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Aculight Will Study Optical Cochlear Implants
 Aculight Will Study Optical Cochlear Implants 11/16/2007 Aculight Corp. (Bothell, Wash.), in conjunction with Northwestern University (Evanston, Ill.), has received a $750,000 Phase II Small Business Innovation Research (SBIR) award from the National Institutes of Health to develop an optical cochlear implant. The SBIR funding will be used to produce a laser-based implant that can be used in research studies at Northwestern University prior to developing a model for clinical applications. Researchers at Northwestern University, led by Professor Claus-Peter Richter, have already demonstrated that they can control firing rates in the auditory nerve of animals using infrared laser radiation. “This two-year effort will be optimizing the parameters needed for stimulation and ongoing safety studies, in particular demonstrating that infrared stimulation is safe in chronic implants,” says Mark Bendett, Aculight’s Director of Medical Products. “In the ultimate implant, the exact mode of aiming the light onto the cochlear nerve has not been determined, but it will certainly either be a glass fiber array or a compact glass lenslet array, To date we have been using low OH glass optical fibers to transmit the light to the target nerve.” A cochlear implant is a neural prosthetic device that restores lost nervous system function. Current implants, which are used by roughly 100,000 profoundly deaf people, work by stimulating the auditory nerve with a string of electrodes placed in the inner ear. But the devices have limitations since the electrical signals spread due to the body’s wet, salty composition. This makes stimulating specific nerve populations inside the cochlea challenging. In addition, concurrent electrical pulses in different locations merge with each other, mistakenly stimulating the entire cochlea. In contrast, optically-based cochlear implants would have much better accuracy since optical pulses in different places on the nerve wouldn’t interfere with each other. Therefore, users would be able to hear subtle tones and nuances in music or distinguish a single voice in a noisy room. For many current cochlear implant users, voices sound mechanical and music sounds washed out. In other words, when a nerve is stimulated using light it reacts very much like it is being stimulated with an auditory signal; i.e., if you stimulate the ear at a single frequency you hear just that frequency. When stimulated by an electrical signal, as in the conventional cochlear implants, the ability to select a specific frequency is limited due to electrical crosstalk (i.e. current spreading along the nerve). As a result the reproduced sound is low fidelity. Another major advantage of an optical implant is that it is minimally invasive. The implant does not require an electrode placed around the cochlear nerve (which destroys any residual hearing), but shines the light onto the nerve in a non-contact manner. Because of this approach any residual hearing that a person has will not be compromised. “Therefore, this may now expand the potential persons who can benefit from this treatment beyond just the profoundly deaf, to those with severe hearing losses that do not get sufficient benefit from conventional hearing aids,” says Bendett. However, as with most new technology, there is still much work to do. Bendett believes initial trials are still five years away and thus it will probably be closer to a decade before such an implant is on the market. << Back to News |
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