Shafaqna Health:Imagine a crowded room. It’s a chaos of sound, teeming with indistinct voices.
Scientists call this the cocktail party problem. To overcome it, most people are able to focus on a single speaker’s voice, which cues the brain to amplify that sound and turn down the rest.
For people who use hearing aids, though, that process becomes a lot harder.
Now, in the journal Nature Neuroscience, a team describes a solution that decodes a person’s brain waves to choose which voice their hearing system will amplify.
It amounts to a “brain-controlled hearing aid,” says Nima Mesgarani, an author of the paper and an associate professor at Columbia University who runs the school’s Neural Acoustic Processing Lab. The new approach could lead to better hearing technology, including hearing aids, assistive listening devices and cochlear implants.
But so far, the approach has been tested only on four people with typical hearing, says Josh McDermott, who runs the Laboratory for Computational Audition at MIT and was not involved in the study.
Whether the system will work as well for people with hearing loss remains an “open question,” he says.
The new research is based on a discovery made in 2012 by Mesgarani and Dr. Eddie Chang, a neurosurgeon at the University of California, San Francisco.
The finding helps explain how the brains of people with typical hearing are able to solve the cocktail party problem by selecting one voice to amplify while filtering out others.
Mesgarani and Chang showed that the key is a distinct pattern of brain waves in the auditory cortex, which processes sounds.
“When you look at the brain of a listener at the cocktail party,” Mesgarani says, “what you see is that these brain waves are tracking only the sound that [the listener] is focusing on, and not the other sources.”
In this image, a hand holds up a Polaroid photo of a person walking down a country road in Tuscany, Italy. The photo overlaps with an actual road in Tuscany that’s in view of the person holding up the photo.
Science
In the brain, objects seen and imagined follow the same neural path
The pattern of activity “gives us a signature,” Mesgarani says. “We can look at someone’s brain and decide, oh yeah, this is the source they want to listen to.”
So the team set out to see whether they could use that neural signature to improve hearing systems. The effort was led by Vishal Choudhari, who was a graduate student in Mesgarani’s lab at the time. He’s currently a research scientist at a startup working on next-generation hearing technologies.
The team did an experiment with four people who were in the hospital for epilepsy treatment.
