SEATTLE -- A research project at the University of Washington is helping hearing-impaired people hear music for the first time through improvements to cochlear implants.
A cochlear implant is a small, electronic device that lets a person who is profoundly deaf or hard of hearing perceive sound. While the technology helps people to comprehend speech, it can be extremely difficult to hear music through a cochlear implant.
But, UW scientists hope to change this. They have developed a new way of processing the signals in cochlear implants to help users hear music better.
"Right now, cochlear-implant subjects do well when it's quiet and there is a single person talking; but with music, noisy rooms or multiple people talking, it's difficult to hear," said Les Atlas, a UW professor of electrical engineering. "We are on the way to solving the issue with music."
Collaborator Jay Rubinstein, a UW professor of otolaryngology and of bioengineering, said music gives humans an opportunity for emotional expression and can improve quality of life and social and cultural connections, but it is rarely considered in clinical evaluations of cochlear implants.
Atlas has personally experienced the effects of a hearing impairment as both his father and grandfather became deaf as they aged. Atlas is currently losing his hearing himself.
"I want to continue to hear music, even as I get older," he said.
Rubinstein recently published researchers’ initial findings in the IEEE Transactions on Neural Systems and Rehabilitation Engineering. A study on eight cochlear-implant users showed that using this new coding strategy let them distinguish between musical instruments much more accurately than with the standard devices.
People who use cochlear implants usually perceive words by their syllables and rhythms, not through tone or inflection. The researchers tested their new processing technique on cochlear-implant users by playing common melodies such as "Twinkle, Twinkle, Little Star" with the rhythms removed. They found that timbre recognition – the ability to distinguish between instruments – increased significantly, but the ability to perceive a melody was still difficult for most people.
"This is the first time anyone has demonstrated increased timbre perception using a different signal-processing system," said Rubinstein, who is also a physician at the UW Medical Center and Seattle Children's hospital and director of the Virginia Merrill Bloedel Hearing Research Center. "With cochlear implants, we've always been oriented more toward speech sounds. This strategy represents a different way of thinking about signal processing for music."
Researchers hope to fine-tune the signal processing to make it compatible with cochlear implants already on the market so users can improve their music perception right away. They also are working on algorithms to better support device users' perception of pitch and melody.