Cochlear implants are small electronic devices that help people who are deaf or hard of hearing to hear better. These devices have benefited over a million individuals globally, as reported by the National Institutes of Health.
Cochlear implants currently in use are only partially implanted and require external hardware placed on the side of the head. This setup limits the users’ activities such as swimming, exercising, or sleeping with the external component attached, leading some individuals to avoid getting the implant altogether.
A collaborative team of researchers from MIT, Massachusetts Eye and Ear, Harvard Medical School, and Columbia University is working towards creating a fully internalized cochlear implant. They have developed an implantable microphone that matches the performance of commercial external hearing aid microphones, addressing a major obstacle to achieving a fully internalized cochlear implant.
The tiny microphone, made from a biocompatible piezoelectric material, measures small movements on the underside of the eardrum. Piezoelectric materials produce an electric charge when compressed or stretched. To enhance the device’s performance, the team also designed a low-noise amplifier to boost the signal while reducing electronic noise.
Despite the challenges ahead before integrating such a microphone with a cochlear implant, the research team is optimistic about refining and testing this prototype further. The foundation for this project was laid over a decade ago at MIT and Mass Eye and Ear.
Researchers aim to have this device implanted simultaneously with the cochlear implant and internalized processor by optimizing the surgical procedure without disrupting the ear’s internal structures. The newly developed UmboMic, a motion sensor smaller than a grain of rice, is designed to capture minute vibrations of the umbo in the middle ear for improved hearing capabilities.
The team also addressed the issue of noise reduction through a unique PVDF sandwich design and developed their low-noise amplifier to amplify the tiny signals captured by the UmboMic. Through rigorous testing on human ear bones, the researchers confirmed the device’s strong performance within the range of human speech frequencies.
The study, funded in part by various organizations including the National Institutes of Health, showcased the potential of this innovative approach to revolutionize cochlear implant technology. Future research will focus on animal studies to further refine the UmboMic technology for practical use.
