For elderly gamers, this could be the biggest hit since Wii Sports: a new video game helped older people with hearing loss get better at tracking speech in noisy environments, new research says.

The game had players complete a puzzle by listening for clues as background noise steadily got louder over time. After two months of playing, elderly adults with hearing loss could hear 25 percent more words spoken under noisy conditions than they could before, according to the study published in the journal Current Biology. It won’t replace hearing aids, but it could boost their effectiveness.

“That was a holy shit moment.”

There’s a growing interest in using video games as digital medicine to treat disorders like ADHD or lazy eye, but the idea is somewhat controversial. Playing a game might make you better at winning it, but there’s less evidence that it could boost your performance in real-world situations.

Still, researchers led by Daniel Polley at Massachusetts Eye and Ear Infirmary and Harvard Medical School suspect that if a game is well designed and engaging enough, it could act like a kind of brain boot camp. Since middle-aged musicians don’t seem to have as much trouble as non-musicians at filtering out background noise, the researchers created a video game to capture some of the challenges of playing a musical instrument.

“Every subject we trained, on one of these speech in noise tests their accuracy went up,” Polley says. “I mean, this is science, nothing is that consistent. That was a holy shit moment.”

About one-third of people between ages of 65 and 74 have some degree of hearing loss. Typically, they come to the clinic and say, “‘I’m having a lot of trouble understanding at restaurants, or at family events,’” says study co-author Jonathan Whitton. “It’s about their social life, really, and being able to connect with people.”

“It’s about ... being able to connect with people.”

Hearing aids don’t help with tracking a single voice in a chorus of chatter, because they just turn up the volume on everything. But people who’ve been playing music their whole lives don’t seem to have quite as much trouble hearing voices through background noise — both when they’re young, or even as they get older. Of course, scientists are still figuring out why exactly that is, and there’s a lot of individual variation.

Polley and his team suspect that it has something to do with the feedback loop of predicting how a note will sound, trying to play it, and hearing the result. So they designed a video game to harness those characteristics. The changing tones guide the player as they use their finger to trace the outline of a hidden puzzle piece on a tablet’s screen — kind of like listening for the right note as you move your finger along a guitar’s fretboard. The game works a lot like a child’s game of hot and cold, but with two catches: there aren’t any words, and the background noise keeps getting louder, making the changing tones harder to hear.

Polley, Whitton, and their colleagues recruited 24 people with hearing loss, all of them around 70 years old. After testing how well they could hear single words and whole sentences against increasing levels of background noise, the researchers randomly divided up the participants into two groups. One group played the tracing game. Another played a memory game, where the player would have to remember nonsensical strings of words like “ready Laker go to green four now” in order to complete a puzzle.

After eight weeks of training, the researchers tested the participants’ hearing again. The group that played the memory game didn’t get any better at hearing spoken words through background noise. But the group that played the tracing game could hear 25 percent more of the words in sentences and gibberish phrases — even though their game had just involved sounds, not speech.

The researchers suspect that the study participants that played the tracing game got better at tracking the thread of a specific sound through a noisy soundscape. And even though the game only used non-verbal sounds like whirrs and clicks, that skill carried over to being able to pick out one person’s voice in a chorus of background chatter. But, like with playing an instrument, the study participants got rusty without practice. By about two months after they stopped playing the game, their improvements disappeared.

“Sound is invisible. And yet some of the most powerful forces in our lives, like gravity, are invisible.”

Of course, the scientists don’t know exactly why this game helped people get better at discriminating speech, or if there might be better game designs. That’s the next step, Polley says. “We probably didn’t nail it the first time,” he says. The study was also small, so it’s possible that this video game might have very different effects on people of different ages, musical backgrounds, video game expertise, or degrees of hearing loss.

Still, this video game succeeds at skill-building outside the confines of the game and boosting performance in a real-world, speech perception task, says Nima Mesgarani, an electrical engineer at Columbia University’s Zuckerman Institute who was not involved in the research. It’s “a promising step in this area,” he says.

“It is important work, and people need to appreciate how trainable the nervous system is,” agrees Nina Kraus, an auditory neuroscientist at Northwestern University. “We live in such a materialistic world where if we don’t see a thing, if it isn’t shiny and jangly, we often don’t pay attention to it — and sound is invisible. And yet some of the most powerful forces in our lives, like gravity, are invisible.”