Speech intelligibility with bilateral bone-anchored hearing aids: the Birmingham experience

The Birmingham bone-anchored hearing aid (BAHA) programme, since its inception in 1988, has fitted more than 300 patients with unilateral bone-anchored hearing aids. Recently, some of the patients who benefited extremely well with unilateral aids applied for bilateral amplification. To date, 15 patients have been fitted with bilateral BAHAs. The benefits of bilateral amplification have been compared to unilateral amplification in 11 of these patients who have used their second BAHA for 12 months or longer. Following a subjective analysis in the form of comprehensive questionnaires, objective testing was undertaken to assess specific issues such as 'speech recognition in quiet', 'speech recognition in noise' and a modified 'speech-in-simulated-party-noise' (Plomp) test. 'Speech in quiet' testing revealed a 100 per cent score with both unilateral and bilateral BAHAs. With 'speech in noise' all 11 patients scored marginally better with bilateral aids compared to best unilateral responses. The modified Plomp test demonstrated that bilateral BAHAs provided maximum flexibility when the origin of noise cannot be controlled as in day-to-day situations. In this small case series the results are positive and are comparable to the experience of the Nijmegen BAHA group.     

Pilot study on the effectiveness of the conventional CROS, the transcranial CROS and the BAHA transcranial CROS in adults with unilateral inner ear deafness

The objective of the present pilot study is to evaluate the effectiveness of three conventional contralateral routing of sound (CROS) hearing aids in adults with unilateral inner ear deafness. The study included tertiary referral center. Ten patients with unilateral inner ear deafness and normal hearing in the contralateral ear were selected to evaluate three different methods of amplification: the CROS hearing aid, the completely in the canal hearing aid and the bone-anchored hearing aid CROS (BAHA). Each of the three hearing aids was tried in a random order for a period of 8 weeks. Audiometric performance, including speech-in-noise, directional hearing and subjective benefit were measured after each trial period, using the APHAB, SSQ and single-sided deafness questionnaire. Sound localization performance was essentially at chance level in all four conditions. Mixed results were seen on the other patient outcome measures that alternated in favor of one of the three CROS devices. After the trial, three patients chose to be fitted with the BAHA CROS and one with the conventional CROS. In conclusion, most of the patients experienced some degree of benefit with each of the three hearing aids. Preference for one of the three hearing aids was independent of the order in which they were tried. It would be worthwhile to formulate selection criteria; still, we recommend that all patients with unilateral inner ear deafness should be offered a trial with at least the BAHA CROS.     

Disability,handicap and benefit analysis with the bone-anchored hearing aid: the Glasgow hearing aid benefit and difference profiles

The Birmingham bone-anchored hearing aid programme began in 1988 and by autumn 2000 a total of 351 patients had been fitted with such an aid. The aim of this study was to assess the effectiveness of hearing rehabilitation with the bone-anchored hearing aid. This was a prospective interview-based questionnaire study carried out in the autumn 2000. A total of 84 adult patients were interviewed. Each patient had worn their BAHA for more than one year. The questionnaire used during these interviews was the Glasgow hearing aid benefit profile (GHABP) and the Glasgow hearing aid difference profile (GHADP). This was first derived and validated by Gatehouse in 1999. The use of bone-anchored hearing aids was found to reduce the level of disability and handicap and provided the most patient benefit and satisfaction.     

Audiometric Results of Bilateral Bone-Anchored Hearing Aid Application in Patients With Bilateral Congenital Aural Atresia

The effect of bilateral application of bone-anchored hearing aids (BAHAs) was examined in terms of directional hearing and speech recognition in quiet and in noise in four patients with bilateral congenital atresia who, out of pure necessity, had been using a unilateral bone-conduction hearing aid since early life. This study comprised a prospective clinical evaluation in a single subject design; four patients with bilateral congenital atresia originating from the Nijmegen BAHA series participated. Three patients had Treacher Collins syndrome. All four patients had conductive, most probably, symmetrical, hearing loss. Recently these patients had applied for a second BAHA and were subsequently fitted bilaterally. With two BAHAs, all four patients showed significant improvement in sound localization. Also, speech perception in quiet showed significant improvement with bilateral application, and a significant improvement was found in speech perception in noise in three patients. These results suggest that patients with congenital conductive, symmetrical hearing loss will benefit from bilateral BAHAs.     

The Glasgow benefit inventory in the evaluation of patient satisfaction with the bone-anchored hearing aid: quality of life issues

The Birmingham osseointegration programme began in 1988 and during the following 10 years there were a total of 351 bone-anchored hearing aid (BAHA) implantees. In the summer of 2000, a postal questionnaire study was undertaken to establish the impact of the bone-anchored hearing aid on all aspects of patients' lives. We used the Glasgow benefit inventory (GBI), which is a subjective patient orientated post-interventional questionnaire especially developed to evaluate any otorhinolaryngological surgery and therapy. It is maximally sensitive to any change in health status brought about by a specific event: in this case the provision of a BAHA. A total of 312 bone-anchored hearing aid patients, who had used their aids for a minimum period of six months, were sent GBI questionnaires. Two hundred and twenty-seven questionnaires were returned and utilized in the study. The results revealed that the use of a bone-anchored hearing aid significantly enhanced general well being (patient benefit), improved the patient's state of health (quality of life) and finally was considered a success by patients and their families.     

An intra-individual comparison of the previous conventional hearing aid with the bone-anchored hearing aid: The Nijmegen group questionnaire

By spring 2000, a total of 351 patients were implanted in the Birmingham bone-anchored hearing aid (BAHA) programme. This group consisted of 242 adults and 109 children. The aim of this retrospective questionnaire study was to directly assess patient satisfaction with their current bone-anchored hearing aid in comparison with their previous conventional air and/or bone-conduction hearing aids. The Nijmegen group questionnaire was sent by post to 312 patients who used their BAHA for six months or longer. The questionnaire used was first described by Mylanus et al. (Nijmegen group) in 1998. The total response rate was 72 per cent (227 of 312 patients). The bone-anchored hearing aid was found to be significantly superior to prior conventional hearing aids in all respects.     

Patients’ opinions on bilateral bone anchored hearing aid fitting

Introduction. Patients’ opinions on bilateral bone-anchored hearing air (BAHA) fitting compared to unilateral fitting were evaluated. Patients and methods. A study was carried out of 11 patients who had been using a unilateral BAHA before being fitted bilaterally. All patients showed conductive or mixed hearing loss, with an (almost) symmetrical sensorineural hearing loss component. Four out of the 11 patients had bilateral congenital aural atresia and the rest of the patients had a history of chronic otitis media. All 11 patients filled in two questionnaires. Questionnaire 1 consisted of questions about thepatients’ preference in different listening situations. It was filled in 10 weeks after bilateral BAHA fitting. Questionnaire 2 consisted of questions that compared the previous situation (with only a unilateral BAHA) to the situation with the more recent bilateral BAHA application. This questionnaire was filled in before and 10 weeks after bilateral fitting. Results. Ten out of the 11 patients clearly favoured the bilateral BAHA above unilateral. Conclusion. Eight patients were very satisfied and three patients were satisfied with the second BAHA. These positive results agreed with the previously found positive audiological results.     

Bone-anchored hearing aid: comparison of benefit by patient subgroups

OBJECTIVES/HYPOTHESIS: The osseointegrated bone-anchored hearing aid, using the Branemark system, is well established and has proven benefit. The aim was to study quality of life benefits within patient subgroups using the validated Glasgow Benefit Inventory (GBI). STUDY DESIGN: Retrospective questionnaire study. METHODS: Ninety-four consecutive patients were enrolled into the study. Mean patient age was 49 years, with a female-to-male ratio of 1.1:1. Patient subgroups were discharging mastoid cavities, chronic active otitis media, congenital ear problems, otosclerosis, and acoustic neuroma and other unilateral hearing losses. RESULTS: The response rate was 73%. The score for total benefit of bone-anchored hearing aid fitting for the entire group was +33.3 (95% confidence interval [CI], 25-42). Glasgow Benefit Inventory scores for each subgroup were all greater than +20. The congenital atresia group scored highest with +45 (95% CI, 28-61). Variation in benefit across the subgroups has been demonstrated. Fitting of BAHA following acoustic neuroma surgery was shown to be of benefit with a score of +22.2. General benefits scored highest in all subgroups compared with physical and social benefits. CONCLUSION: The study demonstrated the differences in benefit within patient subgroups. Its results can be used to give patients a predictive value at the time of preoperative counseling. The study identified congenital ear disorders as the group likely to obtain maximal benefit. Notably, for the first time, the study demonstrated the documented benefit of restoring stereo hearing to patients who have acquired unilateral hearing loss following acoustic neuroma surgery using a BAHA.     

Bilateral bone-anchored hearing aids (BAHAs): an audiometric evaluation

OBJECTIVES: Since the technique to implant bone-anchored hearing aids (BAHAs) with the use of osseointegrated implants was developed in 1977, more than 15,000 patients have been fitted with BAHAs worldwide. Although the majority have bilateral hearing loss, they are primarily fitted unilaterally. The main objective of this study was to reveal benefits and drawbacks of bilateral fitting of BAHAs in patients with symmetric or slight asymmetric bone-conduction thresholds. The possible effects were divided into three categories: hearing thresholds, directional hearing, and binaural hearing. STUDY DESIGN: Prospective study of 12 patients with bilateral BAHAs. METHODS: Baseline audiometry, directional hearing, speech reception thresholds in quiet and in noise, and binaural masking level difference were tested when BAHAs were fitted unilaterally and bilaterally. RESULTS: Eleven of the 12 patients used bilateral BAHAs on a daily basis. Tests performed in the study show a significant improvement in sound localization with bilateral BAHAs; the results with unilateral fitting were close to the chance level. Furthermore, with bilateral application, the improvement of the speech reception threshold in quiet was 5.4 dB. An improvement with bilateral fitting was also found for speech reception in noise. CONCLUSIONS: Overall, the results with bilateral fitted BAHAs were better than with unilaterally fitted BAHA; the benefit is not only caused simply by bilateral stimulation but also, to some extent, by binaural hearing. Bilateral BAHAs should be considered for patients with bilateral hearing loss otherwise suitable for BAHAs.     

Bilateral fitting of BAHAs and BAHA fitted in unilateral deaf persons: acoustical aspects

The benefit of a bone-anchored hearing aid (BAHA) to a patient fitted bilaterally; and the benefit of a BAHA to a unilaterally deaf person was estimated by four acoustical measurements: directional sensitivity of a BAHA placed at the skull, vibration transmission in the skull, gain, and estimated transcranial attenuation of bone conducted sound. Provided a patient has a similar bone conduction hearing ability at both cochlea, it was found that a patient should, theoretically, benefit from bilateral fitting of BAHAs in terms of better hearing thresholds from the front, and better overall hearing ability from the surround. The data indicates further, that bilateral fitting facilitates extraction of interaural cues, which should lead to greater ability to determine the direction of a sound source, as well as better hearing in noise. However, due to the cross-hearing of bone conducted sound, the binaural processing for the patient fitted bilaterally with BAHAs is less than for normal binaural air conduction hearing. Finally, the data showed that the benefit of fitting a BAHA in a unilaterally deaf person, depends on that person's transcranial attenuation.     

A bone-anchored hearing aid for patients with pure sensorineural hearing impairment: a pilot study

This pilot study assesses the potential benefits of an optimized bone-anchored hearing aid (BAHA) for patients with a mild to moderate pure sensorineural high frequency hearing impairment. The evaluation was conducted with eight first-time hearing aid users by means of psycho-acoustic sound field measurements and a questionnaire on subjective experience; all of the patients benefited from the BAHA. On average, the eight patients showed improvement in PTA threshold of 3.4 dB and in speech intelligibility in noise of 14%. Seven of the subjects, also fitted with present standard air conduction hearing aids (ACHA) found the ACHA thresholds to be improved more than the BAHA ones. In speech tests, the ACHA was only slightly better; these patients chose between their different hearing aids according to the sound environment. Although the BAHA was preferred for wearing and sound comfort, it cannot be used as the sole aid for patients with pure sensorineural impairment.     

Does the bone-anchored hearing aid have a complementary effect on audiological and subjective outcomes in patients with unilateral conductive hearing loss?

OBJECTIVES: To study the effect of a bone-anchored hearing aid (BAHA) in patients with unilateral conductive hearing loss. STUDY DESIGN: Prospective evaluation on 18 subjects. METHODS: Aided and unaided binaural hearing was assessed in the sound field using a sound localization test and a speech recognition in noise test with spatially separated sound and noise sources. The patients also filled out a disability-specific questionnaire. PATIENTS: 13 out of the 18 subjects had normal hearing on one side and acquired conductive hearing loss in the other ear. The remaining 5 patients had a unilateral air-bone gap and mild symmetrical sensorineural hearing loss. RESULTS: Sound localization with the BAHA improved significantly. Speech recognition in noise with spatially separated speech and noise sources also improved with the BAHA. Fitting a BAHA to patients with unilateral conductive hearing loss had a complementary effect on hearing. Questionnaire results showed that the BAHA was of obvious benefit in daily life. CONCLUSIONS: The BAHA proved to be a beneficial means to optimize binaural hearing in patients with severe (40-60 dB) unilateral conductive hearing loss according to audiometric data and patient outcome measures.     

Evolving applications in the use of bone-anchored hearing aids

The bone-anchored hearing aid (BAHA) is an effective means of intervention, its use being well documented in persons with chronic conductive pathology and congenital aural anomalies. This article describes the standard guidelines (both auditory and extraauditory aspects) for patient selection and expands the criteria to include bilateral BAHA implantation, unilateral conductive hearing loss, and unilateral profound sensorineural hearing loss. The BAHA's development, design features, and patient outcomes are also reviewed. Suggestions are presented for fitting, counseling, and following BAHA users.     

BAHA in children and adolescents with unilateral or bilateral conductive hearing loss: a study of outcome

OBJECTIVES: Bilateral BAHAs in adults with bilateral hearing loss (BHL) have proven to be superior to unilateral fitting, in both audiologically measurements and in overall patient satisfaction. There have been no similar studies in children. Furthermore, a recent meta-analysis of children with unilateral hearing loss (UHL) has shown numerous negative consequences. The objectives of the study were to investigate whether fitting of bilateral BAHAs in children with conductive BHL give additional hearing benefits, to investigate the effects of unilateral hearing aids in children with conductive UHL, and to identify different aspects of auditory problems in children with conductive UHL or BHL. STUDY DESIGN: This was a prospective study involving 22 children with either conductive UHL (unaided or with unilateral hearing aid) or conductive BHL (with unilateral or bilateral BAHAs) and 15 controls. METHODS: Baseline audiometry, tone thresholds in a sound field, speech recognition in noise and sound localization were tested without, and with unilateral and bilateral hearing aids. Two questionnaires, MAIS & MUSS and IOI-HA, were completed. RESULTS: Two problem areas were identified in the children with hearing impairment: in reactions to sounds and in intelligibility of speech. An additional BAHA in the children with BHL resulted in a tendency to have improved hearing in terms of better sound localization and speech recognition in noise. Fitting of unilateral hearing aids in the children with UHL gave some supplementary benefit in terms of better speech recognition in noise but no positive effect on ability to localize sound could be detected. Even so, all children fitted with hearing aids - either unilaterally or bilaterally - reported a positive outcome with their devices in the self-assessment questionnaire. CONCLUSIONS: Children with either UHL or BHL displayed several problems within the hearing domain. Fitting of bilateral BAHAs in children with BHL and of a single-sided hearing aid in children with UHL appears to have some supplementary audiological benefits and also renders high patient satisfaction. In order to investigate the possible supplementary effects of hearing aids, a 3-month trial of BAHA on Softband, either unilaterally or bilaterally, may be of value in children with conductive UHL or BHL, respectively.     

Audiological effect of bone-anchored hearing aid

The bone-anchored hearing aid (BAHA) has proved to be a valuable alternative to conventional air and bone conduction hearing aids for patients suffering from chronic otitis media or bilateral aural atresia. The BAHA gave better sound quality and greater comfort than conventional hearing aids (HAs), but only 1 study has been done in Japan. We implanted BAHAs in 6 hard-of-hearing patients in the last 2 years. One patient suffered skin problems around the abutment and used the BAHA only briefly. Free-field audiometry, the speech discrimination test (SDT), and the speech recognition test (SRT) were conducted in all subjects. They were evaluated either with the HA or BAHA. The SDT and SRT showed better hearing results in quiet for the BAHA than the conventional HA, but there was a minimum difference in SDT and SRT in noise. Subjects assessed the HA and BAHA using questionnaires. Subjects reported that the BAHA offers a number of important advantages, including greater cosmetic acceptability, improved speech intelligibility, and better sound quality.     

Amplification in the rehabilitation of unilateral deafness: speech in noise and directional hearing effects with bone-anchored hearing and contralateral routing of signal amplification.

OBJECTIVE: Vibromechanical stimulation with a semi-implantable bone conductor (Entific BAHA device) overcomes some of the head-shadow effects in unilateral deafness. What specific rehabilitative benefits are observed when the functional ear exhibits normal hearing versus moderate sensorineural hearing loss (SNHL)? DESIGN: The authors conducted a prospective trial of subjects with unilateral deafness in a tertiary care center. PATIENTS: This study comprised adults with unilateral deafness (pure-tone average [PTA] > 90 dB; Sp.D. < 20%) and either normal monaural hearing (n = 18) or moderate SNHL (PTA = 25-50 dB: Sp.D. > 75%) in the contralateral functional ear (n = 5). INTERVENTIONS: Subjects were fit with contralateral routing of signal (CROS) devices for 1 month and tested before (mastoid) implantation, fitting, and testing with a bone-anchored hearing aid (BAHA). OUTCOME MEASURES: Outcome measures were: 1) subjective benefit; 2) source localization tests (Source Azimuth Identification in Noise Test [SAINT]); 3) speech discrimination in quiet and in noise assessed with Hearing In Noise Test (HINT) protocols. RESULTS: There was consistent satisfaction with BAHA amplification and poor acceptance of CROS amplification. General directional hearing decreased with CROS use and was unchanged by BAHA and directional microphone aids. Relative to baseline and CROS, BAHA produced significantly better speech recognition in noise. Twenty-two of 23 subjects followed up in this study continue to use their BAHA device over an average follow-up period of 30.24 months (range, 51-12 months). CONCLUSION: BAHA amplification on the side of a deaf ear yields greater benefit in subjects with monaural hearing than does CROS amplification. Advantages likely related to averting the interference of speech signals delivered to the better ear, as occurs with conventional CROS amplification, while alleviating the negative head-shadow effects of unilateral deafness. The advantages of head-shadow reduction in enhancing speech recognition with noise in the hearing ear outweigh disadvantages inherent in head-shadow reduction that can occur by introducing noise from the deaf side. The level of hearing impairment correlates with incremental benefit provided by the BAHA. Patients with a moderate SNHL in the functioning ear perceived greater increments in benefit, especially in background noise, and demonstrated greater improvements in speech understanding with BAHA amplification.     

Audiometric evaluation of bilaterally fitted bone-anchored hearing aids

Bilateral fittings of bone-anchored hearing aids (BAHA) were evaluated in 25 patients with at least 3 months experience with using two BAHAs. For all patients, air conduction hearing aids were contraindicated due to either recurrent otorrhoea or otitis externa (19 cases) or to congenital aural atresia (six cases). Candidacy for bilateral fitting was primarily based on symmetry of bone conduction thresholds. For all patients, measurements comprised sound localisation, speech recognition in quiet and in noise. In addition, in a subgroup of nine patients, release from masking for pure-tone stimuli in noise with interaural phase differences (binaural masking level difference. BMLD) was measured. The percentage of correct localisation judgments with 500-Hz and 2-kHz noise bursts increased significantly (p<0.01) from 22.2 per cent and 24.3 per cent for unilateral fittings to 41.8 per cent and 45.3 per cent for bilateral fittings, respectively. With unilateral fittings sound localisation judgments appeared to be strongly biased to the ipsilateral BAHA side. whereas with bilateral fittings, judgments were far more symmetrical. The speech reception threshold for sentences in quiet was significantly (p<0.01) better for the bilateral fittings compared to the unilateral fittings: 37.5 dBA versus 41.7 dBA. Speech recognition in noise was measured with the speech signal presented in front of the listener and a 65-dBA masking noise at either +90 degrees or -90 degrees azimuth. For noise presented at the ipsilateral side of the first fitted BAHA, the signal-to-noise ratio was significantly reduced (p<0.01) from -0.7 dB for the unilateral fitting to -4.0 dB for the bilateral fitting. The speech reception threshold in noise was not significantly different (p>0.05) for unilateral and bilateral fittings when the noise was presented at the contralateral side of the first fitted BAHA. The results for the six patients with congenital atresia are comparable with those for the other patients. So, directional hearing and speech recognition in noise improve significantly with a second BAHA. The BMLD measurements showed a significant (p<0.01) release from masking of 6.1, 6.0 and 6.6 dB for 125-Hz, 250-Hz and 500-Hz stimuli, respectively. The BMLD effect of 4.1 dB at 1,000 Hz was not significant at the 5 per cent level. The positive results with the bilateral fittings in quiet can be ascribed to increased stimulus levels due to diotic summation of signals from either side. The results for localisation, speech recognition in noise and BMLD measurements indicate that bilaterally fitted BAHAs do indeed (to some extent) result in binaural hearing.     

Results of the bone-anchored hearing aid in unilateral hearing loss

OBJECTIVES: The advantages of binaural hearing are well established and universally accepted. However, a tendency remains to withhold the benefits of binaural hearing to adults and children with one normal ear. The purpose of this study is to demonstrate the benefit of the bone-anchored hearing aid (BAHA) in a group of patients with unilateral conductive or mixed hearing loss. STUDY DESIGN: This is a prospective study of nine patients (five males and four female patients) with conductive or mixed hearing loss who met the criteria for BAHA except for having normal hearing in the other ear. They had congenital aural atresia or mastoidectomies secondary to chronic ear infections with or without cholesteatoma or had a temporal bone tumor excised METHODS: Patients had evaluations before and after implantation, including audiological testing and responses to a standardized hearing handicap questionnaire. Statistical analyses of the data were made using the Wilcoxon signed rank test and the paired Student t test for repeated measures. RESULTS: All patients had tonal and spondee threshold improvement with BAHA when compared with thresholds before treatment. Speech recognition performance in BAHA-aided conditions was comparable to the patient's best score in unaided condition. Patients reported a significant improvement in their hearing handicap scores with the BAHA. CONCLUSIONS: The use of BAHA has significantly improved the hearing handicap scores in patients with unilateral conductive or mixed hearing loss. The proven safety and efficacy of the device promote its use in unilateral cases that traditionally had been left unaided.     

Bone-anchored hearing aids in unilateral inner ear deafness: an evaluation of audiometric and patient outcome measurements.

OBJECTIVE: To evaluate the benefit of a bone-anchored hearing aid contralateral routing of sound hearing aid (BAHA CROS hearing aid) in 29 patients with unilateral inner ear deafness. STUDY DESIGN: Prospective clinical follow-up study. SETTING: Tertiary referral center. PATIENTS: Thirty patients were recruited. There were 19 patients with a history of acoustic neuroma surgery and 11 patients with unilateral inner ear deafness due to other causes; 1 patient was excluded. The first 21 patients had also participated in a previous evaluation. INTERVENTION: Audiometric measurements were taken before intervention, when fitted with a conventional CROS, and after BAHA implementation. Patients' subjective benefit was quantified with four different hearing aid-specific instruments: the Abbreviated Profile of Hearing Aid Benefit, the Glasgow Hearing Aid Benefit Profile, the International Outcome Inventory for Hearing Aids, and the Single-Sided Deafness questionnaire. MAIN OUTCOME MEASURES: The same instruments were used at a mean long-term follow-up of 1 year after BAHA implantation. RESULTS: Sound localization in an audiologic test setting was no different from chance level. The main effect of the BAHA CROS that was found was the "lift the head shadow" effect in the speech-in-noise measurements. All instruments also showed positive results in favor of the BAHA CROS at long-term follow-up. CONCLUSIONS: The poor sound-localization results in an audiologic test setting illustrated the inability of patients with unilateral inner ear deafness to localize sounds. The speech-in-noise measurements demonstrated the efficacy of the BAHA CROS to lift the head shadow. Patients were still satisfied at 1-year follow-up, according to the four instruments.