Scientists at Belgium’s KU Leuven University have designed a cochlear implant that successfully reads a user’s brain waves to allow deaf people to hear again. Measuring these brain waves – instead of detecting noises via external microphones – is more reflective of a person’s hearing, and is important for the development of “smart” hearing devices.

A cochlear implant is a standard device that enables people with severe hearing loss to hear again. Small children or dementia sufferers, however, may not understand what’s being asked of them when the device is being calibrated to their needs, or they may not be able to express themselves clearly – if it were possible to read their brain waves when test sounds were being made, it might objectively determine how well they were hearing those sounds.

“A cochlear implant contains electrodes that stimulate the auditory nerve,” says postdoctoral researcher Ben Somers from the Experimental Oto-rhino-laryngology unit. “We have succeeded in using these implanted electrodes to record the brain waves that arise in response to sound. That is a first.

“An additional advantage is that by carefully choosing the right measuring electrodes, we can measure larger brain responses than the classical EEG (electroencephalogram) with electrodes on the head.”

The scientists were able to detect such hearing-related brain waves in volunteers wearing an electrode-equipped skull cap just last year; forgoing the electrode cap means that patients wouldn’t have to be tested in a clinical setting, and in fact could provide better, real-world readings over a period of several days while going about their daily routine. It is hoped that ultimately, such smart cochlear implants could automatically adjust themselves in response to the user’s brain waves.

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