Are songbirds the key to better hearing aid technology?
Although it sounds like something straight out of a fairy tale, songbirds are, in fact, helping build the next generation of hearing aids. Scientists at the University of California at Berkeley have been studying the talented tweeters for the past two years and the results have brought exciting possibilities to the future of hearing aid technology.
Of course we know that song is an important form of communication among the birds, but it turns out that the avian world also has much to teach humans about how the hearing part of the brain works. In fact, new research into the way songbirds distinguish the call of their mate from that of hundreds — or even thousands — of other birds might just represent the future of hearing aid technology.
According to UC Berkeley neuroscientist Fredericâ€‹ Theunissen, head of the study, a hearing aid that processes sound the way the brain does, by focusing on "signal sound" and nearly eliminating unwanted background noise, could be in our near future. Theunissen and his team of graduate students at UC Berkeley spent two years studying how exactly songbirds are able to focus in on that “signal sound," in the hopes that humans experiencing hearing loss could benefit.
So how can the highly developed auditory function of a bird be helpful to humans?
Birds have a highly developed sense of hearing which starts in the egg. During courtship and pairing, songbirds learn to recognize their mate by certain voice characteristics, such as pitch and frequency. Thereafter, songbirds have the ability to focus in on just their mate’s call amid the din of hundreds of other birds. In humans, a healthy brain and healthy ears can also tune in to “signal sounds” in the same way a bird can.
Think of it this way; for those with healthy hearing, the ability to focus on a certain sound, or “signal sound," in a noisy environment is something often taken for granted. Even amid a cacophony of other sounds, those with healthy hearing are usually able to distinguish familiar voices. For individuals with hearing loss who wear hearing aids, however, crowded restaurants or loud parties can present tremendous difficulties. Hearing aids tend to amplify all sounds including background noise, burying a particular voice in the din. Songbirds, however, are highly skilled in honing in on just one “signal sound," like the call of a mate, and blocking out the rest of the noise.
“In a crowded place, it can be very difficult to follow a conversation even if you don’t have hearing deficits,” Theunissen said in a medical press release. “That situation can be terrible for a person wearing a hearing aid, which amplifies everything.”
Using brain imaging of songbirds, Theunissen and his team of scientists were able to identify the exact neurons that the birds use to shine an “auditory spotlight” on a signal, kind of like locking in on a target. In humans, the ear combines with those neurons to search for and locate certain frequencies and pitches. The neurons focus in on one sound while the rest of the noise is suppressed. After identifying those neurons, the researchers then replicated the “auditory spotlight” in the form of an algorithm.
With an algorithm, the scientists have information that can be loaded into hearing aids which means future hearing aids could be equipped with the technology to detect the “signal sound” in noisy environments. They would be able to focus on the signal sound, boost the signal sound while suppressing unwanted background noise, yet not entirely suppress background or render it unpleasant.
“This hearing aid should not eliminate all of the noise or distort the signal,” Theunissen says. “That wouldn’t sound real, and the real sound is the most pleasant and the one that we want to hear."
Be sure to check with your hearing healthcare professional for updates on these exciting new developments in hearing aid technology. And the next time you’re out for a walk and hear the fee-bee of a chickadee, remember it’s not just birdsong; it could be the wave of the future when it comes to hearing aids.