A.F.M. Snik

Consensus statements on the BAHA system: where do we stand at present?

After more than 25 years of clinical experience, the BAHA (bone-anchored hearing aid) system is a well-established treatment for hearing-impaired patients with conductive or mixed hearing loss. Owing to its success, the use of the BAHA system has spread and the indications for application have gradually become broader. New indications, as well as clinical applications, were discussed during scientific roundtable meetings in 2004 by experts in the field, and the outcomes of these discussions are presented in the form of statements. The issues that were discussed concerned BAHA surgery, the fitting range of the BAHA system, the BAHA system compared to conventional devices, bilateral application, the BAHA system in children, the BAHA system in patients with single-sided deafness, and, finally, the BAHA system in patients with unilateral conductive hearing loss.

Bone-anchored hearing aid in unilateral inner ear deafness: a study of 20 patients.

Objective: To evaluate the benefit of a bone-anchored hearing aid (BAHA) contralateral routing of sound (CROS) in 20 patients with unilateral inner ear deafness. Subjects: 21 patients were recruited; 15 had undergone acoustic neuroma surgery and 6 patients had unilateral profound hearing loss due to other causes; 1 patient was excluded. Only patients with thresholds of better than 25 dB HL (500–2000 Hz) and an air-bone gap of less than 10 dB in the best ear were included. Methods: Evaluation involved audiometric measurements before intervention, when fitted with a conventional CROS and after implementation and quantification of the patients’ subjective benefit with a hearing aid-specific instrument: the Abbreviated Profile of Hearing Aid Benefit (APHAB). Results: Lateralization scores were not significantly different from chance (50%) in any of the three conditions. Measurements of speech perception in noise showed an increase in the signal to noise ratio (S/N ratio) with the conventional CROS (p = 0.001) and with the BAHA CROS compared to the unaided condition when speech was presented at the front with noise on the poor hearing side. On the other hand, a lower S/N ratio was seen with the BAHA CROS (p = 0.003) compared to the unaided situation when noise was presented at the front with speech on the poor hearing side. The patient outcome measure (APHAB) showed improvement, particularly with the BAHA CROS. Conclusions: The poor sound localization results illustrate the inability of patients with unilateral inner ear deafness to localize sounds. The speech-in-noise measurements reflect the benefit of a BAHA CROS in lifting the head shadow while avoiding some of the disadvantages of a conventional CROS. The benefit of the BAHA CROS was most clearly reflected in the patients’ opinion measured with the APHAB.

Sound localization ability of young children with bilateral cochlear implants.

Objective: To evaluate the benefit of bilateral cochlear implantation in young children. Study Design: Clinical trial comparing a group of bilaterally implanted children with a group of unilaterally implanted children. Setting: Tertiary referral center. Patients: Five bilaterally implanted children (mean age at testing, 3 yr 7 mo) were compared with 5 unilaterally implanted children (mean age at testing, 5 yr 3 mo). Meningitis was the cause of deafness in all of the children. Methods: Children were asked to localize a prerecorded melody band limited from 500 to 4,000 Hz presented from loudspeakers placed at either −90 or 90 degrees or −30 or 30 degrees azimuth. Their parents filled in the Speech, Spatial and Qualities of Hearing Scale (SSQ) and PedsQL questionnaires on hearing and health-related quality of life of their children. Results: The bilaterally implanted children had significantly better scores on the localization test than the children with unilateral cochlear implants. The scores of the children with bilateral cochlear implants were also significantly higher on the spatial domain of the SSQ, which concerns localization. No significant differences were found in the speech and quality of hearing domains and the total scores on the SSQ or the PedsQL between the two groups. Conclusion: Children with bilateral cochlear implantation already demonstrate an advantage over unilaterally implanted children at a young age.

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<0.0l) 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° or -90° azimuth. For noise presented at the ipsilateral side of the first fitted BAHA, the signal-to-noise ratio was significantly reduced (p<0.0l) 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 signifícant (p<0.0l) 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 1000 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. Se evaluó la adaptación de auxiliares auditivos tipo vibrador óseo (BAHA) bilateral en 25 pacientes que tenían al menos tres meses utilizeándolo. En todos los casos estaba contraindicado el uso de auxiliares auditivos por vía aérea debido a otorrea recurrente u otitis externa (19 casos) o atresia auricular congénita (6 casos). La indicateón de adaptación bilateral se basó primordialmente en la simetría de los umbrales por vía ósea. En todos los casos se midió la localizatión sonora y el reconocimiento del habla en silencio y en ruido. Además, en un subgrupo de 9 pacientes se midió la diferencia al eliminar al eliminar el enmascaramiento con tonos puros en ruido con diferencia de fase interaural (nivel de diferencial binaural con enmascaramiento [BMLD). El porcentaje correcto de localización con bursts de 500Hz y 2kHz aumentó significativamente (p<0.01) de 22.2% a 24.3% en las adaptaciones unilaterales a 48.1% y 45.3% en las bilaterales respectivamente. En los casos de adaptación unilateral, los juicios de localización sonora parecían estar conducidos hacia el lado del vibrador mientras que en las adaptaciones bilaterales los juicios fueron mucho más simétricos. El nivel de recepción del habla para frases en silencio fue significativamente (p<0.01) mejor en los casos de adaptación bilateral, que los unilaterales: 37.5dBA vs 41.7dBA. Se mídió la discriminateón del habla en ambiente ruidoso presentando la señal vocal frente al sujeto y un ruido de enmascaramiento a 65dBA ya fuera a 190° o a 290°. Para presentar el ruido ipsilateral al vibrador adaptado inicialmente, se redujo significativamente la diferencia señal/ruido (p<0.01) de 20.7dB para el adaptado unilateralmente a 24.0dB en el caso bilateral. El nivel de recepción del habla en ambiente ruidoso no mostró diferencia significativa (p<0.05) en la adaptación uni o bilateral, cuando el ruido se presentaba contralateralmente al BAHA inicialmente adaptado. Los resultados de los pacientes con atresia aural congénita son comparables a los otros casos. Así, la localización sonora y discriminación del habla en ambiente ruidoso mejora significativamente al adaptar el segundo BAHA. Los resultados de BMLD muestran una elimination significativa (p<0.01) de enmascaramiento de 6.1, 6.0 y 6.6 dB para estímulos de 125Hz, 250Hz y 500Hz respectivamente. El efecto BMLD de 4.1dB a 1000Hz no fue significativo en el nivel de 5%. Los resultados positivos con la adaptación bilateral en silencio pueden atribuirse al aumento de intensidad de los estímulos por sumación dicótica de las señal de cualquiera de los lados. Los resultados de localización, discriminación del habla en ambiente ruidoso y las mediciones de BMLD indican que los BAHA adaptados bilateralmente sí proporcionan (hasta cierto punto) audition binaural.

Candidacy for the Bone-Anchored Hearing Aid

The BAHA (bone-anchored hearing aid) is a bone conduction hearing aid with percutaneous transmission of sound vibrations to the skull. The device has been thoroughly evaluated by various implant groups. These studies showed that, in audiological terms, the BAHA is superior to conventional bone conduction devices. In comparison with air conduction devices, the results are ambiguous. However, a positive effect is found with respect to aural discharge. The most powerful BAHA can be applied to patients with a sensorineural hearing loss component of up to 60 dB HL. It was shown that bilateral BAHA application leads to binaural sound processing. Preliminary results on the application of the BAHA in patients with unilateral conductive hearing loss suggest that stereophonic hearing can be re-established. The application of the BAHA as a transcranial CROS (contralateral routing of signal) device in unilateral deafness minimizes head shadow effects.

The relation between age at the time of cochlear implantation and long-term speech perception abilities in congenitally deaf subjects

The issue of whether an upper age limit should be set for cochlear implantation in congenitally deaf subjects has often been debated. To gain more insight, the speech perception abilities were analyzed of 12 congenitally deaf subjects whose age at the time of cochlear implantation ranged from 4 to 33 years. Subjects implanted during adulthood only showed progress during the first few months after the speech processor had been fitted and their long-term results were poor compared to those of children implanted early in life. This latter group showed steady improvement over the whole evaluation period. The present results support the notion that the earlier in life implantation is performed, the better the development of speech perception. Based on the progress-over-time profiles and data on actual daily use of the cochlear implant, it can be suggested that implantation of congenitally deaf subjects during or after puberty offers only limited benefit.

The Baha Softband A new treatment for young children with bilateral congenital aural atresia

The Baha (bone-anchored hearing aid) Softband appears to be an effective mean of hearing rehabilitation for children with a congenital bilateral aural atresia who are too young for the amplification of a Baha on an implant. The aided hearing threshold with a Baha Softband is almost equal to that achieved with a conventional bone conductor. The speech development of the children studied with a Baha Softband is on a par with peers with good hearing.

The effect of otitis media with effusion at preschool age on some aspects of auditory perception at school age

The relationship between otitis media with effusion (OME) at preschool age and performance on five tests of auditory perception was studied in 89 school-age children who had OME histories well documented from participation in serial screening for OME at 2-4 yr of age. The tests used at 7.5-8 yr of age were: speech-in-noise, filtered speech, binaural fusion, dichotic speech, and auditory memory. A significant effect of OME was found on the speech-in-noise test. No additional effects were demonstrated by this particular group of children.

Bone-anchored hearing aid system application for unilateral congenital conductive hearing impairment: audiometric results.

Objective: To study the audiologic outcome of bone-anchored hearing aid (BAHA) application in patients with congenital unilateral conductive hearing impairment. Study Design: Prospective audiometric evaluation on 20 patients. Setting: Tertiary referral center. Patients: The experimental group comprised 20 consecutive patients with congenital unilateral conductive hearing impairment, with a mean air-bone gap of 50 dB. Methods: Aided and unaided hearing was assessed using sound localization and speech recognition-in-noise tests. Results: Aided hearing thresholds and aided speech perception thresholds were measured to verify the effect of the BAHA system on the hearing acuity. All patients fulfilled the criteria that the aided speech reception thresholds or the mean aided sound field thresholds were 25 dB or better in the aided situation. Most patients were still using the BAHA almost every day. Sound localization scores varied widely in the unaided and aided situations. Many patients showed unexpectedly good unaided performance. However, nonsignificant improvements of 3.0 (500 Hz) and 6.9 degrees (3,000 Hz) were observed in favor of the BAHA. Speech recognition in noise with spatially separated speech and noise sources also improved after BAHA implantation, but not significantly. Conclusion: Some patients with congenital unilateral conductive hearing impairment had such good directional hearing and speech-in-noise scores in the unaided situation that no overall significant improvement occurred after BAHA fitting in our setup. Of the 18 patients with a complete data set, 6 did not show any significant improvement at all. However, compliance with BAHA use in this patient group was remarkably high. Observations of consistent use of the device are highly suggestive of patient benefit. Further research is recommended to get more insight into these findings.

International consensus on Vibrant Soundbridge® implantation in children and adolescents☆

OBJECTIVE Active middle ear implants augment hearing in patients with sensorineural, conductive, and mixed hearing losses with great success. However, the application of active middle ear implants has been restricted to compromised ears in adults only. Recently, active middle ear implants have been successfully implanted in patients younger than 18 years of age with all types of hearing losses. The Vibrant Soundbridge (VSB) active middle ear implant has been implanted in more than 60 children and adolescents worldwide by the end of 2008. In October 2008, experts from the field with experience in this population met to discuss VSB implantation in patients below the age of 18. METHODS A consensus meeting was organized including a presentation session of cases from worldwide centers and a discussion session in which implantation, precautions, and alternative means of hearing augmentation were discussed. At the end of the meeting, a consensus statement was written by the participating experts. The present consensus paper describes the outcomes and medical/surgical complications: the outcomes are favourable in terms of hearing thresholds, speech intelligibility in quiet and in noise, with a low incidence of intra- and postoperative complications. CONCLUSIONS Taken together, the VSB offers another viable treatment for children and adolescents with compromised hearing. However, other treatment options should also be taken into consideration. The advantages and disadvantages of all possible treatment options should be weighed against each other in the light of each individual case to provide the best solution; counseling should include a.o. surgical issues and MRI compatibility.