Hearing aids that read your brain to create the cocktail-party effect
Imagine you’re trying to have a catch-up with your best friend in the middle of a noisy pub. Despite the chatter around you, you’re able to filter out the distracting background noise, and hear the latest gossip. This so-called “cocktail-party effect” comes naturally to many of us, but for people who use hearing aids, coping with irrelevant noises is difficult and frustrating.
Cue the potentially transformative new system, led by researchers at Columbia University that enables users to single out a speaker in a noisy room - using the brain to amplify the voice you want to listen.
To understand the listener’s intention, it uses electrodes placed on the auditory cortex, the section of the brain (just inside the ear) that processes sounds. As the brain focuses on each voice, it generates a telltale electrical signature for each speaker.
The system, described in Science Advances, is a deep-learning algorithm that was trained to differentiate between different voices looks for the closest match between this signature and that of the various speakers in the room. It then amplifies the voice that matches best, helping the listener focus on the desired one.
The obvious drawback: the current system involves brain surgery to implant the electrodes. However, the researchers say brain waves could be measured using sensors placed in or over the ear, meaning the system could eventually be embedded into a hearing aid (although this would be less accurate). It could also be used by people without hearing loss who want to boost their ability to focus on one voice.
Another difficulty is the time lag. It’s just a few seconds, but it could mean missing the start of someone’s sentence, says Nima Mesgarani, at Columbia University’s Neural Acoustic Processing Lab, who coauthored the paper. There’s an inherent tension between accuracy and speed at zeroing in on a specific speaker, he says—in other words, the longer the system has to listen, the more accurate it is. This issue requires further research to solve, but he says this sort of device could be commercially available in just five years.