Implantable Transducer Systems for Auditory Prostheses - PROJECT SUMMARY:
In this application, we seek to design, fabricate, and test implantable, packaged accelerometers that sense
incoming sound by transducing the motion of the middle ear (ME) bones (ossicles). We will test the
performance of these devices using benchtop calibration and quantification tests as well as using acoustic
stimulation of accelerometers implanted in cadaveric temporal bone preparations. We seek to create a device
that meets the stringent geometric, acoustic, weight, and power requirements for prostheses by using a multi-
resonant (multi-band) piezoelectric-micro-electro-mechanical systems (piezo-MEMS) sensor co-designed with
an application specific integrated circuit (ASIC) with addressable filtering and amplifying circuitry. A novel flip-
chip packaging strategy is proposed which can deliver a 5-milligram piezo-MEMS-ASIC packaged device by
eliminating the need for printed circuit board mounting. State-of-the-art thin piezoelectric film materials and
deposition will be explored to further reduce the device size and improve performance. Separate, component-
level piezo-MEMS die and ASIC testing in combination with system-level testing in a benchtop setting will
enable characterization of the complete system. Tested sensor systems will be implanted in male and female
cadaveric temporal bone samples, and the acoustic sensitivity and noise floor characterized. We will consider
locations along the ossicular chain to reduce device impact on the ME mechanics, ease surgical implantation
(minimize invasiveness), and maximize sensitivity (as the accelerometer is sensitive to both translation and
rotation). The objective of this present application is to develop implantable sensors, because accomplishing
this objective is a necessary step in achieving our long-term goal of a totally implantable auditory prosthesis
(e.g., hearing aids and cochlear implants with all components housed invisibly). This line of research aims to
provide new implantable options to treat hearing loss, thereby increasing the number of auditory prosthesis
users by enhancing the usability, safety, cosmetic appeal, and performance of the device and improving
patient quality of life.