A research study published online last month in Nature Neuroscience, has broken new ground in exploring how people with hearing impairment process sounds in noisy environments. The findings could be very useful for designing hearing aids and assistive technologies in the future.
A research study published online last month in Nature Neuroscience, has broken new ground
in exploring how people with hearing impairment process sounds in noisy
environments. The findings could be very useful for designing hearing aids and
assistive technologies in the future.
Background noise causes the ears of people with hearing impairments to work
differently, according to the research. One of the study’s authors, Kenneth S.
Henry, commented that for people with a hearing impairment, background noise is
like "turning on a dozen television screens and asking someone to focus on
one program. When immersed in the noise, the neurons of the inner ear must work
harder because they are spread too thin. The results can be fuzzy because these
neurons get distracted by other information." Dr. Kenneth S. Henry is a
postdoctoral researcher in the Department of Speech, Language and Hearing
Sciences at Purdue University.
“Previous studies on how the inner ear processes sound have failed to find
connections between hearing impairment and degraded temporal coding in auditory
nerve fibers, which transmit messages from the inner ear to the brain,” noted
study co-author Dr. Michael G. Heinz, an associate professor of speech,
language, and hearing sciences, who studies auditory neuroscience. “The
difference is that such earlier studies were done in quiet environments, but
when the same tests are conducted in a noisy environment, there is a physical
difference in how auditory nerve fibers respond to sound.”
During the study, researchers measured a variety of physiological markers in
chinchillas, which have a similar hearing range to humans. Some of the subjects
had normal hearing and others had a cochlear hearing loss, as they listened to
tones in quiet and noisy environments that simulated what people would hear in
a crowded room.
“The study confirmed that there is essentially no change, even for those
with hearing loss, in terms of how the cochlear neurons are processing the
tones in quiet, but once noise was added, we did observe a diminished coding of
the temporal structure,” Henry says.