Bone-anchored Hearing Aid Fitting Research Articles

Application of Acceptable Noise Level to Confirm Fitting Strategy for Bone-Anchored Hearing Aid

Since there is no standardized fitting procedure for bone-anchored hearing aid (BAHA) patients, many clinics have failed to perform their successful fitting. The present case study tried to identify whether acceptable noise level (ANL) was clinically applied as one of fitting procedures for the BAHA users. Four hearing-impaired adults with BAHA (3 female and 1 male) who had a period of hearing deprivation for at least 8 years and the BAHA experience of more than 1 year participated. They conducted ANL in their unaided and aided BAHA conditions after being familiar with the ANL instruction. Also, the subjects responded to a self-report of Korean version of Profile of Hearing Aid Benefit (K-PHAB) to subjectively check amount of satisfaction with BAHA. Compared to the unaided condition, two out of four BAHA users showed a decreased ANL in the aided condition whereas the other users had a slightly increased ANL. Regardless, their levels were examined within the permissible range except for one subject. Their K-PHAB scores were similar to the ANL results in the aided condition. Although measured ANLs were slightly differed from the users, the current results suggest that ANL might be a tool to measure individual’s inherent value when the BAHA fitting being appropriated while also supported by K-PHAB scores. In the following study, we need to confirm a typical pattern of many BAHA users with longitudinal measures of ANL.

Quality of life improvement for bone-anchored hearing aid users and their partners

Bone-anchored hearing aid recipients experience well documented improvements in their audiometric performance and quality of life. While hearing aid recipients may understate their functional improvement, their partners may be more aware of such improvement. We sought to investigate patients' partners' perceptions of functional improvement following bone-anchored hearing aid fitting. Surveys were sent to 153 patients who had received a bone-anchored hearing aid through the Nova Scotia bone-anchored hearing aid programme. The validated survey asked patients' partners to give their subjective impression of the bone-anchored hearing aid recipient's functional status. Surveys were completed by 90 patients (58.8 per cent), of whom 72 reported having a partner. Partners reported a significant improvement in hearing (p ≤ 0.0001). Partners reported improvement in 87.0 per cent of functional scenarios, no change in 12.6 per cent, and a decline in 0.4 per cent. These findings demonstrate a significant improvement in the emotional and social effects of hearing impairment, as perceived by bone-anchored hearing aid recipients' partners.

Benefit and Quality of Life After Bone-Anchored Hearing Aid Fitting in Children With Unilateral or Bilateral Hearing Impairment

To evaluate the benefits of a bone-anchored hearing aid (BAHA) in the daily lives of hearing-impaired children. Retrospective questionnaire study. Nijmegen Medical Centre, Nijmegen, the Netherlands. Thirty-eight BAHA users with a minimum age of 4 years at BAHA fitting and 1 to 4 years of use, divided into groups with bilateral conductive or mixed hearing loss and either normal cognition or mental disability and a group with unilateral conductive hearing loss. Scores on the Glasgow Children's Benefit Inventory, Abbreviated Profile of Hearing Aid Benefit, and Health Utilities Index Mark 3. The Glasgow Children's Benefit Inventory showed a subjective overall benefit of +32, +16, and +26 in the 3 groups (on a scale of -100 to +100). The Abbreviated Profile of Hearing Aid Benefit also showed an overall mean benefit in the groups. On an individual level, a clinically significant benefit was reported by more children in the group with bilateral hearing loss and normal cognition (7 patients [70%]) than in the unilateral hearing loss group (4 patients [27%]). Overall mean health utility scores and disability index scores on the Health Utility Index Mark 3 were comparable among the 3 groups. Overall, BAHA fitting can be considered effective and beneficial in children with bilateral or unilateral hearing loss.

Subjective Benefit After BAHA System Application in Patients With Congenital Unilateral Conductive Hearing Impairment

To study whether unilateral Bone-anchored Hearing Aid (BAHA) fitting led to subjective hearing benefit in patients with congenital unilateral conductive hearing impairment. Prospective evaluation on 20 patients. Tertiary referral center. Ten adults and 10 children with congenital unilateral conductive hearing impairment, with a mean air-bone gap of 50 dB, were included. Subjective bilateral hearing benefit after BAHA fitting was measured using 2 disability-specific questionnaires: Chung and Stephens and the Speech, Spatial and Qualities of hearing profile (children's version in the patients aged <18 yr). The Glasgow children's benefit inventory was also used to measure patient's health benefit after BAHA fitting. Chung and Stephens' questionnaire showed an overall preference for the BAHA in several specific hearing situations. The Glasgow children's benefit inventory demonstrated an overall mean improvement of +34, which was the most prominent in the learning domain. The 10 adults showed an already good score on the Speech, Spatial and Qualities of hearing scale in the unaided situation. The BAHA was well accepted by most of the patients with congenital unilateral conductive hearing impairment. A preoperative trial of the BAHA system with the BAHA on a headband is part of the preoperative procedure. In children with unilateral conductive hearing loss, with regard to possible childs' development and communication difficulties, intervention with BAHA can be considered as an option.

Bone-Anchored Hearing Aid System Application for Unilateral Congenital Conductive Hearing Impairment

To study the audiologic outcome of bone-anchored hearing aid (BAHA) application in patients with congenital unilateral conductive hearing impairment. Prospective audiometric evaluation on 20 patients. Tertiary referral center. The experimental group comprised 20 consecutive patients with congenital unilateral conductive hearing impairment, with a mean air-bone gap of 50 dB. Aided and unaided hearing was assessed using sound localization and speech recognition-in-noise tests. 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. 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.

Physiological aspects regarding bilateral fitting of BAHAs

Normally, when we hear a sound, the sound is transmitted through the outer and middle ear to the inner ear where the sound energy is converted to nerve impulses. These impulses are transmitted further to the cochlear nucleus and superior olivary complex where information from both ears is mixed, compared and analysed. It is here the binaural process occur which allows us to determine the direction of the sound source as well as improve hearing in noise when the useful sound source and noise source is spatially separated. Hence, a patient with a bilateral hearing loss and fitted with airconduction (AC) hearing aids generally benefits from binaural fitting compared with monaural fitting. When a bone-anchored hearing aid (BAHA) is used, the sound is transmitted via bone conduction (BC) to the inner ear. The difference between the stimulation level of the contralateral and ipsilateral cochlea, often referred to as the transcranial attenuation, is normally in the range of 0–20 dB for frequencies up to 10 kHz. Hence, the side-specific stimulation of the inner ears is less with BC than with AC, which affects the binaural effect of the hearing. Due to the overhearing between the cochleae with BC, it is questionable whether binaural hearing is possible using BC stimulation and, consequently, BAHAs. Proceedings of the 4th International Symposium on Electronic Implants in Otology 83

Physiological aspects regarding bilateral fitting of BAHAs

Normally, when we hear a sound, the sound is transmitted through the outer and middle ear to the inner ear where the sound energy is converted to nerve impulses. These impulses are transmitted further to the cochlear nucleus and superior olivary complex where information from both ears is mixed, compared and analysed. It is here the binaural process occur which allows us to determine the direction of the sound source as well as improve hearing in noise when the useful sound source and noise source is spatially separated. Hence, a patient with a bilateral hearing loss and fitted with airconduction (AC) hearing aids generally benefits from binaural fitting compared with monaural fitting. When a bone-anchored hearing aid (BAHA) is used, the sound is transmitted via bone conduction (BC) to the inner ear. The difference between the stimulation level of the contralateral and ipsilateral cochlea, often referred to as the transcranial attenuation, is normally in the range of 0–20 dB for frequencies up to 10 kHz. Hence, the side-specific stimulation of the inner ears is less with BC than with AC, which affects the binaural effect of the hearing. Due to the overhearing between the cochleae with BC, it is questionable whether binaural hearing is possible using BC stimulation and, consequently, BAHAs. Proceedings of the 4th International Symposium on Electronic Implants in Otology 83

Bilateral fitting of BAHAs and BAHA® fitted in unilateral deaf persons: Acoustical aspectsAdaptación bilateral de BAHA y adaptación de BAHA en sorderas unilaterales: Aspectos acústicos

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.

Patients' opinions on bilateral bone anchored hearing aid fitting

Patients' opinions on bilateral bone anchored hearing aid fitting