Comparisons of Sound Processors Based on Osseointegrated Implants in Patients With Conductive or Mixed Hearing Loss

A Multimodal Investigation of Listening Effort in Single-Sided Deafness

PURPOSE

For patients with single-sided deafness (SSD), choosing between bone conduction devices (BCDs) and contralateral routing of signal hearing aids (CROS) is challenging due to mixed evidence on their benefits. The lack of clear guidelines complicates clinical decision making. This study explores whether realistic spatial listening measures can reveal a clinically valid benefit and if the optimal choice varies among patients. By assessing listening effort through objective and subjective measures, this research evaluates the efficacy of BCD and CROS, seeking to provide evidence-based recommendation anchored in the effectiveness of these devices in real-world scenarios.

METHOD

Thirteen participants with SSD performed the Hearing-in-Noise Test while using a BCD, CROS hearing aids, and no hearing device (unaided). Subjective listening effort was assessed using the National Aeronautics and Space Administration Task Load Index (NASA-TLX) questionnaire after each testing block. An objective measurement of listening effort was obtained by measuring the peak pupil dilation (PPD) during the task using eye tracking glasses.

RESULTS

No significant difference of either PPD or NASA-TLX scores was observed between the three device conditions (BCD, CROS, and unaided). However, a trend is noted toward reduced PPD in the BCD and CROS conditions. The lack of significance in pupillometry results does not stem from technical issues, as the study's findings confirm its effectiveness in measuring task difficulty, and validate its use for assessing listening effort.

CONCLUSIONS

Although the results from the present study cannot significantly differentiate the hearing devices, we observe a trend that points toward reduced listening effort when using hearing devices. Future investigations should aim to optimize metrics of listening effort, perhaps making them clinically useful on an individual level.

Long-Term, Multicenter Results With the First Transcutaneous Bone Conduction Implant

OBJECTIVE

Investigation of long-term safety and performance of an active, transcutaneous bone conduction implant in adults and children up to 36 months post-implantation.

STUDY DESIGN

Prospective, single-subject repeated-measures design.

SETTING

Otolaryngology departments of eight German and Austrian hospitals.∗†‡§||¶#∗∗†† Affiliations listed above that did not participate in the study.‡‡§§||||¶¶.

PATIENTS

Fifty seven German-speaking patients (49 adults and eight children) suffering from conductive or mixed hearing loss, with an upper bone conduction threshold limit of 45 dB HL at frequencies between 500 and 3000 Hz.

INTERVENTION

Implantation of the Bonebridge transcutaneous bone conduction hearing implant (tBCI).

MAIN OUTCOME MEASURES

Patients' audiometric pure tone averages (PTA4) (0.5, 1, 2, 4 kHz) thresholds (air conduction, bone conduction, and sound field) and speech perception (word recognition scores [WRS] and speech reception thresholds [SRT50%]) were tested preoperatively and up to 36 months postoperatively. Patients were also monitored for adverse events and administered quality-of-life questionnaires.

RESULTS

Speech perception (WRS: pre-op: 17.60%, initial activation [IA]: 74.23%, 3M: 83.65%, 12M: 83.46%, 24M: 84.23%, 36M: 84.42%; SRT50%: pre-op: 65.56 dB SPL, IA: 47.67 dB SPL, 3M: 42.61 dB SPL, 12M: 41.11 dB SPL, 24M: 41.74 dB SPL, 36M: 42.43 dB SPL) and sound field thresholds (pre-op: 57.66 dB HL, IA: 33.82 dB HL, 3M: 29.86 dB HL, 12M: 28.40 dB HL, 24M: 28.22 dB HL, 36M: 28.52 dB HL) improved significantly at all aided postoperative visits. Air and bone conduction thresholds showed no significant changes, confirming preservation of patients' residual unaided hearing. All adverse events were resolved by the end of the study.

CONCLUSIONS

Safety and performance of the tBCI was demonstrated in children and adults 36 months postoperatively.

Psychosocial outcome measures for conductive and mixed hearing loss treatment: An overview of the relevant literature

OBJECTIVE

To identify the psychosocial assessments utilized with individuals with conductive and/or mixed hearing loss as part of a broader effort by the Auditory Rehabilitation Outcomes Network (AURONET) group to develop a core set of patient-centred outcome measures.

DESIGN

A review of articles published between 2006 and 2016 was completed. Included studies had more than three adult participants, were available in English, and reported a psychosocial outcome from any treatment of mixed and/or conductive hearing loss.

STUDY SAMPLE

Sixty-six articles from seven databases.

RESULTS

Sixty-six articles met our inclusion/exclusion criteria. Within this set, 15 unique psychosocial or patient-reported outcome measures (PROs) were identified, with the Abbreviated Profile of Hearing Aid Benefit (APHAB) and Glasgow Benefit Inventory (GBI) being the most frequently dispensed. Five of the fifteen were only administered in one study. In-house questionnaires (IHQs) were reported in 19 articles.

CONCLUSIONS

Only 66 (22%) of the 300 articles with outcomes contained a PRO. Some of the mostly frequently employed PROs (e.g., APHAB) were judged to include only social items and no psychological items. Lack of PRO standardization and the use of IHQs make psychosocial comparisons across treatments in this population difficult for patients, clinicians and stakeholders.

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.

A Multinational Cost-Consequence Analysis of a Bone Conduction Hearing Implant System-A Randomized Trial of a Conventional vs. a Less Invasive Treatment With New Abutment Technology

Background: It is hypothesized that, for patients with hearing loss, surgically placing an implant/abutment combination whilst leaving the subcutaneous tissues intact will improve cosmetic and clinical results, increase quality of life (QoL) for the patient, and reduce medical costs. Here, incremental costs and consequences associated with soft tissue preservation surgery with a hydroxyapatite (HA)-coated abutment (test) were compared with the conventional approach, soft tissue reduction surgery with an all-titanium abutment (control). Methods: A cost-consequence analysis was performed based on data gathered over a period of 3 years in an open randomized (1:1) controlled trial (RCT) running in four European countries (The Netherlands, Spain, France, and Sweden). Subjects with conductive or mixed hearing loss or single-sided sensorineural deafness were included. Results: During the first year, in the Netherlands (NL), France (FR), and Spain (ES) a net cost saving was achieved in favor of the test intervention because of a lower cost associated with surgery time and adverse event treatments [NL €86 (CI -50.33; 219.20), FR €134 (CI -3.63; 261.30), ES €178 (CI 34.12; 97.48)]. In Sweden (SE), the HA-coated abutment was more expensive than the conventional abutment, which neutralized the cost savings and led to a negative cost (SE €-29 CI -160.27; 97.48) of the new treatment modality. After 3 years, the mean cost saving reduced to €17 (CI -191.80; 213.30) in the Netherlands, in Spain to €84.50 (CI -117.90; 289.50), and in France to €80 (CI -99.40; 248.50). The mean additional cost in Sweden increased to €-116 (CI -326.90; 68.10). The consequences in terms of the subjective audiological benefit and Health-related quality of life (HRQoL) were comparable between treatments. A trend was identified for favorable results in the test group for some consequences and statistical significance is achieved for the cosmetic outcome as assessed by the clinician. Conclusions: From this multinational cost-consequence analysis it can be discerned that health care systems can achieve a cost saving during the first year that regresses after 3 years, by implementing soft tissue preservation surgery with a HA-coated abutment in comparison to the conventional treatment. The cosmetic results are better. (sponsored by Cochlear Bone Anchored Solutions AB; Clinical and health economic evaluation with a new Baha® abutment design combined with a minimally invasive surgical technique, ClinicalTrials.gov NCT01796236).

Retrospective Analysis of Hearing-Impaired Adult Patients Treated With an Active Transcutaneous Bone Conduction Implant

OBJECTIVE

To determine the therapeutic success and safety of an active transcutaneous bone conduction implant (tBCI) in adult patients with conductive or mixed hearing loss.

STUDY DESIGN

Retrospective case review.

SETTING

Five university hospitals in Frankfurt, Hannover, Dresden, Würzburg, and Vienna.

PATIENTS

Data were analyzed from 61 patients (31 women, 30 men) with a mean age of 50 years (min. 26, max. 80). Forty patients had mixed, and 21 conductive hearing loss. Typical etiologies were history of otitis media (n = 20) and cholesteatoma (n = 17).

INTERVENTIONS

Implantation of the active tBCI.

MAIN OUTCOME MEASURES

Data were analyzed for the following time points: up to 6 months postoperatively ("short-term"), 6 to 37 months postoperatively ("long-term"), and the last available measurement per patient ("most recent"). Pure-tone audiometry (air and bone conduction, AC and BC) and sound field thresholds with warble tones (WT), word recognition scores with Freiburger monosyllables (WRS), as well as speech reception thresholds (SRT) using the Oldenburg sentence test (OLSA) in quiet (SRT) and in noise (signal-to-noise ratio, SNR) were collected.

RESULTS

No significant changes in air- and bone-conduction thresholds were observed after implantation. A mean WRS improvement of 54% using the active tBCI was shown at the short-term assessment, i.e., a mean score of 79% compared with 25% in the unaided condition. Results remained stable, with a mean score of 75% at the long-term assessment. SRT in noise improved by 3.6 dB SNR in the implanted ear at the short-term assessment. Overall six adverse events and four serious adverse events were reported, resulting in a rate of 9.84 and 6.56%, respectively.

CONCLUSION

The tBCI clearly improves speech intelligibility in patients with conductive or mixed hearing loss, showing stable results up to 1 year post-implantation.

[Cochlear implant treatment of patients with single-sided deafness or asymmetric hearing loss. German version]

BACKGROUND

The rehabilitation of patients with single-sided deafness (SSD) or asymmetric hearing loss can be achieved with conventional (bilateral) contralateral routing of signals ((Bi)CROS) hearing aids ((Bi)CROS-HA, (Bi)CROS), bone-anchored hearing systems (BAHS) or cochlear implants (CI). To date, only small case series have been published on treatment outcomes in SSD patients after CI surgery and there are only a few comparative studies evaluating rehabilitation outcomes.

OBJECTIVE

The aim of this study was to provide evidence of successful treatment of SSD and asymmetric hearing loss with a CI compared to the untreated monaural hearing condition and the BAHS and (Bi)CROS treatment options in a large number of patients.

MATERIALS AND METHODS

In a single-centre study, 45 patients with SSD and 40 patients with asymmetric hearing loss were treated with a CI after careful evaluation for CI candidacy. Monaural speech comprehension in noise and localisation ability were examined with (Bi)CROS-HA and BAHS devices (on a test rod) both preoperatively and at 12 months after CI switch-on. At the same intervals, subjective evaluation of hearing ability was conducted using the Speech, Spatial and Qualities of Hearing Scale (SSQ).

RESULTS

This report presents the first evidence of successful binaural rehabilitation with CI in a relatively large patient cohort and the advantages over (Bi)CROS and BAHS in smaller subgroups, thus confirming the indication for CI treatment. Moreover, patients with long-term acquired deafness (>10 years) show a benefit from the CI comparable to that observed in patients with shorter-term deafness.

Long term benefit of bone anchored hearing systems in single sided deafness

CONCLUSION

Bone Anchored Hearing Systems (BAHS) can be expected to still be used by ∼85% of patients with single sided deafness (SSD) 5 years after implantation, and by ∼50% after 10 years.

OBJECTIVES

To investigate the long-term use of BAHS and the reasons to stop.

METHOD

This was a retrospective chart review of all 33 German speaking adults with SSD who had been implanted with a BAHS at one center and of whom the implant status and use of the BAHS were known.

RESULTS

Ranging from 2.6-12.3 years after BAHS implantation, 21 implantees (63.6%) were still using their device (average use = 7.9 years). Seven (21.2%) had stopped using their BAHS because of insufficient benefit (audiologic reasons). The subjective assessment of the benefit of the BAHS differs significantly from the users. Five former users (15.2%) became non-users for reasons unrelated to their hearing performance, namely infections, implant loss, difficulties with the handling, or aesthetic reasons.

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).

The bone conduction implant: Clinical results of the first six patients

OBJECTIVE

To investigate audiological and quality of life outcomes for a new active transcutaneous device, called the bone conduction implant (BCI), where the transducer is implanted under intact skin.

DESIGN

A clinical study with sound field audiometry and questionnaires at six-month follow-up was conducted with a bone-anchored hearing aid on a softband as reference device.

STUDY SAMPLE

Six patients (age 18-67 years) with mild-to-moderate conductive or mixed hearing loss.

RESULTS

The surgical procedure was found uneventful with no adverse events. The first hypothesis that BCI had a statistically significant improvement over the unaided condition was proven by a pure-tone-average improvement of 31.0 dB, a speech recognition threshold improvement in quiet (27.0 dB), and a speech recognition score improvement in noise (51.2 %). At speech levels, the signal-to-noise ratio threshold for BCI was - 5.5 dB. All BCI results were better than, or similar to the reference device results, and the APHAB and GBI questionnaires scores showed statistically significant improvements versus the unaided situation, supporting the second and third hypotheses.

CONCLUSIONS

The BCI provides significant hearing rehabilitation for patients with mild-to-moderate conductive or mixed hearing impairments, and can be easily and safely implanted under intact skin.

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.

Speech understanding with a new implant technology: a comparative study with a new nonskin penetrating Baha system

OBJECTIVE

To compare hearing and speech understanding between a new, nonskin penetrating Baha system (Baha Attract) to the current Baha system using a skin-penetrating abutment.

METHODS

Hearing and speech understanding were measured in 16 experienced Baha users. The transmission path via the abutment was compared to a simulated Baha Attract transmission path by attaching the implantable magnet to the abutment and then by adding a sample of artificial skin and the external parts of the Baha Attract system. Four different measurements were performed: bone conduction thresholds directly through the sound processor (BC Direct), aided sound field thresholds, aided speech understanding in quiet, and aided speech understanding in noise.

RESULTS

The simulated Baha Attract transmission path introduced an attenuation starting from approximately 5 dB at 1000 Hz, increasing to 20-25 dB above 6000 Hz. However, aided sound field threshold shows smaller differences and aided speech understanding in quiet and in noise does not differ significantly between the two transmission paths.

CONCLUSION

The Baha Attract system transmission path introduces predominately high frequency attenuation. This attenuation can be partially compensated by adequate fitting of the speech processor. No significant decrease in speech understanding in either quiet or in noise was found.

Digital processing technology for bone-anchored hearing aids: randomised comparison of two devices in hearing aid users with mixed or conductive hearing loss

Objective:

This study compared the performance of two new bone-anchored hearing aids with older bone-anchored hearing aids that were not fully digital.

Methods:

Fourteen experienced bone-anchored hearing aid users participated in this cross-over study. Performance of their existing bone-anchored hearing aid was assessed using speech-in-noise testing and questionnaires. Participants were then fitted with either a Ponto Pro or a BP100 device. After four weeks of use with each new device, the same assessments were repeated.

Results:

Speech-in-noise testing for the 50 per cent signal-to-noise ratio (the ratio at which 50 per cent of responses were correct) showed no significant differences between the Ponto Pro and the BP100 devices (p = 0.1) However, both devices showed significant improvement compared with the participants' previous bone-anchored hearing aid devices (p < 0.001). There were no significant differences between the two new devices in the questionnaire data.

Conclusion:

Both fully digital bone-anchored hearing aids demonstrated superior speech processing compared with the previous generation of devices. There were no substantial differences between the two digital devices in either objective or subjective tests.

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.

PORP vs. TORP: a meta-analysis

After the surgical procedure of ossicular chain reconstruction, the effectiveness and/or stability of partial ossicular replacement prosthesis (PORP) or total ossicular replacement prosthesis (TORP) were systematically compared and evaluated using meta-analysis. A total of 40 eligible investigations with 4,311 subjects were included in our study. There was a significant difference in the effectiveness of the reconstruction of the ossicular chain between PORP and TORP; the data showed a combined risk ratio (RR) of 1.28 (95 % CI 1.17-1.41, p < 0.00001), but no notable difference was obtained in staged procedures subgroup and cholesteatoma subgroup, with a combined RR of 1.13 (95 % CI 0.60-2.11, p = 0.70) in staged procedures subgroup and RR of 2.60 (95 % CI 0.20-36.21, p = 0.59 in cholesteatoma subgroup). There was a statistically significant difference in the stability of the prostheses in long-term follow-up, with a combined RR of 0.37 (95 % CI 0.16-0.85, p = 0.02), but no significant difference was observed in the total sample, with a combined RR of 0.64 (95 % CI 0.40-1.03, p = 0.06). Our overall results suggest that the effectiveness of PORP was higher than TORP, except within staged procedures subgroup and cholesteatoma subgroup. In addition, the stability of PORP was significantly superior to TORP in long-term follow-ups, but no significant effect was detected in the general study.

Hearing performance benefits of a programmable power baha® sound processor with a directional microphone for patients with a mixed hearing loss

Objectives

New signal processing technologies have recently become available for Baha® sound processors. These technologies have led to an increase in power and to the implementation of directional microphones. For any new technology, it is important to evaluate the degree of benefit under different listening situations.

Methods

Twenty wearers of the Baha osseointegrated hearing system participated in the investigation. The control sound processor was the Baha Intenso and the test sound processor was the Cochlear™ Baha® BP110power. Performance was evaluated in terms of free-field audibility with narrow band noise stimuli. Speech recognition of monosyllabic phonetically balanced (PB) words in quiet was performed at three intensity settings (50, 65, and 80 dB sound pressure level [SPL]) with materials presented at 0 degrees azimuth. Speech recognition of sentences in noise using the Hearing in Noise Test (HINT) in an adaptive framework was performed with speech from 0 degrees and noise held constant at 65 dB SPL from 180 degrees. Testing was performed in both the omni and directional microphone settings. Loudness growth was assessed in randomly presented 10 dB steps between 30 and 90 dB SPL to narrow band noise stimuli at 500 Hz and 3,000 Hz.

Results

The test sound processor had significantly improved high frequency audibility (3,000-8,000 Hz). Speech recognition of PB words in quiet at three different intensity levels (50, 65, and 80 dB SPL) indicated a significant difference in terms of level (P<0.0001) but not for sound processor type (P>0.05). Speech recognition of sentences in noise demonstrated a 2.5 dB signal-to-noise ratio (SNR) improvement in performance for the test sound processor. The directional microphone provided an additional 2.3 dB SNR improvement in speech recognition (P<0.0001). Loudness growth functions demonstrated similar performance, indicating that both sound processors had sufficient headroom and amplification for the required hearing loss.

Conclusion

The test sound processor demonstrated significant improvements in the most challenging listening situation (speech recognition in noise). The implementation of a directional microphone demonstrated a further potential improvement in hearing performance. Both the control and test sound processors demonstrated good performance in terms of audibility, word recognition in quiet and loudness growth.