In traditional cochlear implants, a large sound processor is worn outside the head and sends signals to an internal receiver-stimulator implanted in bone under the skin. This in turn sends signals to the electrodes implanted in the cochlea to stimulate auditory nerves. The ear canal, eardrum, and bones in the middle ear are bypassed.

These large external processors tend to raise reliability issues, and social and cosmetic considerations, and limiting patients from performing certain functions such as swimming. Now, Darrin J. Young , a University of Utah engineer, and colleagues in Ohio have developed a tiny prototype microphone that can be implanted in the middle ear which would supplant the large external processor.

The proof-of-concept device (pictured below) has been successfully tested in the ears of four cadavers, the researchers report in a study just published online in the Institute of Electrical and Electronics Engineers journal Transactions on Biomedical Engineering.

While the current prototype is 2.5-by-6.2mm (about the size of an eraser on a pencil) and weighs less than a thousandth of an ounce, developers still want to reduce the size to 2-by-2mm and improve its ability to detect quieter, low-pitched sounds. The device won’t be ready for human tests for about another 3 years.

As disturbing as this may sound, you may visit our website blog to hear a recording of the start of Beethoven’s Ninth Symphony through the new microphone implanted in a cadaver’s middle ear.

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