Comparison of the Audiologic Results Obtained With the Bone-Anchored Hearing Aid Attached to the Headband, the Testband, and to the "Snap" Abutment

Abstract

Objectives: 1) To quantify the audiometric differences between the preoperative tests with the Bone-Anchored Hearing Aid (BAHA) attached to the headband or the testband and the final postoperative result with the BAHA positioned at the implanted abutment. 2) To compare the results obtained with the headband and the testband. 3) To quantify the magnitude of the damping through the skin for the BAHA placed at the testband (important for comparison with the implantable hearing aids). Study Design: Prospective. Setting: Tertiary otological referral centre. Patients: Ten adult (≥14 yr old) BAHA patients (6 male and 4 female subjects) with bilateral air-bone gaps of minimum 40-dB hearing loss and with more than 6 months of BAHA experience with the BAHA "Compact." Methods: Audiometric free-field thresholds and speech audiometry scores (Consonant-Vowel-Consonant lists, phonemic score) have been evaluated for 3 conditions: BAHA attached to the implanted "Snap" abutment, to the headband, or to the testband. Results: For frequencies 1 to 4 kHz, significant differences in the range of 5 to 20 dB were found between the BAHA coupled with the Snap abutment and the preoperative testing conditions with the BAHA positioned at the headband or the testband. These differences were also reflected in the speech audiometry with a difference in speech reception threshold of approximately 4 to 7 dB. Conclusion: 1) Significant differences in the audiometric thresholds and the speech understanding scores were found between the preoperative test conditions and the final postoperative result. 2) Audiometric results obtained with the headband and the testband are comparable; therefore, the more comfortable headband is also suitable for the preoperative audiologic evaluation. 3) The magnitude of the skin damping must be accounted for when referring to the audiometric results obtained with the BAHA attached to the testband or headband.