Cochlear implant concept (via University of Utah)
Cochlear implants have improved the hearing for over 220,000 deaf people around the globe, but they have their drawbacks. Not being able to swim or wear helmets comfortably due to the delicate microphone and related electronics worn on the outside of the ear are just some of the tip of the limitation. A team of engineers, led by Associate Professor Darrin Young from the University of Utah, are looking to fix those issues by implanting the cochlear microphone inside the ear itself, giving the user an increased level of freedom in otherwise damaging environments.
Typical implants house the microphone, signal processor and transmitter coil in a plastic shroud worn behind the ear. The mic picks up sound and sends it to an internal receiver-stimulator attached to bone under the skin by the microphone housing. From there, sound is sent to electrodes attached to cochlea which in-turn stimulates auditory nerves making it possible for the user to hear. Young’s design places all the external components normally worn outside the ear inside by placing an accelerometer sensor that’s attached to a chip on the ears umbo part of the tympanic membrane to detect vibration. This converts sound into electrical signals that are then sent to the electrodes attached to the cochlea which is powered by an implanted battery enabling the user to hear.
Recharging the battery is done at night while the user sleeps using a charger located behind the user’s ear in much the same fashion as wearing a typical cochlear implant. Successful testing was done using several cadavers (yes, you read that right) implanted with the new cochlear system. A laser was then used to measure the vibration on bones inside the ear to see which one was more efficient at picking up normal-level sound after which it was found that the umbo was the most successful. In order to test this device, the implanted microphone was wired to speakers with Beethoven’s Ninth Symphony acting as the test medium. While the sound was ‘muffled,’ Young states that ‘the muffling can be filtered out’. The team hopes to improve the overall sound quality in future versions so clinical trials are still a few years away but anything that can assist the disabled is still a hopeful future.
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