluded, eCAP thresholds were significantly higher in the CAD group. In addition, there was a trend for eCAP thresholds to be higher if the contralateral ear was not also fitted with a CI.

CONCLUSIONS

The significantly higher eCAPs in CAD may be explained by different neural survival but also by different fittings and MC levels. The audiuologist's subjectivity must be considered as a potential bias but also as potentially valuable input variable contributing to the variance in the fitting parameters and outcomes. Better fitting of T and MC levels focusing on behavioural and developmental responses may lead to a longer wearing time. To support the audiologist and the fitting process, it is necessary to interpret the response thresholds in the aided soundfield threshold against the background of the medical diagnosis and observations from everyday life should be considered. To ensure optimal development of CAD children according to their individual abilities, a multi-professional, family-centred intervention programme including videoanalyses should be implemented at an early stage, ideally from the decision process for a cochlear implant.

Neural Processing of Speech Sounds in Autistic Kindergarteners as a Predictor of Reading Outcomes

Phonology is an important foundation of reading development; however, little is known about the neural substrates of speech sound processing and reading development in autistic children. We investigated early auditory event-related potentials (ERPs) in response to speech sounds and their association with reading ability (word recognition and reading comprehension). 56 kindergarteners (28 ASD, 28 TD) completed an ERP task using rhyming, bisyllabic pseudowords (/gibu/ and /bidu/) in an old/new design: 50% "old" and 50% "new" stimuli presented following a sensitization block of 100% "old" stimuli. Behavioral measures of reading ability were completed at kindergarten entry and exit. Results from generalized linear mixed models revealed a significant three-way interaction between stimuli ("new" vs. "old"), diagnosis (ASD vs. TD), and reading ability (for word recognition and reading comprehension) for P1 and P2 amplitude. Follow-up analyses revealed that autistic children with lower reading abilities showed greater P1 and P2 amplitudes for "new" vs. "old" stimuli, with effects ranging from marginal to significant (p's 0.04-0.07). Regression analyses revealed that old/new ERP difference scores significantly predicted later word recognition at kindergarten year-end (P1 amplitude: p = .05; P2 amplitude: p = .04), but not reading comprehension, controlling for sex and nonverbal IQ. Autistic children with poorer reading skills, specifically those with weaker word recognition abilities, show neural differences when processing speech sounds compared to autistic peers with greater reading ability and typically developing children. A better understanding of the neural basis of speech sound processing could enhance our insight into the heterogeneity in reading among individuals with ASD and guide future treatment approaches.

A longitudinal study on the development trajectory of auditory processing and its relationship with language development in Chinese preschool children with autism spectrum disorder: study protocol

BACKGROUND

It was reported that more than 96% of autism spectrum disorder (ASD) children are accompanied with different degrees of sensory processing abnormalities, and up to 50% of ASD children exhibit abnormal auditory response. Studies have confirmed that some ASD children's abnormal auditory response may be related to their abnormal auditory processing. Prior research demonstrated that ASD children's auditory processing has high heterogeneity, thus, ASD children's auditory processing may have different developmental trajectories. However, no study has concentrated on the developmental trajectories of ASD children's auditory processing. In addition, auditory processing plays a crucial role in ASD children's language development, thus, ASD children's different language development outcomes may be related to different auditory processing development tracks. Therefore, this study aims to explore the developmental trajectory of auditory processing in ASD children and analyze the relationship between different developmental trajectories of auditory processing and language impairment.

METHODS/DESIGN

In this study, 220 ASD children aging 3 years and 0 months to 4 years and 11 months are recruited as the research objects, and their demographic characteristics are collected. The subjects are tested for peripheral hearing, intelligence, and autism symptoms. Furthermore, ASD children's auditory processing and language development are evaluated at baseline, 1 year, and 2 years later. In addition, ASD children's auditory processing is evaluated by electrophysiological test and the Preschool Auditory Processing Assessment Scale. Moreover, ASD children's language skills are assessed using the Language Development Assessment Scale for Children Aged 1-6. The various categories of the developmental trajectory of ASD children's auditory processing are examined through the latent category growth model. Additionally, a hierarchical regression model is developed to analyze the predictive impact of different auditory processing development trajectories on language impairment in ASD children.

DISCUSSION

This longitudinal study will explore the categories of auditory processing developmental trajectories in ASD children, and analyze the relationship between different categories of auditory processing developmental trajectories and language development, providing new ideas and targeted targets for the rehabilitation training of language impairment in ASD children, as well as promoting early and accurate interventions for ASD children.

Aphantasia and autism: An investigation of mental imagery vividness

OBJECTIVE

The present study investigated whether autistic adults report different levels of mental imagery vividness than non-autistic adults, and, moreover, if autism is associated with aphantasia which is defined as a condition of reduced or absent voluntary imagery.

DESIGN AND METHODS

Clinically diagnosed and self-identifying autistic participants were compared with non-autistic participants in their mental imagery vividness (vision, sound, smell, taste, touch, bodily sensation and emotional feeling) and autistic traits using an online survey (N = 121).

RESULTS

The autistic group scored significantly lower than the non-autistic group on imagery vividness (d = -0.44), in addition to having a higher proportion of participants scoring at cut-off for aphantasia. Moreover, a similar difference was observed for the emotional feel (η2 = 0.11).

CONCLUSION

The vividness of visual and emotional mental imagery was on average lower for autistic individuals, with a higher proportion presenting at cut-off to be considered an aphantasic.

Different hemispheric lateralization for periodicity and formant structure of vowels in the auditory cortex and its changes between childhood and adulthood

The spectral formant structure and periodicity pitch are the major features that determine the identity of vowels and the characteristics of the speaker. However, very little is known about how the processing of these features in the auditory cortex changes during development. To address this question, we independently manipulated the periodicity and formant structure of vowels while measuring auditory cortex responses using magnetoencephalography (MEG) in children aged 7-12 years and adults. We analyzed the sustained negative shift of source current associated with these vowel properties, which was present in the auditory cortex in both age groups despite differences in the transient components of the auditory response. In adults, the sustained activation associated with formant structure was lateralized to the left hemisphere early in the auditory processing stream requiring neither attention nor semantic mapping. This lateralization was not yet established in children, in whom the right hemisphere contribution to formant processing was strong and decreased during or after puberty. In contrast to the formant structure, periodicity was associated with a greater response in the right hemisphere in both children and adults. These findings suggest that left-lateralization for the automatic processing of vowel formant structure emerges relatively late in ontogenesis and pose a serious challenge to current theories of hemispheric specialization for speech processing.

Preventive effects of resveratrol against early-life impairments in the animal model of autism induced by valproic acid

Background

Autism Spectrum Disorder (ASD) is a neurodevelopmental condition characterized by social interaction deficits and repetitive/stereotyped behaviors. Its prevalence is increasing, affecting one in 36 children in the United States. The valproic acid (VPA) induced animal model of ASD is a reliable method for investigating cellular, molecular, and behavioral aspects related to the disorder. Trans-Resveratrol (RSV), a polyphenol with anti-inflammatory and antioxidant effects studied in various diseases, has recently demonstrated the ability to prevent cellular, molecular, sensory, and social deficits in the VPA model. In this study, we examined the effects of prenatal exposure to VPA and the potential preventive effects of RSV on the offspring.

Method

We monitored gestational weight from embryonic day 6.5 until 18.5 and assessed the onset of developmental milestones and morphometric parameters in litters. The generalized estimating equations (GEE) were used to analyze longitudinal data.

Results

Exposure to VPA during rat pregnancy resulted in abnormal weight gain fold-changes on embryonic days 13.5 and 18.5, followed by fewer animals per litter. Additionally, we discovered a positive correlation between weight variation during E15.5-E18.5 and the number of rat pups in the VPA group.

Conclusion

VPA exposure led to slight length deficiencies and delays in the onset of developmental milestones. Interestingly, the prenatal RSV treatment not only prevented most of these delays but also led to the early onset of certain milestones and improved morphometric characteristics in the offspring. In summary, our findings suggest that RSV may have potential as a therapeutic intervention to protect against the negative effects of prenatal VPA exposure, highlighting its importance in future studies of prenatal neurodevelopmental disorders.

Circuit-level theories for sensory dysfunction in autism: convergence across mouse models

Individuals with autism spectrum disorder (ASD) exhibit a diverse range of behavioral features and genetic backgrounds, but whether different genetic forms of autism involve convergent pathophysiology of brain function is unknown. Here, we analyze evidence for convergent deficits in neural circuit function across multiple transgenic mouse models of ASD. We focus on sensory areas of neocortex, where circuit differences may underlie atypical sensory processing, a central feature of autism. Many distinct circuit-level theories for ASD have been proposed, including increased excitation-inhibition (E-I) ratio and hyperexcitability, hypofunction of parvalbumin (PV) interneuron circuits, impaired homeostatic plasticity, degraded sensory coding, and others. We review these theories and assess the degree of convergence across ASD mouse models for each. Behaviorally, our analysis reveals that innate sensory detection behavior is heightened and sensory discrimination behavior is impaired across many ASD models. Neurophysiologically, PV hypofunction and increased E-I ratio are prevalent but only rarely generate hyperexcitability and excess spiking. Instead, sensory tuning and other aspects of neural coding are commonly degraded and may explain impaired discrimination behavior. Two distinct phenotypic clusters with opposing neural circuit signatures are evident across mouse models. Such clustering could suggest physiological subtypes of autism, which may facilitate the development of tailored therapeutic approaches.

Event-Related Potentials in Assessing Visual Speech Cues in the Broader Autism Phenotype: Evidence from a Phonemic Restoration Paradigm

Audiovisual speech perception includes the simultaneous processing of auditory and visual speech. Deficits in audiovisual speech perception are reported in autistic individuals; however, less is known regarding audiovisual speech perception within the broader autism phenotype (BAP), which includes individuals with elevated, yet subclinical, levels of autistic traits. We investigate the neural indices of audiovisual speech perception in adults exhibiting a range of autism-like traits using event-related potentials (ERPs) in a phonemic restoration paradigm. In this paradigm, we consider conditions where speech articulators (mouth and jaw) are present (AV condition) and obscured by a pixelated mask (PX condition). These two face conditions were included in both passive (simply viewing a speaking face) and active (participants were required to press a button for a specific consonant-vowel stimulus) experiments. The results revealed an N100 ERP component which was present for all listening contexts and conditions; however, it was attenuated in the active AV condition where participants were able to view the speaker's face, including the mouth and jaw. The P300 ERP component was present within the active experiment only, and significantly greater within the AV condition compared to the PX condition. This suggests increased neural effort for detecting deviant stimuli when visible articulation was present and visual influence on perception. Finally, the P300 response was negatively correlated with autism-like traits, suggesting that higher autistic traits were associated with generally smaller P300 responses in the active AV and PX conditions. The conclusions support the finding that atypical audiovisual processing may be characteristic of the BAP in adults.

Influence of Auditory Integrative Training on Casein Kinase 2 and Its Impact on Behavioral and Social Interaction in Children with Autism Spectrum Disorder

Considerable disturbances in post-translational protein phosphorylation have recently been discovered in multiple neurological disorders. Casein kinase-2 (CK2) is a tetrameric Ser/Thr protein kinase that phosphorylates a large number of substrates and contributes in several cellular physiological and pathological processes. CK2 is highly expressed in the mammalian brain and catalyzes the phosphorylation of a large number of substrates that are crucial in neuronal or glial homeostasis and inflammatory signaling processes across synapses. In this study, we investigated the impact of auditory integration therapy (AIT) for the treatment of sensory processing abnormalities in autism on plasma CK2 levels. A total of 25 ASD children, aged between 5 and 12 years, were enrolled and participated in the present research study. AIT was performed for two weeks, for a period of 30 min, twice a day, with a 3 h interval between sessions. Before and after AIT, the Childhood Autism Rating Scale (CARS), Social Responsiveness Scale (SRS), and Short Sensory Profile (SSP) scores were calculated, and plasma CK2 levels were assayed using an ELISA test. The CARS and SRS indices of autism severity improved as a result of AIT, which could be related to the decreased level of plasma CK2. However, the mean value of the SSP scores was not significantly increased after AIT. The relationship between CK2 downregulation and glutamate excitotoxicity, neuro-inflammation, and leaky gut, as etiological mechanisms in ASD, was proposed and discussed. Further research, conducted on a larger scale and with a longer study duration, are required to assess whether the cognitive improvement in ASD children after AIT is related to the downregulation of CK2.

Loss of oligodendrocyte ErbB receptor signaling leads to hypomyelination, reduced density of parvalbumin-expressing interneurons, and inhibitory function in the auditory cortex

For a long time, myelin was thought to be restricted to excitatory neurons, and studies on dysmyelination focused primarily on excitatory cells. Recent evidence showed that axons of inhibitory neurons in the neocortex are also myelinated, but the role of myelin on inhibitory circuits remains unknown. Here we studied the impact of mild hypomyelination on both excitatory and inhibitory connectivity in the primary auditory cortex (A1) with well-characterized mouse models of hypomyelination due to loss of oligodendrocyte ErbB receptor signaling. Using laser-scanning photostimulation, we found that mice with mild hypomyelination have reduced functional inhibitory connections to A1 L2/3 neurons without changes in excitatory connections, resulting in altered excitatory/inhibitory balance. These effects are not associated with altered expression of GABAergic and glutamatergic synaptic components, but with reduced density of parvalbumin-positive (PV⁺ ) neurons, axons, and synaptic terminals, which reflect reduced PV expression by interneurons rather than PV⁺ neuronal loss. While immunostaining shows that hypomyelination occurs in both PV⁺ and PV^- axons, there is a strong correlation between MBP and PV expression, suggesting that myelination influences PV expression. Together, the results indicate that mild hypomyelination impacts A1 neuronal networks, reducing inhibitory activity, and shifting networks towards excitation.

A Wholistic View of How Bumetanide Attenuates Autism Spectrum Disorders

The specific NKCC1 cotransporter antagonist, bumetanide, attenuates the severity of Autism Spectrum Disorders (ASD), and many neurodevelopmental or neurodegenerative disorders in animal models and clinical trials. However, the pervasive expression of NKCC1 in many cell types throughout the body is thought to challenge the therapeutic efficacy of bumetanide. However, many peripheral functions, including intestinal, metabolic, or vascular, etc., are perturbed in brain disorders contributing to the neurological sequels. Alterations of these functions also increase the incidence of the disorder suggesting complex bidirectional links with the clinical manifestations. We suggest that a more holistic view of ASD and other disorders is warranted to account for the multiple sites impacted by the original intra-uterine insult. From this perspective, large-spectrum active repositioned drugs that act centrally and peripherally might constitute a useful approach to treating these disorders.