Causation of permanent unilateral and mild bilateral hearing loss in children

Differences in Hearing Devices and Speech Therapy Utilization Between Children With Permanent Unilateral Versus Bilateral Hearing Loss

OBJECTIVES

In this study, we aimed to describe differences in diagnosis and both auditory and speech/language intervention utilization between children with permanent unilateral hearing loss as compared with bilateral hearing loss.

DESIGN

A retrospective cohort study was performed of children evaluated in a multidisciplinary hearing loss clinic at a tertiary care pediatric hospital. Children aged 0 to 18 years with either permanent unilateral or bilateral hearing loss were included.

RESULTS

One hundred fourteen children with unilateral hearing loss and 268 children with bilateral hearing loss were studied for a total of 382 children. There were no demographic differences between children with permanent unilateral versus bilateral hearing loss. Rates of newborn hearing screening and referred screening results were similar between those with unilateral and bilateral hearing loss. Despite similar rates of referred newborn hearing screening, those with bilateral hearing loss were diagnosed at a younger age (mean 3.6 years, SD 3.8 years) as compared with those with unilateral hearing loss (mean 5.0 years, SD 4.2 years). Children with unilateral hearing loss had similar severity of hearing loss in their poorer hearing ear as compared with children with bilateral hearing loss, yet they were significantly less likely to be fitted with hearing devices (53% versus 78%) or receive speech/language therapy (36% versus 54%) as compared with children with bilateral hearing loss. Multivariate analysis found that bilateral hearing loss and earlier age of hearing loss diagnosis were associated with hearing device use.

CONCLUSIONS

Early diagnosis and intervention for childhood hearing loss have a significant impact on a child's educational success and social relationships. However, little is known about differences in diagnosis and resource utilization between children with permanent unilateral hearing loss versus bilateral hearing loss. Children with unilateral hearing loss were diagnosed at a later age and were less likely to utilize hearing devices or speech/language therapy compared with those with bilateral hearing loss, despite having similar severity of hearing loss in the poorer hearing ear. There is a strong body of evidence that children with unilateral hearing loss have improved hearing outcomes with hearing devices, which suggests there is room for improvement in identifying unilateral hearing loss and providing adequate services to optimize educational success. However, speech therapy is generally implemented in response to language delays. Therefore, children with unilateral loss may have lower rates of language delays as compared with those with bilateral hearing loss, thereby explaining differences in speech therapy utilization.

Characterisation of the treatment provided for children with unilateral hearing loss

BACKGROUND

Children with permanent unilateral hearing loss (UHL) are an understudied population, with limited data to inform the guidelines on clinical management. There is a funding gap in healthcare provision for the children with UHL in the United Kingdom, where genetic screening, support services, and devices are not consistently provided or fully funded in all areas. They are a disparate population with regard to aetiology and their degree of hearing loss, and hence their device choice and use. Despite having one "good ear", some children with UHL can have similar outcomes, socially, behaviourally, and academically, to children with bilateral hearing loss, highlighting the importance of understanding this population. In this longitudinal cohort study, we aimed to characterise the management of the children with UHL and the gaps in the support services that are provided for the children in Nottingham, United Kingdom.

METHODS

A cohort study was conducted collecting longitudinal data over 17 years (2002-2019) for 63 children with permanent congenital confirmed UHL in a large tertiary regional referral centre for hearing loss in Nottingham, United Kingdom. The cases of UHL include permanent congenital, conductive, mixed, or sensorineural hearing loss, and the degree of hearing loss ranges from mild to profound. The data were taken from their diagnostic auditory brainstem responses and their two most recent hearing assessments. Descriptors were recorded of the devices trialled and used and the diagnoses including aetiology of UHL, age of first fit, degree of hearing loss, when and which type of device was used, why a device was not used, the support services provided, concerns raised, and who raised them.

RESULTS

Most children (45/63; 71%) trialled a device, and the remaining 18 children had no device trial on record. Most children (20/45; 44%) trialled a bone-conduction device, followed by contralateral routing of signal aid (15/45; 33%) and conventional hearing aids (9/45; 20%). Most children (36/45; 80%) who had a device indicated that they wore their device "all day" or every day in school. Few children (8/45; 18%) reported that they wore their device rarely, and the reasons for this included bullying (3/8), feedback from the device (2/8), and discomfort from the device (2/8). Only one child reported that the device was not helping with their hearing. The age that the children were first fitted with their hearing device varied a median of 2.5 years for hearing aids and bone-conduction devices and 7 years for a contralateral routing of signal aid. The length of time that the children had the device also varied widely (median of 26 months, range 3-135 months); the children had their bone-conduction hearing aid for the longest period of time (median of 32.5 months). There was a significant trend where more recent device fittings were happening for children at a younger age. Fifty-one children were referred by the paediatric audiologist to a support service, 72.5% (37/51) were subsequently followed up by the referred service with no issue, whilst the remaining 27.5% (14/51) encountered an issue leading to an unsuccessful provision of support. Overall, most children (65%, 41/63) had no reported concerns, and 28.5% (18/63) of the children went on to have a documented concern at some point during their audiological care: five with hearing aid difficulties, five with speech issues, four with no improvement in hearing, three facing self-image or bullying issues, and one case of a child struggling to interact socially with friends. Three of these children had not trialled a device. We documented every concern reported from the parents, clinicians, teachers of the deaf, and from the children themselves. Where concerns were raised, more than half (58.6%, 10/18) were by schools and teachers, the remaining four concerns were raised by the family, and further four concerns were raised by the children themselves.

CONCLUSION

To discover what management will most benefit which children with permanent UHL, we first must characterise their treatment, their concerns, and the support services available for them. Despite the children with UHL being a highly disparate population-in terms of their aetiology, their device use, the degree of hearing loss, and the age at which they trial a device-the majority report they use their device mostly in school. In lieu of available data and in consideration of the devices that are available to them, it could be useful to support families and clinicians in understanding the devices which are most used and where they are used. Considering the reasons for cessation of regular device use counselling and support services would be vital to support the children with UHL.

Children With Unilateral Hearing Loss After Newborn Hearing Screening in Taiwan

PURPOSE

We explored the intervention characteristics and language outcomes of children with unilateral hearing loss (UHL) in Taiwan after the implementation of universal newborn hearing screening (UNHS) to highlight changes in attitudes and actions toward hearing-related treatments.

METHOD

Data of 132 children with UHL in birth cohorts from 2012 to 2019 were included. This retrospective study examined differences in age at identification, hearing aid (HA) fitting, and seeking supportive services. Commonly requested attributes of services, reasons for HA rejection, and children's language performance were investigated.

RESULTS

The age at identification decreased from 50.3 months in 2012 to 2.6 months in 2019. Similar trends of declining age were obtained for the age at HA fitting and age at first service contact. In addition, 40% of the parents did not seek support until the child became older (M = 30.5 months) and showed more noticeable behaviors related to hearing loss, and only 64% of the children were consistent HA users. Children with UHL enrolled in the intervention programs approximated the average language performance of the assessment norm; however, they showed depressed language levels when compared to the norm group at the 75th percentile.

CONCLUSIONS

UNHS had a positive impact on early identification and intervention in children with UHL. Compared to parents of children with all types of hearing loss, parents of children with UHL seemed to be more uncertain about aural habilitation at the early stage.

Listening-Related Fatigue in Children With Unilateral Hearing Loss

Purpose Listening-related fatigue is an understudied construct that may contribute to the auditory, educational, and psychosocial problems experienced by children with unilateral hearing loss (UHL). Herein, we present an overview of listening-related fatigue in school-age children with hearing loss (CHL), with a focus on children with UHL. Method Following a review of research examining listening-related fatigue in adults and CHL, we present preliminary findings exploring the effects of unilateral and bilateral hearing loss on listening-related fatigue in children. For these exploratory analyses, we used data collected from our ongoing work developing and validating a tool, the Vanderbilt Fatigue Scale, for measuring listening-related fatigue in children. Presently, we are assessing 3 versions of the fatigue scale-child self-report, parent proxy, and teacher proxy. Using these scales, data have been collected from more than 900 participants. Data from children with unilateral and bilateral hearing loss and for children with no hearing loss are compared with adult Vanderbilt Fatigue Scale data. Results Results of our literature review and exploratory analyses suggest that adults and CHL are at increased risk for listening-related fatigue. Importantly, this increased risk was similar in magnitude regardless of whether the loss was unilateral or bilateral. Subjective ratings, based on child self-report and parent proxy report, were consistent, suggesting that children with unilateral and bilateral hearing loss experienced greater listening-related fatigue than children with no hearing loss. In contrast, results based on teacher proxy report were not sensitive to the effects of hearing loss. Conclusions Children with UHL are at increased risk for listening-related fatigue, and the magnitude of fatigue is similar to that experienced by children with bilateral hearing loss. Problems of listening-related fatigue in school-age CHL may be better identified by CHL themselves and their parents than by teachers and specialists working with the children.

An fMRI-study on single-sided deafness: Spectral-temporal properties and side of stimulation modulates hemispheric dominance

Objective

Our main aim was to investigate the blood oxygenation level dependent (BOLD) response to monaural and binaural speech- and non-speech stimuli as measured with fMRI in subjects with single-sided deafness and in normal hearing controls. We hypothesised that the response to monaural stimulation in both normal hearing subjects and persons with single-sided deafness would vary with the complexity and nature of the stimuli and the side of stimulation.

Design

Patients with left- and right single-sided deafness and controls with normal hearing receiving either binaural or monaural stimuli were tested using speech and non-speech auditory stimuli in an event-related fMRI experiment.

Study sample

Twenty-two patients with single-sided deafness after treatment for vestibular schwannoma and 50 normal hearing controls.

Results

Normal hearing persons receiving right side monaural stimuli activate bilateral temporal regions. Activation following left side monaural stimulation is more right lateralized. Persons with single-sided deafness respond similarly to controls to monaural stimulation. Persons with right side single-sided deafness show activation of frontal cortical regions not seen in persons with left side single-sided deafness following speech stimuli. This is possibly related to increased effort and more frequently reported problems with communication. Right side single-sided deafness is related to increased activation of areas usually related to processing of degraded input, including the thalamus.

Conclusion

Hemispheric dominance following monaural auditory stimulation is modulated by the spectral-temporal properties of the stimuli and by which ear is stimulated. Differences between patients with right- and left side deafness suggests that right side deafness is related to increased activation of areas involved in processing of degraded input.

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Hemispheric dominance following monaural stimulation is modulated by stimuli properties and by which ear is stimulated

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Results suggests that right side deafness is related to increased activation of eares involved in processing degraded input

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Self-assessed communication ability and the BOLD-response to phonetic stimuli correlate in several brain regions.

The impact of permanent early-onset unilateral hearing impairment in children - A systematic review

BACKGROUND

Decision-making on treatment and (re)habilitation needs to be based on clinical expertise and scientific evidence. Research evidence for the impact of permanent unilateral hearing impairment (UHI) on children's development has been mixed and, in some of the reports, based on fairly small, heterogeneous samples. Additionally, treatment provided has been highly variable, ranging from no action taken or watchful waiting up to single-sided cochlear implantation. Published information about the effects of treatment has also been heterogeneous. Moreover, earlier reviews and meta-analyses published on the impact of UHI on children's development have generally focused on select areas of development.

OBJECTIVES

This systematic review aimed to summarize the impact of children's congenital or early onset unilateral hearing impairment on listening and auditory skills, communication, speech and language development, cognitive development, educational achievements, psycho-social development, and quality of life.

METHODS

Literature searches were performed to identify reports published from inception to February 16th, 2018 with the main electronic bibliographic databases in medicine, psychology, education, and speech and hearing sciences as the data sources. PubMed, CINALH, ERIC, LLBA, PsychINFO, and ISI Web of Science were searched for unilateral hearing impairment with its synonyms and consequences of congenital or early onset unilateral hearing impairment. Eligible were articles written in English, German, or Swedish on permanent unilateral hearing impairments that are congenital or with onset before three years of age. Hearing impairment had to be of at least a moderate degree with PTA ≥40 dB averaged over frequencies 0.5 to 2 or 0.5-4 kHz, hearing in the contralateral ear had to have PTA_{0.5-2 kHz} or PTA_{0.5-4 kHz} ≤ 20 dB, and consequences of unilateral hearing impairment needed to be reported in an unanimously defined population in at least one of the areas the review focused on. Four researchers independently screened 1618 abstracts and 566 full-text articles for evaluation of study eligibility. Eligible full-text articles were then reviewed to summarize the results and assess the quality of evidence. Additionally, data from 13 eligible case and multi-case studies, each having less than 10 participants, were extracted to summarize their results. Quality assessment of evidence was made adapting the Grades of Recommendations, Assessment, Development, and Evaluation (GRADE) process, and reporting of the results adheres to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards.

RESULTS

Three articles with the quality of evidence graded as very-low to low, fulfilled the eligibility criteria set. Due to the heterogeneity of the articles, only a descriptive summary could be generated from the results. Unilateral hearing impairment was reported to have a negative impact on preverbal vocalization of infants and on sound localization and speech perception both in quiet and in noise.

CONCLUSIONS

No high-quality studies of consequences of early-onset UHI in children were found. Inconsistency in assessing and reporting outcomes, the relatively small number of participants, low directness of evidence, and the potential risk of confounding factors in the reviewed studies prevented any definite conclusions. Further well-designed prospective research using larger samples is warranted on this topic.

Benefits to Speech Perception in Noise From the Binaural Integration of Electric and Acoustic Signals in Simulated Unilateral Deafness

OBJECTIVES

This study used vocoder simulations with normal-hearing (NH) listeners to (1) measure their ability to integrate speech information from an NH ear and a simulated cochlear implant (CI), and (2) investigate whether binaural integration is disrupted by a mismatch in the delivery of spectral information between the ears arising from a misalignment in the mapping of frequency to place.

DESIGN

Eight NH volunteers participated in the study and listened to sentences embedded in background noise via headphones. Stimuli presented to the left ear were unprocessed. Stimuli presented to the right ear (referred to as the CI-simulation ear) were processed using an eight-channel noise vocoder with one of the three processing strategies. An Ideal strategy simulated a frequency-to-place map across all channels that matched the delivery of spectral information between the ears. A Realistic strategy created a misalignment in the mapping of frequency to place in the CI-simulation ear where the size of the mismatch between the ears varied across channels. Finally, a Shifted strategy imposed a similar degree of misalignment in all channels, resulting in consistent mismatch between the ears across frequency. The ability to report key words in sentences was assessed under monaural and binaural listening conditions and at signal to noise ratios (SNRs) established by estimating speech-reception thresholds in each ear alone. The SNRs ensured that the monaural performance of the left ear never exceeded that of the CI-simulation ear. The advantages of binaural integration were calculated by comparing binaural performance with monaural performance using the CI-simulation ear alone. Thus, these advantages reflected the additional use of the experimentally constrained left ear and were not attributable to better-ear listening.

RESULTS

Binaural performance was as accurate as, or more accurate than, monaural performance with the CI-simulation ear alone. When both ears supported a similar level of monaural performance (50%), binaural integration advantages were found regardless of whether a mismatch was simulated or not. When the CI-simulation ear supported a superior level of monaural performance (71%), evidence of binaural integration was absent when a mismatch was simulated using both the Realistic and the Ideal processing strategies. This absence of integration could not be accounted for by ceiling effects or by changes in SNR.

CONCLUSIONS

If generalizable to unilaterally deaf CI users, the results of the current simulation study would suggest that benefits to speech perception in noise can be obtained by integrating information from an implanted ear and an NH ear. A mismatch in the delivery of spectral information between the ears due to a misalignment in the mapping of frequency to place may disrupt binaural integration in situations where both ears cannot support a similar level of monaural speech understanding. Previous studies that have measured the speech perception of unilaterally deaf individuals after CI but with nonindividualized frequency-to-electrode allocations may therefore have underestimated the potential benefits of providing binaural hearing. However, it remains unclear whether the size and nature of the potential incremental benefits from individualized allocations are sufficient to justify the time and resources required to derive them based on cochlear imaging or pitch-matching tasks.

Convergent and divergent functional connectivity patterns in patients with long-term left-sided and right-sided deafness

Cortical reorganization may be induced in long-term single-sided deafness (SD); however, the influence of the deafness side on the functional changes remains poorly understood. Here, we investigated whole-brain functional connectivity patterns in long-term SD patients. The normalized voxel-based functional connectivity strength (FCS) was determined using resting-state fMRI (rs-fMRI) in 17 left-sided deafness (LD) patients, 21 right-sided deafness (RD) patients and 21 healthy controls (HCs). Relative to the HCs, both the LD and RD patients exhibited a reduction in the FCS in the ipsilateral visual cortex. However, compared to that in the HCs, a significantly higher FCS was observed in some regions in the salience and default-mode networks in the RD patients, but this FCS alternation pattern was not observed in the LD patients. A direct comparison of the two patient groups revealed a significantly increased FCS in the supplemental motor area in the LD group. Altogether, the long-term SD groups with LD and RD exhibited convergent and divergent functional connectivity patterns in whole-brain networks, providing promising evidence that the functional changes in long-term SD are highly deafness-side-dependent.

Bow hunter's syndrome in a patient with vertebral artery atresia, an arcuate foramen, and unilateral deafness: a case report

Bow hunter's syndrome (BHS) is a rare cause of vertebrobasilar insufficiency that occurs when the vertebral artery (VA) is occluded on rotation of the head and neck. This dynamic occlusion of the VA can occur anywhere along its course after it arises from the subclavian artery. Although most cases are associated with compression by osteophytes, cervical spondylosis, or lateral disc herniation, BHS has a highly variable clinical course that depends on the patient's specific anatomy. Therefore, it may be important for clinicians to be aware of anatomical variants that predispose individuals to BHS. Here, we report on a patient with BHS who was found to have two uncommon anatomical anomalies: an atretic right VA and a left-sided arcuate foramen.

Assessment of the cochlear nerve to facial nerve size ratio using MR multiplanar reconstruction of the internal auditory canal in patients presenting with acquired long-standing hearing loss

OBJECTIVE

To test using the facial nerve as a reference for assessment of the cochlear nerve size in patients with acquired long-standing sensorineural hearing loss (SNHL) using MRI multiplanar reconstruction.

METHODS

The study was retrospectively performed on 86 patients. Group 1 (study group, n = 53) with bilateral long-standing SNHL. Group 2 (control group, n = 33) without hearing loss. The nerve size was measured by drawing a region of interest around the cross-sectional circumference of the nerve in multiplanar reconstruction images.

RESULTS

No significant correlation was noted between the cochlear nerve and facial nerve size, and the patient's age, gender and weight (p > 0.05). In Group 1, the mean ratio of the cochlear to facial nerve size was 0.99 ± 0.30 (range: 0.52-1.86) and 1.12 ± 0.35 (range: 0.34-2.3) for the right and left sides, respectively. In Group 2, it was 1.18 ± 0.23 (range: 0.78-1.71) and 1.25 ± 0.25 (range: 0.85-1.94) for the right and left sides, respectively. The cochlear nerve size was statistically (p = 0.0004) smaller in Group 1 than in Group 2.

CONCLUSION

The cochlear nerve size and the cochlear to facial nerve size ratio are significantly smaller in patients with acquired long-standing SNHL. Advances in knowledge: The facial nerve can be used as a reference for assessment of the cochlear nerve in patients with acquired long-standing SNHL.

Minimal Hearing Loss: From a Failure-Based Approach to Evidence-Based Practice

PURPOSE

A representative sample of the literature on minimal hearing loss (MHL) was reviewed to provide evidence of challenges faced by children with MHL and to establish the need for evidence-based options for early intervention.

METHOD

Research articles published from 1950 to 2013 were searched in the Medline database using the keywords minimal hearing loss, unilateral hearing loss, and mild hearing loss. References cited in retrieved articles were also reviewed.

RESULTS

In total, 69 articles contained relevant information about pediatric outcomes and/or intervention for unilateral hearing loss, 50 for mild hearing loss, and 6 for high-frequency hearing loss. Six challenges associated with MHL emerged, and 6 interventions were indicated. Evidence indicates that although some individuals may appear to have no observable speech-language or academic difficulties, others experience considerable difficulties. It also indicates that even though children with MHL may appear to catch up in some areas, difficulties in select domains continue into adulthood.

CONCLUSIONS

Evidence indicates significant risks associated with untreated MHL. Evidence also demonstrates the need for early intervention and identifies several appropriate intervention strategies; however, no single protocol is appropriate for all children. Therefore, families should be educated about the impact of MHL and about available interventions so that informed decisions can be made.

A cool approach to reducing electrode-induced trauma: Localized therapeutic hypothermia conserves residual hearing in cochlear implantation

OBJECTIVE

The trauma caused during cochlear implant insertion can lead to cell death and a loss of residual hair cells in the cochlea. Various therapeutic approaches have been studied to prevent cochlear implant-induced residual hearing loss with limited success. In the present study, we show the efficacy of mild to moderate therapeutic hypothermia of 4 to 6 °C applied to the cochlea in reducing residual hearing loss associated with the electrode insertion trauma.

APPROACH

Rats were randomly distributed in three groups: control contralateral cochleae, normothermic implanted cochleae and hypothermic implanted cochleae. Localized hypothermia was delivered to the middle turn of the cochlea for 20 min before and after implantation using a custom-designed probe perfused with cooled fluorocarbon. Auditory brainstem responses (ABRs) were recorded to assess the hearing function prior to and post-cochlear implantation at various time points up to 30 days. At the conclusion of the trials, inner ears were harvested for histology and cell count. The approach was extended to cadaver temporal bones to study the potential surgical approach and efficacy of our device. In this case, the hypothermia probe was placed next to the round window niche via the facial recess or a myringotomy.

MAIN RESULTS

A significant loss of residual hearing was observed in the normothermic implant group. Comparatively, the residual hearing in the cochleae receiving therapeutic hypothermia was significantly conserved. Histology confirmed a significant loss of outer hair cells in normothermic cochleae receiving the surgical trauma when compared to the hypothermia treated group. In human temporal bones, a controlled and effective cooling of the cochlea was achieved using our approach.

SIGNIFICANCE

Collectively, these results suggest that therapeutic hypothermia during cochlear implantation may reduce traumatic effects of electrode insertion and improve conservation of residual hearing.

Cochlear implantation in adults with unilateral deafness: A review of the assessment/evaluation protocols

OBJECTIVES

Cochlear implantation is becoming widely used outside the tertiary research centers for treatment of unilateral deafness (UD). No consensus exists, however, on the most suitable assessment/evaluation protocols for this group of adult patients. This paper aims to review the assessment and evaluation protocols used by various research groups and to propose a protocol for the use in the clinical setting.

METHODS

The PubMed, Embase, and Cochrane Library databases were searched with the keywords 'cochlear', 'implant', 'single-sided', 'deafness', 'adults', 'unilateral', and 'deafness'. The words were either used individually, combined in pairs, or in groups of 5. All articles reporting on prospective studies, retrospective studies, or case studies were included.

RESULTS

Sixteen published studies met the inclusion criteria. Measures of hearing performance, tinnitus, subjective quality of hearing, and quality of life varied greatly among studies.

DISCUSSION

Adaptive speech in noise testing, localization, tinnitus measurement questionnaires, and self-rated hearing improvement are widely used among the research groups. These tools in conjunction assess and evaluate the main issues associated with UD.

CONCLUSION

The test battery most commonly used to assess and evaluate adult cochlea implant users with UD consists of (a) a subjective self-rating of hearing performance, (b) localization testing, and

Cortical Plasticity and Reorganization in Pediatric Single-sided Deafness Pre- and Postcochlear Implantation: A Case Study

HYPOTHESIS

The purpose of this study was to examine changes in cortical development and neuroplasticity in a child with single-sided deafness (SSD) before and after cochlear implantation (CI).

BACKGROUND

The extent to which sensory pathways reorganize in childhood SSD is not well understood and there is currently little evidence demonstrating the efficacy of CI in children with SSD.

METHODS

High-density 128-channel electroencephalography (EEG) was used to collect cortical auditory evoked potentials (CAEP), cortical visual evoked potentials (CVEP), and cortical somatosensory evoked potentials (CSSEP) in a child with SSD, pre-CI and at subsequent sessions until approximately 3 years post-CI in her right ear which occurred at age 9.86 years. Behavioral correlates of speech perception and sound localization were also measured.

RESULTS

Pre-CI, high-density EEG showed evidence of delayed auditory cortical response morphology, auditory cortical development strongly contralateral (to the normal hearing ear), evidence of increased cognitive load, and cross-modal reorganization by the visual and somatosensory modalities. The post-CI developmental trajectory provided clear evidence of age-appropriate development of auditory cortical responses, and decreased cross-modal reorganization, consistent with improved speech perception and sound localization.

CONCLUSION

Post-CI, the child demonstrated age-appropriate auditory cortical development and improved speech perception and sound localization suggestive of significant benefits from cochlear implantation. Reversal of somatosensory recruitment was clearly apparent, and only a residual amount of visual cross-modal plasticity remained postimplantation. Overall, our results suggest that CI in pediatric SSD patients may benefit from a highly plastic cortex in childhood.

Monaural Congenital Deafness Affects Aural Dominance and Degrades Binaural Processing

Cortical development extensively depends on sensory experience. Effects of congenital monaural and binaural deafness on cortical aural dominance and representation of binaural cues were investigated in the present study. We used an animal model that precisely mimics the clinical scenario of unilateral cochlear implantation in an individual with single-sided congenital deafness. Multiunit responses in cortical field A1 to cochlear implant stimulation were studied in normal-hearing cats, bilaterally congenitally deaf cats (CDCs), and unilaterally deaf cats (uCDCs). Binaural deafness reduced cortical responsiveness and decreased response thresholds and dynamic range. In contrast to CDCs, in uCDCs, cortical responsiveness was not reduced, but hemispheric-specific reorganization of aural dominance and binaural interactions were observed. Deafness led to a substantial drop in binaural facilitation in CDCs and uCDCs, demonstrating the inevitable role of experience for a binaural benefit. Sensitivity to interaural time differences was more reduced in uCDCs than in CDCs, particularly at the hemisphere ipsilateral to the hearing ear. Compared with binaural deafness, unilateral hearing prevented nonspecific reduction in cortical responsiveness, but extensively reorganized aural dominance and binaural responses. The deaf ear remained coupled with the cortex in uCDCs, demonstrating a significant difference to deprivation amblyopia in the visual system.

Asymmetric Hearing During Development: The Aural Preference Syndrome and Treatment Options

Deafness affects ∼2 in 1000 children and is one of the most common congenital impairments. Permanent hearing loss can be treated by fitting hearing aids. More severe to profound deafness is an indication for cochlear implantation. Although newborn hearing screening programs have increased the identification of asymmetric hearing loss, parents and caregivers of children with single-sided deafness are often hesitant to pursue therapy for the deaf ear. Delayed intervention has consequences for recovery of hearing. It has long been reported that asymmetric hearing loss/single-sided deafness compromises speech and language development and educational outcomes in children. Recent studies in animal models of deafness and in children consistently show evidence of an "aural preference syndrome" in which single-sided deafness in early childhood reorganizes the developing auditory pathways toward the hearing ear, with weaker central representation of the deaf ear. Delayed therapy consequently compromises benefit for the deaf ear, with slow rates of improvement measured over time. Therefore, asymmetric hearing needs early identification and intervention. Providing early effective stimulation in both ears through appropriate fitting of auditory prostheses, including hearing aids and cochlear implants, within a sensitive period in development has a cardinal role for securing the function of the impaired ear and for restoring binaural/spatial hearing. The impacts of asymmetric hearing loss on the developing auditory system and on spoken language development have often been underestimated. Thus, the traditional minimalist approach to clinical management aimed at 1 functional ear should be modified on the basis of current evidence.

Electroacoustic stimulation: now and into the future

Cochlear implants have provided hearing to hundreds of thousands of profoundly deaf people around the world. Recently, the eligibility criteria for cochlear implantation have been relaxed to include individuals who have some useful residual hearing. These recipients receive inputs from both electric and acoustic stimulation (EAS). Implant recipients who can combine these hearing modalities demonstrate pronounced benefit in speech perception, listening in background noise, and music appreciation over implant recipients that rely on electrical stimulation alone. The mechanisms bestowing this benefit are unknown, but it is likely that interaction of the electric and acoustic signals in the auditory pathway plays a role. Protection of residual hearing both during and following cochlear implantation is critical for EAS. A number of surgical refinements have been implemented to protect residual hearing, and the development of hearing-protective drug and gene therapies is promising for EAS recipients. This review outlines the current field of EAS, with a focus on interactions that are observed between these modalities in animal models. It also outlines current trends in EAS surgery and gives an overview of the drug and gene therapies that are clinically translatable and may one day provide protection of residual hearing for cochlear implant recipients.

A partial hearing animal model for chronic electro-acoustic stimulation

OBJECTIVE

Cochlear implants (CIs) have provided some auditory function to hundreds of thousands of people around the world. Although traditionally carried out only in profoundly deaf patients, the eligibility criteria for implantation have recently been relaxed to include many partially-deaf patients with useful levels of hearing. These patients receive both electrical stimulation from their implant and acoustic stimulation via their residual hearing (electro-acoustic stimulation; EAS) and perform very well. It is unclear how EAS improves speech perception over electrical stimulation alone, and little evidence exists about the nature of the interactions between electric and acoustic stimuli. Furthermore, clinical results suggest that some patients that undergo cochlear implantation lose some, if not all, of their residual hearing, reducing the advantages of EAS over electrical stimulation alone. A reliable animal model with clinically-relevant partial deafness combined with clinical CIs is important to enable these issues to be studied. This paper outlines such a model that has been successfully used in our laboratory.

APPROACH

This paper outlines a battery of techniques used in our laboratory to generate, validate and examine an animal model of partial deafness and chronic CI use.

MAIN RESULTS

Ototoxic deafening produced bilaterally symmetrical hearing thresholds in neonatal and adult animals. Electrical activation of the auditory system was confirmed, and all animals were chronically stimulated via adapted clinical CIs. Acoustic compound action potentials (CAPs) were obtained from partially-hearing cochleae, using the CI amplifier. Immunohistochemical analysis allows the effects of deafness and electrical stimulation on cell survival to be studied.

SIGNIFICANCE

This animal model has applications in EAS research, including investigating the functional interactions between electric and acoustic stimulation, and the development of techniques to maintain residual hearing following cochlear implantation. The ability to record CAPs via the CI has clinical direct relevance for obtaining objective measures of residual hearing.

A longitudinal study of hearing and middle ear status of individuals with cleft palate with and without additional malformations/syndromes

Objective : To describe and compare the middle ear status and hearing sensitivity in adolescence with isolated cleft palate plus additional malformations and/or syndromes with those with only an isolated cleft palate. Design : Retrospective and longitudinal. Two groups of individuals with isolated cleft palate were compared. Participants : A cohort of individuals born over 4 years in the western region of Sweden. The cohort was divided into one group with isolated cleft palate (n = 31; ICP) and one group with isolated cleft palate plus additional malformations and/or syndromes (n = 37; ICP+). Methods : Middle ear status and hearing thresholds were collected from the medical records at 7, 10, 13, and 16 years of age, examined, and compared within and between groups over time. Results : The ICP+ group demonstrated a significantly higher prevalence of abnormal middle ear status and elevated hearing thresholds as compared with the ICP group. As the individuals aged, the prevalence of abnormal middle ear status decreased. The hearing levels in both groups decreased in the low to middle frequencies as individuals aged; however, the hearing in the high frequencies did not. Conclusions : Individuals with cleft palate need to be followed routinely for middle ear status and hearing thresholds to ensure optimal audiological rehabilitation, with particular attention to those with additional malformations and/or syndromes.

Single-sided deafness leads to unilateral aural preference within an early sensitive period

Unilateral deafness has a high incidence in children. In addition to children who are born without hearing in one ear, children with bilateral deafness are frequently equipped only with one cochlear implant, leaving the other ear deaf. The present study investigates the effects of such single-sided deafness during development in the congenitally deaf cat. The investigated animals were either born with unilateral deafness or received a cochlear implant in one ear and were subjected to chronic monaural stimulation. In chronically stimulated animals, implantation ages were at the following three critical developmental points: 'early' during the peak of functional cortical synaptogenesis in deaf animals; 'intermediate' at the age when synaptic activity in the deaf cats dropped to the level of hearing control cats and finally, 'late' at the age when the evoked synaptic activity fell below the level of hearing control cats. After periods of unilateral hearing, local field potentials were recorded from the cortical surface using a microelectrode at ∼100 recording positions. Stimulation was with cochlear implants at both ears. The measures evaluated were dependent only on the symmetry of aural input: paired differences of onset latencies and paired relations of peak amplitudes of local field potentials. A massive reorganization of aural preference in favour of the hearing ear was found in these measures if the onset of unilateral hearing was early (before or around the peak of functional synaptogenesis). The effect was reduced if onset of unilateral hearing was in the intermediate period, and it disappeared if the onset was late. In early onset of unilateral deafness, the used ear became functionally dominant with respect to local field potential onset latency and amplitude. This explains the inferior outcome of implantations at the second-implanted ear compared with first-implanted ear in children. However, despite a central disadvantage for the deaf ear, it still remained capable of activating the auditory cortex. Appropriate training may thus help to improve the performance at the second-implanted ear. In conclusion, periods of monaural stimulation should be kept as short as possible, and training focused on the deaf ear should be introduced after delayed second implantation in children.

Features of unilateral hearing loss detected by newborn hearing screening programme in different regions of Turkey

OBJECTIVE

Newborn hearing screening (NHS) works well for babies with bilateral hearing loss. However, for those with unilateral loss, it has yet to be established some standard rules like age of diagnose, risk factors, hearing loss degree. The aim of this study is to identify the demographic characteristics of newborns with unilateral hearing loss to obtain evidence based data in order to see what to be done for children with unilateral hearing loss (UHL).

METHOD

Newborn hearing screening data of 123 babies with unilateral hearing loss, 71 (57.7%) male and 52 (42.3%) female, were investigated retrospectively. Data provided from the archives of six referral tertiary audiology centers from four regions in Turkey. Data, including type of hearing loss; age of diagnosis; prenatal, natal and postnatal risk factors; familial HL and parental consanguinity was analyzed in all regions and each of the Regions 1-4 separately.

RESULT

The difference between data obtained in terms of gender and type of hearing loss was detected as statistically significant (p<0.05). While UHL was significantly higher in females at Region 1, and in males at other Regions of 2-4; SNHL was the most detected type of UHL in all regions with the rate of 82.9-100.0%. There were not significant differences between regions in terms of the degree of hearing loss, presence of risk factors, family history of hearing loss, age at diagnosis and parental consanguinity (p>0.05). Diagnosis procedure was completed mostly at 3-6 months in Region 4; whereas, in other regions (Regions 1-3), completion of procedure was delayed until 6 months-1 year.

CONCLUSION

This study indicates that the effect of postnatal risk factors, i.e. curable hyperbilirubinemia, congenital infection and intensive care is relatively high on unilateral hearing loss, precautions should be taken regarding their prevention, as well as physicians and other health personnel should be trained in terms of these risks. For early and timely diagnosis, families will be informed about hearing loss and NHS programme; will be supported, including financial support of diagnosis process. By dissemination of the NHS programme to the total of country by high participation rate, risk factors can be determined better and measures can be increased. Additionally, further studies are needed with more comprehensive standard broad data for more evidence based consensus.

Value of systematic aetiological investigation in children with sensorineural hearing loss

Sensorineural hearing loss is the most common form of sensory impairment in children. As a precise aetiological diagnosis has major prognostic and management implications, it is useful to evaluate the contents of the aetiological investigation of sensorineural hearing loss in France. This article presents a retrospective review of professional practices by comparing the aetiological investigation of hearing loss in children with a cochlear implant and children without a cochlear implant.

PATIENTS AND METHODS

One hundred and seven children under the age of 18 years with unilateral or bilateral sensorineural hearing loss attending the paediatric ENT department for the first time between January 2007 and January 2009 were included in the study. Data from the clinical interview and all complementary investigations were analysed.

RESULTS

The various aetiologies of hearing loss were classified as genetic, acquired, or unknown in each of the two populations. Hearing loss was of unknown origin in 52% of the 87 non-implanted children and 15% of the 20 children with a cochlear implant.

CONCLUSION

This study demonstrates the heterogeneous practices in terms of aetiological investigation of sensorineural hearing loss as a function of the target population. A more systematic aetiological investigation was performed in children fitted with a cochlear implant, requiring multidisciplinary management. This study indicates the need to define a standard aetiological investigation for all children with sensorineural hearing loss.

Findings from multidisciplinary evaluation of children with permanent hearing loss

OBJECTIVES

To describe clinical findings from a multidisciplinary program for children with permanent hearing loss (PHL).

METHODS

Retrospective chart review at a tertiary care children's hospital.

PATIENTS

Two hundred patients charts were selected from the population of 260 children with permanent hearing loss presenting between July 2005 and December 2006.

MAIN OUTCOME MEASURES

PHL etiology; radiographic findings; clinical findings by genetics, ophthalmology, developmental pediatrics, speech pathology, and aural rehabilitation.

RESULTS

Etiology of hearing loss was determined in 60% of subjects. Genetic causes of hearing loss were identified or presumed (positive history of first degree relative with hearing loss) in 27% of the children. Structural ear anomalies were found in 20% of children. Among the 36% of children with CNS imaging, abnormal findings were noted in 32%. There were a high rate of ophthalmological findings (53%) among children seen by ophthalmology (n = 105). Neurodevelopmental evaluations were completed in 58% of subjects and clinically significant findings were noted in 68%. Of the 61% of children who receiving received speech/language evaluations, 77% required intervention. Over half of the 40% of subjects who had an aural rehabilitation evaluation needed therapy. There were not significant differences in rates of findings for children with mild or unilateral hearing loss as compared to children with more severe degrees of hearing loss.

CONCLUSIONS

Interdisciplinary medical evaluation of children with PHL allows for the identification and treatment of clinically significant ophthalmologic, neurodevelopmental, genetic, and speech/language disorders. A high rate of CNS and temporal bone abnormalities were identified. These findings provide an understanding of the importance of considering thorough medical and developmental evaluations among children who are deaf/hard of hearing.

School Nurses' Role in Identifying and Referring Children at Risk of Noise-Induced Hearing Loss

Young people are likely to experience noise-induced hearing loss (NIHL), as the use of personal listening devices and other damaging factors (e.g., video games) increases. Little research has examined the role of school health personnel in the prevention and early identification of hearing impairment. A 32-item, valid and reliable survey was developed regarding elementary and middle school nurses' practices concerning hearing loss screening and prevention. The survey instrument was based on the Stages of Change theory and the Health Belief Model. A random sample of 800 nurses was obtained from The National Association of School Nurses. A two-wave mailing was used to achieve a 58% response rate. Forty eight percent indicated there were not many educational programs that addressed NIHL in students. Performing hearing screenings routinely can help identify those students at risk. School nurses need to become advocates for policies and programs that mandate hearing screenings and educational programs to help reduce hearing loss.

Adolescent development of psychosis as an outcome of hearing impairment: a 10-year longitudinal study

BACKGROUND

It has long been acknowledged that hearing impairment may increase the risk for psychotic experiences. Recent work suggests that young people in particular may be at risk, indicating a possible developmental mechanism.

METHOD

The hypothesis that individuals exposed to hearing impairment in early adolescence would display the highest risk for psychotic symptoms was examined in a prospective cohort study of a population sample of originally 3021 adolescents and young adults aged 14-24 years at baseline, in Munich, Germany (Early Developmental Stages of Psychopathology Study). The expression of psychosis was assessed at multiple time points over a period of up to 10 years, using a diagnostic interview (Munich Composite International Diagnostic Interview; CIDI) administered by clinical psychologists.

RESULTS

Hearing impairment was associated with CIDI psychotic symptoms [odds ratio (OR) 2.04, 95% confidence interval (CI) 1.10-3.81], particularly more severe psychotic symptoms (OR 5.66, 95% CI 1.64-19.49). The association between hearing impairment and CIDI psychotic symptoms was much stronger in the youngest group aged 14-17 years at baseline (OR 3.28, 95% CI 1.54-7.01) than in the older group aged 18-24 years at baseline (OR 0.82, 95% CI 0.24-2.84).

CONCLUSIONS

The finding of an age-specific association between hearing impairment and psychotic experiences suggests that disruption of development at a critical adolescent phase, in interaction with other personal and social vulnerabilities, may increase the risk for psychotic symptoms.

Audiologia em comunidade: relato de experiência

OBJETIVO: caracterizar queixas, sintomas e fatores de risco relacionados à perda auditiva em crianças com suspeita de perda auditiva no Distrito Sanitário I do Recife/Brasil. MÉTODOS: relato de experiência de atuação fonoaudiológica em parceria com Agentes Comunitários de Saúde - ACS que foram capacitados sobre saúde auditiva para identificar crianças com queixas de audição. Foram realizadas visitas aos domicílios indicados e ao posto de saúde e entrevistadas 80 mães obtendo-se informações a respeito de 117 crianças de 0 a 7 anos. Para as análises dos dados foram privilegiadas informações sobre: queixas otológicas, audiológicas e fatores de risco para a audição. RESULTADOS: 35 crianças (29%) apresentaram uma ou mais queixas otológicas e/ou auditivas. Os dois principais sintomas otológicos referidos foram: otalgia (74,2%) e otorréia (34,2%). Os sintomas auditivos mais freqüentes foram: dificuldade de compreender o que os outros falam (25,7%) e diminuição da audição (20%). Com relação aos fatores de risco, verificou-se que 57 (48,7%) crianças possuíam um ou mais fatores, sendo eles: uso materno de álcool (59,6%) durante a gestação, antecedentes hereditários para a surdez (43,8%) e uso materno de drogas ilícitas (39,8%) durante a gestação. CONCLUSÃO: a otalgia foi o principal sintoma referido e a dificuldade de compreensão foi a queixa mais freqüente. Os fatores de risco mais importantes foram o uso materno de álcool e de drogas ilícitas como maconha e craque durante a gestação.

Unilateral hearing loss is associated with worse speech-language scores in children

OBJECTIVE

To determine whether children with unilateral hearing loss (UHL) demonstrate worse language skills than their siblings with normal hearing, and whether children with UHL are more likely to receive extra assistance at school.

PATIENTS AND METHODS

We conducted a case-control study of 6- to 12-year-old children with UHL compared with sibling controls (74 pairs, n = 148). Scores on the oral portion of the Oral and Written Language Scales (OWLS) were the primary outcome measure. Multivariable analysis was used to determine whether UHL independently predicted OWLS scores after we controlled for potential confounding variables.

RESULTS

Children with UHL had worse scores than their siblings on language comprehension (91 vs 98; P = .003), oral expression (94 vs 101; P = .007), and oral composite (90 vs 99; P < .001). UHL independently predicted these OWLS scores when multivariable regression was used with moderate effect sizes of 0.3 to 0.7. Family income and maternal education were also independent predictors of oral expression and oral composite scores. No differences were found between children with right- or left-ear UHL or with varying severity of hearing loss. Children with UHL were more likely to have an individualized education plan (odds ratio: 4.4 [95% confidence interval: 2.0-9.5]) and to have received speech-language therapy (odds ratio: 2.6 [95% confidence interval: 1.3-5.4]).

CONCLUSIONS

School-aged children with UHL demonstrated worse oral language scores than did their siblings with normal hearing. These findings suggest that the common practice of withholding hearing-related accommodations from children with UHL should be reconsidered and studied, and that parents and educators should be informed about the deleterious effects of UHL on oral language skills.