A tiny microphone implanted in the ear would improve existing cochlear implants by providing continuous hearing day and night for people who are deaf.
Cochlear implants (pictured) are generally placed in the temporal bone under your ear. While hearing aids acoustically amplify sound, these implants convert sound energy into electrical signals that are delivered directly to nerve fibers.
These implants have been around for a while and helped thousands of deaf people around the world hear for the first time.
However, New Scientist reports, existing implants can’t be worn all the time because only a small part of the device is actually inside the cochlea (the snail shell part of the inner ear).
A fragile external unit containing the power supply, processors, and the microphone has to be hooked onto the ear and linked magnetically to the implant beneath the skin.
"Patients can't normally wear them in their sleep, in the shower, the rain, or when they swim," says study researcher Herman Jenkins of the University of Colorado. "A fully implanted system would get rid of all that because you could wear it round the clock.”
But developing an internal microphone for such a system has proved challenging.
Four years ago Sydney-based firm Cochlear ran trials of a prototype implant in 3 patients.
"People clearly appreciated the ability to hear 24/7," says Cochlear's Jan Janssen. But because the microphone was actually inside the ear it would also pick up bodily sounds of eating, swallowing, hair rustling, and heart beating.
Cochlear turned to Boulder company Otologics, which was developing a fully implantable hearing aid with a new microphone that incorporates two sensors: one for all sounds, another for only internal noises. By comparing the two signals, software can remove the unwanted bodily noises.
So far, 4 people have the internal microphones implanted and hooked up to their normal cochlear implant, with 2 more trials to follow later this year.
These patients are hearing about 80% of what an external microphone would provide, according to Jenkins.
Cochlear is now licensing Otologics's technology and hopes to have a complete system working within 5 years. But, having this fully implantable device would also mean having additional surgeries to replace the batteries every decade or so.
Preliminary findings will be presented at the American Otolaryngology Society meeting in Chicago later this month.
Via New Scientist.
Image: NIH via Wiki
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