Autism and hearing loss

Is autism a PIN1 deficiency syndrome? A proposed etiological role for glyphosate

Autism is a neurodevelopmental disorder, the prevalence of which has increased dramatically in the United States over the past two decades. It is characterized by stereotyped behaviors and impairments in social interaction and communication. In this paper, we present evidence that autism can be viewed as a PIN1 deficiency syndrome. Peptidyl-prolyl cis/trans isomerase, NIMA-Interacting 1 (PIN1) is a peptidyl-prolyl cis/trans isomerase, and it has widespread influences in biological organisms. Broadly speaking, PIN1 deficiency is linked to many neurodegenerative diseases, whereas PIN1 over-expression is linked to cancer. Death-associated protein kinase 1 (DAPK1) strongly inhibits PIN1, and the hormone melatonin inhibits DAPK1. Melatonin deficiency is strongly linked to autism. It has recently been shown that glyphosate exposure to rats inhibits melatonin synthesis as a result of increased glutamate release from glial cells and increased expression of metabotropic glutamate receptors. Glyphosate's inhibition of melatonin leads to a reduction in PIN1 availability in neurons. In this paper, we show that PIN1 deficiency can explain many of the unique morphological features of autism, including increased dendritic spine density, missing or thin corpus callosum, and reduced bone density. We show how PIN1 deficiency disrupts the functioning of powerful high-level signaling molecules, such as nuclear factor erythroid 2-related factor 2 (NRF2) and p53. Dysregulation of both of these proteins has been linked to autism. Severe depletion of glutathione in the brain resulting from chronic exposure to oxidative stressors and extracellular glutamate leads to oxidation of the cysteine residue in PIN1, inactivating the protein and further contributing to PIN1 deficiency. Impaired autophagy leads to increased sensitivity of neurons to ferroptosis. It is imperative that further research be conducted to experimentally validate whether the mechanisms described here take place in response to chronic glyphosate exposure and whether this ultimately leads to autism.

Contribution of the serotonergic system to developmental brain abnormalities in autism spectrum disorder

This review highlights a key role of the serotonergic system in brain development and in distortions of normal brain development in early stages of fetal life resulting in cascades of abnormalities, including defects of neurogenesis, neuronal migration, neuronal growth, differentiation, and arborization, as well as defective neuronal circuit formation in the cortex, subcortical structures, brainstem, and cerebellum of autistic subjects. In autism, defects in regulation of neuronal growth are the most frequent and ubiquitous developmental changes associated with impaired neuron differentiation, smaller size, distorted shape, loss of spatial orientation, and distortion of cortex organization. Common developmental defects of the brain in autism include multiregional focal dysplastic changes contributing to local neuronal circuit distortion, epileptogenic activity, and epilepsy. There is a discrepancy between more than 500 reports demonstrating the contribution of the serotonergic system to autism's behavioral anomalies, highlighted by lack of studies of autistic subjects' brainstem raphe nuclei, the center of brain serotonergic innervation, and of the contribution of the serotonergic system to the diagnostic features of autism spectrum disorder (ASD). Discovery of severe fetal brainstem auditory system neuronal deficits and other anomalies leading to a spectrum of hearing deficits contributing to a cascade of behavioral alterations, including deficits of social and verbal communication in individuals with autism, is another argument to intensify postmortem studies of the type and topography of, and the severity of developmental defects in raphe nuclei and their contribution to abnormal brain development and to the broad spectrum of functional deficits and comorbid conditions in ASD.

Comparing narrative storytelling ability in individuals with autism and fetal alcohol spectrum disorders

BACKGROUND

Narrative discourse, or storytelling, is used in daily conversation and requires higher-level language and social communication skills that are not always captured by standardised assessments of language. Many autistic individuals and individuals with fetal alcohol spectrum disorders (FASD) have difficulties with both social communication and language skills, and narrative discourse analysis offers an ecologically relevant approach to assessing those challenges.

AIMS

This study investigated narrative discourse in individuals with autism and FASD, as well as an age- and sex-matched comparison group.

METHODS AND PROCEDURES

Narratives from 45 adolescents and adults, 11 with autism, 11 with FASD and 23 age- and sex-matched comparison participants were elicited using a wordless storybook. They were then transcribed orthographically, formatted to the Systematic Analyses of Language Transcript (SALT) convention and scored based on the SALT Narrative Scoring Scheme (NSS), a standardised language analysis protocol. In addition to the NSS total score, which assesses the overall structure and cohesion of the narratives produced, local and global measures of language ability were also employed. The local language measures included the number of mental state and temporal relation terms produced, while the global language measures included mean length of utterance, total different words, total words, total utterances, rate of speech, the number of mazes (e.g., repetitions, 'um', 'uh' or self-corrections) per total word and the NSS total score.

OUTCOMES AND RESULTS

Using the SALT Language Sample Analysis tool, our results revealed that on global language measures, group differences were found on rate of speech, number of mazes per total words and the description of conflict/resolution in the narratives produced. The autism group produced significantly more mazes per total word and scored higher on the NSS conflict/resolution category score compared to the FASD and comparison groups. Both the autism and FASD groups spoke at a lower rate than the comparison group. On local language measures of narrative production, all groups were comparable, on average.

CONCLUSIONS AND IMPLICATIONS

While many aspects of narrative discourse in the autism and FASD groups were similar to each other and to the comparison group, we observed group differences on global measures of narrative production and significant individual variability within groups, suggesting that narrative abilities considered at an individual level may provide important clinical information for intervention planning. Future research should also consider additional variables that influence narrative discourse, such as motivation, distractibility or decision-making of individual participants.

WHAT THIS PAPER ADDS

What is already known on the subject Narrative discourse, or storytelling, is used in daily conversational interactions and reveals higher-level language skills that may not be well captured by standardised assessments of language. Many autistic individuals and individuals with fetal alcohol spectrum disorders (FASD) show difficulty with pragmatic and expressive language skills. What this paper adds to existing knowledge We found that many aspects of the narratives produced by the adolescents/young adults in the autism and FASD groups were comparable to each other and to the neurotypical group. However, the groups differed on three global measures of narrative production: rate of speech, number of mazes per total words and the description of conflict/resolution in the narratives produced. Also, significant variability was observed within groups, suggesting that narrative abilities should be considered at an individual level as opposed to their clinical groups. What are the potential or actual clinical implications of this work? This study showed that narrative discourse is an appropriate task that can be added to routine clinical assessments of language abilities in autistic adolescents/young adults as well as those with FASD or typical development and has the potential to reveal higher-level, real-world language skills. An important clinical implication of this study is that narrative language abilities should be considered at an individual level and individual-tailored interventions based on ability level due to the variability observed across individuals.

Alterations in KIDINS220/ARMS Expression Impact Sensory Processing and Social Behavior in Adult Mice

Kinase D-interacting substrate of 220 kDa (Kidins220) is a transmembrane protein that participates in neural cell survival, maturation, and plasticity. Mutations in the human KIDINS220 gene are associated with a neurodevelopmental disorder ('SINO' syndrome) characterized by spastic paraplegia, intellectual disability, and in some cases, autism spectrum disorder. To better understand the pathophysiology of KIDINS220-linked pathologies, in this study, we assessed the sensory processing and social behavior of transgenic mouse lines with reduced Kidins220 expression: the CaMKII-driven conditional knockout (cKO) line, lacking Kidins220 in adult forebrain excitatory neurons, and the Kidins220floxed line, expressing constitutively lower protein levels. We show that alterations in Kidins220 expression levels and its splicing pattern cause impaired response to both auditory and olfactory stimuli. Both transgenic lines show impaired startle response to high intensity sounds, with preserved pre-pulsed inhibition, and strongly reduced social odor recognition. In the Kidins220floxed line, olfactory alterations are associated with deficits in social memory and increased aggressive behavior. Our results broaden our knowledge of the SINO syndrome; understanding sensory information processing and its deviations under neuropathological conditions is crucial for devising future therapeutic strategies to enhance the quality of life of affected individuals.

Incidence of Otolaryngological Manifestations in Individuals with Autism Spectrum Disorder: A Special Focus on Auditory Disorders

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized by stereotyped and repetitive behavior patterns. In addition to neurological and behavioral problems, individuals with ASD commonly experience otolaryngological comorbidities. Individuals with ASD often have auditory disorders including hearing loss and auditory processing disorders such as central auditory processing disorder (CAPD), as well as both chronic and recurrent otitis media. These challenges negatively impact a person's ability to effectively communicate and may further impact their neurological functioning, particularly when not appropriately treated. Individuals diagnosed with ASD also have difficulty sleeping which contributes to increased irritability and may further aggravate the core behavioral symptoms of autism. The individuals with ASD also have a higher rate of sinusitis which contributes to the worsening of the autism behavior phenotype. The high prevalence of otolaryngological comorbidities in individuals with ASD warrants a better collaboration between their various healthcare providers and otolaryngologists with expertise in auditory, sleep, and sinus disorders in pursuit of improving the quality of life of affected individuals and their families/caregivers.

Enhanced sensitivity to pitch perception and its possible relation to language acquisition in autism

Background and aims

Fascinations for or aversions to particular sounds are a familiar feature of autism, as is an ability to reproduce another person's utterances, precisely copying the other person's prosody as well as their words. Such observations seem to indicate not only that autistic people can pay close attention to what they hear, but also that they have the ability to perceive the finer details of auditory stimuli. This is consistent with the previously reported consensus that absolute pitch is more common in autistic individuals than in neurotypicals. We take this to suggest that autistic people have perception that allows them to pay attention to fine details. It is important to establish whether or not this is so as autism is often presented as a deficit rather than a difference. We therefore undertook a narrative literature review of studies of auditory perception, in autistic and nonautistic individuals, focussing on any differences in processing linguistic and nonlinguistic sounds.

Main contributions

We find persuasive evidence that nonlinguistic auditory perception in autistic children differs from that of nonautistic children. This is supported by the additional finding of a higher prevalence of absolute pitch and enhanced pitch discriminating abilities in autistic children compared to neurotypical children. Such abilities appear to stem from atypical perception, which is biased toward local-level information necessary for processing pitch and other prosodic features. Enhanced pitch discriminating abilities tend to be found in autistic individuals with a history of language delay, suggesting possible reciprocity. Research on various aspects of language development in autism also supports the hypothesis that atypical pitch perception may be accountable for observed differences in language development in autism.

Conclusions

The results of our review of previously published studies are consistent with the hypothesis that auditory perception, and particularly pitch perception, in autism are different from the norm but not always impaired. Detail-oriented pitch perception may be an advantage given the right environment. We speculate that unusually heightened sensitivity to pitch differences may be at the cost of the normal development of the perception of the sounds that contribute most to early language development.

Implications

The acquisition of speech and language may be a process that normally involves an enhanced perception of speech sounds at the expense of the processing of nonlinguistic sounds, but autistic children may not give speech sounds this same priority.

Development and validation of a paediatric version of the Khalfa Hyperacusis Questionnaire for children with and without autism

OBJECTIVE

Hyperacusis is reported to occur in 3.2-17.1% of the general paediatric population with higher rates in clinical populations such as autism spectrum disorders (ASD). Although hyperacusis is a relatively common form of decreased sound tolerance (DST), no valid paediatric hyperacusis measures are currently available. The purpose of the present study was to develop and validate a paediatric version of the Khalfa Hyperacusis Questionnaire (HQ) as a first step towards filling this measurement gap.

DESIGN

A cross-sectional design was used to evaluate therapist opinions of the paediatric version (P-HQ) and to field test the P-HQ in parents of children with and without ASD. Total scores were compared between ASD and non-ASD groups.

STUDY SAMPLE

Eleven paediatric occupational and speech therapists with expertise in ASD, 64 parents of children with ASD and 37 parents of children without ASD completed online questionnaires. Psychometric analyses were conducted.

RESULTS

A unidimensional construct was found underlying P-HQ and all items displayed sufficient theoretical relevance to hyperacusis and adequate psychometric properties.

CONCLUSIONS

The P-HQ demonstrates good internal consistency and shows promise as a potential screening tool for identifying DST in ASD. Further research is warranted to establish normative data and validate cut-off scores.

Exploratory evidence for differences in GABAergic regulation of auditory processing in autism spectrum disorder

Altered reactivity and responses to auditory input are core to the diagnosis of autism spectrum disorder (ASD). Preclinical models implicate ϒ-aminobutyric acid (GABA) in this process. However, the link between GABA and auditory processing in humans (with or without ASD) is largely correlational. As part of a study of potential biosignatures of GABA function in ASD to inform future clinical trials, we evaluated the role of GABA in auditory repetition suppression in 66 adults (n = 28 with ASD). Neurophysiological responses (temporal and frequency domains) to repetitive standard tones and novel deviants presented in an oddball paradigm were compared after double-blind, randomized administration of placebo, 15 or 30 mg of arbaclofen (STX209), a GABA type B (GABAB) receptor agonist. We first established that temporal mismatch negativity was comparable between participants with ASD and those with typical development (TD). Next, we showed that temporal and spectral responses to repetitive standards were suppressed relative to responses to deviants in the two groups, but suppression was significantly weaker in individuals with ASD at baseline. Arbaclofen reversed weaker suppression of spectral responses in ASD but disrupted suppression in TD. A post hoc analysis showed that arbaclofen-elicited shift in suppression was correlated with autistic symptomatology measured using the Autism Quotient across the entire group, though not in the smaller sample of the ASD and TD group when examined separately. Thus, our results confirm: GABAergic dysfunction contributes to the neurophysiology of auditory sensory processing alterations in ASD, and can be modulated by targeting GABAB activity. These GABA-dependent sensory differences may be upstream of more complex autistic phenotypes.

Temporal dynamics of normalization reweighting

For decades, neural suppression in early visual cortex has been thought to be fixed. But recent work has challenged this assumption by showing that suppression can be reweighted based on recent history; when pairs of stimuli are repeatedly presented together, suppression between them strengthens. Here we investigate the temporal dynamics of this process using a steady-state visual evoked potential (SSVEP) paradigm that provides a time-resolved, direct index of suppression between pairs of stimuli flickering at different frequencies (5 and 7 Hz). Our initial analysis of an existing electroencephalography (EEG) dataset (N = 100) indicated that suppression increases substantially during the first 2-5 seconds of stimulus presentation (with some variation across stimulation frequency). We then collected new EEG data (N = 100) replicating this finding for both monocular and dichoptic mask arrangements in a preregistered study designed to measure reweighting. A third experiment (N = 20) used source-localized magnetoencephalography and found that these effects are apparent in primary visual cortex (V1), consistent with results from neurophysiological work. Because long-standing theories propose inhibition/excitation differences in autism, we also compared reweighting between individuals with high versus low autistic traits, and with and without an autism diagnosis, across our three datasets (total N = 220). We find no compelling differences in reweighting that are associated with autism. Our results support the normalization reweighting model and indicate that for prolonged stimulation, increases in suppression occur on the order of 2-5 seconds after stimulus onset.

Understanding Auditory Processing Disorder: A Narrative Review

Auditory processing disorder (APD) is defined as difficulty in listening despite possessing hearing thresholds within the normal limit. Understanding rapid speech, following complex instructions, and listening in the existence of background noise are some of the difficulties in APD. APD has been observed in diverse clinical populations with suspected or diagnosed disorders, such as attention deficit-hyperactivity disorder, dyslexia, aphasia, and Alzheimer's disease; however, it should be differentiated from these disorders. Despite the research on APD, its awareness is limited, resulting in it often being undiagnosed. Therefore, improving the awareness and understanding of APD is important. The current paper aims to review the literature on APD with a focus on school-age children. The prevalence, etiology, screening, and diagnosis of APD are discussed along with correlated disorders, interpretation of tests, and management strategies.

Auditory evoked potentials in adolescents with autism: An investigation of brain development, intellectual impairment, and neural encoding

Limited research has evaluated neural encoding of sounds from a developmental perspective in individuals with autism (ASD), especially among those with intellectual disability. We compared auditory evoked potentials (AEPs) in autistic adolescents with a wide range of intellectual abilities (n = 40, NVIQ 30-160) to both age-matched cognitively able neurotypical adolescent controls (NT-A, n = 37) and younger neurotypical children (NT-C, n = 27) to assess potential developmental delays. In addition to a classic measure of peak amplitude, we calculated a continuous measure of intra-class correlation (ICC) between each adolescent participant's AEP and the age-normative, average AEP waveforms calculated from NT-C and NT-A to study differences in signal morphology. We found that peak amplitudes of neural responses were significantly smaller in autistic adolescents compared to NT-A. We also found that the AEP morphology of autistic adolescents looked more like NT-A peers than NT-C but was still significantly different from NT-A AEP waveforms. Results suggest that AEPs of autistic adolescents present differently from NTs, regardless of age, and differences cannot be accounted for by developmental delay. Nonverbal intelligence significantly predicted how closely each adolescent's AEP resembled the age-normed waveform. These results support an evolving theory that the degree of disruption in early neural responses to low-level inputs is reflected in the severity of intellectual impairments in autism.

The interface of paediatric ENT and autism spectrum disorder: a complex conundrum for otolaryngologists

OBJECTIVE

Autism spectrum disorder is a lifelong neurodevelopmental condition encompassing complex physical and neurological symptoms, including complex sensory symptoms. This review explores the interface between autism spectrum disorder and paediatric ENT.

METHODS

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses ('PRISMA') guideline, a robust literature search and review was conducted by two researchers. Thirty-four papers were filtered into the final review.

RESULTS

Published literature clearly demonstrates potential for autism spectrum disorder to present in the form of auditory and other sensory symptoms to ENT surgeons and audiologists who may not fully appreciate this complex condition. Despite this well-documented link, auditory symptoms, auditory processing disorders and hearing loss within autism spectrum disorder remain poorly understood.

CONCLUSION

Improved recognition and understanding of autism spectrum disorder by otolaryngologists could enable more effective diagnostic and management strategies for autistic children who present with auditory and other sensory symptoms. In light of the current 'autism epidemic,' there is an urgent need for further research on this theme.

Habituation of auditory responses in young autistic and neurotypical children

Prior studies suggest that habituation of sensory responses is reduced in autism and that diminished habituation could be related to atypical autistic sensory experiences, for example, by causing brain responses to aversive stimuli to remain strong over time instead of being suppressed. While many prior studies exploring habituation in autism have repeatedly presented identical stimuli, other studies suggest group differences can still be observed in habituation to intermittent stimuli. The present study explored habituation of electrophysiological responses to auditory complex tones of varying intensities (50-80 dB SPL), presented passively in an interleaved manner, in a well-characterized sample of 127 autistic (MDQ  = 65.41, SD = 20.54) and 79 typically developing (MDQ  = 106.02, SD = 11.50) children between 2 and 5 years old. Habituation was quantified as changes in the amplitudes of single-trial responses to tones of each intensity over the course of the experiment. Habituation of the auditory N2 response was substantially reduced in autistic participants as compared to typically developing controls, although diagnostic groups did not clearly differ in habituation of the P1 response. Interestingly, the P1 habituated less to loud 80 dB sounds than softer sounds, whereas the N2 habituated less to soft 50 dB sounds than louder sounds. No associations were found between electrophysiological habituation and cognitive ability or participants' caregiver-reported sound tolerance (Sensory Profile Hyperacusis Index). The results present study results extend prior research suggesting habituation of certain sensory responses is reduced in autism; however, they also suggest that habituation differences observed using this study's paradigm might not be a primary driver of autistic participants' real-world sound intolerance.

Prevalence and Profiles of Late-Onset Hearing Loss in Preschool Children with Autism Spectrum Disorder Who Passed Newborn Hearing Screening in a South East Asian Population

Prevalence of hearing loss in children with autism spectrum disorder (ASD) is uncertain, as it is more challenging to assess hearing function in children with developmental difficulties (DD). We aimed to determine the prevalence and profiles of hearing loss in preschool children with ASD in a Southeast-Asian population who passed newborn hearing screening. A retrospective study of preschool children with DD (ASD, Global Developmental Delay (GDD), and Speech and Language Delay (SLD)) attending the Child Development Unit (CDU) at our hospital was performed. Three hundred and thirty-three children (ASD: n = 129; GDD: n = 110; and SLD: n = 94) underwent hearing assessments. Of these, 10.8% of children (n = 36, comprising 15 with ASD, 12 with GDD and 9 with SLD) had confirmed hearing loss. Hearing loss was predominantly bilateral in children with ASD and GDD; in those with SLD, unilateral and bilateral hearing loss were equally common. Conductive hearing loss occurred as frequently as sensorineural hearing loss in children with ASD and SLD, but was the dominant subtype in those with GDD. Moderate to severe hearing loss (n = 2) was noted only in children with ASD. Children with ASD and GDD required significantly more audiology visits and procedures to obtain conclusive hearing test results, compared to those with SLD. The need to identify hearing loss and monitor for resolution is particularly important in vulnerable populations with communication deficits, such as in those with ASD.

Associations between autistic traits and early ear and upper respiratory signs: a prospective observational study of the Avon Longitudinal Study of Parents and Children (ALSPAC) geographically defined childhood population

OBJECTIVE

To determine whether early ear and upper respiratory signs are associated with the development of high levels of autistic traits or diagnosed autism.

DESIGN

Longitudinal birth cohort: Avon Longitudinal Study of Parents and Children (ALSPAC).

SETTING

Area centred on the city of Bristol in Southwest England. Eligible pregnant women resident in the area with expected date of delivery between April 1991 and December 1992 inclusive.

PARTICIPANTS

10 000+ young children followed throughout their first 4 years. Their mothers completed three questionnaires between 18-42 months recording the frequency of nine different signs and symptoms relating to the upper respiratory system, as well as ear and hearing problems.

OUTCOME MEASURES

Primary-high levels of autism traits (social communication, coherent speech, sociability, and repetitive behaviour); secondary-diagnosed autism.

RESULTS

Early evidence of mouth breathing, snoring, pulling/poking ears, ears going red, hearing worse during a cold, and rarely listening were associated with high scores on each autism trait and with a diagnosis of autism. There was also evidence of associations of pus or sticky mucus discharge from ears, especially with autism and with poor coherent speech. Adjustment for 10 environmental characteristics made little difference to the results, and substantially more adjusted associations were at p<0.001 than expected by chance (41 observed; 0.01 expected). For example, for discharge of pus or sticky mucus from ears the adjusted odds ratio (aOR) for autism at 30 months was 3.29 (95% CI 1.85 to 5.86, p<0.001), and for impaired hearing during a cold the aOR was 2.18 (95% CI 1.43 to 3.31, p<0.001).

CONCLUSIONS

Very young children exhibiting common ear and upper respiratory signs appear to have an increased risk of a subsequent diagnosis of autism or demonstrated high levels of autism traits. Results suggest the need for identification and management of ear, nose and throat conditions in autistic children and may provide possible indicators of causal mechanisms.

Sensory profiles, behavioral problems, and auditory findings in children with autism spectrum disorder

Objective

This study examined the relationship between sensory processing (SP) differences and behavioral problems in children with autism spectrum disorder (ASD). We also investigated whether audiological test results could objectively detect auditory processing differences.

Method

Forty-six children with ASD, ages 3-9 years, were enrolled in the study. Problematic behaviors and sensory processing of children were assessed using scales. The otolaryngologist performed a detailed head and neck examination and a formal audiological examination was performed by an audiologist.

Results

Stereotypy, hyperactivity, and irritability were related to sensation seeking. Stereotypy was also associated with visual processing. Touch processing differences was related to irritability and inappropriate speech. Lethargy was associated with auditory processing. There were no differences in SP and behavior problems in the children whose audiological profiles could be measured between those who passed or failed the test.

Conclusion

There was an association between SP differences and behavioral problems in children with ASD, supporting previous studies. Audiological test results did not reveal the SP differences documented in the parent forms.

Commentary: Best practices and processes for assessment of autism spectrum disorder - the intended role of standardized diagnostic instruments

Development of standardized diagnostic instruments has facilitated the systematic characterization of individuals with autism spectrum disorders (ASD) in clinical and research settings. However, overemphasis on scores from specific instruments has significantly detracted from the original purpose of these tools. Rather than provide a definitive "answer," or even a confirmation of diagnosis, standardized diagnostic instruments were designed to aid clinicians in the process of gathering information about social communication, play, and repetitive and sensory behaviors relevant to diagnosis and treatment planning. Importantly, many autism diagnostic instruments are not validated for certain patient populations, including those with severe vision, hearing, motor, and/or cognitive impairments, and they cannot be administered via a translator. In addition, certain circumstances, such as the need to wear personal protective equipment (PPE), or behavioral factors (e.g., selective mutism) may interfere with standardized administration or scoring procedures, rendering scores invalid. Thus, understanding the uses and limitations of specific tools within specific clinical or research populations, as well as similarities or differences between these populations and the instrument validation samples, is paramount. Accordingly, payers and other systems must not mandate the use of specific tools in cases when their use would be inappropriate. To ensure equitable access to appropriate assessment and treatment services, it is imperative that diagnosticians be trained in best practice methods for the assessment of autism, including if, how, and when to appropriately employ standardized diagnostic instruments.

Identifying reduced hearing in children who have developmental disabilities: Insights for inclusive research practices with electronic health records

Introduction

Recent advancements in big data analytics and the formation of large-scale clinical data repositories provide a unique opportunity to determine the current state of pediatric hearing health care for children who have developmental disabilities. Before answering unresolved questions about diagnostic practice, it is paramount to determine a standard and reliable method for identifying children who have reduced hearing because clinical management is affected by hearing status. The purpose of this study was to compare 5 different methods for identifying cases of reduced hearing from pure-tone thresholds based on developmental disability status.

Methods

Using retrospective clinical data from 100,960 children (0–18 years), hearing status was determined for a total of 226,580 encounters from three clinical sites. 9% of the children had a diagnosis of intellectual disability, autism spectrum disorder, Down syndrome, or cerebral palsy.

Results

Results revealed that encounters from children who have developmental disabilities were more likely to have insufficient data to allow hearing status to be determined. Moreover, methods with higher data demands (i.e., number of thresholds and ear-specific thresholds) resulted in fewer classifiable encounters. The average child age when hearing status was classified for the first time was older for children who have developmental disabilities than for children in the comparison group. Allowing thresholds to build up over multiple test sessions did result in more children who have developmental disabilities being classified than for single-encounter methods, but a meaningful decrease in child age at the time of classification was not seen for this strategy. Compared to the comparison group, children who have developmental disabilities were more likely to have reduced hearing that was stable over time, yet their hearing status was determined at older ages.

Discussion

Results provide key guidance to researchers for how to determine hearing status in children for big data applications using electronic health records. Furthermore, several assessment disparities are spotlighted for children who have developmental disabilities that warrant further investigation.

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.

Rapid auditory processing of puretones is associated with basic components of language in individuals with autism spectrum disorders

The goal of this study was to identify the specific domains of language that may be affected by deficits in rapid auditory processing in individuals with ASD. Auditory evoked fields were collected from 63 children diagnosed with ASD in order to evaluate processing of puretone sounds presented in rapid succession. Measures of language and its components were assessed via standardized clinical tools to quantify expressive and receptive language, vocabulary, articulation, and phonological processing abilities. Rapid processing was significantly and bilaterally associated with phonological awareness, vocabulary, and articulation. Phonological processing was found to mediate the relationship between rapid processing and language. M100 response latency was not significantly associated with any language measures. Results suggest that rapid processing deficits may impact the basic components of language such as phonological processing, and the downstream effect of this impact may in turn impact overall language development.

Auditory Pitch Perception in Autism Spectrum Disorder: A Systematic Review and Meta-Analysis

PURPOSE

Pitch plays an important role in auditory perception of music and language. This study provides a systematic review with meta-analysis to investigate whether individuals with autism spectrum disorder (ASD) have enhanced pitch processing ability and to identify the potential factors associated with processing differences between ASD and neurotypicals.

METHOD

We conducted a systematic search through six major electronic databases focusing on the studies that used nonspeech stimuli to provide a qualitative and quantitative assessment across existing studies on pitch perception in autism. We identified potential participant- and methodology-related moderators and conducted metaregression analyses using mixed-effects models.

RESULTS

On the basis of 22 studies with a total of 464 participants with ASD, we obtained a small-to-medium positive effect size (g = 0.26) in support of enhanced pitch perception in ASD. Moreover, the mean age and nonverbal IQ of participants were found to significantly moderate the between-studies heterogeneity.

CONCLUSIONS

Our study provides the first meta-analysis on auditory pitch perception in ASD and demonstrates the existence of different developmental trajectories between autistic individuals and neurotypicals. In addition to age, nonverbal ability is found to be a significant contributor to the lower level/local processing bias in ASD. We highlight the need for further investigation of pitch perception in ASD under challenging listening conditions. Future neurophysiological and brain imaging studies with a longitudinal design are also needed to better understand the underlying neural mechanisms of atypical pitch processing in ASD and to help guide auditory-based interventions for improving language and social functioning.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.21614271.

Sensitivity to interaural level and time differences in individuals with autism spectrum disorder

Individuals with autism spectrum disorders (ASD) are reported to exhibit degraded performance in sound localization. This study investigated whether the sensitivity to the interaural level differences (ILDs) and interaural time differences (ITDs), major cues for horizontal sound localization, are affected in ASD. Thresholds for discriminating the ILD and ITD were measured for adults with ASD and age- and IQ-matched controls in a lateralization experiment. Results show that the ASD group exhibited higher ILD and ITD thresholds than the control group. Moreover, there was a significant diversity of ITD sensitivity in the ASD group, and it contained a larger proportion of participants with poor ITD sensitivity than the control group. The current study suggests that deficits in relatively low-level processes in the auditory pathway are implicated in degraded performance of sound localization in individuals with ASD. The results are consistent with the structural abnormalities and great variability in the morphology in the brainstem reported by neuroanatomical studies of ASD.

Multisensory integration and interactions across vision, hearing, and somatosensation in autism spectrum development and typical development

Most prior studies of multisensory integration (MSI) in autism have measured MSI in only a single combination of modalities - typically audiovisual integration. The present study used onset reaction times (RTs) and 125-channel electroencephalography (EEG) to examine different forms of bimodal and trimodal MSI based on combinations of auditory (noise burst), somatosensory (finger tap), and visual (flash) stimuli presented in a spatially-aligned manner using a custom desktop apparatus. A total of 36 autistic and 19 non-autistic adolescents between the ages of 11-14 participated. Significant RT multisensory facilitation relative to summed unisensory RT was observed in both groups, as were significant differences between summed unisensory and multisensory ERPs. Although the present study's statistical approach was not intended to test effect latencies, these interactions may have begun as early as ∼45 ms, constituting "early" (<100 ms) MSI. RT and ERP measurements of MSI appeared independent of one another. Groups did not significantly differ in multisensory RT facilitation, but we found exploratory evidence of group differences in the magnitude of audiovisual interactions in ERPs. Future research should make greater efforts to explore MSI in under-represented populations, especially autistic people with intellectual disabilities and nonspeaking/minimally-verbal autistic people.

Appraising the need for audiological assessment before autism spectrum disorder referral

Objectives

Mandatory audiological testing before autism spectrum disorder (ASD) assessment is common practice. Hearing impairment (HI) in the general paediatric population is estimated at 3%; however, hearing impairment prevalence among children with ASD is poorly established. Our objective was to determine which children referred for ASD assessment require preliminary audiological assessment.

Methods

Retrospective chart review of children (n=4,173; 0 to 19 years) referred to British Columbia's Autism Assessment Network (2010 to 2014). We analyzed HI rate, risk factors, and timing of HI diagnosis relative to ASD referral.

Results

ASD was diagnosed in 53.4%. HI rates among ASD referrals was 3.3% and not significantly higher in children with ASD (ASD+; 3.5%) versus No-ASD (3.0%). No significant differences in HI severity or type were found, but more ASD+ females (5.5%) than ASD+ males (3.1%) had HI (P<0.05). Six HI risk factors were significant (problems with intellect, language, vision/eye, ear, genetic abnormalities, and prematurity) and HI was associated with more risk factors (P<0.01). Only 12 children (8.9%) were diagnosed with HI after ASD referral; all males 6 years or younger and only one had no risk factors. ASD+ children with HI were older at ASD referral than No-ASD (P<0.05).

Conclusions

Children with ASD have similar hearing impairment rates to those without ASD. HI may delay referral for ASD assessment. As most children were diagnosed with HI before ASD referral or had at least one risk factor, we suggest that routine testing for HI among ASD referrals should only be required for children with risk factors.

Rhythmic Relating: Bidirectional Support for Social Timing in Autism Therapies

We propose Rhythmic Relating for autism: a system of supports for friends, therapists, parents, and educators; a system which aims to augment bidirectional communication and complement existing therapeutic approaches. We begin by summarizing the developmental significance of social timing and the social-motor-synchrony challenges observed in early autism. Meta-analyses conclude the early primacy of such challenges, yet cite the lack of focused therapies. We identify core relational parameters in support of social-motor-synchrony and systematize these using the communicative musicality constructs: pulse; quality; and narrative. Rhythmic Relating aims to augment the clarity, contiguity, and pulse-beat of spontaneous behavior by recruiting rhythmic supports (cues, accents, turbulence) and relatable vitality; facilitating the predictive flow and just-ahead-in-time planning needed for good-enough social timing. From here, we describe possibilities for playful therapeutic interaction, small-step co-regulation, and layered sensorimotor integration. Lastly, we include several clinical case examples demonstrating the use of Rhythmic Relating within four different therapeutic approaches (Dance Movement Therapy, Improvisational Music Therapy, Play Therapy, and Musical Interaction Therapy). These clinical case examples are introduced here and several more are included in the Supplementary Material (Examples of Rhythmic Relating in Practice). A suite of pilot intervention studies is proposed to assess the efficacy of combining Rhythmic Relating with different therapeutic approaches in playful work with individuals with autism. Further experimental hypotheses are outlined, designed to clarify the significance of certain key features of the Rhythmic Relating approach.

John T, Lau BK. Auditory Attention Deployment in Young Adults with Autism Spectrum Disorder

Difficulty listening in noisy environments is a common complaint of individuals with autism spectrum disorder (ASD). However, the mechanisms underlying such auditory processing challenges are unknown. This preliminary study investigated auditory attention deployment in adults with ASD. Participants were instructed to maintain or switch attention between two simultaneous speech streams in three conditions: location (co-located versus ± 30° separation), voice (same voice versus male-female contrast), and both cues together. Results showed that individuals with ASD can selectively direct attention using location or voice cues, but performance was best when both cues were present. In comparison to neurotypical adults, overall performance was less accurate across all conditions. These findings warrant further investigation into auditory attention deployment differences in individuals with ASD.

Cochlear Implantation Can Improve Auditory Skills, Language and Social Engagement of Children With Autism Spectrum Disorder

OBJECTIVE

To review outcomes of cochlear implantation (CI) in children diagnosed with autism spectrum disorder (ASD).

STUDY DESIGN

Retrospective case review and parent survey.

SETTING

Tertiary care children's hospital.

PATIENTS

Thirty children with ASD who underwent CI between 1991 and 2018. Mean age at CI = 3.5 years (0.8-11.8), mean age at diagnosis of ASD = 5.1 years (2.0-15.0) (22/30 diagnosed after CI), mean follow-up = 10.5 years (1.4-21.6). Parents of 7 children returned a survey.

INTERVENTION

Unilateral or bilateral cochlear implantation.

MAIN OUTCOME MEASURES

Speech perception; expressive communication mode; educational placement; social engagement; consistency of CI use; parent survey of child behavior change.

RESULTS

Thirty-three percent of all and 45% of the 22 consistent device users developed measurable open-set speech perception by an average of 4.5 years of device use. Educational placement at last follow-up included 13% mainstreamed without interpreter, 50% Special Education programs, 10% therapeutic residential or day programs, 23% total communication programs, and one home schooled. Spoken language alone was used by 31% and spoken plus sign by 14%, with the remainder using sign alone, augmentative communication devices or no mode of communication. By parent report, 86% showed improvement in social engagement compared to pre-CI. Survey results showed the behaviors most frequently ranked as most affected by CI were communication and attention, while awareness of environment had the lowest (most affected) mean ranking.

CONCLUSIONS

Findings support a growing body of literature that cochlear implantation has the potential to improve auditory skills, language, and enhance social engagement in some deaf children with autism spectrum disorder.

Screening for autism spectrum disorder in deaf adults with intellectual disability: Feasibility and accuracy of two autism screening instruments

BACKGROUND

There is a lack of autism screening instruments for deaf or hard of hearing (DHH) adults with intellectual disability.

AIMS

This study examined the diagnostic validity of the Pervasive Developmental Disorder in Mental Retardation Scale and the Diagnostic Behavioral Assessment for autism spectrum disorder - Revised in this rare population.

METHODS AND PARTICIPANTS

56 DHH adults with intellectual disability living in three specialized therapeutic communities were examined, 9 of whom met criteria for autism.

OUTCOMES AND RESULTS

With minimal adaptions regarding item interpretation, both tools showed good diagnostic and high convergent validity. Items probing for difficulties in reciprocal social interaction and restricted interests were discriminant between individuals with and without autism.

CONCLUSION

These data suggest that both autism screening tools are feasible and psychometrically sound when used with appropriate adaptations for DHH adults with intellectual disability.

Evaluation of the Auditory System in Autistic Children Using Evoked Otoacoustic Emissions and a Contralateral Suppression Test

In this study, we evaluated the cochlea, medial olivocochlear system, and brainstem function in autistic children using evoked otoacoustic emissions (OAEs) and a noninvasive contralateral suppression (CLS) test. In total, we included 21 autistic children with normal hearing (study group) and 11 healthy children (control group). Transient-evoked OAEs (TEOAEs) and CLS of TEOAE were evaluated in the left and right ears of all patients. In a silent room, spontaneous, transient, and dP ILO292 were evaluated. The mean age of the study and control group was 9.1 years (range: 6-13 and 6-12 years, respectively). For the study group, there was no statistically significant difference between the OAE and CLS values of the right ear (P > .05). However, for the left ears, OAE values were statistically significantly higher than the CLS values (P < .05). In the control group, the OAE values of both ears were statistically significantly higher than the CLS values (P < .05). In autistic children with normal hearing, the medial olivocochlear system functions more effectively in the right ear than the left ear. Asymmetry between the ears is likely responsible for the peripheral auditory lateralization and independence in auditory function between the left and right ears.

Auditory Profile of Children With Some Rare Neurodevelopmental Disorders

Neurodevelopmental disorder is an umbrella term comprising many muscular, skeletal, metabolic, endocrinal, systemic, and immune-related diseases, which are caused due to the improper/inaccurate development of the central nervous system. Most of these disorders are highly prevalent, but some express rarely in human beings. Such disorders with least prevalence rates are known as rare neurodevelopmental disorders. The sensory system is affected in all individuals with these rare neurodevelopmental disorders, although to a varying extent. Sensory processing in terms of hearing loss is reported by many researchers in many rare neurodevelopmental disorders, but the pathophysiology of audiological findings are seldom investigated. In this chapter, the authors highlight the possible relationship between underlying cause and the resultant audiological symptoms in some of the rare neurodevelopmental disorders. Further, the research studies on the audiological profiling in such disorders are discussed.

Cochlear Implantation in Children with Autism Spectrum Disorder: A Systematic Review and Pooled Analysis

OBJECTIVE

To determine outcomes following cochlear implantation (CI) in children with autism spectrum disorder (ASD).

DATABASES REVIEWED

MEDLINE, Embase, Web of science, Cochrane Library, and Clinicaltrial.gov.

METHODS

The review was performed according to the PRISMA statement. Primary outcomes measures were changes in speech perception and speech production scores. Secondary outcome measures included communication mode, device use, parental recommendation of implant, postoperative hyperacusis, and quality of life measures. Pooled analysis of outcomes was performed if possible.

RESULTS

Twenty-four studies reported on 159 children with ASD. There were improvements in speech perception in 78% of cases and in speech expression in 63% of cases, though the extent of this improvement was variable. Seventy-four percent of children with ASD and CI are nonoral communicators. Intermittent/nonuse rate was 31%. Hearing outcomes are worse compared to children with other disabilities. The vast majority of parents would recommend CI based on their experiences.

CONCLUSION

Outcome in children with ASD and CI are highly variable and significantly poorer compared to non-ASD children. Despite this, most parents report positive experiences and the evidence supports the use of CI in children with ASD.

Hearing loss and brain disorders: A review of multiple pathologies

Several causative factors are associated with hearing loss (HL) and brain disorders. However, there are many unidentified disease modifiers in these conditions. Our study summarised the most common brain disorders associated with HL and highlighted mechanisms of pathologies. We searched the literature for published articles on HL and brain disorders. Alzheimer's disease/dementia, Parkinson's disease, cognitive impairment, autism spectrum disorder, ataxia, epilepsy, stroke, and hypoxic-ischaemic encephalopathy majorly co-interact with HL. The estimated incidence rate was 113 per 10,000 person-years. Genetic, epigenetic, early life/neonatal stress, hypoxia, inflammation, nitric oxide infiltration, endoplasmic reticulum stress, and excess glutamate were the distinguished modifiers identified. Various mechanisms like adhesion molecules, transport proteins, hair cell apoptosis, and neurodegeneration have been implicated in these conditions and are serving as potential targets for therapies. To improve the quality of life of patients, these understandings will improve clinical diagnoses and management of HL and brain disorders.

Auditory hypersensitivity and processing deficits in a rat model of fragile X syndrome

Fragile X (FX) syndrome is one of the leading inherited causes of autism spectrum disorder (ASD). A majority of FX and ASD patients exhibit sensory hypersensitivity, including auditory hypersensitivity or hyperacusis, a condition in which everyday sounds are perceived as much louder than normal. Auditory processing deficits in FX and ASD also afford the opportunity to develop objective and quantifiable outcome measures that are likely to translate between humans and animal models due to the well-conserved nature of the auditory system and well-developed behavioral read-outs of sound perception. Therefore, in this study we characterized auditory hypersensitivity in a Fmr1 knockout (KO) transgenic rat model of FX using an operant conditioning task to assess sound detection thresholds and suprathreshold auditory reaction time-intensity (RT-I) functions, a reliable psychoacoustic measure of loudness growth, at a variety of stimulus frequencies, bandwidths, and durations. Male Fmr1 KO and littermate WT rats both learned the task at the same rate and exhibited normal hearing thresholds. However, Fmr1 KO rats had faster auditory RTs over a broad range of intensities and steeper RT-I slopes than WT controls, perceptual evidence of excessive loudness growth in Fmr1 KO rats. Furthermore, we found that Fmr1 KO animals exhibited abnormal perceptual integration of sound duration and bandwidth, with diminished temporal but enhanced spectral integration of sound intensity. Because temporal and spectral integration of sound stimuli were altered in opposite directions in Fmr1 KO rats, this suggests that abnormal RTs in these animals are evidence of aberrant auditory processing rather than generalized hyperactivity or altered motor responses. Together, these results are indicative of fundamental changes to low-level auditory processing in Fmr1 KO animals. Finally, we demonstrated that antagonism of metabotropic glutamate receptor 5 (mGlu5) selectively and dose-dependently restored normal loudness growth in Fmr1 KO rats, suggesting a pharmacologic approach for alleviating sensory hypersensitivity associated with FX. This study leverages the tractable nature of the auditory system and the unique behavioral advantages of rats to provide important insights into the nature of a centrally important yet understudied aspect of FX and ASD.

Development of Masked Speech Detection Thresholds in 2- to 15-year-old Children: Speech-Shaped Noise and Two-Talker Speech Maskers

OBJECTIVES

On the basis of the data from school-aged children, there is consistent evidence that there is a prolonged course of auditory development for perceiving speech embedded in competing background sounds. Furthermore, age-related differences are prolonged and pronounced for a two-talker speech masker compared to a speech-shaped noise masker. However, little is known about the course of development during the toddler and preschool years because it is difficult to collect reliable behavioral data from this age range. The goal of this study was to extend our lower age limit to include toddlers and preschoolers to characterize the developmental trajectory for masked speech detection thresholds across childhood.

DESIGN

Participants were 2- to 15-year-old children (n = 67) and adults (n = 17), all with normal hearing. Thresholds (71%) were measured for detecting a two-syllable word embedded in one of two maskers: speech-shaped noise or two-talker speech. The masker was presented at 55 dB SPL throughout testing. Stimuli were presented to the left ear via a lightweight headphone. Data were collected using an observer-based testing method in which the participant's behavior was judged by an experimenter using a two-interval, two-alternative testing paradigm. The participant's response to the stimulus was shaped by training him/her to perform a conditioned play-based response to the sound. For children, receptive vocabulary and working memory were measured. Data were fitted with a linear regression model to establish the course of development for each masker condition. Appropriateness of the test method was also evaluated by determining if there were age-related differences in training data, inter-rater reliability, or slope or upper asymptote estimates from pooled psychometric functions across different age groups.

RESULTS

Child and adult speech detection thresholds were poorer in the two-talker masker than in the speech-shaped noise masker, but different developmental trajectories were seen for the two masker conditions. For the speech-shaped noise masker, threshold improved by about 5 dB across the age span tested, with adult-like performance being reached around 10 years of age. For the two-talker masker condition, thresholds improved by about 7 dB between 2.5 and 15 years. However, the linear fit for this condition failed to achieve adult-like performance because of limited data from teenagers. No significant age-related differences were seen in training data, probe hit rate, or inter-rater reliability. Furthermore, slope and upper asymptote estimates from pooled psychometric functions were similar across different child age groups.

CONCLUSIONS

Different developmental patterns were seen across the two maskers, with more pronounced child-adult differences and prolonged immaturity during childhood for the two-talker masker relative to the speech-shaped noise masker. Our data do not support the idea that there is rapid improvement of masked speech detection thresholds between 2.5 and 5 years of age. This study also highlights that our observer-based method can be used to collect reliable behavioral data from toddlers and preschoolers-a time period where we know little about auditory development.

Hyperacusis in Autism Spectrum Disorders

Hyperacusis is highly prevalent in the autism spectrum disorder (ASD) population. This auditory hypersensitivity can trigger pragmatically atypical reactions that may impact social and academic domains. Objective: The aim of this report is to describe the relationship between decreased sound tolerance disorders and the ASD population. Topics covered: The main topics discussed include (1) assessment and prevalence of hyperacusis in ASD; (2) etiology of hyperacusis in ASD; (3) treatment of hyperacusis in ASD. Conclusions: Knowledge of the assessment and treatment of decreased sound tolerance disorders within the ASD population is growing and changing.

Cochlear implantation in children with Autism Spectrum Disorder (ASD): Outcomes and implant fitting characteristics

BACKGROUND

Little is known regarding fitting parameters and receptive and expressive language development in cochlear-implanted children (CCI) with profound sensorineural hearing loss (SHL) who are diagnosed with Autism Spectrum Disorder (ASD). The aim of the study was to evaluate a group of ASD CCI users in order to describe their ASD clinical features and CCI outcomes; report on the average electrical charge requirements; and evaluate the possible correlations between electrical and psychophysical outcomes with ASD characteristics.

MATERIALS AND METHODS

A multicentre observational study of 22 ASD children implanted in four cochlear implant (CI) centers. Data concerning profound SHL diagnosis, ASD diagnosis, CI timing and CI compliance were collected. Sound Field (SF) was assessed through repeated behavioural measurements. Categories of Auditory Perception (CAP) and Categories of Language (CL) were used to evaluate speech perception and language skills at short (≤2 yrs), medium (5 yrs) and long term (>10 yrs) follow-up. Fitting parameters such as comfortable thresholds, pulse-width (pw, μsec) and clinical units converted into units of charge/phase were collected. The diagnosis of ASD was acquired by the referral neuropsychiatric department and severity was assessed through the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) and the Childhood Autism Rating Scale (CARS).

RESULTS

At the final follow-up session the median SF threshold for CI outcomes was 30 dB HL (min 15 - max 60). CAP score was extremely variable: 45.5% showed no improvement over time and only 22% of children reached CAP scores of 5-7. CL 45.5% showed no improvement over time and score was 1-2 in the majority of ASD children (72.7%), while only 18.2% reached the highest level of language skills. There were no statistically significant differences at each follow-up between subjects with or without comorbidities. CAP and CL were inversely correlated with DSM-V A and B domains, corresponding to lower speech and language scores in children with more severe ASD symptoms, and maintained their correlation at mid and long follow-ups whilst controlling for age at CI. Electrical charge requirements did not correlate with SF or age at implant but did inversely correlate with ASD severity. With regards to CI compliance: only 13.6% children (3) with severe DSM-V A/B levels and CARS score were partial/intermittent users.

CONCLUSION

The present study is a targeted contribution to the current literature to support clinical procedures for CI fitting and audiological follow-up in children with ASD. The findings indicate that the outcomes of CI use and the fitting procedures are both influenced by the severity of the ASD symptoms rather than the demographic variables or associated disorders.

Central Auditory and Vestibular Dysfunction Are Key Features of Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by repetitive behaviors, poor social skills, and difficulties with communication. Beyond these core signs and symptoms, the majority of subjects with ASD have some degree of auditory and vestibular dysfunction. Dysfunction in these sensory modalities is significant as normal cognitive development depends on an accurate representation of our environment. The hearing difficulties in ASD range from deafness to hypersensitivity and subjects with ASD have abnormal sound-evoked brainstem reflexes and brainstem auditory evoked potentials. Vestibular dysfunction in ASD includes postural instability, gait dysfunction, and impaired gaze. Untreated vestibular dysfunction in children can lead to delayed milestones such as sitting and walking and poor motor coordination later in life. Histopathological studies have revealed that subjects with ASD have significantly fewer neurons in the auditory hindbrain and surviving neurons are smaller and dysmorphic. These findings are consistent with auditory dysfunction. Further, the cerebellum was one of the first brain structures implicated in ASD and studies have revealed loss of Purkinje cells and the presence of ectopic neurons. Together, these studies suggest that normal auditory and vestibular function play major roles in the development of language and social abilities, and dysfunction in these systems may contribute to the core symptoms of ASD. Further, auditory and vestibular dysfunction in children may be overlooked or attributed to other neurodevelopmental disorders. Herein we review the literature on auditory and vestibular dysfunction in ASD. Based on these results we developed a brainstem model of central auditory and vestibular dysfunction in ASD and propose that simple, non-invasive but quantitative testing of hearing and vestibular function be added to newborn screening protocols.

Prevalence of Hyperacusis in the General and Special Populations: A Scoping Review

Objectives: To study the prevalence of hyperacusis in the general population and the special population, and to determine the effect of population differences on hyperacusis.

Methods: The two authors followed a scoping review methodology and screened nearly 30 years of English literature in Pubmed, Web of Science, OVID, and EBSCO. Then, the extracted results of each study were discussed in groups and subgroups.

Results: The authors selected 42 pieces of scientific literature that met the requirements, studying a total of 34,796 subjects, including the general population (28,425 subjects), the special occupation population (2,746 subjects), and the patients with concomitant diseases (5,093 subjects). The prevalence was 0.2–17.2% in the general population, 3.8–67% in the special occupation population, and 4.7–95% in the patients with special diseases. It was found that in the general population, the high prevalence occurs in adolescents and older adults. The prevalence of hyperacusis in women is significantly higher than in men. In people with hearing disorders, the prevalence of hyperacusis is significantly higher than in people with normal hearing. Various diseases (such as Williams syndrome, tinnitus, and autism), as well as various occupations (musicians, music students, teachers, and others), have been found to be high risk factors for hyperacusis.

Conclusion: The high prevalence of hyperacusis and the large differences between reported prevalence in different studies deserves our great attention. Additionally, in order to increase the comparability of the studies, a standardized set of criteria are needed to study the prevalence of hyperacusis.

Family Experiences of Decreased Sound Tolerance in ASD

Decreased sound tolerance (DST) is the most common sensory difficulty experienced by autistic individuals. Parents of 88 autistic children and young adults between the ages of 3 and 30 described coping strategies and physical and emotional responses used to deal with distressing sounds, and their impact on daily activities. Loud, sudden, and high-pitched sounds were most commonly endorsed as distressing, most often causing autistic children and young adults to cover their ears or yell, while producing stress, irritation, fear, and anxiety. Parents reported warning their child, providing breaks, or avoiding noisy settings as the most used coping strategies. Overall, findings indicate that DST leads to fewer opportunities for autistic children and young adults to participate at home, at school, and in the community. Further, results suggest hyperacusis, misophonia, and phonophobia, subtypes of DST, are present in autistic children and young adults.

Hearing Loss in Neurological Disorders

Sensorineural hearing loss (SNHL) affects approximately 466 million people worldwide, which is projected to reach 900 million by 2050. Its histological characteristics are lesions in cochlear hair cells, supporting cells, and auditory nerve endings. Neurological disorders cover a wide range of diseases affecting the nervous system, including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), autism spectrum disorder (ASD), etc. Many studies have revealed that neurological disorders manifest with hearing loss, in addition to typical nervous symptoms. The prevalence, manifestations, and neuropathological mechanisms underlying vary among different diseases. In this review, we discuss the relevant literature, from clinical trials to research mice models, to provide an overview of auditory dysfunctions in the most common neurological disorders, particularly those associated with hearing loss, and to explain their underlying pathological and molecular mechanisms.

Assessment of Autism Spectrum Disorder in Deaf Adults with Intellectual Disability: Feasibility and Psychometric Properties of an Adapted Version of the Autism Diagnostic Observation Schedule (ADOS-2)

This study describes the adaptation of the autism diagnostic observation schedule (ADOS-2) to assess autism spectrum disorder (ASD) in adults with intellectual disability (ID) and hearing loss who communicate primarily visually. This adapted ADOS-2 was applied to residents of specialized therapeutic living communities (n = 56). The internal consistency of the adapted ADOS-2 was excellent for the Social Affect of modules 2 and 3 and acceptable for Restricted and Repetitive Behaviors subscale of module 2, but poor for module 3. Interrater reliability was comparable to standard ADOS-2 modules 1–3. Results suggest that autism symptoms of deaf adults with ID can be reliably identified by an adapted ADOS-2, provided adequate expertise in deafness, ID, ASD and proficiency in signed language by the administrator.

Using Clustering to Examine Inter-individual Variability in Topography of Auditory Event-Related Potentials in Autism and Typical Development

Although prior studies have compared sensory event-related potential (ERP) responses between groups of autistic and typically-developing participants, it is unclear how heterogeneity contributes to the results of these studies. The present study used examined individual differences in these responses. 130 autistic children and 81 typically-developing children, aged between 2 and 5 years, listened to tones at four identity levels while 61-channel electroencephalography was recorded. Hierarchical clustering was used to group participants based on rescaled ERP topographies between 51 and 350 ms. The hierarchical clustering analysis revealed substantial heterogeneity. Some of the seven clusters defined in this analysis were characterized by prolonged fronto-central positivities and/or weak or absent N2 negativities. However, many other participants fell into clusters in which N2 responses were present at varying latencies. Atypical response morphologies such as absent N2 responses and/or prolonged positive-going responses found in some autistic participants may account for prior research findings of attenuated N2 amplitudes in autism. However, there was also considerable overlap between groups, with participants of both groups appearing in all clusters. These results emphasize the utility of using clustering to explore individual differences in brain responses, which can expand on and clarify the results of analyses of group mean differences.

Auditory Discrimination in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is increasingly common with 1 in 59 children in the United States currently meeting the diagnostic criteria. Altered sensory processing is typical in ASD, with auditory sensitivities being especially common; in particular, people with ASD frequently show heightened sensitivity to environmental sounds and a poor ability to tolerate loud sounds. These sensitivities may contribute to impairments in language comprehension and to a worsened ability to distinguish relevant sounds from background noise. Event-related potential tests have found that individuals with ASD show altered cortical activity to both simple and speech-like sounds, which likely contribute to the observed processing impairments. Our goal in this review is to provide a description of ASD-related changes to the auditory system and how those changes contribute to the impairments seen in sound discrimination, sound-in-noise performance, and language processing. In particular, we emphasize how differences in the degree of cortical activation and in temporal processing may contribute to errors in sound discrimination.

Auditory brainstem responses in adults with autism spectrum disorder

OBJECTIVE

To investigate possible differences in the auditory peripheral and brainstem functions between adults with autism spectrum disorder (ASD) and neurotypical (NT) adults.

METHODS

Click-evoked auditory brainstem responses (ABRs) were obtained from 17 high-functioning ASD adults (aged 21-38 years) and 20 NT adults (aged 22-36 years). A relatively large number of stimulus presentations (6000) were adopted, and ABRs by horizontal and vertical electrode montages were evaluated, in order to allow precise evaluations of early ABR components.

RESULTS

Waves I, II, III, and V were identified in the vertical electrode montage, and wave I and the summating potential (SP) in electrocochleograms were identified in the horizontal electrode montage. There were no significant group differences in the wave I, II, III, and V latencies or the interpeak latencies (IPLs) in the vertical electrode montage. In the horizontal montage, the ASD adults exhibited significantly shortened SP latencies compared with the NT adults, whereas there was no significant group difference in the wave I latency.

CONCLUSION

The ASD adults may have the abnormalities of processing more in the peripheral auditory system than in the brainstem.

SIGNIFICANCE

The current study suggests that the peripheral abnormality is associated with ASD.

Disruption of the autism-related gene Pak1 causes stereocilia disorganization, hair cell loss, and deafness in mice

Several clinical studies have reported that hearing loss is correlated with autism in children. However, little is known about the underlying mechanism between hearing loss and autism. p21-activated kinases (PAKs) are a family of serine/threonine kinases that can be activated by multiple signaling molecules, particularly the Rho family of small GTPases. Previous studies have shown that Pak1 mutations are associated with autism. In the present study, we take advantage of Pak1 knockout (Pak1^-/-) mice to investigate the role of PAK1 in hearing function. We find that PAK1 is highly expressed in the postnatal mouse cochlea and that PAK1 deficiency leads to hair cell (HC) apoptosis and severe hearing loss. Further investigation indicates that PAK1 deficiency downregulates the phosphorylation of cofilin and ezrin-radixin-moesin and the expression of βII-spectrin, which further decreases the HC synapse density in the basal turn of cochlea and disorganized the HC stereocilia in all three turns of cochlea in Pak1^-/- mice. Overall, our work demonstrates that the autism-related gene Pak1 plays a crucial role in hearing function. As the first candidate gene linking autism and hearing loss, Pak1 may serve as a potential target for the clinical diagnosis of autism-related hearing loss.