A New Floating Piezoelectric Microphone for Fully Implantable Cochlear Implants in Middle Ear

Area of Science:

• Biomedical Engineering
• Otolaryngology
• Medical Devices

Background:

• Totally implantable cochlear implants (TICIs) require advanced internal components for optimal function.
• Developing sensitive and durable microphones is crucial for TICI performance.
• Existing microphones may face challenges with long-term implantation and sealing.

Purpose of the Study:

• To design and evaluate a novel floating piezoelectric microphone (NFPM) for TICI applications.
• To assess the sensitivity and effectiveness of the NFPM in detecting middle-ear vibrations.
• To determine the feasibility of the NFPM for intraoperative use during cochlear implant surgery.

Main Methods:

• The NFPM was constructed using laser welding and vacuum packaging for durability and sealing.
• In vivo experiments were conducted on cats, and intraoperative tests were performed on human patients.
• The NFPM was positioned on the ossicular chain and in the tympanic cavity to analyze frequency responses and signal output.

Main Results:

• The NFPM demonstrated higher sensitivity in detecting ossicular chain vibrations compared to tympanic cavity placement in both cat and human tests.
• Signal output levels correlated with acoustic stimulation strength during intraoperative testing.
• The NFPM was successfully removed post-testing without causing damage to the middle-ear structures of the cats.

Conclusions:

• The NFPM is effective and sensitive for detecting middle-ear vibrations.
• The device's performance in intraoperative testing supports its feasibility for TICI applications.
• The NFPM represents a promising advancement for implantable microphones in hearing restoration technology.