Performance evaluation of a novel piezoelectric subcutaneous bone conduction device

Area of Science:

• Biomedical Engineering
• Audiology
• Medical Devices

Background:

• Bone conduction hearing aids offer an alternative for hearing loss treatment.
• Piezo-electric actuators present a novel approach for sound transduction in these devices.

Purpose of the Study:

• To evaluate the transfer function efficiency of a new piezo-electric actuator for subcutaneous bone conduction hearing aids.
• To compare the efficacy of different implantation locations for the actuator.

Main Methods:

• Experiments were conducted on four Thiel embalmed whole head cadaver specimens.
• A piezo-electric transducer actuator (PZTA) was implanted in three locations: posterior to the pinna (two sites) and the traditional bone-anchored hearing aid (BAHA) location.
• Cochlear promontory motion was measured using laser Doppler vibrometry (LDV) on both ipsilateral and contralateral sides, with and without mastoidectomy.

Main Results:

• Stimulation at locations posterior to the pinna (1 and 2) showed a trend for higher promontory motion above 1 kHz compared to the BAHA location (3).
• Location 1 demonstrated improved dB levels at mid and high frequencies (2-8 kHz).
• In-plane motion components were dominant at mid and high frequencies, and mastoidectomy negatively affected high-frequency response at location 1.

Conclusions:

• The study quantified the sound transfer function efficacy of a novel subcutaneous bone conduction device.
• The findings suggest that implantation sites posterior to the pinna may offer advantages over the traditional BAHA location.
• The influence of stimulation location and mastoidectomy on promontory motion was analyzed.