Bone-anchored hearing aids for people with bilateral hearing impairment: a systematic review

Assessing Chronic Ear Symptoms in Bone-Conduction Hearing Implant (BCHI) Patients Using the Chronic Otitis Media Benefit Inventory (COMBI) Score

OBJECTIVE

This study aimed to determine improvement in health-related quality of life (HRQoL) using a validated disease-specific patient-reported outcome measure (PROM) questionnaire in patients undergoing bone-conduction hearing implant (BCHI) insertion.

STUDY DESIGN

A mixed retrospective and prospective correlational study.

SETTING

Single tertiary referral center in the United Kingdom.

PATIENTS

All adult patients undergoing their first BCHI over 6 years (April 1, 2017, to March 3, 2023).

MAIN OUTCOME MEASURES

The Chronic Otitis Media Benefit Inventory (COMBI) score (postintervention) and the Glasgow Health Status Inventory (GHSI) (pre-and post-BCHI questionnaire).

RESULTS

Improvements were seen across all COMBI domains. The mean total COMBI score was 46.3 (standard deviation = 5.3). Although expected significant improvements were seen in hearing and social domains, there were also notable gains in ear symptoms and reduced medical intervention post-BCHI. There was a statistically significant improvement in all GHSI scores post-BCHI (median total difference 67.1, p < 0.0001).

CONCLUSIONS

This study reports very favorable outcomes for BCHI patients using two different PROMs: COMBI and GHSI. Although these PROMs complement each other, they also offer different perspectives on the same cohort of patients, with COMBI providing a unique insight into specific ear symptoms. This is the first reported study using this complement of PROMS in BCHI patients and offers further evidence for the wide-reaching improvements BCHI can have for patients.

Bone-Anchored Hearing Aid Effects on Vestibular Function: A Preliminary Report

OBJECTIVE

Cochlear receptors are sensitive to vibratory stimuli. Based on this sensibility, bone-anchored hearing aids have been introduced to correct unilateral or bilateral conductive or mixed hearing loss and unilateral deafness. The vestibular system is also sensitive to the vibratory stimulus and this type of response is used in clinics to test its functionality. Being aware of this double separated sensibility, we wondered whether bone vibration, which activates the acoustic receptors of patients with bone conduction aids, can also influence the functionality of the vestibular system.

METHODS

To this end, we recruited 12 patients with a bone-anchored hearing aid and evaluated their vestibular function with and without an activated vibratory acoustic device.

RESULTS

Our results show that the vibratory stimulus delivered by the bone conduction aid also reaches and stimulates the vestibular receptors; this stimulation is evidenced by the appearance or modification of some nystagmus findings during bedside vestibular testing. Despite this, none of these patients complained of dizziness or vertigo during prosthesis use. Nystagmus that appeared or changed during acoustic vibratory stimulation through the prosthesis was almost all predominantly horizontal, unidirectional with respect to gaze or body position, inhibited by fixation, and most often consistent with vestibular function tests indicating peripheral vestibular damage.

CONCLUSIONS

The findings of sound-evoked nystagmus seem to indicate peripheral rather than central vestibular activation. The occurrence of some predominantly horizontal and high-frequency induced nystagmus seems to attribute the response mainly to the utricle and lateral semicircular canal.

Spatial Release From Masking With Bilateral Bone Conduction Stimulation at Mastoid for Normal Hearing Subjects

This study investigates the effect of spatial release from masking (SRM) in bilateral bone conduction (BC) stimulation at the mastoid. Nine adults with normal hearing were tested to determine SRM based on speech recognition thresholds (SRTs) in simulated spatial configurations ranging from 0 to 180 degrees. These configurations were based on nonindividualized head-related transfer functions. The participants were subjected to sound stimulation through either air conduction (AC) via headphones or BC. The results indicated that both the angular separation between the target and the masker, and the modality of sound stimulation, significantly influenced speech recognition performance. As the angular separation between the target and the masker increased up to 150°, both BC and AC SRTs decreased, indicating improved performance. However, performance slightly deteriorated when the angular separation exceeded 150°. For spatial separations less than 75°, BC stimulation provided greater spatial benefits than AC, although this difference was not statistically significant. For separations greater than 75°, AC stimulation offered significantly more spatial benefits than BC. When speech and noise originated from the same side of the head, the "better ear effect" did not significantly contribute to SRM. However, when speech and noise were located on opposite sides of the head, this effect became dominant in SRM.

Clinical consensus document for fitting non-surgical transcutaneous bone conduction hearing devices to children

This clinical consensus document addresses the assessment, selection, and fitting considerations for non-surgical bone conduction hearing devices (BCHD) for children under the age of 5 years identified as having unilateral or bilateral, permanent conductive or mixed hearing losses. Children with profound unilateral sensorineural hearing losses are not addressed. The document was developed based on evidence review and consensus by The Paediatric Bone Conduction Working Group, which is composed of audiologists from North America who have experience working with BCHDs in children. The document aims to provide clinical direction for an area of paediatric audiology practice that is under development and is therefore lacking in standard protocols or guidelines. This work may serve as a basis for future research and clinical contributions to support prospective paediatric audiology practices.

The Merits of Bilateral Application of Bone-Conduction Devices in Children With Bilateral Conductive Hearing Loss

OBJECTIVES

This study aims to characterize lateralization of sounds and localization of sounds in children with bilateral conductive hearing loss (BCHL) when listening with either one or two percutaneous bone conduction devices (BCDs).

DESIGN

Sound lateralization was measured with the minimum audible angle test in which children were asked to indicate from which of the two visible speakers the sound originated. Sound localization was measured with a test in which stimuli were presented from speakers that were not visible to the children. In the sound localization test, 150 ms broadband noise bursts were presented, and sound level was roved over a 20-dB range. Because speakers were not visible the localization response was not affected by any visual cue. The sound localization test provides a clear distinction between lateralization and localization of sounds. Ten children with congenital BCHL and one child with acquired BCHL participated.

RESULTS

Both lateralization and sound localization were better with bilateral BCDs compared with the unilaterally aided conditions. In the bilateral BCD condition, lateralization was close to normal in nearly all the children. The localization test demonstrated lateralization rather than sound localization behavior when listening with bilateral BCDs. Furthermore, in the unilateral aided condition, stimuli presented at different sound levels were mainly perceived at the same location.

CONCLUSIONS

This study demonstrates that, in contrast to listening with two BCDs, children demonstrated difficulties in lateralization of sounds and in sound localization when listening with just one BCD (i.e., one BCD turned off). Because both lateralization and sound localization behavior were tested, it could be demonstrated that these children are more able to lateralize than localize sounds when listening with bilateral BCDs. The present study provides insight in (sub-optimal) sound localization capabilities of children with congenital BCHL in the unilateral-aided and bilateral-aided condition. Despite the sub-optimal results on sound localization, this study underlines the merits of bilateral application of BCDs in such children.

Comparative effects of unilateral and bilateral bone conduction hearing devices on functional hearing and sound localization abilities in patients with bilateral microtia-atresia

Background: Various amplification options are available for patients with congenital bilateral conductive hearing loss. Unilateral bone conduction hearing device (BCHD) is widely used for these patients, whereas benefits of bilateral BCHDs in certain subgroups of patients require further exploration.Objectives: To evaluate functional and directional hearing in patients with unilateral Bonebridge (MEDEL) and contralateral ADHEAR (MEDEL) devices.Materials and methods: This study included 32 patients (20 males, 12 females), of mean age 11.8 years (range 7-27 years). Hearing thresholds, speech perception and sound localization were tested three months after activation of the Bonebridge under three conditions: unaided, unilateral BHCD (Bonebridge) and bilateral BHCDs (Bonebridge plus contralateral ADHEAR). Patient acceptance of these devices in daily life was evaluated by questionnaire.Results: Compared with unaided, the mean hearing thresholds (0.5, 1, 2, and 4 kHz) and speech perception with unilateral BCHD and bilateral BCHDs were improved significantly (p < .05 each). Markers of directional hearing ability, including percentages of accurate responses, bias angles and RMS errors, were significantly better with bilateral BCHDs than unilateral BHCD (p < .05 each). Questionnaire revealed high patient satisfaction with both unilateral and bilateral devices.Conclusions: Functional hearing and sound localization abilities were better with bilateral BCHDs than unilateral BCHD.

Efficacy of Auditory Implants for Patients With Conductive and Mixed Hearing Loss Depends on Implant Center

INTRODUCTION

Although from a technological point of view, progress is impressive, most implantable hearing devices for conductive or mixed hearing loss have a limited capacity. These devices all bypass the impaired middle ear; therefore, the desired amplification (gain) should be based on the cochlear hearing loss (component) only. The aim of the study is to review the literature with regard to accomplished gain with current implantable devices.

METHOD

Thirty-one articles could be included. Aided thresholds were compared with prescribed values, based on cochlear hearing loss (bone-conduction thresholds), according to the well-validated NAL rule.

RESULTS

For the majority of the studies, NAL targets were not met. Variation in accomplished gain between implant teams was unacceptably large, largely independent of the type of device that was used. NAL targets were best met at 2 kHz, with worse results at the other frequencies.

CONCLUSION

Large variations in reported results were found, which primarily depended on implant center. Based on the analyses, a pragmatic fitting procedure is proposed which should minimize the differences between implant centres.

The effect of an active transcutaneous bone conduction device on spatial release from masking

Objective: The aim was to quantify the effect of the experimental active transcutaneous Bone Conduction Implant (BCI) on spatial release from masking (SRM) in subjects with bilateral or unilateral conductive and mixed hearing loss.Design: Measurements were performed in a sound booth with five loudspeakers at 0°, +/-30° and +/-150° azimuth. Target speech was presented frontally, and interfering speech from either the front (co-located) or surrounding (separated) loudspeakers. SRM was calculated as the difference between the separated and the co-located speech recognition threshold (SRT).Study Sample: Twelve patients (aged 22-76 years) unilaterally implanted with the BCI were included.Results: A positive SRM, reflecting a benefit of spatially separating interferers from target speech, existed for all subjects in unaided condition, and for nine subjects (75%) in aided condition. Aided SRM was lower compared to unaided in nine of the subjects. There was no difference in SRM between patients with bilateral and unilateral hearing loss. In aided situation, SRT improved only for patients with bilateral hearing loss.Conclusions: The BCI fitted unilaterally in patients with bilateral or unilateral conductive/mixed hearing loss seems to reduce SRM. However, data indicates that SRT is improved or maintained for patients with bilateral and unilateral hearing loss, respectively.

Minimal Reporting Standards for Active Middle Ear Hearing Implants

There is currently no standardized method for reporting audiological, surgical and subjective outcome measures in clinical trials with active middle ear implants (AMEIs). It is often difficult to compare studies due to data incompatibility and to perform meta-analyses across different centres is almost impossible. A committee of ENT and audiological experts from Germany, Austria and Switzerland decided to address this issue by developing new minimal standards for reporting the outcomes of AMEI clinical trials. The consensus presented here aims to provide a recommendation to enable better inter-study comparability.

Estimating the benefit of a second bone anchored hearing implant in unilaterally implanted users with a testband

Conclusion Using a second bone anchored hearing implant (BAHI) mounted on a testband in unilaterally implanted BAHI users to test its potential advantage pre-operatively under-estimates the advantage of two BAHIs placed on two implants. Objectives To investigate how well speech understanding with a second BAHI mounted on a testband approaches the benefit of bilaterally implanted BAHIs. Method Prospective study with 16 BAHI users. Eight were implanted unilaterally (group A) and eight were implanted bilaterally (group B). Aided speech understanding was measured. Speech was presented from the front and noise came either from the left, right, or from the front in two conditions for group A (with one BAHI, and with two BAHIs, where the second device was mounted on a testband) and in three conditions for group B (same two conditions as group A, and in addition with both BAHIs mounted on implants). Results Speech understanding in noise improved with the additional device for noise from the side of the first BAHI (+0.7 to +2.1 dB) and decreased for noise from the other side (-1.8 dB to -3.9 dB). Improvements were highest (+2.1 dB, p = 0.016) and disadvantages were smallest (-1.8 dB, p = 0.047) with both BAHIs mounted on implants. Testbands yielded smaller advantages and higher disadvantages of the additional BAHI (average difference = -0.9 dB).

Binaural hearing ability with mastoid applied bilateral bone conduction stimulation in normal hearing subjects

The ability to use binaural cues when stimulation was by bilaterally applied bone conduction (BC) transducers was investigated in 20 normal hearing participants. The results with BC stimulation were compared with normal air conduction (AC) stimulation through earphones. The binaural hearing ability was tested by spatial release from masking, binaural intelligibility level difference (BILD), binaural masking level difference (BMLD) using chirp stimulation, and test of the precedence effect. In all tests, the participants revealed a benefit of bilateral BC stimulation indicating use of binaural cues. In the speech based tests, the binaural benefit for BC stimulation was approximately half that with AC stimulation. For the BC BMLD test with chirp stimulation, there were indications of superposition of the ipsilateral and contralateral pathways at the cochlear level affecting the results. The precedence effect test indicated significantly worse results for BC stimulation than for AC stimulation with low-frequency stimulation while they were close for high-frequency stimulation; broad-band stimulation gave results that were slightly worse than the high-frequency results.

The myc road to hearing restoration

Current treatments for hearing loss, the most common neurosensory disorder, do not restore perfect hearing. Regeneration of lost organ of Corti hair cells through forced cell cycle re-entry of supporting cells or through manipulation of stem cells, both avenues towards a permanent cure, require a more complete understanding of normal inner ear development, specifically the balance of proliferation and differentiation required to form and to maintain hair cells. Direct successful alterations to the cell cycle result in cell death whereas regulation of upstream genes is insufficient to permanently alter cell cycle dynamics. The Myc gene family is uniquely situated to synergize upstream pathways into downstream cell cycle control. There are three Mycs that are embedded within the Myc/Max/Mad network to regulate proliferation. The function of the two ear expressed Mycs, N-Myc and L-Myc were unknown less than two years ago and their therapeutic potentials remain speculative. In this review, we discuss the roles the Mycs play in the body and what led us to choose them to be our candidate gene for inner ear therapies. We will summarize the recently published work describing the early and late effects of N-Myc and L-Myc on hair cell formation and maintenance. Lastly, we detail the translational significance of our findings and what future work must be performed to make the ultimate hearing aid: the regeneration of the organ of Corti.