Optical cochlear implants come a rodent step closer

Scientists based in different institutions in Germany achieved a breakthrough by designing multichannel LED cochlear implants (CIs) that use optogenetics to stimulate spiral ganglion neurons (SGNs). The classical neuroprosthetic CI device is based on electrodes implanted in the cochlea and used to electrically stimulate the SGNs to partially restore hearing. But even with the help of algorithms, these are limited in their sensitivity, even early implantations in children rarely achieving good intelligibility in noisy environments or the possibility to enjoy music.

Optogenetics enables direct interaction with neurons, so an implant that converts sound waves to light signals instead of electrical signals might offer greater spectral sensitivity to the user. This was confirmed by the study carried out by Keppeler et al., published this July 2020 in Science Translational Medicine.

On experimenting with rats and gerbils implanted with optical CIs (oCIs), the authors confirmed improved spectral selectivity through direct demonstration via recordings from the auditory midbrain, demonstrating "hearing restoration with improved spectral selectivity by an LED-based multichannel oCI system".

Source: Science Translational Medicine