Objective: To compare the functional gain of different Symphonix Soundbridge audioprocessors (HF-processor and D-processor) to preoperatively fitted conventional hearing aids of patients with mild to severe sensorineural hearing loss in the high-frequency range.
Study design: In a prospective study, the Symphonix Soundbridge (HF-processor and D-processor) fitting results were evaluated and compared with conventional hearing aids. Postoperative air and bone conductances, the functional gain of warble-tone measurements, speech audiometric, and subjective outcome testing (Abbreviated Profile of Hearing Aid Benefit questionnaire) were studied.
Setting: Tertiary referral center.
Patients: Five patients (ages, 54-69 yr) with mild to severe sensorineural deafness in the high-frequency range, but no progression of hearing loss during the last two years, were initially fitted with the so-called HF-processor, then subsequently fitted with the D-processor, which was a fully digital one.
Results: One year after implantation of the Symphonix Soundbridge device, unchanged, stable air and bone conductances were found (except for one minor change). Over the whole frequency range (0.5-8.0 kHz), a mean gain of 16.1 dB (HF-processor), 27.1 dB (D-processor), and 15.2 dB (hearing aid) was found. The Symphonix Soundbridge device with different audioprocessors led to improved hearing in speech audiometric testing. The data show a significant improvement of hearing compared with conventional hearing aids in quiet, and a better functional gain in noise for the Symphonix Soundbridge system. The Abbreviated Profile of Hearing Aid Benefit questionnaire also revealed that the implant resulted in significant differences compared with conventional hearing aids in almost all subcategories.
Conclusion: The Symphonix Soundbridge device can improve the hearing benefit of moderately to severely hearing handicapped patients-particularly in those with a high-frequency hearing loss-when compared with the conventional hearing aids of these patients, as evidenced by objective and subjective measurements. The Symphonix Soundbridge D-processor showed further improvements and resulted in an additional hearing benefit that was superior to that of the previously fitted HF-audioprocessor. This is owing to the refinements and upgrades in audioprocessor technology.