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

Brazilian Society of Otology task force - single sided deafness - recommendations based on strength of evidence

OBJECTIVE

To make evidence-based recommendations for the treatment of Single-Sided Deafness (SSD) in children and adults.

METHODS

Task force members were instructed on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on SSD were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 3 parts: (1) Impact of SSD in children; (2) Impact of SSD in adults; and (3) SSD in patients with temporal bone tumors.

CONCLUSIONS

Decision-making for patients with SSD is complex and multifactorial. The lack of consensus on the quality of outcomes and on which measurement tools to use hinders a proper comparison of different treatment options. Contralateral routing of signal hearing aids and bone conduction devices can alleviate the head shadow effect and improve sound awareness and signal-to-noise ratio in the affected ear. However, they cannot restore binaural hearing. Cochlear implants can restore binaural hearing, producing significant improvements in speech perception, spatial localization of sound, tinnitus control, and overall quality of life. However, cochlear implantation is not recommended in cases of cochlear nerve deficiency, a relatively common cause of congenital SSD.

Bidirectional remodeling of the central auditory system caused by unilateral auditory deprivation

Unilateral auditory deprivation (UAD) results in cross-modal reorganization of the auditory cortex (AC), which can impair auditory and cognitive functions and diminish the recovery effect of cochlear implantation. Moreover, the subcortical areas provide extensive ascending projections to the AC. To date, a thorough systematic study of subcortical auditory neural plasticity has not been undertaken. Therefore, this review aims to summarize the current evidence on the bidirectional remodeling of the central auditory system caused by UAD, particularly the changes in subcortical neural plasticity. Lateral changes occur in the cochlear nucleus, lateral superior olive, medial nucleus of the trapezoid body, inferior colliculus, and AC of individuals with UAD. Moreover, asymmetric neural activity becomes less prominent in the higher auditory nuclei, which may be due to cross-projection regulation of the bilateral pathway. As a result, subcortical auditory neural plasticity caused by UAD may contribute to the outcomes of cochlear implantation in patients with single-sided deafness (SSD), and the development of intervention strategies for patients with SSD is crucial. Considering that previous studies have focused predominantly on the neural plasticity of the AC, we believe that bidirectional remodeling of subcortical areas after UAD is also crucial for investigating the mechanisms of interventions.

Speech, language, functional communication, psychosocial outcomes and QOL in school-age children with congenital unilateral hearing loss

Introduction

Children with early-identified unilateral hearing loss (UHL) might be at risk for delays in early speech and language, functional communication, psychosocial skills, and quality of life (QOL). However, a paucity of relevant research prohibits strong conclusions. This study aimed to provide new evidence relevant to this issue.

Methods

Participants were 34 children, ages 9;0 to 12;7 (years;months), who were identified with UHL via newborn hearing screening. Nineteen children had been fitted with hearing devices, whereas 15 had not. Assessments included measures of speech perception and intelligibility; language and cognition; functional communication; psychosocial abilities; and QOL.

Results and discussion

As a group, the children scored significantly below the normative mean and more than one standard deviation below the typical range on speech perception in spatially separated noise, and significantly below the normative mean on written passage comprehension. Outcomes in other aspects appear typical. There was however considerable within participant variation in the children's degree of hearing loss over time, raising the possibility that this pattern of results might change as children get older. The current study also revealed that participants with higher levels of nonverbal ability demonstrated better general language skills and better ability to comprehend written passages. By contrast, neither perception of speech in collocated noise nor fitting with a hearing device accounted for unique variance in outcome measures. Future research should, however, evaluate the fitting of hearing devices using random assignment of participants to groups in order to avoid any confounding influence of degree of hearing loss or children's past/current level of progress.

Two-Year Outcomes of Cochlear Implant Use for Children With Unilateral Hearing Loss: Benefits and Comparison to Children With Normal Hearing

OBJECTIVES

Children with severe-to-profound unilateral hearing loss, including cases of single-sided deafness (SSD), lack access to binaural cues that support spatial hearing, such as recognizing speech in complex multisource environments and sound source localization. Listening in a monaural condition negatively impacts communication, learning, and quality of life for children with SSD. Cochlear implant (CI) use may restore binaural hearing abilities and improve outcomes as compared to alternative treatments or no treatment. This study investigated performance over 24 months of CI use in young children with SSD as compared to the better hearing ear alone and to children with bilateral normal hearing (NH).

DESIGN

Eighteen children with SSD who received a CI between the ages of 3.5 and 6.5 years as part of a prospective clinical trial completed assessments of word recognition in quiet, masked sentence recognition, and sound source localization at regular intervals out to 24-month postactivation. Eighteen peers with bilateral NH, matched by age at the group level, completed the same test battery. Performance at 24-month postactivation for the SSD group was compared to the performance of the NH group.

RESULTS

Children with SSD have significantly poorer speech recognition in quiet, masked sentence recognition, and localization both with and without the use of the CI than their peers with NH. The SSD group experienced significant benefits with the CI+NH versus the NH ear alone on measures of isolated word recognition, masked sentence recognition, and localization. These benefits were realized within the first 3 months of use and were maintained through the 24-month postactivation interval.

CONCLUSIONS

Young children with SSD who use a CI experience significant isolated word recognition and bilateral spatial hearing benefits, although their performance remains poorer than their peers with NH.

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.

Benefits of bone conduction hearing aid in children with unilateral aural atresia

Objective

To assess the hearing benefit with a unilateral bone conduction hearing aid in a cohort of children with unilateral aural atresia.

Methods

Cross-sectional case series pilot study involving 7 children (median age: 10 years, range 6-11). All patients underwent pure-tone, speech, aided sound field and aided speech audiometry and Simplified Italian Matrix Test (SIMT) with and without bone conduction hearing aid (Baha 5^® Cochlear^TM). Cognitive abilities were assessed in 5 patients.

Results

The mean air conduction pure-tone average (PTA) of the atretic ear was 63.2 ± 6.9 dB, while the bone conduction PTA was 12.6 ± 4.7 dB. Speech discrimination score of the atretic ear was 88.6 ± 3.8 dB, while with the hearing aid it was 52.8 ± 1.9 dB. In the contralateral ear, there was no significant air-bone gap, and PTAs for air and bone conduction thresholds were within normal range (PTA ≤ 25 dB). The mean aided air conduction hearing threshold was 26.2 ± 7.97. Mean speech recognition threshold without the hearing aid was -5.1 ± 1.9 dB, and -6.0 ± 1.7 dB with the hearing aid tested with the SIMT. The mean score of the cognitive test was 46.8 ± 42.8.

Conclusions

These preliminary findings should encourage clinicians in proposing a unilateral bone conduction hearing aid in children with unilateral atresia.

Impact of unilateral hearing loss in early development

PURPOSE OF REVIEW

The purpose of this review is to provide an update on current literature as it relates to the impact of unilateral hearing loss for the pediatric population.

RECENT FINDINGS

Current studies further corroborate past research findings which reveal the potential consequences of unilateral hearing loss on spatial hearing, language, and neurocognitive functioning. Deficits among children with unilateral hearing loss may parallel those seen in children with bilateral hearing loss, further challenging historic views that hearing in one ear in childhood is sufficient for normal development. The potential deficiencies seen in children with unilateral hearing loss can be subtler than those seen with bilateral hearing loss, but may nonetheless also impact school performance, patient fatigue, parental stress, and quality of life. Early interventions within a sensitive period of development of the central auditory system may circumvent potential barriers in cognitive, academic, and psychosocial development.

SUMMARY

This review synthesizes the latest research on the impact of unilateral hearing loss in childhood and the role for possible interventions. The summarized information may serve to support the development of new guidelines for the evaluation and treatment of children with unilateral hearing loss.

Hearing attention and quality of listening in children with unilateral hearing loss with and without hearing aid

Objective

Methods

Results

Conclusions

Newborn Hearing Screening and Intervention in Children with Unilateral Hearing Impairment: Clinical Practices in Three Nordic Countries

Studies have limitedly considered children with early-identified unilateral hearing impairment (UHI), and clinical practices regarding screening, diagnostics and habilitation in this group are rarely documented. In this study, routines for newborns with UHI from screening to diagnostics and habilitation were explored in Norway, Sweden and Finland. An online survey was sent to hospitals responsible for the hearing diagnostics of children requesting information about their practices regarding congenital UHI. Responses covered 95% of the children born in the three included countries. The results revealed large variations in ways of organising healthcare and in clinical decisions regarding hearing screening, diagnostics and habilitation of children with congenital UHI. Finally, implications for policy making and research are also discussed.

Decision-making following identification of an infant's unilateral hearing loss: Parent and professional perspectives

BACKGROUND

Parents of infants identified with unilateral hearing loss (UHL) make decisions about managing their infant's hearing loss based on limited evidence and before knowing whether their infant will require additional support.

OBJECTIVES

The decision-making processes of parents and clinicians regarding the management of UHL following newborn hearing screening were examined.

PROCEDURE

Two convenience samples were recruited: 15 parents of children with permanent UHL aged under 4 years, and 14 clinicians. Applied thematic analysis of the semi-structured interviews elicited insight into the complexities surrounding decision-making from a parent and clinician perspective.

RESULTS

Three main themes captured the decision-making process: motivation for decision-making, limited evidence creates uncertainty, and available evidence builds certainty. The diverse experiences and opinions of parents and clinicians highlight the complexity of decision-making when there are contested opinions and no clear best management option.

CONCLUSIONS

The choices parents make about the management of their child's UHL can have lifelong implications for their child. Many questions need answering before parents can effectively evaluate the short- and long-term consequences of their options and whether the advantages outweigh the disadvantages in the long-term. This uncertainty is challenging for professionals and parents and risks cognitive biases influencing clinical and parental decision-making.

Benefits of Cartilage Conduction Hearing Aids for Speech Perception in Unilateral Aural Atresia

Severe conductive hearing loss due to unilateral aural atresia leads to auditory and developmental disorders, such as difficulty in hearing in challenging situations. Bone conduction devices compensate for the disability but unfortunately have several disadvantages. The aim of this study was to evaluate the benefits of cartilage conduction (CC) hearing aids for speech perception in unilateral aural atresia. Eleven patients with unilateral aural atresia were included. Each participant used a CC hearing aid in the atretic ear. Speech recognition scores in the binaural hearing condition were obtained at low speech levels to evaluate the contribution of aided atretic ears to speech perception. Speech recognition scores were also obtained with and without presentation of noise. These assessments were compared between the unaided and aided atretic ear conditions. Speech recognition scores at low speech levels were significantly improved under the aided atretic ear condition (p < 0.05). A CC hearing aid in the unilateral atretic ear did not significantly improve the speech recognition score in a symmetrical noise presentation condition. The binaural hearing benefits of CC hearing aids in unilateral aural atresia were predominantly considered a diotic summation. Other benefits of binaural hearing remain to be investigated.

Early Prelingual Auditory Development of Infants and Toddlers With Unilateral Hearing Loss

OBJECTIVE

To assess the influence of congenital and permanent unilateral hearing loss (UHL) on early prelingual auditory development (EPLAD) of infants and toddlers.

STUDY DESIGN

A cross-sectional and case-controlled design.

SETTING

Tertiary referral center.

PATIENTS

Sixty-five young children (median with interquartile ranges: 4.4 [3.3, 7.7] mo) with UHL, 70 children (6.0 [3.8, 9.0] mo) with bilateral normal hearing (BNH) and 32 children (5.8 [3.9, 12.1] mo) with bilateral mild hearing loss (BMHL) were enrolled and grouped. Children with UHL were further grouped according to the severity of impairment and the ear that was impaired.

INTERVENTIONS

Children involved were assessed by the 9-item Infant-toddler Meaningful Auditory Integration Scale (ITMAIS).

MAIN OUTCOME MEASURES

1) EPLAD assessed by ITMAIS, 2) functions of sound detection, sound discrimination and identification and preverbal vocalization assessed by dividing ITMAIS into three sections, 3) trajectories of EPLAD estimated by ITMAIS.

RESULTS

Compared with BNH, children with UHL lagged behind in the function of sound discrimination and identification, preverbal vocalization, as well as trajectory of EPLAD. Children with severe to profound UHL exhibited more severe EPLAD handicaps than children with mild to moderate losses. The auditory functions and EPLAD trajectory of children with UHL were similar to those with BMHL.

CONCLUSIONS

Children with congenital and permanent UHL demonstrate delays in EPLAD, which are evident soon after birth before initial development of speech and language. The ITMAIS is an appropriate tool to identify these delays both in children with unilateral and bilateral hearing impairment.

Correlation of cochlear aperture stenosis with cochlear nerve deficiency in congenital unilateral hearing loss and prognostic relevance for cochlear implantation

The use of neonatal hearing screening has enabled the identification of congenital unilateral sensorineural hearing loss (USNHL) immediately after birth, and today there are several intervention options available to minimize potential adverse effects of this disease, including cochlear implantation. This study aims to analyze the characteristics of the inner ear of a homogeneous group of congenital non-syndromic USNHL to highlight the features of the inner ear, which can help in clinical, surgical, and rehabilitative decision-making. A retrospective chart review was carried out at a tertiary referral center. Systematic diagnostic work-up and rigorous inclusion-exclusion criteria were applied to 126 children with unilateral hearing impairment, leading to a selection of 39 strictly congenital and non-syndromic USNHL cases, undergoing computed tomography (CT) and magnetic resonance (MR) imaging studies. The frequency and type of malformations of the inner ear in USNHL and unaffected contralateral ears were assessed, with an in-depth analysis of the deficiency of the cochlear nerve (CND), the internal auditory canal (IAC) and the cochlear aperture (CA). Inner ear anomalies were found in 18 out of 39 (46%) of the USNHL patients. In 1 subject, the anomalies were bilateral, and the CND resulted in the predominant identified defect (78% of our abnormal case series), frequently associated with CA stenosis. Only 3 out of 14 children with CND presented stenosis of the IAC. CND and CA stenosis (and to a much lesser extent IAC stenosis) are a frequent association within congenital and non-syndromic USNHL that could represent a distinct pathological entity affecting otherwise healthy infants. In the context of a diagnostic work-up, the evaluation with CT and MRI measurements should take place in a shared decision-making setting with thorough counseling. Both imaging techniques have proven useful in differentiating the cases that will most likely benefit from the cochlear implant, from those with potentially poor implant performance.

Single-sided deafness and unilateral auditory deprivation in children: current challenge of improving sound localization ability

Interaural time difference and interaural level difference signals are insufficient in patients with single-sided deafness (SSD). This insufficiency leads to an absence of sound localization abilities and a decrease in speech intelligibility in noisy environments. SSD occurring in children further affects their language learning and cognitive abilities and their academic performance because they lack spatial abilities and binaural hearing. The early stages of central auditory system development are critical for auditory function development and morphological refinement. SSD occurring in the critical period can cause significant lateralization in the bilateral auditory pathway. This may increase the risk that affected individuals cannot re-establish binaural benefits after rehabilitation of hearing loss in the post-sensitive period. For otorhinolaryngologists, there is the concern that children with congenital SSD cannot benefit from cochlear implantation. Only a few studies have investigated auditory rehabilitation in children with congenital SSD with cochlear implantation and their results were inconsistent. The present review aims to clarify the main problems and challenges of clinical rehabilitation of congenital SSD, particularly focusing on the effect of CI on sound localization ability in children with congenital SSD.

Therapeutic challenges and clinical characteristics of single-sided deafness in children

INTRODUCTION

The clinical implications of single-sided deafness (SSD) in children has historically been underappreciated by patients and providers alike, despite a large body of literature on the wide-ranging neurocognitive, language, scholastic, and functional impairments that occur. Conventional amplification options are marked by variable results and frequent loss of follow-up.

METHODS

Retrospective case series for pediatric SSD from 2008 to 2018.

RESULTS

88 children with congenital SSD were identified. Seventeen (N = 17/88, 23.9%) passed their newborn hearing screen. Median age at first otolaryngology evaluation was 0.65 years (range 0.1-16.9 years). Most common etiologies included cochlear nerve deficiency (N = 39, CND, 44.3%), unknown (N = 30, 35.2%), inner ear malformation (N = 7, 8.0%), and congenital cytomegalovirus (N = 6, 6.8%). 32.5% of patients elected for continued observation only, followed by bone conduction hearing aid (27.7%), contralateral routing of sound aid (20.5%), conventional hearing aid (13.3%), or cochlear implant (6%). Lack of follow-up at ≥1 year was common (39.8%). Of those with device use data (N = 39), 84.7% reported either discontinued or <6 h of daily use.

CONCLUSIONS

Despite early diagnosis and evaluation, the pediatric SSD cohort is characterized by high rates of loss of follow-up and amplification discontinuation. Cochlear nerve deficiency is commonly seen in congenital SSD. Early specialist referral is critical for habilitation evaluation. Patients and caregivers should be educated on the significant implications of unilateral hearing loss.