West Lafayette, Ind.- (BUSINESS WIRE) - A Purdue University researcher's innovation may make it possible for people with severe hearing loss to hear high-frequency sounds.
Joshua Alexander, an assistant professor in Purdue's Department of Speech, Language and Hearing Sciences, said conventional hearing aids do not help listeners with severe hearing loss.
"People with severe hearing loss have lost the ability to hear certain pitches, and most commonly they're the highest pitches," he said. "Current hearing aid technology works best for people with some residual ability to hear these pitches, but there are too many challenges for it to help listeners with a very restricted pitch range."
Alexander tested variants of existing hearing aid technology, which use algorithms to move information from higher pitches to lower.
"Those who need this technology the most are people with severe hearing loss. Unfortunately, because their pitch range is so limited, everything is placed into a very narrow area which makes different speech sounds too similar to one another. There is less to separate them," he said. "Listeners have to relearn how to perceive a lot of information in the new pitch range, assuming the sounds can be made different from one another in the first place."
Alexander discovered what listeners needed to enhance perception in the new pitch range, and then designed an algorithm to accommodate these needs.
"Unlike other algorithms that simply shift high-frequency sounds to a lower pitch range, this algorithm mirrors and flips them. By moving the highest pitched speech sounds, like 's,' to the lowest pitches, the listener can more easily relearn them because they are still different from other speech sounds in the mid-pitch range, like 'sh,'" he said. "This also means the listener doesn't need to relearn the speech sounds in the mid-pitch range because the algorithm hasn't displaced them as far. Most of the change is at the extremities."
The algorithm takes advantage of other differences between speech sounds to enhance perception, and multiple features can be customized. It is meant to complement existing hearing aid technology, and may even be used in conjunction with cochlear implants, which are surgically implanted electronic devices.
"A new protocol is to give the person with a cochlear implant a hearing aid, too. Implants give the high pitches that a listener is missing, but not the low," he said. "The algorithm could provide redundancy as the listener hears high pitches from both the implant and the hearing aid."
Alexander spoke about his innovation during the International Hearing Aid Conference in Lake Tahoe, Calif. He has received funding from a National Institutes of Health Challenge Grant and Purdue's Entrepreneurial Leadership Academy.
The Purdue Office of Technology Commercialization has filed a patent application on Alexander's algorithm. For more information about developing and commercializing it, contact the Purdue Office of Technology Commercialization at 765-588-3479, otcpatent@prf.org.
