Current Developments and Challenge of Implantable Bone Conduction Hearing Aids / 대한이비인후과학회지

It is acknowledged that implantable bone conduction hearing aids such as a bone anchored hearing aid provide benefit and satisfaction to patients with unilateral hearing loss in terms of sound localization and speech perception under noise circumstances. This review paper introduces current models of the implantable bone conduction hearing aids, their candidacy, brief surgical procedures, and general audiological examinations. A table summary was used for nine published research papers which have very similar results by three points, i.e., no change in ability of sound localization, better performance of Hearing-In-Noise Test, and improved satisfaction of sound quality using questionnaires after the implantation. Unfortunately, systematic fitting strategy for users of the implantable bone conduction hearing aids has not been either studied or developed yet. Futhermore, there is no scientific based approach of reason why the implantation has no benefit in sound localization but still provides better performance for speech perception in noise. In conclusion, specific and effective fitting strategy of the current implantable bone conduction hearing aids should be developed and also support effect of the implantation with sensitivity and specificity for both clinicians and patients while accompanying their advanced technology.

Hearing Rehabilitation of Single-Sided Deafness: Benefit and Selection Criteria of Bone Anchored Hearing Aid and Contralateral Routing of Signal Hearing Aid / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: There are two ways to route sound from a deaf hemifield to a functional ear: the bone anchored hearing aid (BAHA) and the contralateral routing of signal hearing aid (CROS HA). BAHA uses transcranial bone conduction; on the other hand, CROS HA uses air conduction. The objectives of this study were to evaluate the benefit of these auditory rehabilitation devices objectively and subjectively, and to analyze factors that affect daily using time. SUBJECTS AND METHOD: We retrospectively reviewed the medical records of 19 patients who selected BAHA and 9 patients who selected CROS HA to undergo rehabilitation of unilateral hearing loss. Preoperative pure tone air and bone conduction thresholds, BAHA-aided thresholds and CROS HA-aided thresholds were measured. Hearing in noise test (HINT) was measured with unaided and aided in signal to noise ratio 10 (signal 75 dB HL, noise 65 dBA). Bern Benefit in Single-Sided Deafness Questionnaire (BBSS) was evaluated for all patients to assess subjective satisfaction and also, daily device using time was investigated. RESULTS: The aided pure tone audiometry was 44.58 dB HL, 42.71 dB HL for in BAHA and CROS HA, respectively, whereas the unaided PTA was 111.29, 103.28 dB HL for BAHA and CROS HA, respectively. The aided HINT was 63.03 and 64.06%, whereas the unaided HINT was 22.13% and 37.44% for BAHA and CROS, respectively. BBSS showed more satisfactory results with BAHA and CROS HA when compared unaided in all items. Daily using time did not correlate with the degree of satisfaction, better ear hearing levels or etiology. CONCLUSION: It was found that not only the preoperative BAHA rod test and HA trials but also the customized and detail counseling were needed for single sided deaf patients to use auditory rehabilitation devices frequently.

Hearing Rehabilitation with Bone Anchored Hearing Aid: Experience in 14 Patients / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Bone anchored hearing aid (BAHA) is an alternative method applicable to patients with chronic draining ear, congenital aural atresia and single sided deafness, who cannot benefit from conventional air conduction hearing aids. The objective of this study was to evaluate the experience of 14 patients who underwent BAHA surgery. SUBJECTS AND METHOD: We retrospectively reviewed the medical records of 14 patients who underwent BAHA surgery. Preoperative pure tone air and bone conduction thresholds and air-bone gap, postoperative BAHA-aided thresholds were measured. Hearing improvement as a result of implantation and complications related to implant were evaluated. RESULTS: The most common indication for BAHA was congenital aural atresia (8 patients) and the rest consisted of chronic otitis media (3 patients) and unilateral sensorineural hearing loss (3 patients). The average threshold improvement with BAHA was 40 dB and 34 dB in patients with congenital aural atresia and chronic otitis media, respectively. Patients with unilateral hearing loss had a postoperative aided threshold of 25 dB. Complications were limited to the periabutment skin problem in two patients. One patient received revision surgery replacing the diseased skin with split-thickness skin graft from a thigh and the other patient received surgery to remove the abutment and the wound was closed with rotation flap, leaving the fixture underneath the skin. CONCLUSION: BAHA could be one of the safe and reliable treatment options available for auditory rehabilitation. Systematic evaluation for candidate selection might be needed to increase hearing gain and decrease co-morbidity.