Cochlear implants are implanted electronic devices that help the hearing-impaired in the hearing-impaired by stimulating auditory nerves through electrodes placed near the inner ear. In recent years, cochlear implants have become the routine method of treating severe deafness to total deafness. But cochlear implants are not without flaws. Implant surgery often injures the patient with only a little hearing, and electrical signals can also be transmitted through nerve tissue to nearby cells as noise in the patient's ears. However, recently, a new research results have been achieved using laser stimulation of auditory nerve, may further improve the performance of cochlear implants.
The new study, from the Swiss Center for Electron and Microtechnology, is based on the recently discovered "photoacoustic effect," in which cells are stimulated with pulses of infrared light. But the exact principle of this effect has been the subject of much debate.
One explanation states that rapid cell heating caused by light pulses causes them to depolarize, producing an action potential. Another explanation, however, says laser pulses cause rapid heating of water molecules in the inner ear, producing small shock waves and stimulating ear hair in a manner similar to sonic waves.
Today, the Nicle Kallweit team at the Hannover Laser Center in Germany found direct evidence to confirm the second explanation: their system can not work on Dutch pigs who have auditory nerves but lack the ear hair cells.
However, their system once again confirmed the existence of photoacoustic stimulation. They said the effect will be used to develop a new generation of cochlear implants. The next step is to minimize system energy consumption and improve battery life. However, this technique does not completely replace existing cochlear implants, but instead uses the electrodes together with the cochlea to stimulate nerves, giving the user more flexibility.