A bionic brain implant may soon replace old-fashioned hearing aids

A brain-controlled implant may boost hearing more than traditional hearing aids, a study suggests.

More than one in seven Americans - 50 million people - are living with some degree of hearing loss, with nearly 30 million of them likely eligible for hearing aids.

And those numbers are climbing, with the number of hearing loss patients expected to skyrocket to 73 million by 2060.

Hearing loss is traditionally treated with removable hearing aids that sit on or around the ear, picking up sound through a microphone and amplifying it while suppressing background noise.

However, they cannot separate and enhance specific noises, such as a conversation at a crowded party, which can make it difficult for people with hearing loss to hone in on a particular voice.

Now, researchers at Columbia University may have found a solution.

The team looked at patients who had small electrodes implanted into their brains and used them to measure brain activity as they focused on one of two overlapping conversations.

The device was able to automatically detect which conversation a patient was paying attention to and adjust the volume in real time, turning the volume up on that while quieting down the other.

This allowed participants to concentrate on specific speakers in crowded situations, much like the brain of someone with normal hearing can.

Researchers behind the new study, published in Nature Neuroscience, believe the technology could be adapted into more advanced hearing devices.

'We have developed a system that acts as a neural extension of the user, leveraging the brain’s natural ability to filter through all the sounds in a complex environment to dynamically isolate the specific conversation they wish to hear,' Dr Nima Mesgarani, senior study author and principal investigator at Columbia's Zuckerman Institute, said.

'This science empowers us to think beyond traditional hearing aids, which simply amplify sound, toward a future where technology can restore the sophisticated, selective hearing of the human brain.'

The new research is based on a 2012 finding from Mesgarani and Dr Eddie Chang, a neurosurgeon at the University of California, San Francisco.

The duo had found that brain waves in the auditory cortex, which processes sounds, are responsible for selecting one voice in a crowd and amplifying it while filtering out others.

This gave the researchers a pattern of activity to look at and identify which sound source they want to hear.

To build on this finding, the Columbia team looked at four individuals who were hospitalized for epilepsy treatment. These patients, who had typical hearing, were chosen because they already had electrodes in their brains as part of their treatment, which allowed the researchers to monitor signals coming from their auditory cortex.

Two loudspeakers were placed in front of each patient, each one playing a different conversation.

The device automatically adjusted the volume of the conversations based on their brain waves and correctly identified which conversation the person wanted to hear up to 90 percent of the time.

'The central unanswered question was whether brain-controlled hearing technology could move beyond incremental advances, towards a prototype that could help someone hear better in real time,' Vishal Choudhari, the paper's first author who led the development and evaluation of the hearing system, said.

'For the first time, we have shown that such a system that reads brain signals to selectively enhance conversations can provide a clear real-time benefit. This moves brain-controlled hearing from theory toward practical application.'

The researchers noted that while the accuracy may diminish when looking at brain waves from people with hearing loss, more research is worth pursuing because even advanced hearing aids cannot focus on specific voices.

'The results mark an important step toward a new generation of brain-controlled hearing technologies that align with the listener’s intent, potentially transforming how people navigate noisy, multi-talker environments,' Choudhari said.