Scientists at the University of Utah led by researcher Richard Rabbitt, have found a way to stimulate inner ear cells with infrared laser light
. Using low-powered optical signals, the researchers triggered the inner ear hair cells of an oyster toadfish
to send signals to its brain, raising the possibility of using the technology to restore hearing to the deaf. Rabbitt believes the cells released neurotransmitters because the mitochondria they contain are sensitive to infrared wavelengths. Current hearing implants rely on electrodes that use electrical simulation, but only deliver a limited range of frequencies (usually eight). By contrast, the human ear is capable of hearing over 3,000 frequencies, and Rabbitt believes that optical stimulation, which can be focused on narrow sets of cells and tuned to different wavelengths, could restore the full range of hearing to patients.
Rabbitt said the research is at least five to ten years away from implementation in a viable optical cochlear implant. To be practical, the size of the power supply and light source would have to be dramatically reduced, and power consumption would also have to be minimized to run on tiny batteries similar to those used in hearing aids. The research also has potential for treating vision impairment, balance problems and movement disorders like Parkinson's. The team also developed an infrared laser-based pacemaker, but current electrical pacemakers work well enough that no one is clamoring for a laser-powered replacement.