A lowly fly may offer hope to hearing loss sufferers

Photo credit: Jpaur licensed under CC BY-SA 3.0

And Michelle Pucci, TVO, tells us how in her article, “How a tiny fly on a treadmill could lead to better hearing aids.” Pucci introduces us to the research team studying the ormia ochracea, a small fly that is drawn to “crickets’ singing, but no one quite knows how it manages to pick out that sound amid the cacophony of the natural world and locate it so precisely.” Why is this important?  Because if researchers can determine how the fly “pinpoints individual sounds in a noisy setting,” writes Pucci, “it could help solve the so-called cocktail party problem — the one that makes it tough for your grandmother to hear what you’re saying at family functions (and causes her to shout at you), because her hearing aid picks up too much background noise.”

Andrew Mason, a biologist at the University of Toronto explains that the fly’s “eardrums work like a scale, and incoming noises tip the balance.” Unlike humans, the fly’s “eardrums are connected — which Mason says could explain why the fly tries to interpret the different levels of sound it receives in both ears.”  Humans, on the other hand, can “locate and isolate the sounds they want to listen to, even in noisy environments, if the sources are far enough away from one another.”

The problem hearing aid wearers experience is that “it’s impossible to focus on a single conversation in a noisy room…because hearing aids trick the ear into thinking all those sounds are the same distance away.” That is, the hearing aid amplifies everything, making the task of concentrating on one conversation among many impossible. As researchers learn more about the ormia ochracea’s excellent sound-location abilities, engineers have used that knowledge.  Today, mics in some hearing aid design “mimic the fly’s ear structure,” and “research groups around the world are working on hearing aids that would allow the wearer to home in on different frequencies.”

So why do ormia ochracea search for crickets?  The answer is pretty grim:

[T]he female deposits its spawn inside the crickets, who sing when looking for a mate. Black-striped larvae then hatch inside the doomed cricket and scrape at its innards for 10 days…before “bursting out of the side like in Alien.”

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