Plasticity in the developing auditory cortex: evidence from children with sensorineural hearing loss and auditory neuropathy spectrum disorder

Towards universal access: A review of global efforts in ear and hearing care

Hearing loss affects 1.6 billion people worldwide and disproportionately affects those in low- and middle-income countries. Despite being largely preventable or treatable, ear and hearing conditions result in significant and lifelong morbidity such as delayed language development, reduced educational attainment, and diminished social well-being. There is a need to augment prevention, early identification, treatment, and rehabilitation for these conditions. Expanded access to hearing screening, growth of the hearing health workforce, and innovations in ear and hearing care delivery systems are among the changes that are needed. To that end, the World Health Organization has prioritized ear and hearing care as a component of Universal Health Coverage, and recent publications have advanced the priority for ear and hearing care. Efforts are underway at the national levels around the world, as evidenced by countries like Zambia and Nigeria that have integrated ear and hearing care within national health strategies. While significant strides have been made in improving access, a critical need remains for additional research, advocacy, and intervention to ensure that no one is left behind in the goal to achieve universal access to ear and hearing care.

Comparative Analysis of Intellectual Quotient in Developmental Population with Severe Hearing Loss: Hearing Aids vs. Cochlear Implant Users

The development of language, memory and intellectual functions is linked to normal hearing and correct sounds interpretation. Hearing loss (HL), especially in its severe form, negatively affects the development of these functions. This prospective study aimed at comparing the Intelligent Quotients (IQ) of children with cochlear implants (CI) with the ones of people wearing hearing aids (HA) after one year of hearing rehabilitation. 21 subjects with severe/profound bilateral hearing loss (deafness) were included in this study. Eleven children with congenital profound HL underwent CI and ten children with moderate to severe HL (congenital and acquired) were rehabilitated by HA. Children's IQs were assessed at enrolment (T0) and 12 months after hearing aids/CI use plus speech therapy. Statistical analyses were performed to analyze the data within and between groups. Comparison of IQs showed no statistically significant differences between CI and HA none at T0 and T1. The subtests showed lower scores in verbal comprehension and process speed index in patients treated with HA when compared to CI. This study showed that auditory rehabilitation can support the normal development of cognitive function in children between six and eight years of age. The use of the correct hearing aids based on the patient's hearing thresholds is important to maximize the rehabilitation outcomes. Due to the small sample size, although stratified for age, our results must be considered preliminary and further analyses on larger samples are needed to confirm our data.

Sensory deprivation arrests cellular and synaptic development of the night-vision circuitry in the retina

Experience regulates synapse formation and function across sensory circuits. How inhibitory synapses in the mammalian retina are sculpted by visual cues remains unclear. By use of a sensory deprivation paradigm, we find that visual cues regulate maturation of two GABA synapse types (GABAA and GABAC receptor synapses), localized across the axon terminals of rod bipolar cells (RBCs)-second-order retinal neurons integral to the night-vision circuit. Lack of visual cues causes GABAA synapses at RBC terminals to retain an immature receptor configuration with slower response profiles and prevents receptor recruitment at GABAC synapses. Additionally, the organizing protein for both these GABA synapses, LRRTM4, is not clustered at dark-reared RBC synapses. Ultrastructurally, the total number of ribbon-output/inhibitory-input synapses across RBC terminals remains unaltered by sensory deprivation, although ribbon synapse output sites are misarranged when the circuit develops without visual cues. Intrinsic electrophysiological properties of RBCs and expression of chloride transporters across RBC terminals are additionally altered by sensory deprivation. Introduction to normal 12-h light-dark housing conditions facilitates maturation of dark-reared RBC GABA synapses and restoration of intrinsic RBC properties, unveiling a new element of light-dependent retinal cellular and synaptic plasticity.

A Hybrid Deep Learning Approach to Identify Preventable Childhood Hearing Loss

OBJECTIVE

Childhood hearing loss has well-known, lifelong consequences. Infection-related hearing loss disproportionately affects underserved communities yet can be prevented with early identification and treatment. This study evaluates the utility of machine learning in automating tympanogram classifications of the middle ear to facilitate layperson-guided tympanometry in resource-constrained communities.

DESIGN

Diagnostic performance of a hybrid deep learning model for classifying narrow-band tympanometry tracings was evaluated. Using 10-fold cross-validation, a machine learning model was trained and evaluated on 4810 pairs of tympanometry tracings acquired by an audiologist and layperson. The model was trained to classify tracings into types A (normal), B (effusion or perforation), and C (retraction), with the audiologist interpretation serving as reference standard. Tympanometry data were collected from 1635 children from October 10, 2017, to March 28, 2019, from two previous cluster-randomized hearing screening trials (NCT03309553, NCT03662256). Participants were school-aged children from an underserved population in rural Alaska with a high prevalence of infection-related hearing loss. Two-level classification performance statistics were calculated by treating type A as pass and types B and C as refer.

RESULTS

For layperson-acquired data, the machine-learning model achieved a sensitivity of 95.2% (93.3, 97.1), specificity of 92.3% (91.5, 93.1), and area under curve of 0.968 (0.955, 0.978). The model's sensitivity was greater than that of the tympanometer's built-in classifier [79.2% (75.5, 82.8)] and a decision tree based on clinically recommended normative values [56.9% (52.4, 61.3)]. For audiologist-acquired data, the model achieved a higher AUC of 0.987 (0.980, 0.993), had an equivalent sensitivity of 95.2 (93.3, 97.1), and a higher specificity of 97.7 (97.3, 98.2).

CONCLUSIONS

Machine learning can detect middle ear disease with comparable performance to an audiologist using tympanograms acquired either by an audiologist or a layperson. Automated classification enables the use of layperson-guided tympanometry in hearing screening programs in rural and underserved communities, where early detection of treatable pathology in children is crucial to prevent the lifelong adverse effects of childhood hearing loss.

Objective Assessment of Binaural Benefit from Acoustical Treatment in Real Primary School Classrooms

Providing students with an adequate acoustic environment is crucial for ensuring speech intelligibility in primary school classrooms. Two main approaches to control acoustics in educational facilities consist of reducing background noise and late reverberation. Prediction models for speech intelligibility have been developed and implemented to evaluate the effects of these approaches. In this study, two versions of the Binaural Speech Intelligibility Model (BSIM) were used to predict speech intelligibility in realistic spatial configurations of speakers and listeners, considering binaural aspects. Both versions shared the same binaural processing and speech intelligibility backend processes but differed in the pre-processing of the speech signal. An Italian primary school classroom was characterized in terms of acoustics before (reverberation, T20 = 1.6 ± 0.1 s) and after (T20 = 0.6 ± 0.1 s) an acoustical treatment to compare BSIM predictions to well-established room acoustic measures. With shorter reverberation time, speech clarity and definition improved, as well as speech recognition thresholds (SRTs) (by up to ~6 dB), particularly when the noise source was close to the receiver and an energetic masker was present. Conversely, longer reverberation times resulted (i) in poorer SRTs (by ~11 dB on average) and (ii) in an almost non-existent spatial release from masking at an angle (SRM).

Auditory Brainstem Response in Autistic Children: Implications for Sensory Processing

Purpose

Autistic individuals frequently experience sensory processing difficulties. Such difficulties can significantly impact important functions and quality of life. We are only beginning to understand the neural mechanisms of atypical sensory processing. However, one established way to measure aspects of auditory function is the auditory brainstem response (ABR). While ABR has been primarily hypothesized thus far as a means of early detection/diagnosis in autism, it has the potential to aid in examining sensory processing in this population.

Method

Thus, we investigated standard ABR waveform characteristics in age-matched groups of autistic and typically developing children during various stimulus and intensity conditions. We also examined within ear waveform cross correlations and inter-aural cross correlations (IACC) to assess replicability and synchrony of participants' ABRs, which was a novel approach to ABR analysis in this population.

Results

We observed longer peak latencies (esp. wave III and V) and interpeak latencies in the autism and typically developing groups in different conditions. There were no statistically significant results in cross correlation or IACC.

Conclusions

These results suggest that brainstem auditory function may differ slightly, but is mostly similar, between autistic and typically developing children. We discuss these findings in terms of their implications for sensory processing and future utility.

Processing of auditory information in forebrain regions after hearing loss in adulthood: Behavioral and electrophysiological studies in a rat model

Background

Hearing loss was proposed as a factor affecting development of cognitive impairment in elderly. Deficits cannot be explained primarily by dysfunctional neuronal networks within the central auditory system. We here tested the impact of hearing loss in adult rats on motor, social, and cognitive function. Furthermore, potential changes in the neuronal activity in the medial prefrontal cortex (mPFC) and the inferior colliculus (IC) were evaluated.

Materials and methods

In adult male Sprague Dawley rats hearing loss was induced under general anesthesia with intracochlear injection of neomycin. Sham-operated and naive rats served as controls. Postsurgical acoustically evoked auditory brainstem response (ABR)-measurements verified hearing loss after intracochlear neomycin-injection, respectively, intact hearing in sham-operated and naive controls. In intervals of 8 weeks and up to 12 months after surgery rats were tested for locomotor activity (open field) and coordination (Rotarod), for social interaction and preference, and for learning and memory (4-arms baited 8-arms radial maze test). In a final setting, electrophysiological recordings were performed in the mPFC and the IC.

Results

Locomotor activity did not differ between deaf and control rats, whereas motor coordination on the Rotarod was disturbed in deaf rats (P < 0.05). Learning the concept of the radial maze test was initially disturbed in deaf rats (P < 0.05), whereas retesting every 8 weeks did not show long-term memory deficits. Social interaction and preference was also not affected by hearing loss. Final electrophysiological recordings in anesthetized rats revealed reduced firing rates, enhanced irregular firing, and reduced oscillatory theta band activity (4–8 Hz) in the mPFC of deaf rats as compared to controls (P < 0.05). In the IC, reduced oscillatory theta (4–8 Hz) and gamma (30–100 Hz) band activity was found in deaf rats (P < 0.05).

Conclusion

Minor and transient behavioral deficits do not confirm direct impact of long-term hearing loss on cognitive function in rats. However, the altered neuronal activities in the mPFC and IC after hearing loss indicate effects on neuronal networks in and outside the central auditory system with potential consequences on cognitive function.

Correlation between the effect of orofacial somatosensory inputs in speech perception and speech production performance

Introduction

Orofacial somatosensory inputs modify the perception of speech sounds. Such auditory-somatosensory integration likely develops alongside speech production acquisition. We examined whether the somatosensory effect in speech perception varies depending on individual characteristics of speech production.

Methods

The somatosensory effect in speech perception was assessed by changes in category boundary between /e/ and /ø/ in a vowel identification test resulting from somatosensory stimulation providing facial skin deformation in the rearward direction corresponding to articulatory movement for /e/ applied together with the auditory input. Speech production performance was quantified by the acoustic distances between the average first, second and third formants of /e/ and /ø/ utterances recorded in a separate test.

Results

The category boundary between /e/ and /ø/ was significantly shifted towards /ø/ due to the somatosensory stimulation which is consistent with previous research. The amplitude of the category boundary shift was significantly correlated with the acoustic distance between the mean second - and marginally third - formants of /e/ and /ø/ productions, with no correlation with the first formant distance.

Discussion

Greater acoustic distances can be related to larger contrasts between the articulatory targets of vowels in speech production. These results suggest that the somatosensory effect in speech perception can be linked to speech production performance.

Younger Age at Cochlear Implant Activation Results in Improved Auditory Skill Development for Children With Congenital Deafness

PURPOSE

The U.S. Food and Drug Administration indications for cochlear implantation in children is currently 9 months of age and older for children with bilateral profound sensorineural hearing loss (SNHL). Studies have shown that earlier activation of a cochlear implant (CI) can lead to better spoken language outcomes. As auditory skills are a precursor to the development of spoken language, this study was developed to investigate the influence of age at CI activation on auditory skill acquisition in young children. A secondary aim was to describe the auditory skills of children implanted prior to 9 months of age as compared to children with older ages of activation.

METHOD

Functional Listening Index (FLI) scores obtained during routine clinical visits were reviewed for 78 pediatric CI recipients with congenital bilateral profound hearing loss who were activated before 2 years of age. A linear mixed-effects model assessed the effect of age at CI activation on cumulative FLI scores over time.

RESULTS

There was a significant interaction between age at activation and chronological age at the time of evaluation, indicating that children with earlier access to sound achieved a greater number of auditory skills than those with later CI activations when measured at the same chronological age. Children activated before the age of 9 months approximated scores expected of children with typical hearing, whereas children activated between 9 and 24 months of age did not.

CONCLUSIONS

Younger age at CI activation is associated with increased auditory skills over time. Children who undergo cochlear implantation and CI activation before 9 months achieve more auditory skills by 4 years of age than children who are activated at later ages. These data suggest that reducing the approved age at cochlear implantation for children with congenital bilateral profound SNHL may support optimal auditory skill acquisition.

A basic protocol for the acoustic characterization of small and medium-sized classrooms

To promote a fast and effective characterization of the sound environment in small and medium-sized classrooms, a basic measurement protocol, based on a minimum number of parameters and positions, is provided. Measurements were taken in 29 occupied classrooms belonging to 13 primary schools in Turin, Italy, that differ in location and typology. The background noise level was acquired during silent and group activities, and the reverberation time, speech clarity, useful-to-detrimental ratio and speech level, were acquired along the main axis of each classroom and in one or two offset positions. To reduce the number of measured parameters that can be used to fully characterize classroom acoustics, data were divided into two groups on the basis of a cutoff value of maximum occupied reverberation time in the case of moderate and severe requirements. Given the strong correlation among the quantities, thresholds were identified for the other acoustical parameters, and their accuracy and precision were tested to assess their ability to classify the acoustic quality as compliant or non-compliant. Results suggest that more convenient parameters, like clarity in the central position of the classroom, can be used instead of reverberation time to classify classroom acoustics.

A Retrospective Evaluation to Assess Reliability of Electrophysiological Methods for Diagnosis of Hearing Loss in Infants

Background: An electrophysiological investigation with auditory brainstem response (ABR), round window electrocochleography (RW-ECoG), and electrical-ABR (E-ABR) was performed in children with suspected hearing loss with the purpose of early diagnosis and treatment. The effectiveness of the electrophysiological measures as diagnostic tools was assessed in this study. Methods: In this retrospective case series with chart review, 790 children below 3 years of age with suspected profound hearing loss were tested with impedance audiometry and underwent electrophysiological investigation (ABR, RW-ECoG, and E-ABR). All implanted cases underwent pure-tone audiometry (PTA) of the non-implanted ear at least 5 years after surgery for a long-term assessment of the reliability of the protocol. Results: Two hundred and fourteen children showed bilateral severe-to-profound hearing loss. In 56 children with either ABR thresholds between 70 and 90 dB nHL or no response, RW-ECoG showed thresholds below 70 dB nHL. In the 21 infants with bilateral profound sensorineural hearing loss receiving a unilateral cochlear implant, no statistically significant differences were found in auditory thresholds in the non-implanted ear between electrophysiological measures and PTA at the last follow-up (p > 0.05). Eight implanted children showed residual hearing below 2000 Hz worse than 100 dB nHL and 2 children showed pantonal residual hearing worse than 100 dB nHL (p > 0.05). Conclusion: The audiological evaluation of infants with a comprehensive protocol is highly reliable. RW-ECoG provided a better definition of hearing thresholds, while E-ABR added useful information in cases of auditory nerve deficiency.

From Bench to Booth: Examining Hair-Cell Regeneration Through an Audiologist's Scope

Damage to auditory hair cells is a key feature of sensorineural hearing loss due to aging, noise exposure, or ototoxic drugs. Though hair-cell loss is permanent in humans, research in bird species led to the discovery that analogous hair cells of the avian basilar papilla are able to regenerate after being damaged by ototoxic agents. Regeneration appears to occur through a combination of the mitotic expansion of a precursor population of supporting cells and direct transdifferentiation of supporting cells into functioning hair cells. This review will synthesize the relevant anatomy and pathophysiology of sensorineural hearing loss, the historical observations that led to the genesis of the hair-cell regeneration field, and perspectives on initial human hair-cell regeneration trials.

Audiometric profiles in children with speech sound disorder: Subclinical hearing loss as a potential factor

In the present study, hearing sensitivity in children with speech sound disorder (SSD) is scrutinized. Middle ear function (wideband tympanometry and acoustic stapedial reflexes, ASR) and inner ear function (audiometric thresholds in the conventional_{1-8 kHz} and extended_{10-16 kHz} high frequency (EHF) range, and distortion product otoacoustic emissions (DPOAEs_{2-10 kHz}) were investigated. Hearing results were analyzed in relation to speech discrimination of phonemic contrasts (quiet and in noise conditions) and reproduction. Thirty-two children with SSD and 41 children with typical development (TD) ages 4-5 years participated. Children with SSD exhibited significantly less sensitive hearing compared to children with TD. This was demonstrated as more absent contralateral ASR (right ear SSD 43.7%; TD 22.0%), a higher prevalence of minimal hearing loss (MHL, > 15 dB HL at one or more frequencies or ears_{1-8 kHz} and PTA ≤ 20 dB HL, SSD 53.1%; TD 24.3%) and EHF hearing impairment (EHF HI, > 20 dB HL at one or more frequencies or ears_{10-16 kHz}, SSD 31.3%; TD 24.3%). At 2 kHz bilaterally, children with SSD showed significantly higher hearing thresholds than children with TD (mean difference, left ear 3.4 dB: right ear 4.3 dB), together with a significantly lower SNR in DPOAEs at 2.2 kHz (left ear 5.1 dB mean difference between groups). In all children, audiometric thresholds at the key-frequencies for speech, 2 and 4 kHz and DPOAEs within similar spectral regions, predicted 7-12% of the variance in phonemic discrimination and reproduction. Overall, these results suggest that hearing should be more fully investigated in children with SSD.

Central auditory maturation and behavioral outcomes after cochlear implantation in prelingual auditory neuropathy spectrum disorder related to OTOF variants (DFNB9): Lessons from pilot study

The cortical auditory evoked potential (CAEP)-based P1 component acts as a biomarker for cochlear implantation (CI) outcomes in children with auditory neuropathy spectrum disorder (ANSD). To date, early intervention primarily before the age of two years and six months of CI usage is necessary and sufficient to achieve age-appropriate cortical maturation and good prognosis. However, varying degrees of neural dyssynchrony, resulting from the etiological heterogeneity of ANSD, may preclude uniform application of this hypothesis to ensure auditory cortical maturation. Thus, a focused evaluation of those carrying OTOF variants, which may be the salient molecular etiology of prelingual ANSD, would circumvent the issue of heterogeneity. Here, we sought to provide a much better understanding of the brain perspectives (i.e., P1 maturation) in OTOF-associated ANSD subjects and set the stage for an optimal strategy to enhance language development. We conducted a preliminary study comprising 10 subjects diagnosed with OTOF-related ANSD who underwent CI by a single surgeon and subsequently underwent measurements of the P1 component. We observed that DFNB9 subjects who received CI after 2 years of age exhibited “absent” or “anomalous” P1 components that correspond to delayed language development. However, timely implantation, as early as 12 months of age per se, might be insufficient to achieve age-appropriate cortical maturation of DFNB9 in cases with six to seven months of device use. This suggests the importance of sustained rehabilitation in DFNB9 than in other etiologies. Indeed, an additional follow-up study showed that a reduction in P1 latency was linked to an improvement in auditory performance. Collectively, our results suggest that central auditory maturation and successful outcome of CI in DFNB9 may have more demanding requirements, that is, earlier implantation and more sustained rehabilitation. We believe that the current study opens a new path toward genome-based neuroimaging in the field of hearing research.

A Novel Bone Conduction Hearing System May Improve Memory Function in Children with Single Side Hearing loss: A Case-Control Study

OBJECTIVES

To evaluate the effects of an adhesive adapter prosthesis (AAP) on memory function in pediatric subjects with single side hearing loss (SSHL).

MATERIALS AND METHODS

Case-control study. 19 pediatric subjects with mild to moderate SSHL treated with AAP and 15 subjects with normal hearing (control group) were included in this study. Working and short-term memory functions were tested in all subjects, in silence and noise conditions. In SSHL subjects, tests were performed before the AAP was applied (T0) and at 1-month (T1) follow-up. The control group was tested once.

RESULTS

AAP significantly improved working memory function in noise as measured at T1 (p<0.01) compared with T0, but T1 scores in children with SSHL remained significantly different from the ones of the control group (p<0.01). AAP also significantly improved short- term memory function test scores at T1 compared with T0 (p<0.01), but despite being in the normal range for the subjects' age, the scores remained significantly different from those of the control group (p<0.01).

CONCLUSION

In pediatric subjects with mild, moderate, and moderate-severe SSHL, restoration of bilateral hearing through AAP improved short-term memory function and working memory function in noise, as measured at 1 month follow-up; however, AAP did not seem to lead to a full restoration of such functions as measured by a comparison with healthy controls. Further studies with longer follow-ups might help elucidate whether AAP can elicit further improvements in memory functions.

Cortical Neurophysiologic Correlates of Auditory Threshold in Adults and Children With Normal Hearing and Auditory Neuropathy Spectrum Disorder

Purpose Auditory threshold estimation using the auditory brainstem response or auditory steady state response is limited in some populations (e.g., individuals with auditory neuropathy spectrum disorder [ANSD] or those who have difficulty remaining still during testing and cannot tolerate general anesthetic). However, cortical auditory evoked potentials (CAEPs) can be recorded in many such patients and have been employed in threshold approximation. Thus, we studied CAEP estimates of auditory thresholds in participants with normal hearing, sensorineural hearing loss, and ANSD. Method We recorded CAEPs at varying intensity levels to speech (i.e., /ba/) and tones (i.e., 1 kHz) to estimate auditory thresholds in normal-hearing adults (n = 10) and children (n = 10) and case studies of children with sensorineural hearing loss and ANSD. Results Results showed a pattern of CAEP amplitude decrease and latency increase as stimulus intensities declined until waveform components disappeared near auditory threshold levels. Overall, CAEP thresholds were within 10 dB HL of behavioral thresholds for both stimuli. Conclusions The above findings suggest that CAEPs may be clinically useful in estimating auditory threshold in populations for whom such a method does not currently exist. Physiologic threshold estimation in difficult-to-test clinical populations could lead to earlier intervention and improved outcomes.

Future directions for screening and treatment in congenital hearing loss

Hearing loss is the most common neurosensory deficit. It results from a variety of heritable and acquired causes and is linked to multiple deleterious effects on a child's development that can be ameliorated by prompt identification and individualized therapies. Diagnosing hearing loss in newborns is challenging, especially in mild or progressive cases, and its management requires a multidisciplinary team of healthcare providers comprising audiologists, pediatricians, otolaryngologists, and genetic counselors. While physiologic newborn hearing screening has resulted in earlier diagnosis of hearing loss than ever before, a growing body of knowledge supports the concurrent implementation of genetic and cytomegalovirus testing to offset the limitations inherent to a singular screening modality. In this review, we discuss the contemporary role of screening for hearing loss in newborns as well as future directions in its diagnosis and treatment.

Neurodevelopmental Aspects and Cortical Auditory Maturation in Children with Cochlear Implants

Background and objectives: The cochlear implant is not only meant to restore auditory function, but it also has a series of benefits on the psychomotor development and on the maturation of central auditory pathways. In this study, with the help of neuropsychological tests and cortical auditory potentials (CAEPs), we intend to identify a series of instruments that allow us to monitor children with a cochlear implant, and later on, to admit them into an individualized rehabilitation program. Materials and methods: This is a longitudinal study containing 17 subjects (6 boys and 11 girls) diagnosed with congenital sensorineural hearing loss. The average age for cochlear implantation in our cohort is 22 months old. Each child was tested before the cochlear implantation, tested again 3 months after the implant, and then 6 months after the implant. To test the general development, we used the Denver Developmental Screening Test (DDST II). CAEPs were recorded to assess the maturation of central auditory pathways. Results: The results showed there was progress in both general development and language development, with a significant statistical difference between the overall DQ (developmental quotient) and language DQ before the cochlear implantation and three and six months later, respectively. Similarly, CAEP measurements revealed a decrease of positive-going component (P1) latency after cochlear implantation. Conclusion: CAEPs and neuropsychological tests prove to be useful instruments for monitoring the progress in patients with cochlear implants during the rehabilitation process.

Identification of Perinatal Risk Factors for Auditory Neuropathy Spectrum Disorder

OBJECTIVES/HYPOTHESIS

To identify medical risk factors associated with auditory neuropathy spectrum disorder (ANSD).

STUDY DESIGN

Retrospective case-control study.

METHODS

During a 2-year period (2013-2014) patients with newly diagnosed ANSD were identified at a tertiary care facility. Twenty-two patients (n = 22) were identified aged 0.5 to 8.1 years. There were 15 males and seven females. Sixteen had bilateral, four had left-sided, and two had right-sided ANSD. Two age-matched, side-matched, and gender-matched control groups were then collected. The first group was 22 normal-hearing children (n = 22). The second was 22 children with sensorineural hearing loss (SNHL) (n = 22) who did not meet the criteria for ANSD. The chart of each subject was reviewed for the following five-predictor variables: prematurity, low birth weight, jaundice, use of mechanical ventilation, and administration of ototoxic medications. Analysis of variance was performed to analyze the prevalence of perinatal risk factors among the three groups. Multivariate linear regression was then applied.

RESULTS

When comparing the ANSD group to both the normal-hearing and SNHL groups, the subjects with ANSD had statistically significant higher rates of prematurity, low birth weight, jaundice, and mechanical ventilation. Multiple regression analysis was performed to identify predictors of ANSD compared to each control group individually. Jaundice in the first month of life approached significance when comparing the ANSD group to the normal-hearing group, and was the only medical risk factor found to be statistically significant when comparing the ANSD group to the SNHL group.

CONCLUSIONS

A history of neonatal hyperbilirubinemia was significantly more common in children with ANSD compared to children with severe SNHL.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:671-674, 2021.

Assessment of Cortical Auditory Function Using Electrophysiological and Neuropsychological Measurements in Children with Bone-Anchored Hearing Aids

Children suffering from conductive or mixed hearing loss may benefit from a bone-anchored hearing aid system (BAHA Attract implantable prosthesis). After audiological rehabilitation, different aspects of development are improving. The objective of this case report is to propose a comprehensive framework for monitoring cortical auditory function after implantation of a bone-anchored hearing aid system by using electrophysiological and neuropsychological measurements.

We present the case of a seven-year-old boy with a congenital hearing loss due to a plurimalformative syndrome, including outer and middle ear malformation. After the diagnosis of hearing loss and the audiological rehabilitation with a BAHA Attract implantable prosthesis, the cortical auditory evoked potentials were recorded. We performed a neuropsychological evaluation using the Wechsler Intelligence Scale for Children – Fourth Edition, which was applied according to a standard procedure.

The P1 latency was delayed according to the age (an objective biomarker for quantifying cortical auditory function). The neuropsychological evaluation revealed that the child's working memory and verbal reasoning abilities were in the borderline range comparing with his nonverbal reasoning abilities and processing abilities, which were in the average and below-average range, respectively.

Cortical auditory evoked potentials, along with neuropsychological evaluation, could be an essential tool for monitoring cortical auditory function in children with hearing loss after a bone-anchored hearing aid implantation.

Temporal representation impairment in developmental dyslexia for unisensory and multisensory stimuli

Dyslexia has been associated with a problem in visual-audio integration mechanisms. Here, we investigate for the first time the contribution of unisensory cues on multisensory audio and visual integration in 32 dyslexic children by modelling results using the Bayesian approach. Non-linguistic stimuli were used. Children performed a temporal task: they had to report whether the middle of three stimuli was closer in time to the first one or to the last one presented. Children with dyslexia, compared with typical children, exhibited poorer unimodal thresholds, requiring greater temporal distance between items for correct judgements, while multisensory thresholds were well predicted by the Bayesian model. This result suggests that the multisensory deficit in dyslexia is due to impaired audio and visual inputs rather than impaired multisensory processing per se. We also observed that poorer temporal skills correlated with lower reading skills in dyslexic children, suggesting that this temporal capability can be linked to reading abilities.

Contemporary Speech and Oral Language Care for Deaf and Hard-of-Hearing Children Using Hearing Devices

Contemporary speech and language interventions are not limited to disabilities but embrace the pragmatics of communication behaviors from the perspective of functional social participation. Accordingly, current speech and language therapies for deaf and hard-of-hearing children include a broad spectrum of approaches and techniques. This paper explores contemporary approaches and techniques for speech and oral language interventions for deaf and hard-of-hearing children using hearing devices, evidence of efficacy and how they are implemented in diverse clinical practices.

Influence of Classroom Acoustics on Noise Disturbance and Well-Being for First Graders

Several studies have shown so far that poor acoustics inside classrooms negatively affects the teaching and learning processes, especially at the lowest grades of education. However, the extent to which noise exposure or excessive reverberation affect well-being of children at school in their early childhood is still unanswered, as well as their awareness of noise disturbance. This work is a pilot study to investigate to which extent classroom acoustics affects the perceived well-being and noise disturbance in first graders. About 330 pupils aged from 6 to 7 years participated in the study. They belonged to 20 classes of 10 primary schools located in Torino (Italy), where room acoustic measurements were performed and where noise level was monitored during classes. The school buildings and the classrooms were balanced between socioeconomic status and acoustic conditions. Trained experimenters administered questionnaires in each class, where pupils answered all together during the last month of the school year (May). Questions included the happiness scale, subscales assessing self-esteem, emotional health, relationship at home and with friends, enjoyment of school, intensity and noise disturbance due to different sound sources, and quality of voice. The findings of the study suggest that long reverberation times, which are associated with poor classroom acoustics as they generate higher noise levels and degraded speech intelligibility, bring pupils to a reduced perception of having fun and being happy with themselves. Furthermore, bad classroom acoustics is also related to an increased perception of noise intensity and disturbance, particularly in the case of traffic noise and noise from adjacent school environments. Finally, happy pupils reported a higher perception of noise disturbance under bad classroom acoustic conditions, whereas unhappy pupils only reported complaints in bad classroom acoustics with respect to the perception of pleasances with himself or herself and of fitting in at school. Being a mother tongue speaker is a characteristic of children that brings more chances of attending classes in good acoustics, of being less disturbed, and of having more well-being, and richer districts presented better acoustic conditions, in turn resulting in richer districts also revealing a greater perception of well-being.

Study of the neural plasticity in adults and older adults new hearing aid users

ABSTRACT Purpose: to monitor, with long-latency auditory evoked potentials, the plasticity of the central auditory pathways in adults and older adults, new users of hearing aids. Methods: a total of 15 adults and older adults, aged 55 to 85 years, participated in the research. They had a symmetric bilateral mild to moderate sensorineural hearing loss, without previous experience with any type of hearing aid. The long-latency auditory evoked potentials were conducted with and without amplification, at 60 and 75 dBnHL, with speech stimulus in a sound field, in two assessment moments: up to one week after fitting the hearing aid and after six months of its use. The Student’s t-test was used for statistical analysis, considering significant the p-value < 0.05. Results: responses with lower latency values were observed for the right ear in the second assessment. Comparing the first with the second assessment, both with and without the hearing aid, an increase in the amplitude of P2-N2 was observed, as well as an increase in the latency of the P2 component at the intensity of 75 dBnHL. No statistically significant differences were observed at the intensity of 60 dBnHL. Conclusion:the use of the hearing aid promoted the plasticity of the central auditory pathways, increasing the number of neurons responsive to the sound stimuli.

Early general development and central auditory system maturation in children with cochlear implants - A case series

OBJECTIVES

A cochlear implant (CI) has the potential to improve the functioning of a deaf child in many aspects. Nevertheless, the dynamics of the general development, beyond the typically measured language abilities, directly after CI, is still unknown, especially if a child is implanted early. In this study we present a methodological framework for assessment of different domains of development, as well as the central auditory nervous system (CANS) maturation in infants and toddlers with a CI.

METHODS

Three children with bilateral congenital hearing loss and a unilateral CI, aged below 2.5 years, participated in a longitudinal study. Children were tested at three time points after cochlear implantation using the Polish Children Development Scale (CDS) consisting of a comprehensive battery of tests, as well as recordings of Cortical Auditory Evoked Potentials (CAEP).

RESULTS

All three children revealed gradual improvement in the overall CDS result as well as most of the CDS subscales. After 9 months of CI experience two younger children showed age-appropriate performance. In CAEP measurements a decrease of latency of the P1 component (an established biomarker of cortical auditory maturation) was observed in the same two children, with one achieving normal ranges of P1 latency after 9 months of CI use.

CONCLUSIONS

Our novel methodological framework can be successfully applied in small children with cochlear implants. It contributes to better understanding of the general development in early implanted children. The preliminary results indicate variability in children's performance in various developmental domains and thus the need to monitor the development of each child individually and holistically.

Altered Functional Connectivity in Patients With Sloping Sensorineural Hearing Loss

Background

Sensory deprivation, such as hearing loss, has been demonstrated to change the intrinsic functional connectivity (FC) of the brain, as measured with resting-state functional magnetic resonance imaging (rs-fMRI). Patients with sloping sensorineural hearing loss (SNHL) are a unique population among the hearing impaired, as they have all been exposed to some auditory input throughout their lifespan and all use spoken language.

Materials and Methods

Twenty patients with SNHL and 21 control subjects participated in a rs-fMRI study. Whole-brain seed-driven FC maps were obtained, with audiological scores of patients, including hearing loss severity and speech performance, used as covariates.

Results

Most profound differences in FC were found between patients with prelingual (before language development, PRE) vs. postlingual onset (after language development, POST) of SNHL. An early onset was related to enhancement in long-range network connections, including the default-mode network, the dorsal-attention network and the fronto-parietal network, as well as in local sensory networks, the visual and the sensorimotor. A number of multisensory brain regions in frontal and parietal cortices, as well as the cerebellum, were also more internally connected. We interpret these effects as top-down mechanisms serving optimization of multisensory experience in SNHL with a prelingual onset. At the same time, POST patients showed enhanced FC between the salience network and multisensory parietal areas, as well as with the hippocampus, when they were compared to those with PRE hearing loss. Signal in several cortex regions subserving visual processing was also more intra-correlated in POST vs. PRE patients. This outcome might point to more attention resources directed to multisensory as well as memory experience. Finally, audiological scores correlated with FC in several sensory and high-order brain regions in all patients.

Conclusion

The results show that a sloping hearing loss is related to altered resting-state brain organization. Effects were shown in attention and cognitive control networks, as well as visual and sensorimotor regions. Specifically, we found that even in a partial hearing deficit (affecting only some of the hearing frequency ranges), the age at the onset affects the brain function differently, pointing to the role of sensitive periods in brain development.

Glendonald Auditory Screening Procedure (GASP): clinical markers of the development of auditory recognition and comprehension abilities in children using cochlear implants

PURPOSE

To verify the influence of the age of implantation in the development of closed-set auditory recognition and auditory comprehension abilities in children using unilateral cochlear implants (CI), comparing distinct groups and determining clinical markers.

METHODS

Participants were 180 children operated and activated until 36 months of age and who used a CI for at least 60 months. Abilities of auditory recognition in closed-set and auditory comprehension were analyzed through the GASP Tests 5 and 6. The influence of age of implantation was investigated with three groups of children: implanted before 18 months (G1), between 19 and 24 months (G2) and between 25 and 36 months of age (G3).

RESULTS

There was no statistically significant difference when comparing the three groups. Children progressively developed auditory abilities, presenting auditory recognition ability together at approximately 41±4 months of CI use and auditory comprehension at 53±4 months.

CONCLUSION

There was no correlation between hearing performance and age of implantation for children implanted before 36 months of age. For the abilities of auditory recognition and comprehension, the clinical marker was 41±4 and 53±4 months of auditory age, respectively. Therefore, it is expected that, around 60 months of CI use, children implanted during the sensitive period can understand speech without the aid of orofacial reading, reaching the most complex hearing abilities.

Spatial Cues Influence Time Estimations in Deaf Individuals

Recent studies have reported a strong interaction between spatial and temporal representation when visual experience is missing: blind people use temporal representation of events to represent spatial metrics. Given the superiority of audition on time perception, we hypothesized that when audition is not available complex temporal representations could be impaired, and spatial representation of events could be used to build temporal metrics. To test this hypothesis, deaf and hearing subjects were tested with a visual temporal task where conflicting and not conflicting spatiotemporal information was delivered. As predicted, we observed a strong deficit of deaf participants when only temporal cues were useful and space was uninformative with respect to time. However, the deficit disappeared when coherent spatiotemporal cues were presented and increased for conflicting spatiotemporal stimuli. These results highlight that spatial cues influence time estimations in deaf participants, suggesting that deaf individuals use spatial information to infer temporal environmental coordinates.

Automated cortical auditory evoked potentials threshold estimation in neonates

Introduction

The evaluation of cortical auditory evoked potential has been the focus of scientific studies in infants. Some authors have reported that automated response detection is effective in exploring these potentials in infants, but few have reported their efficacy in the search for thresholds.

Objective

To analyze the latency, amplitude and thresholds of cortical auditory evoked potential using an automatic response detection device in a neonatal population.

Methods

This is a cross-sectional, observational study. Cortical auditory evoked potentials were recorded in response to pure-tone stimuli of the frequencies 500, 1000, 2000 and 4000 Hz presented in an intensity range between 0 and 80 dB HL using a single channel recording. P1 was performed in an exclusively automated fashion, using Hotelling's T² statistical test. The latency and amplitude were obtained manually by three examiners. The study comprised 39 neonates up to 28 days old of both sexes with presence of otoacoustic emissions and no risk factors for hearing loss.

Results

With the protocol used, cortical auditory evoked potential responses were detected in all subjects at high intensity and thresholds. The mean thresholds were 24.8 ± 10.4 dB NA, 25 ± 9.0 dB NA, 28 ± 7.8 dB NA and 29.4 ± 6.6 dB HL for 500, 1000, 2000 and 4000 Hz, respectively.

Conclusion

Reliable responses were obtained in the assessment of cortical auditory potentials in the neonates assessed with a device for automatic response detection.

Influence of classroom acoustics on the reading speed: A case study on Italian second-graders

The need of tuning into speech in noisy and reverberant classrooms is a challenge for good speech communication and literacy development at school. Reading development can be compromised if children are exposed to inadequate acoustics, especially those with poor neural processing in speech discrimination. This work reports preliminary results on the influence of classroom acoustics on the reading speed of 94 Italian second-graders. Speech clarity (C50) was found to be significantly correlated with all the investigated reading tasks, while no significant correlations were found with reverberation time.

Cortical Auditory Evoked Potentials in Children with Auditory Neuropathy/Dys-Synchrony

Auditory neuropathy/spectrum disorder (ANSD), also referred to as auditory neuropathy/dys-synchrony (AN/AD) is a recently described form of hearing impairment. Many studies have shown that changing the pattern of afferent input to the cortex significantly affects cortical organization and there is little studies about cortical neuromaturation and plasticity in children with ANSD. Study of P1 component of cortical auditory evoked potentials (CAEPs) in children with ANSD. This survey was descriptive cross-sectional. During that 97 hearing impairment children were under hearing screening tests. Of these, 14 selected subjects (ear = 28) diagnosed with ANSD (an average age of 8.5 years) and evaluated by P1 component of CAEPs. Based on latency results of p1 wave, the ears of the subjects fell into two seperate groups: Control (normal: n = 10) and case {total: n = 18 (delayed: n = 12) + (absent: n = 6)}. The averages of mean latency of P1 components of the case group in the right and the left ears compared to the control group had significant differences (p < 0.05). Abnormal latency of p1 component in ANSD children shows the possibility of different scales of disturbances in cortical auditory maturation and grow.

Neural Correlates of Sensory Abnormalities Across Developmental Disabilities

Abnormalities in sensory processing are a common feature of many developmental disabilities (DDs). Sensory dysfunction can contribute to deficits in brain maturation, as well as many vital functions. Unfortunately, while some patients with DD benefit from the currently available treatments for sensory dysfunction, many do not. Deficiencies in clinical practice surrounding sensory dysfunction may be related to lack of understanding of the neural mechanisms that underlie sensory abnormalities. Evidence of overlap in sensory symptoms between diagnoses suggests that there may be common neural mechanisms that mediate many aspects of sensory dysfunction. Thus, the current manuscript aims to review the extant literature regarding the neural correlates of sensory dysfunction across DD in order to identify patterns of abnormality that span diagnostic categories. Such anomalies in brain structure, function, and connectivity may eventually serve as targets for treatment.

Efeito do estado atencional na detecção automática das respostas auditivas corticais em neonatos

RESUMO Objetivo O objetivo desse estudo foi comparar a latência e amplitude do potencial evocado auditivo cortical P1i entre neonatos em estado de alerta e durante o sono leve. Métodos Vinte e cinco neonatos com emissões otoacústicas evocadas transientes presentes foram testados, por meio do potencial evocado auditivo cortical (PEAC), sendo dez em estado de alerta e 15 durante o sono leve. Para pesquisa dos potenciais corticais, utilizou-se o equipamento Hearlab System, de um canal, no módulo Cortical Tone Evaluation (CTE). O potencial P1i foi pesquisado de forma monoaural, na intensidade de 80 dBnNA, para as frequências de 500, 1000, 2000 e 4000Hz. A detecção do P1i foi feita de maneira automática pelo equipamento. A marcação da latência e amplitude foi realizada por três juízes. Resultados Não houve diferença estatisticamente significativa entre os dois grupos de neonatos para os valores de amplitude e latência, nas quatro frequências testadas. Conclusão Não houve influência do estado comportamental dos neonatos na avaliação do potencial cortical P1i.

Audio-visual temporal perception in children with restored hearing

It is not clear how audio-visual temporal perception develops in children with restored hearing. In this study we measured temporal discrimination thresholds with an audio-visual temporal bisection task in 9 deaf children with restored audition, and 22 typically hearing children. In typically hearing children, audition was more precise than vision, with no gain in multisensory conditions (as previously reported in Gori et al. (2012b)). However, deaf children with restored audition showed similar thresholds for audio and visual thresholds and some evidence of gain in audio-visual temporal multisensory conditions. Interestingly, we found a strong correlation between auditory weighting of multisensory signals and quality of language: patients who gave more weight to audition had better language skills. Similarly, auditory thresholds for the temporal bisection task were also a good predictor of language skills. This result supports the idea that the temporal auditory processing is associated with language development.

Altered Brain Functional Activity in Infants with Congenital Bilateral Severe Sensorineural Hearing Loss: A Resting-State Functional MRI Study under Sedation

Early hearing deprivation could affect the development of auditory, language, and vision ability. Insufficient or no stimulation of the auditory cortex during the sensitive periods of plasticity could affect the function of hearing, language, and vision development. Twenty-three infants with congenital severe sensorineural hearing loss (CSSHL) and 17 age and sex matched normal hearing subjects were recruited. The amplitude of low frequency fluctuations (ALFF) and regional homogeneity (ReHo) of the auditory, language, and vision related brain areas were compared between deaf infants and normal subjects. Compared with normal hearing subjects, decreased ALFF and ReHo were observed in auditory and language-related cortex. Increased ALFF and ReHo were observed in vision related cortex, which suggest that hearing and language function were impaired and vision function was enhanced due to the loss of hearing. ALFF of left Brodmann area 45 (BA45) was negatively correlated with deaf duration in infants with CSSHL. ALFF of right BA39 was positively correlated with deaf duration in infants with CSSHL. In conclusion, ALFF and ReHo can reflect the abnormal brain function in language, auditory, and visual information processing in infants with CSSHL. This demonstrates that the development of auditory, language, and vision processing function has been affected by congenital severe sensorineural hearing loss before 4 years of age.

[Preoperative auditory evaluation and postoperative follow-up in cochlear implantees : The role of objective measures]

The primary diagnostic aim prior to cochlear implantation is establishment of a comprehensive and multidisciplinary diagnosis, in order to subsequently begin therapy as early as possible. Audiological evaluation prior to implantation employs a test battery-approach, including subjective and objective procedures. Objective measures show high reliability and therefore play a major role in the diagnosis of difficult-to-test subjects such as infants and young children. During postoperative follow-up, objective measures offer a valid method for analyzing the effects of different stimuli on the auditory system. Particularly in infants, children, and uncooperative patients, the results of these tests enable the speech processor settings to be optimized, the hearing benefit to be assessed, and treatment to be adapted accordingly. Auditory brainstem responses (ABR) offer an excellent test/retest and inter-/intrarater reliability and validity, and are the most commonly used method for objective hearing threshold estimation and evaluation of the functional integrity of the lower auditory pathway. The use of narrow-band stimuli allows frequency-specific threshold estimation; analysis of stationary auditory steady state potentials (ASSR) adds the advantages of automated objective detection. Electrocochleography and electrically evoked ABR give valuable information in special cases. The use of cortical potentials (CAEP) in response to speech stimuli is quite promising, although the high response variability currently limits this method's clinical application. An audiological test-battery approach combining the results of subjective and objective measures leads to significantly increased reliability of preoperative diagnosis and postoperative follow-up in cochlear implantees.

The P1 biomarker for assessing cortical maturation in pediatric hearing loss: a review

We review evidence for a high degree of neuroplasticity of the central auditory pathways in early childhood, citing evidence of studies of the P1 and N1 cortical auditory evoked potentials in congenitally deaf children receiving cochlear implants at different ages during childhood, children with auditory neuropathy spectrum disorder and children with hearing loss and comorbid multiple disabilities. We discuss neuroplasticity, including cortico-cortical de-coupling and cross-modal re-organization that occurs in deafness. We provide evidence for the clinical utility of the P1 cortical auditory evoked potential (CAEP) as a non-invasive biomarker that can be used to objectively assess maturation of auditory cortex in clinical cases of cochlear implant patients and candidates. Finally, we present clinical case studies in which the P1 CAEP biomarker proved useful in clinical decision-making regarding intervention in cases of single-sided deafness, auditory neuropathy spectrum disorder, mild hearing loss and hypoplastic auditory nerve.

Cortical development and neuroplasticity in Auditory Neuropathy Spectrum Disorder

Cortical development is dependent to a large extent on stimulus-driven input. Auditory Neuropathy Spectrum Disorder (ANSD) is a recently described form of hearing impairment where neural dys-synchrony is the predominant characteristic. Children with ANSD provide a unique platform to examine the effects of asynchronous and degraded afferent stimulation on cortical auditory neuroplasticity and behavioral processing of sound. In this review, we describe patterns of auditory cortical maturation in children with ANSD. The disruption of cortical maturation that leads to these various patterns includes high levels of intra-individual cortical variability and deficits in cortical phase synchronization of oscillatory neural responses. These neurodevelopmental changes, which are constrained by sensitive periods for central auditory maturation, are correlated with behavioral outcomes for children with ANSD. Overall, we hypothesize that patterns of cortical development in children with ANSD appear to be markers of the severity of the underlying neural dys-synchrony, providing prognostic indicators of success of clinical intervention with amplification and/or electrical stimulation. This article is part of a Special Issue entitled <Auditory Synaptology>.

Adequate formal language performance in unilateral cochlear implanted children: is it indicative of complete recovery in all linguistic domains? Insights from referential communication

OBJECTIVES

Referential communication (RC) is a key element in achieving a successful communication. This case series aimed to evaluate RC in children with unilateral cochlear implants (CIs) with formal language skills within the normal range.

METHODS AND MATERIALS

A total of 31 children with CIs, with language development within the normal range, were assessed using the Pragmatic Language Skills test (MEDEA).

RESULTS

Of the children with CIs, 83.9% reached performance levels appropriate for their chronological ages. The results confirmed a positive effect of cochlear implantation on RC development, although difficulties remained in some CI users.

CONCLUSIONS

The outcomes emphasize the need to pay greater attention to the pragmatic aspects of language, assessing them with adequate testing in the early phase after cochlear implantation. Clear knowledge of children's communicative competence is the key in optimizing their communicative environments in order to create the basis for future successful interpersonal exchanges and social integration.

Parents' perspectives on the dilemmas with intervention for infants with auditory neuropathy spectrum disorder: A qualitative study

OBJECTIVE

This paper explores parental experiences of choices surrounding auditory management and language and communication development for infants and children with auditory neuropathy spectrum disorder (ANSD) in the light of the heterogeneity of condition, a poor evidence base for best outcomes in relation to management options, and the scarcity of data rooted in parent and family experience.

DESIGN

Qualitative narrative study.

STUDY SAMPLE

Twenty-five parents of 21 children (aged four months to six years) identified with ANSD through the newborn hearing screening programme.

RESULTS

Families identify barriers to early management due to conflicting expert opinions and ANSD-specific challenges with diagnosis and prognosis in infants, and share their accounts on their own evaluations of intervention benefit in their children.

CONCLUSIONS

The results are of relevance to the clinicians and other professionals involved in early intervention, management, and support of infants with ANSD.

An acoustic gap between the NICU and womb: a potential risk for compromised neuroplasticity of the auditory system in preterm infants

The intrauterine environment allows the fetus to begin hearing low-frequency sounds in a protected fashion, ensuring initial optimal development of the peripheral and central auditory system. However, the auditory nursery provided by the womb vanishes once the preterm newborn enters the high-frequency (HF) noisy environment of the neonatal intensive care unit (NICU). The present article draws a concerning line between auditory system development and HF noise in the NICU, which we argue is not necessarily conducive to fostering this development. Overexposure to HF noise during critical periods disrupts the functional organization of auditory cortical circuits. As a result, we theorize that the ability to tune out noise and extract acoustic information in a noisy environment may be impaired, leading to increased risks for a variety of auditory, language, and attention disorders. Additionally, HF noise in the NICU often masks human speech sounds, further limiting quality exposure to linguistic stimuli. Understanding the impact of the sound environment on the developing auditory system is an important first step in meeting the developmental demands of preterm newborns undergoing intensive care.

Results in cochlear implanted children before 5 years of age. a long term follow up

OBJECTIVE

To assess the hearing threshold and linguistic results of cochlear implanted children aged 10 months to 5 years, when they reached the age of 12. We studied the benefits of sequential bilateral implantation.

METHOD AND RESULTS

This is an observational, descriptive, transversal study comprising 57 cochlear implanted subjects. We performed a free field tonal audiometry at 65dB SPL, speech tests and sentences in quiet and noise (SNR+10) tests. The Objective and Criterial Language Battery (BLOC) was used to assess linguistic competence, in its screening version.

RESULTS

Children implanted under the age of 2 and with inter-implant period less than or equal to 4 years reached better statistically significant results in disyllabic and sentences with and without noise (p=0.006) tests and in the disyllabic test with noise (p=0.045) (the hardest speech test). This suggests the acquisition of binaurality, as opposed to children implanted after this age, with inter-implant period longer than 4 years, who do not reach the same performance levels.

RESULTS

of language development in the group implanted at ages 10 months to 2 years are better with respect to implanted children at ages 3-5 (<0.05) in both unilateral and bilateral implanted children in relation to the age of implantation.

CONCLUSION

Children with pre-lingual deafness implanted before the age of 2, when they are 12 years old obtain more benefits in their language development and in their linguistic competence than children implanted after this age. The audiology results are better in children implanted bilaterally under the age of 2.

Developmental and cross-modal plasticity in deafness: evidence from the P1 and N1 event related potentials in cochlear implanted children

Cortical development is dependent on extrinsic stimulation. As such, sensory deprivation, as in congenital deafness, can dramatically alter functional connectivity and growth in the auditory system. Cochlear implants ameliorate deprivation-induced delays in maturation by directly stimulating the central nervous system, and thereby restoring auditory input. The scenario in which hearing is lost due to deafness and then reestablished via a cochlear implant provides a window into the development of the central auditory system. Converging evidence from electrophysiologic and brain imaging studies of deaf animals and children fitted with cochlear implants has allowed us to elucidate the details of the time course for auditory cortical maturation under conditions of deprivation. Here, we review how the P1 cortical auditory evoked potential (CAEP) provides useful insight into sensitive period cut-offs for development of the primary auditory cortex in deaf children fitted with cochlear implants. Additionally, we present new data on similar sensitive period dynamics in higher-order auditory cortices, as measured by the N1 CAEP in cochlear implant recipients. Furthermore, cortical re-organization, secondary to sensory deprivation, may take the form of compensatory cross-modal plasticity. We provide new case-study evidence that cross-modal re-organization, in which intact sensory modalities (i.e., vision and somatosensation) recruit cortical regions associated with deficient sensory modalities (i.e., auditory) in cochlear implanted children may influence their behavioral outcomes with the implant. Improvements in our understanding of developmental neuroplasticity in the auditory system should lead to harnessing central auditory plasticity for superior clinical technique.

Is there a deafness duration limit for cochlear implants in post-lingual deaf adults?

CONCLUSION

Patients with post-lingual deafness should not be excluded from cochlear implantation (CI) on the basis of duration of deafness. We found that the prognosis was favorable in patients who developed deafness after adolescence, even in those with extremely long-term deafness.

OBJECTIVES

CI is an effective treatment for post-lingual deafness. However, it remains unclear whether CI would benefit patients with extremely long-term deafness. We evaluated the auditory performance after CI of patients who had been deaf for more than 30 years.

METHODS

The study enrolled 81 adults with post-lingual deafness. Speech perception tests were performed preoperatively and 12 months postoperatively, and factors affecting the postoperative auditory performance were investigated. The subjects were divided into groups according to the duration of deafness and the postoperative speech perception scores were compared.

RESULTS

A marked improvement in the open-set speech perception scores (mono/disyllabic words and sentences) after implantation was seen in all groups, and no significant difference in the improvement in speech perception scores was observed among the groups. Age at onset of deafness was closely related to the postoperative performance, and patients who had lost their hearing before adolescence performed poorly.

Inter-trial coherence as a marker of cortical phase synchrony in children with sensorineural hearing loss and auditory neuropathy spectrum disorder fitted with hearing aids and cochlear implants

OBJECTIVE

Although brainstem dys-synchrony is a hallmark of children with auditory neuropathy spectrum disorder (ANSD), little is known about how the lack of neural synchrony manifests at more central levels. We used time-frequency single-trial EEG analyses (i.e., inter-trial coherence; ITC), to examine cortical phase synchrony in children with normal hearing (NH), sensorineural hearing loss (SNHL) and ANSD.

METHODS

Single trial time-frequency analyses were performed on cortical auditory evoked responses from 41 NH children, 91 children with ANSD and 50 children with SNHL. The latter two groups included children who received intervention via hearing aids and cochlear implants. ITC measures were compared between groups as a function of hearing loss, intervention type, and cortical maturational status.

RESULTS

In children with SNHL, ITC decreased as severity of hearing loss increased. Children with ANSD revealed lower levels of ITC relative to children with NH or SNHL, regardless of intervention. Children with ANSD who received cochlear implants showed significant improvements in ITC with increasing experience with their implants.

CONCLUSIONS

Cortical phase coherence is significantly reduced as a result of both severe-to-profound SNHL and ANSD.

SIGNIFICANCE

ITC provides a window into the brain oscillations underlying the averaged cortical auditory evoked response. Our results provide a first description of deficits in cortical phase synchrony in children with SNHL and ANSD.