Cochlear implants could be stimulated with an effect similar to white noise in order to improve hearing of their users, according to a new study.
With a background of continuous white noise, hearing pure sounds becomes even more precise, researchers have shown. Their findings could be applied to the further development of cochlear implants according to a study were published in the journal Cell Reports.
The more precisely we can distinguish sound patterns, the better our hearing is. But how does brain manage to distinguish between relevant and less relevant information — especially in an environment with background noise?
Researchers led by Prof. Dr Tania Rinaldi Barkat from the Department of Biomedicine at the University of Basel have investigated the neuronal foundation of sound perception and sound discrimination in a challenging sound environment.
The focus was on research into the auditory cortex — the “auditory brain,” that is, the area of the brain that processes acoustic stimuli. The resulting activity patterns stem from measurements in a mouse brain.
The team was able to demonstrate that the brain’s ability to distinguish subtle tone differences improved when white noise was added to the background. Compared to a quiet environment, the noise thus facilitated auditory perception.
The data of the research group showed that white noise significantly inhibited the activity of the nerve cells in the auditory cortex.
Paradoxically, this suppression of the neuronal excitation led to a more precise perception of the pure tones. “We found that less overlap occurred between populations of neurons during two separate tone representations,” explains Professor Tania Barkat. “As a result, the overall reduction in neuronal activity produced a more distinct tone representation.”
To confirm that the auditory cortex and not another area of the brain was responsible for the change in sound perception, the researchers used the light-controlled technique optogenetic. Their findings could possibly be used to improve auditory perception in situations where sounds are difficult to distinguish. According to Barkat, it is conceivable that cochlear implants could be stimulated with an effect similar to white noise in order to improve the frequency resolution and thus the hearing result of their users.