Benefits of Low-Frequency Attenuation of Baha® in Single-Sided Sensorineural Deafness

Efficacy of the Bonebridge BCI602 for Adult Patients with Single-sided Deafness: A Prospective Multicenter Study

OBJECTIVE

To investigate the safety and efficacy of a novel active transcutaneous bone conduction implant (BCI) device for patients with single-sided deafness (SSD).

STUDY DESIGN

Prospective cohort study.

SETTING

Tertiary referral hospitals.

METHODS

This prospective multicenter study was conducted at 15 institutions nationwide. Thirty adult (aged ≥19 years) SSD patients were recruited. They underwent implantation of an active transcutaneous BCI device (Bonebridge BCI602). Objective outcomes included aided pure-tone thresholds, aided speech discrimination scores (SDSs), and the Hearing in Noise Test (HINT) and sound localization test results. The Bern Benefit in Single-Sided Deafness (BBSS) questionnaire, the Abbreviated Profile of Hearing Aid Benefit (APHAB) questionnaire, and the Tinnitus Handicap Inventory (THI) were used to measure subjective benefits.

RESULTS

The mean aided pure-tone threshold was 34.2 (11.3), mean (SD), dB HL at 500 to 4000 Hz. The mean total BBSS score was 27.5 (13.8). All APHAB questionnaire domain scores showed significant improvements: ease of communication, 33.6 (23.2) versus 22.6 (21.3), P = .025; reverberation, 44.8 (16.6) versus 32.8 (15.9), P = .002; background noise, 55.5 (23.6) versus 35.2 (18.1), P < .001; and aversiveness, 36.7 (22.8) versus 25.8 (21.4), P = .028. Moreover, the THI scores were significantly reduced [47.4 (30.1) versus 31.1 (27.0), P = .003]. Congenital SSD was a significant factor of subjective benefit (-11.643; 95% confidence interval: -21.946 to -1.340).

CONCLUSION

The BCI602 active transcutaneous BCI device can provide functional hearing gain without any adverse effects and is a feasible option for acquired SSD patients with long-term deafness.

Multicenter Results With an Active Transcutaneous Bone Conduction Implant in Patients With Single-sided Deafness

OBJECTIVE

To evaluate the audiological and subjective benefit from hearing rehabilitation with an active bone conduction implant in subjects with single-sided sensorineural deafness (SSD).

STUDY DESIGN

Prospective, multicenter, single-subject repeated measures.

SETTING

Tertiary referral center, five clinics in Germany and Switzerland.

PATIENTS

Seventeen subjects aged 18 years and older with severe to profound unilateral sensorineural hearing loss and contralateral normal hearing were followed up for 24 months.

INTERVENTION

Active bone conduction implant.

MAIN OUTCOME MEASURES

Speech understanding in noise was assessed in three situations: with signal from front, deaf, or normal hearing side (with noise from front in all set-ups). Subjective benefit was evaluated using the Speech, Spatial, and Qualities of Hearing (SSQ-B) and Bern Benefit in Single-Sided Deafness (BBSS) questionnaire.

RESULTS

When the signal was coming from the deaf side the mean improvement of the speech reception threshold in noise ranged from 1.5 up to 2.2 dB with the device and was statistically and clinically significant at all tested timepoints. No significant difference between the aided and unaided situation was found when signal and noise were coming from the front. With the signal from the normal hearing side no clinically significant difference, that is, greater than 1 dB between the aided and unaided situation was found. The SSQ-B and BBSS questionnaire showed an overall improvement with no significant difference between time points.

CONCLUSIONS

The study demonstrates long-term efficacy and benefit of the device in adults with SSD. Patients reported substantial and persistent subjective benefit from the active bone conduction implant.

Evaluation of a New Bone Conduction Device for the Rehabilitation of Single-Sided Deafness: Effects on Speech Understanding in Noise

INTRODUCTION

A new external, adhesive, no-pressure bone-conduction device provides rehabilitation for conductive hearing loss and single-sided deafness (SSD). The purpose of the study is to evaluate speech recognition performance with the bone-conduction contralateral routing of signal (aBC-CROS) and compare it to an air-conduction CROS (AC-CROS) used by subjects for at least 1 year.

METHODS

Ten SSD patients underwent speech understanding in noise tests with their AC-CROS, the aBC-CROS, and unaided. The 1st test session took place the day the aBC-CROS was fitted, with the second session after 2 weeks of aBC-CROS use. Two configurations were used: speech presented on the deaf side and noise on the normal side and the reverse.

RESULTS

The speech recognition threshold (SRT) improved with both devices when speech was presented to the deaf side. Nine patients showed significant improvement (p < 0.016) with the AC-CROS (mean: 2.8 dB) and the aBC-CROS (mean: 3.0 dB). Mean difference of improvement was significant between unaided and aBC-CROS (p = 0.001) or AC-CROS (p = 0.006). The SRT deteriorated by an average of 2.3 dB with the AC-CROS with noise presented on the deaf side, with significance found for six patients (p < 0.016). The aBC-CROS did not affect performance in this configuration (mean improvement: 0.3 dB) and only one patient had a significant SRT degradation (p < 0.016). Mean difference of improvement was significant between the AC-CROS and aBC-CROS (p = 0.021) or unaided (p = 0.05).

DISCUSSION

The aBC-CROS is a good alternative to the existing CROS devices for SSD rehabilitation, as it offers the same benefit with none of the drawbacks when noise is on the patient's deaf side.

Rehabilitation for unilateral deafness - Narrative review comparing a novel bone conduction solution with existing options

Patients with single sided deafness (SSD) struggle with sound localization and speech in noise. Existing treatment options include contralateral routing of signal (CROS) systems, percutaneous bone conduction hearing devices (BCHDs), passive transcutaneous BCHDs, active BCHDs, and cochlear implants. Implanted devices provide benefits in speech in noise compared to CROS devices. Percutaneous BCHDs transmit sound efficiently but have aesthetic drawbacks and skin complications. Scalp attenuation impacts passive transcutaneous BCHD performance. Active BCHDs overcome these issues and provide benefits for speech in noise. Cochlear implantation is the only existing option that restores binaural input but introduces electrical rather than acoustic stimuli to the deaf ear. Active BCHDs have been designed to maintain efficient sound transmission and avoid chronic skin irritation and cosmetic concerns that may occur with percutaneous BCHDs. Cochlear implantation may be a superior option for recently deafened SSD patients, though this requires further study. The duration of deafness, patient age and comorbidities, and a shared decision-making model among patients, surgeons, and audiologists should be considered in device selection. The aim of this manuscript is to review available devices, discuss surgical considerations for implantable devices, review available published results for speech in noise and sound quality with each device, and provide an overview to guide shared decision making for patients and providers. This review consolidates available literature and reviews experience with a newer active transcutaneous active BCHD available for use in the SSD population.

Transcranial attenuation in bone conduction stimulation

In bone conduction (BC) stimulation, the sound travels from the site of stimulation to the ipsilateral and contralateral cochlea. A frequency dependent reduction in BC hearing sensitivity occurs when sound travels to the contralateral cochlea as compared to the ipsilateral cochlea. This effect is called transcranial attenuation (TA) that is affected by several factors. Experimental and clinical studies describe TA and the factors that have an effect on it. These factors include stimulus location, coupling of a bone conduction hearing aid to the underlying tissue, and the properties of the head (such as geometry of the head, thickness of the skin and/or skull, changes due to aging, iatrogenic changes such as bone removal in mastoidectomy, and occlusion of the external auditory canal). While TA has an effect of the patient's benefit of BCHAs, there seems to be a discrepancy between experimental measurements and clinical relevance. The effects are small and the interindividual variability, in comparison, is rather large. However, a better understanding of these factors may help to determine the site of attachment, the coupling mode, and possibly the fitting of a BCHA, depending on its indication.

Systematic review of outcome domains and instruments used in designs of clinical trials for interventions that seek to restore bilateral and binaural hearing in adults with unilateral severe to profound sensorineural hearing loss ('single-sided deafness')

BACKGROUND

This systematic review aimed to identify, compare and contrast outcome domains and outcome instruments reported in studies investigating interventions that seek to restore bilateral (two-sided) and/or binaural (both ears) hearing in adults with single-sided deafness (SSD). Findings can inform the development of evidence-based guidance to facilitate design decisions for confirmatory trials.

METHODS

Records were identified by searching MEDLINE, EMBASE, PubMed, CINAHL, ClinicalTrials.gov, ISRCTN, CENTRAL, WHO ICTRP and the NIHR UK clinical trials gateway. The search included records published from 1946 to March 2020. Included studies were those as follows: (a) recruiting adults aged 18 years or older diagnosed with SSD of average threshold severity worse than 70 dB HL in the worse-hearing ear and normal (or near-normal) hearing in the better-hearing ear, (b) evaluating interventions to restore bilateral and/or binaural hearing and (c) enrolling those adults in a controlled trial, before-and-after study or cross-over study. Studies that fell just short of the participant eligibility criteria were included in a separate sensitivity analysis.

RESULTS

Ninety-six studies were included (72 full inclusion, 24 sensitivity analysis). For fully included studies, 37 exclusively evaluated interventions to re-establish bilateral hearing and 29 exclusively evaluated interventions to restore binaural hearing. Overall, 520 outcome domains were identified (350 primary and 170 secondary). Speech-related outcome domains were the most common (74% of studies), followed by spatial-related domains (60% of studies). A total of 344 unique outcome instruments were reported. Speech-related outcome domains were measured by 73 different instruments and spatial-related domains by 43 different instruments. There was considerable variability in duration of follow-up, ranging from acute (baseline) testing to 10 years after the intervention. The sensitivity analysis identified no additional outcome domains.

CONCLUSIONS

This review identified large variability in the reporting of outcome domains and instruments in studies evaluating the therapeutic benefits and harms of SSD interventions. Reports frequently omitted information on what domains the study intended to assess, and on what instruments were used to measure which domains.

TRIAL REGISTRATION

The systematic review protocol is registered on PROSPERO (International Prospective Register of Systematic Reviews): Registration Number CRD42018084274 . Registered on 13 March 2018, last revised on 7th of May 2019.

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.

Core Rehabilitation Outcome Set for Single Sided Deafness (CROSSSD) study: protocol for an international consensus on outcome measures for single sided deafness interventions using a modified Delphi survey

BACKGROUND

Single-sided deafness (SSD) describes the presence of a unilateral severe to profound sensorineural hearing loss. SSD disrupts spatial hearing and understanding speech in background noise. It has functional, psychological and social consequences. Potential options for rehabilitation include hearing aids and auditory implants. Benefits and harms of these interventions are documented inconsistently in the literature, using a variety of outcomes ranging from tests of speech perception to quality of life questionnaires. It is therefore difficult to compare interventions when rehabilitating SSD. The Core Rehabilitation Outcome Set for Single Sided Deafness (CROSSSD) study is an international initiative that aims to develop a minimum set of core outcomes for use in future trials of SSD interventions.

METHODS/DESIGN

The CROSSSD study adopts an international two-round online modified Delphi survey followed by a stakeholder consensus meeting to identify a patient-centred core outcome domain set for SSD based on what is considered critical and important for assessing whether an intervention for SSD has worked.

DISCUSSION

The resulting core outcome domain set will act as a minimum standard for reporting in future clinical trials and could have further applications in guiding the use of outcome measures in clinical practice. Standardisation will facilitate comparison of research findings.

Bone Conduction Stimulation Applied Directly to the Otic Capsule: Intraoperative Assessment in Humans

OBJECTIVES

Aim was to investigate the innovative method of direct acoustic bone conduction (BC) stimulation applied directly to the otic capsule and measured intraoperatively by promontory displacement in living humans. The objective was to find the best stimulation site that provides the greatest transmission of vibratory energy in a living human and compare it with the results previously obtained in cadavers.

DESIGN

The measurements were performed in 4 adult patients referred to our department for vestibular schwannoma removal via translabyrinthine approach. The measurements were performed in the operated site. The cadaver data were obtained in our previous study and here they are reanalyzed for comparison. Promontory displacement was measured using a commercial scanning laser Doppler vibrometer. The laser Doppler vibrometer points located on the promontory were used to analyze the promontory displacement amplitude. Cochlear stimulation was induced with BC stimulation through an implant positioned at three sites. The first site was on the skull surface at the squamous part of the temporal bone (BC No. 1), the second at the bone forming the ampulla of the lateral semicircular canal (BC No. 2), and the third between the superior and lateral semicircular canals (BC No. 3). BC No. 2 and BC No. 3 were located directly on the otic capsule. Four frequencies in total were tested (500, 1000, 2000, and 4000 Hz), one at a time.

RESULTS

In patients, the detailed analysis of promontory displacement amplitudes revealed the BC No. 1 magnitude to be the smallest and significantly different from BC No. 2 and No. 3 at all measured frequencies. Transmission of vibratory energy at BC No. 2 and BC No. 3 was the most effective and similar with a small and insignificant difference at 500, 1000, and 4000 Hz, and a significant difference at 2000 Hz. The results observed in cadavers were similar to those in living humans. However, a few differences were observed when comparing patients and cadavers. Small and insignificant differences were found for BC No. 1. Almost the same results were obtained for BC No. 2 and BC No. 3 in cadavers as in living humans, with only BC No. 3 measurements results at 500 Hz at the limit of statistical significance, with no other significant differences observed.

CONCLUSIONS

The results of this study indicate that the promontory vibration amplitude increases when the BC stimulation location approaches the cochlea. BC No. 1 stimulation located on the squama caused overall smaller displacement than both BC No. 2 and No. 3 screwed to the ampulla of the lateral semicircular canal and to the midpoint between the semicircular canals, respectively. In our opinion, the results of BC stimulation applied directly to the otic capsule present a potential new stimulation site that could be introduced in the field of BC hearing rehabilitation.

Round Window Membrane Motion Induced by Bone Conduction Stimulation at Different Excitation Sites: Methodology of Measurement and Data Analysis in Cadaver Study

OBJECTIVES

The aim of this study was to investigate the following: (1) the vibration pattern of the round window (RW) membrane in human cadavers during air (AC) and bone conduction (BC) stimulation at different excitation sites; (2) the effect of the stimulation on the fluid volume displacement (VD) at the RW and compare the VD between BC and AC stimulation procedures; (3) the effectiveness of cochlear stimulation by the bone implant at different excitation sites.

DESIGN

The RW membrane vibrations were measured by using a commercial scanning laser Doppler vibrometer. The RW vibration amplitude was recorded at 69 measurement points evenly distributed in the measurement field covering the entire surface of the RW membrane and a part of the surrounding bony surface. RW vibration was induced first with AC and then with BC stimulation through an implant positioned at two sites. The first site was on the skull surface at the squamous part of the temporal bone (implant no. 1), a place typical for bone-anchored hearing aids. The second site was close to the cochlea at the bone forming the ampulla of the lateral semicircular canal (implant no. 2). The displacement amplitude (dP) of the point P on the promontory was determined and used to calculate the relative displacement (drRW) of points on the RW membrane, drRW = dRW - dP. VD parameter was used to analyze the effectiveness of cochlear stimulation by the bone implant screwed at different excitation sites.

RESULTS

RW membrane displacement amplitude of the central part of the RW was similar for AC and BC implant no. 1 stimulation, and for BC implant no. 2 much larger for frequency range >1 kHz. BC implant no. 2 causes a larger displacement amplitude of peripheral parts of the RW and the promontory than AC and BC implant no. 1, and BC implant no. 1 causes larger than AC stimulation. The effect of BC stimulation exceeds that of AC with identical intensity, and that the closer BC stimulation to the otic capsule, the more effective this stimulation is. A significant decrease in the value of VD at the RW is observed for frequencies >2 kHz for both AC and BC stimulation with BC at both locations of the titanium implant placement. For frequencies >1 kHz, BC implant no. 2 leads to a significantly larger VD at the RW compared to BC implant no. 1. Thus, the closer to the otic capsule the BC stimulation is located, the more effective it is.

CONCLUSIONS

Experimental conditions allow for an effective acoustic stimulation of the inner ear by an implant screwed to the osseous otic capsule. The mechanical effect of BC stimulation with a titanium implant placed in the bone of the ampulla of the lateral semicircular canal significantly exceeds the effect of an identical stimulation with an implant placed in the temporal squama at a conventional site for an implant anchored in the bone. The developed research method requires the implementation on a larger number of temporal bones in order to obtain data concerning interindividual variability of the observed mechanical phenomena.

Hearing Instruments for Unilateral Severe-to-Profound Sensorineural Hearing Loss in Adults: A Systematic Review and Meta-Analysis

Objectives:

A systematic review of the literature and meta-analysis was conducted to assess the nature and quality of the evidence for the use of hearing instruments in adults with a unilateral severe to profound sensorineural hearing loss.

Design:

The PubMed, EMBASE, MEDLINE, Cochrane, CINAHL, and DARE databases were searched with no restrictions on language. The search included articles from the start of each database until February 11, 2015. Studies were included that (a) assessed the impact of any form of hearing instrument, including devices that reroute signals between the ears or restore aspects of hearing to a deaf ear, in adults with a sensorineural severe to profound loss in one ear and normal or near-normal hearing in the other ear; (b) compared different devices or compared a device with placebo or the unaided condition; (c) measured outcomes in terms of speech perception, spatial listening, or quality of life; (d) were prospective controlled or observational studies. Studies that met prospectively defined criteria were subjected to random effects meta-analyses.

Results:

Twenty-seven studies reported in 30 articles were included. The evidence was graded as low-to-moderate quality having been obtained primarily from observational before-after comparisons. The meta-analysis identified statistically significant benefits to speech perception in noise for devices that rerouted the speech signals of interest from the worse ear to the better ear using either air or bone conduction (mean benefit, 2.5 dB). However, these devices also degraded speech understanding significantly and to a similar extent (mean deficit, 3.1 dB) when noise was rerouted to the better ear. Data on the effects of cochlear implantation on speech perception could not be pooled as the prospectively defined criteria for meta-analysis were not met. Inconsistency in the assessment of outcomes relating to sound localization also precluded the synthesis of evidence across studies. Evidence for the relative efficacy of different devices was sparse but a statistically significant advantage was observed for rerouting speech signals using abutment-mounted bone conduction devices when compared with outcomes after preoperative trials of air conduction devices when speech and noise were colocated (mean benefit, 1.5 dB). Patients reported significant improvements in hearing-related quality of life with both rerouting devices and following cochlear implantation. Only two studies measured health-related quality of life and findings were inconclusive.

Conclusions:

Devices that reroute sounds from an ear with a severe to profound hearing loss to an ear with minimal hearing loss may improve speech perception in noise when signals of interest are located toward the impaired ear. However, the same device may also degrade speech perception as all signals are rerouted indiscriminately, including noise. Although the restoration of functional hearing in both ears through cochlear implantation could be expected to provide benefits to speech perception, the inability to synthesize evidence across existing studies means that such a conclusion cannot yet be made. For the same reason, it remains unclear whether cochlear implantation can improve the ability to localize sounds despite restoring bilateral input. Prospective controlled studies that measure outcomes consistently and control for selection and observation biases are required to improve the quality of the evidence for the provision of hearing instruments to patients with unilateral deafness and to support any future recommendations for the clinical management of these patients.

Adults with a unilateral severe-to-profound sensorineural hearing loss report difficulties with listening in many everyday situations. Current hearing instruments attempt to alleviate these difficulties either by rerouting sounds from the impaired ear to the non-impaired ear or by restoring hearing in the impaired ear. A systematic review and meta-analysis evaluated the evidence for their use. The evidence was of low-to-moderate quality. Meta-analyses found benefits to speech perception in noise and reductions in listening difficulty. Controlled trials are needed to provide higher-quality evidence for hearing instrument use in unilateral deafness and to support recommendations for the clinical management of these patients.

Supplemental Digital Content is available in the text.

Efficacy of Bone-Anchored Hearing Aids in Single-Sided Deafness: A Systematic Review

OBJECTIVES

Bone-anchored hearing aids (BAHAs) have been known to partially restore some of the functions lost in subjects with single-sided deafness (SSD). Our aims in this systemic review were to analyze the present capabilities of BAHAs in the context of SSD, and to evaluate the efficacy of BAHAs in improving speech recognition in noisy conditions, sound localization, and subjective outcomes.

DESIGN

A systematic search was undertaken until August 2015 by two independent reviewers, with disagreements resolved by consensus. Among 286 references, we analyzed 14 studies that used both subjective and objective indicators to assess the capabilities of a total of 296 patients in the unaided and aided situations.

RESULTS

Although there was "no benefit" of BAHA implantation for sound localization, BAHAs certainly improved subjects' speech discrimination in noisy circumstances. In the six studies that dealt with sound localization, no significant difference was found after the implantation. Twelve studies showed the benefits of BAHAs for speech discrimination in noise. Regarding subjective outcomes of using the prosthesis in patients with SSD (abbreviated profile of hearing aid benefit [APHAB] and the Glasgow hearing aid benefit profile [GHABP], etc.), we noticed an improvement in the quality of life.

CONCLUSIONS

This systematic review has indicated that BAHAs may successfully rehabilitate patients with SSD by alleviating the hearing handicap to a certain degree, which could improve patients' quality of life. This report has presented additional evidence of effective auditory rehabilitation for SSD and will be helpful to clinicians counseling patients regarding treatment options for SSD.

Baha implant as a hearing solution for single-sided deafness after retrosigmoid approach for the vestibular schwannoma: surgical results

Skull base tumors and, in particular, vestibular schwannoma (VS) are among the etiological reasons for single-sided deafness (SSD). Patients with SSD have problems in understanding speech in a noisy environment and cannot localize the direction of sounds. Baha is one of the most frequently used systems for SSD compensation. Out of 38 patients with SSD after retrosigmoid removal of VS who underwent testing with Baha softband, 16 were satisfied and were indicated for Baha implantation. Two surgical approaches have been used-the Nijmegen linear incision technique with subdermal thinning (Group I, implant BI300) and fast surgery technique without subdermal thinning (Group II, implant BIA400). The duration of the surgery, the implant stability measured by Ostell, and skin or soft tissue reactions in long range follow-up were evaluated and compared between Group I and II. There was a difference in duration of surgery, in Group II procedures averaged significantly faster (p > 0.001). In both groups, there was a similar trend of the gradual increase of implant stability. In the Group I and II, there was comparable rate of the skin or soft tissue reactions grade 0, I, II, or III. We have proved Baha to be a suitable possibility for SSD patients after the removal of VS, regardless of the approach. After the retrosigmoid approach to the VS, the key step of Baha implantation must be to reach intact healthy bone to avoid implantation into scar tissue.

Innovation in abutment-free bone-anchored hearing devices in children: Updated results and experience

INTRODUCTION

Bone-anchored hearing devices are an accepted treatment option for hearing restoration in various types of hearing loss. Traditional devices have a percutaneous abutment for attachment of the sound processor that contributes to a high complication rate. Previously, our institution reported on the Sophono (Boulder, CO, USA) abutment-free system that produced similar audiologic results to devices with abutments. Recently, Cochlear Americas (Centennial, CO, USA) released an abutment-free bone-anchored hearing device, the BAHA Attract. In contrast to the Sophono implant, the BAHA Attract utilizes an osseointegrated implant.

OBJECTIVES

This study aims to demonstrate patient benefit abutment-free devices, compare the results of the two abutment-free devices, and examine complication rates.

METHODS

A retrospective chart review was conducted for the first eleven Sophono implanted patients and for the first six patients implanted with the BAHA Attract at our institution. Subsequently, we analyzed patient demographics, audiometric data, clinical course and outcomes.

RESULTS

Average improvement for the BAHA Attract in pure-tone average (PTA) and speech reception threshold (SRT) was 41dB hearing level (dBHL) and 56dBHL, respectively. Considering all frequencies, the BAHA Attract mean improvement was 39dBHL (range 32-45dBHL). The Sophono average improvement in PTA and SRT was 38dBHL and 39dBHL, respectively. The mean improvement with Sophono for all frequencies was 34dBHL (range 24-43dBHL).

CONCLUSION

Significant improvements in both pure-tone averages and speech reception threshold for both devices were achieved. In direct comparison of the two separate devices using the chi-square test, the PTA and SRT data between the two devices do not show a statistically significant difference (p-value 0.68 and 0.56, respectively). The complication rate for these abutment-free devices is lower than that of those featuring the transcutaneous abutment, although more studies are needed to further assess this potential advantage.

Comparison of Performance of Transcranial Contralateral Routing of Signal, Pre-Implanted Trimmer Digital and Digital Bone Anchored Hearing Aid in Adults with Unilateral Hearing Loss

Individuals with unilateral hearing loss of severe-profound degree face listening difficulties while localizing a sound source and while perceiving speech in the presence of noise. The objective was to compare the efficacy of the digitally programmable bone anchored hearing aid (BAHA), trimmer digital BAHA and the transcranial contralateral routing of signal (T-CROS) in improving the listening performance in adults with unilateral hearing loss. Twenty-four adults with unilateral hearing loss was assessed for sound field thresholds, speech perception performance in quiet and noise (direct and indirect conditions) and the subjective quality rating of speech in unaided and aided with either T-CROS or digitally programmable BAHA or trimmer digital BAHA attached to the headband. Results indicated that the participants performed better with both the digitally programmable and the trimmer digital BAHA than the T-CROS in both quiet and noise. However, the digitally programmable BAHA performed better when the speech arrived from the poorer ear side. The current study helps in prioritizing the hearing amplification devices for the trial and also helps in arriving at the appropriate hearing amplification device for the individuals with unilateral hearing loss.

Is complex signal processing for bone conduction hearing aids useful?

OBJECTIVES

To establish whether complex signal processing is beneficial for users of bone anchored hearing aids.

METHODS

Review and analysis of two studies from our own group, each comparing a speech processor with basic digital signal processing (either Baha Divino or Baha Intenso) and a processor with complex digital signal processing (either Baha BP100 or Baha BP110 power). The main differences between basic and complex signal processing are the number of audiologist accessible frequency channels and the availability and complexity of the directional multi-microphone noise reduction and loudness compression systems.

RESULTS

Both studies show a small, statistically non-significant improvement of speech understanding in quiet with the complex digital signal processing. The average improvement for speech in noise is +0.9 dB, if speech and noise are emitted both from the front of the listener. If noise is emitted from the rear and speech from the front of the listener, the advantage of the devices with complex digital signal processing as opposed to those with basic signal processing increases, on average, to +3.2 dB (range +2.3 … +5.1 dB, p ≤ 0.0032).

DISCUSSION

Complex digital signal processing does indeed improve speech understanding, especially in noise coming from the rear. This finding has been supported by another study, which has been published recently by a different research group.

CONCLUSIONS

When compared to basic digital signal processing, complex digital signal processing can increase speech understanding of users of bone anchored hearing aids. The benefit is most significant for speech understanding in noise.

Mitigation of informational masking in individuals with single-sided deafness by integrated bone conduction hearing aids

OBJECTIVES

To confirm an increased susceptibility to informational masking among individuals with single-sided deafness (SSD). To demonstrate a reduction in informational masking when SSD is treated with an integrated bone conduction hearing aid (IBC). To identify the acoustic cues that contribute to IBC-aided masking release. To determine the effects of device experience on the IBC advantage.

DESIGN

Informational masking was evaluated with the coordinate-response measure. Participants performed the task by reporting color and number coordinates that changed randomly within target sentences. The target sentences were presented in free field accompanied by zero to three distracting sentences. Target and distracting sentences were spoken by different talkers and originated from different source locations, creating two sources of information for auditory streaming. Susceptibility to informational masking was inferred from the error rates of unaided SSD patients relative to normal controls. These baseline measures were derived by testing inexperienced IBC users without the device on the day of their initial fitting. The benefits of IBC-aided listening were assessed by measuring the aided performance of users who had at least 3 months' device experience. The acoustic basis of the listening advantage was isolated by correlating response errors with the voice pitch and location of distracting sentences. The effects of learning on cue effectiveness were evaluated by comparing the error rates of experienced and inexperienced users.

RESULTS

Unaided SSD participants (inexperienced users) performed as well as normal controls when tested without distracting sentences but produced significantly higher error rates when tested with distracting sentences. Most errors involved responding with coordinates that were contained in distracting sentences. This increased susceptibility to informational masking was significantly reduced when experienced IBC users were tested with the device. The listening advantage was most strongly correlated with the availability of voice pitch cues, although performance was also influenced by the location of distracting sentences. Directional asymmetries appear to be dictated by location-dependent cues that are derived from the distinctive transmission characteristics of IBC stimulation. Experienced users made better use of these cues than inexperienced users.

CONCLUSIONS

These results suggest that informational masking is a significant source of communication impairment among individuals with SSD. Despite the lateralization of auditory function, unaided SSD subjects experience informational masking when distractors occur in either the deaf or normal spatial hemifield. Restoration of aural sensitivity in the deaf hemifield with an IBC enhances speech intelligibility under complex listening conditions, presumably by providing additional sound-segregation cues that are derived from voice pitch and spatial location. The optimal use of these cues is not immediate, but a significant listening advantage is observed after 3 months of unstructured use.

Bone conduction hearing: device auditory capability to aid in device selection

OBJECTIVE

To obtain identical laboratory measures of 8 (surgical and nonsurgical) bone conduction devices and relate them to clinical function.

STUDY DESIGN

Each device was measured with a single laboratory system and characterized with descriptive statistics.

SETTING

Laboratory.

SUBJECTS AND METHODS

Seven surgical devices (Intenso, BP110, BP100, and Cordelle [Cochlear, Denver, Colorado]; Ponto Pro and Ponto Pro Power [Oticon Medical, Somerset, New Jersey]; and Alpha 2 [Sophono, Inc, Boulder, Colorado]) and 1 nonsurgical dental device (SoundBite; Sonitus Medical, Inc, San Mateo, California) constituted the independent variables. Measured maximum output and gain parameters were the dependent variables.

RESULTS

Maximum output varied across devices in the pure-tone average (PTA; 500-3000 Hz) frequency range (mean, 109.7 dB re 1 µN; range, 98.8-119.2 dB) and in the above-PTA (4000-8000 Hz) frequency range (mean, 102.6 dB re 1 µN; range, 88.99-119.6 dB). Maximum gain varied in the PTA frequency range (mean, 40 dB; range, 29.1-49.1 dB) and was higher in the frequency range above the PTA (mean, 32.0 dB; range, 20.8-46.0 dB).

CONCLUSION

All devices have sufficient maximum output and gain for the PTA frequency range for single-sided deafness (SSD). The devices differed in maximum output and gain for the frequency range above the PTA, a consideration for accommodating presbycusis and optimizing auditory function for SSD. The surgical devices have less maximum output and gain in the above-PTA range than in the PTA range. The nonsurgical dental device had the highest output (up to 30 dB higher) and gain (up to 26 dB higher) in the above-PTA range.

Influence of directionality and maximal power output on speech understanding with bone anchored hearing implants in single sided deafness

Bone-anchored hearing implants (BAHI) are routinely used to alleviate the effects of the acoustic head shadow in single-sided sensorineural deafness (SSD). In this study, the influence of the directional microphone setting and the maximum power output of the BAHI sound processor on speech understanding in noise in a laboratory setting were investigated. Eight adult BAHI users with SSD participated in this pilot study. Speech understanding in noise was measured using a new Slovak speech-in-noise test in two different spatial settings, either with noise coming from the front and noise from the side of the BAHI (S90N0) or vice versa (S0N90). In both spatial settings, speech understanding was measured without a BAHI, with a Baha BP100 in omnidirectional mode, with a BP100 in directional mode, with a BP110 power in omnidirectional and with a BP110 power in directional mode. In spatial setting S90N0, speech understanding in noise with either sound processor and in either directional mode was improved by 2.2-2.8 dB (p = 0.004-0.016). In spatial setting S0N90, speech understanding in noise was reduced by either BAHI, but was significantly better by 1.0-1.8 dB, if the directional microphone system was activated (p = 0.046), when compared to the omnidirectional setting. With the limited number of subjects in this study, no statistically significant differences were found between the two sound processors.

Long-term safety and benefit of a new intraoral device for single-sided deafness

OBJECTIVE

To determine the long-term safety and benefit of a new intraoral bone conduction device (SoundBite Hearing System by Sonitus Medical) for single-sided deafness (SSD).

STUDY DESIGN

A multi-center, controlled, nonrandomized, prospective unblinded study of SSD patients wearing the device over a 6-month period.

SETTINGS

Ambulatory care centers typical of those where SSD patients are diagnosed and treated.

PATIENTS

Adults (N = 22) with acquired, permanent SSD and no current use of any other SSD device.

INTERVENTION

Continual daily wear of the new device for 6 months.

MAIN OUTCOME MEASURES

Comprehensive medical, audiologic, and dental measures; aided thresholds; Abbreviated Profile of Hearing Aid Benefit scores, and an SSD questionnaire.

RESULTS

There were no related adverse events or changes in the medical or audiologic findings at the end of the trial compared with the beginning. There were no significant changes in the mean aided thresholds (p > 0.01) or the mean dental measures (p > 0.05) at 3 or 6 months compared with pretrial measures. The mean Abbreviated Profile of Hearing Aid Benefit benefit scores showed improvement (p < 0.01) for the Background Noise, Reverberation, and Ease of Communication subscales and the Global scale at 3 and 6 months. The results of the SSD questionnaire indicated that the vast majority (>90%) of the subjects reported satisfaction and improvement in a variety of areas after wearing the device long term.

CONCLUSION

The SoundBite system is safe and continues to provide substantial benefit for SSD patients with continual daily use over a 6-month period.