A mind-controlled hearing aid that allows the wearer to focus on specific voices has been developed by scientists who claim it can alter the ability of hearing-impaired people to deal with noisy environments.
The device mimics the brain's natural ability to emphasize and amplify a voice against background talk. So far, even the most advanced hearing aids work so that all voices are raised at once. This can be experienced as a cacophony of sound to the wearer, especially in crowded environments.
Nima Mesgarani, who led the recent progress at Columbia University in New York, said, "The area of the brain where sounds are processed is extremely sensitive and powerful. It can seemingly effortlessly boost one voice over another while today's hearing aids are still pale.
This can significantly affect a carrier's ability to engage in conversation, making busy social events a particular challenge.
Scientists have been working for years solves this problem, the so-called cocktail party effect. The brain-controlled hearing aid appears to have solved the problem through a combination of artificial intelligence and sensors designed to monitor the listener's brain activity.
The hearing aid first uses an algorithm to automatically separate the voices of multiple speakers. These audio tracks are then compared to the brain activity of the listener. Previous work by Mesgarani's lab has shown that it is possible to identify the person someone is watching because their brain activity most closely follows the sound waves of that voice.
The device compares the sound of each speaker with the brain waves of the person wearing the hearing aid. The speaker, whose voice pattern most closely matches the listener's brainwaves, is strengthened over the other, so he can effortlessly adjust to that person.
The scientists developed an earlier version of the system in 201
To test the device, the lab recruited epilepsy patients who had electrodes implanted in their brains prior to planned brain surgery to monitor seizure activity. The electrodes were implanted in their brains.
An algorithm caught the attention of patients as they listened to different speakers they had not heard before. When a patient focused on a loudspeaker, the system automatically amplified that voice with a delay of just a few seconds. When their attention shifted to another speaker, the volumes changed to reflect this shift.
The current version of the hearing aid, which included direct implants in the brain, would be inappropriate for general use. However, the team estimates that it will be possible over the next five years to develop a non-invasive version of the device that can monitor brain activity using electrodes in the ear or under the skin of the scalp.
Mesgarani said that the device could also be used like an audio binocular to covertly listen to people's conversations, although this was not the intended application.
The next step is to test the technology in people with hearing impairment. One question is whether it will be so easy to match the brain activity of people who are partially deaf to sound waves from the language. According to Jesal Vishnuram, technology manager of the charity Action on Hearing Loss, one of the reasons why people find conventional hearing aids uncomfortable in noisy environments is that their brains are unable to filter sounds, and less effectively.
] "One of the reasons why people struggle is that they often wait a long time to get a hearing aid, and in that time the brain forgets how to filter out the noise and focus on the language," said you. "This is a really interesting research, and I would like to see the real effects of it."
The results were published in the journal Science Advances.