Bone-anchored hearing aids in patients with acquired and congenital unilateral inner ear deafness (Baha CROS): clinical evaluation of 56 cases.

Objectives: We performed an evaluation of the audiological and subjective benefits of the bone-anchored hearing aid (Baha) as a device for transcranial routing of sound (Baha CROS) in 56 patients with unilateral inner ear deafness.

Methods: We performed a prospective clinical follow-up study in a tertiary referral center. Previously reported results of 29 patients were supplemented with a second series of 30 patients with unilateral inner ear deafness; 3 patients dropped out during the evaluation. Audiometric measurements were taken before and after Baha CROS fitting. Subjective benefits were quantified with 4 different patient questionnaires.

Results: The sound localization results in a well-structured test setting were not differentiable from chance. The 5 patients with congenital hearing loss showed better scores in the unaided sound localization measurements. Overall, most patients reported some subjective improvement in their capacity to localize sounds with the Baha CROS in daily life. The main effect of the Baha CROS was to alleviate the head shadow effect during the speech-in-noise test.

Conclusions: Poor sound localization in this larger series of patients confirms the findings of previous studies. Improvements in the speech-in-noise scores corroborated the efficacy of the Baha CROS in alleviating the head shadow effect. The 4 different patient questionnaires revealed subjective benefit and satisfaction in various domains.