Sound Localization in Patients With Congenital Unilateral Conductive Hearing Loss With a Transcutaneous Bone Conduction Implant.

OBJECTIVE: There is no consensus regarding the benefit of implantable hearing aids in congenital unilateral conductive hearing loss (UCHL). This study aimed to measure sound source localization performance in patients with congenital UCHL and contralateral normal hearing who received a new bone conduction implant.

STUDY DESIGN: Evaluation of within-subject performance differences for sound source localization in a horizontal plane.

SETTING: Tertiary referral center.

PATIENTS: Five patients with atresia of the external auditory canal and contralateral normal hearing implanted with transcutaneous bone conduction implant at the Medical University of Vienna were tested.

INTERVENTION: Activated/deactivated implant.

MAIN OUTCOME MEASURE: Sound source localization test; localization performance quantified using the root mean square (RMS) error.

RESULTS: Sound source localization ability was highly variable among individual subjects, with RMS errors ranging from 21 to 40 degrees. Horizontal plane localization performance in aided conditions showed statistically significant improvement compared with the unaided conditions, with RMS errors ranging from 17 to 27 degrees. The mean RMS error decreased by a factor of 0.71 (p < 0.001).

CONCLUSION: Analysis revealed improved sound localization performance in a horizontal plane with the activated transcutaneous bone conduction implant. Some patients with congenital UCHL might be capable of developing improved horizontal plane localization abilities with the binaural cues provided by this device.