Bone-anchored hearing aids in unilateral inner ear deafness: an evaluation of audiometric and patient outcome measurements.

OBJECTIVE: To evaluate the benefit of a bone-anchored hearing aid contralateral routing of sound hearing aid (BAHA CROS hearing aid) in 29 patients with unilateral inner ear deafness.

STUDY DESIGN: Prospective clinical follow-up study.

SETTING: Tertiary referral center.

PATIENTS: Thirty patients were recruited. There were 19 patients with a history of acoustic neuroma surgery and 11 patients with unilateral inner ear deafness due to other causes; 1 patient was excluded. The first 21 patients had also participated in a previous evaluation.

INTERVENTION: Audiometric measurements were taken before intervention, when fitted with a conventional CROS, and after BAHA implementation. Patients' subjective benefit was quantified with four different hearing aid-specific instruments: the Abbreviated Profile of Hearing Aid Benefit, the Glasgow Hearing Aid Benefit Profile, the International Outcome Inventory for Hearing Aids, and the Single-Sided Deafness questionnaire.

MAIN OUTCOME MEASURES: The same instruments were used at a mean long-term follow-up of 1 year after BAHA implantation.

RESULTS: Sound localization in an audiologic test setting was no different from chance level. The main effect of the BAHA CROS that was found was the "lift the head shadow" effect in the speech-in-noise measurements. All instruments also showed positive results in favor of the BAHA CROS at long-term follow-up.

CONCLUSIONS: The poor sound-localization results in an audiologic test setting illustrated the inability of patients with unilateral inner ear deafness to localize sounds. The speech-in-noise measurements demonstrated the efficacy of the BAHA CROS to lift the head shadow. Patients were still satisfied at 1-year follow-up, according to the four instruments.