Commentary on the original 2003 New York Times article by Anne Eisenberg, "For Hearing Aids, a Lesson From a Fly on the Wall."
http://www.nytimes.com/2003/12/11/technology/circuits/11next.html?8cir
Hearing aids and cochlear implants are being redesigned based on the minuscule, yet tremendously sensitive ear of the Ormia fly. Hearing loss affects at least 28 million Americans yet only 10% of these people use and are satisfied with the modern hearing aid. One of the major issues with today's hearing aids is their poor sound localization, especially in loud situations when a particular sound or voice is to be distinguished from the background noise. We have long believed the human ear to be the most remarkable hearing systems in nature in terms of sound localization. This superior functionality is largely the result of the distance between our ears which helps us detect the direction of a noise based on the distance in time that it takes the noise to hit one ear relative to the other. However the directional hearing of the Ormia fly easily matches our own ability. When Ron R. Roy discovered that Ormia flies had ears he was surprised but was even more astonished to realize how effective they were. These flies have even better directional hearing capabilities than the human ear yet they are located just millimeters from each other. This means that they can detect directional differences in noise reaching the ears on the timescale of nanoseconds (1000 times smaller time discrepancies than the human ear can detect). The functional unit of the ear that is of greatest interest to engineers looking to mimic the Ormia's ear is the tiny ear drum. The fact that these ears are so tiny means that they could be indiscreetly put or implanted in people's ears and could potentially be inexpensive to manufacture. But how exactly have engineers taken Roy's research on fly ears and transferred this to hearing aids and cochlear implants?
Engineers are using the drum of the Ormia ear as a framework for developing a microphone that can be used in hearing aids and cochlear implants. The use of highly sensitive silicon and new innovations in laser technology combined with the guidance of the Ormia's tympranal structure make this technology feasible on a nanoscale. The mike membrane works by rocking like a seesaw that is hinged on a central pivot and "when acoustic waves come past, the sound pressure drives both sides of the teeter-totter. If sound comes on both sides at exactly the same time and with the same amplitude the mechanism doesn't move. But if the sound comes to one side before the other, it moves because the two pressures are unequal." This replaces the old mike technology which looked more like a drum head and left much to be desired in terms of sound localization.
This innovation is important for the healthcare industry which deals with a large demand for hearing aids, especially if those who have hearing loss but don't currently wear hearing aids are interested in this new technology. Currently medicare and private insurance companies cover hearing aids on more of a case-to-case basis while cochlear implants are universally covered. Therefore the healthcare industry would benefit from a less expensive and more effective hearing aid technology. And if the devices were less expensive consumers may additionally benefit if insurance companies are willing to cover the new price. In addition, there is a large market for hearing aid manufacturers which increases incentives to develop better technologies. This technology would not revolutionize the way that hearing loss is medically addressed, however, it would greatly improve existing biotechnologies for hearing problems.
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