Researchers from Massachusetts Eye and Ear Infirmary (MEEI), Harvard Medical School, and Massachusetts Institute of Technology (MIT) have designed a new, low-power signal-processing proto-type system-on-chip (SoC) that may help begin development of a fully implantable cochlear implant.

Unlike existing versions of cochlear implants, which include a disk-shaped transmitter, a wire, a joint microphone and power source that resembles an oversized hearing aid around the patient’s ear, the low power chip requires no external hardware.

The cosmetic aspect of an invisible cochlear implant eliminates the concerns raised in some individuals with social stigma and limited use in the shower or during water sports.

The device relies on a sound sensor located in the middle ear so that the user can benefit from directional cues provided by the auricle and ear canal. The chip could be wirelessly recharged once a day from an implantable battery.

"Our long-term goal is to develop a fully implantable cochlear implant."

Massachusetts Eye and Ear otologist Dr Konstantina Stankovic, who co-led the study with Dr Anantha Chandrakasan, MIT head of Electrical Engineering and Computer Science said the conventional cochlear implants detect sound by a microphone located outside of the ear so that important directional cues are lost.

"Our long-term goal is to develop a fully implantable cochlear implant," Dr Stankovic. "To facilitate that development, we have developed the SoC and tested it in ears of human cadavers."

Massachusetts Eye and Ear is a Harvard Medical School teaching hospital and this project was a collaboration between the following researchers at MIT, Harvard Medical School and Massachusetts Eye and Ear: Marcus Yip, Rui Yin, Hideko Heidi Nakajima, Konstantina Stankovic and Anantha Chadrakasan.

The researchers presented their findings at the IEEE International Solid State Circuits Conference in San Francisco on 11 February.

Image: Researchers achieve progress in developing a fully implantable cochlear implant. Photo: courtesy of freedigitalphotos.net.