Vibrant semi-implantable hearing device with digital sound processing - Effective gain and speech perception

Background: The Vibrant Soundbridge (Symphonix Devices, San Jose, Calif) is a semi-implantable hearing device. The transducer is attached directly to the incus and is linked by telemetry to the externally worn audioprocessor. A major advantage of this semi-implantable setup, especially during its experimental phase, is that the audioprocessor can be updated. Recently, we replaced the previous 2-channel analog audioprocessor in 14 patients with a 3-channel digital device. Design: Prospective clinical study. Basic functions were measured, including gain as a function of input level and speech perception in quiet. Patients: Patients (n = 14) had moderate to severe sensorineural hearing impairment (average hearing threshold at 0.5, 1.0, 2.0, and 4.0 kHz of 40- to 76-dB hearing level [HL]) and chronic external otitis, which contraindicated use of an ear mold. Results: Gain of the 3-channel audioprocessor for comfortable listening levels and for conversational levels varied from approximately 15- to 30-dB HL, suggesting that the device is suitable for patients with hearing loss of up to 60- to 70-dB HL. In 5 patients, identical measurements were performed using their conventional hearing aids. The other 9 patients did not use a conventional hearing device because of severe external otitis. On average, results obtained with the Vibrant Soundbridge were not as good as those obtained with the conventional device. Nevertheless, patients were satisfied with the Vibrant Soundbridge because they could use it all day without pain or itching. Conclusions: The Vibrant Soundbridge is suitable for patients with hearing loss of up to 70-dB HL. Compared with conventional devices, in audiometric terms, a surplus value of the Vibrant Soundbridge was not found.