Turning the volume down on noise trauma and hearing loss
Canadian television broadcasters have been ordered to turn down the volume on the
commercials they run.
The Canadian Radio-television and Telecommunications Commission has given the TV
industry until September to implement controls on the volume of ads, which are often
much louder than the programs during which they air.
The move will certainly please viewers, but it will also help protect Canadians' hearing - something Sue Becker is passionate about.
The professor in McMaster's Department of Psychology, Neuroscience & Behaviour studies, among other things,
sensory neural hearing loss - which includes that caused by exposure to loud noise.
She says that while any loud noises, including those from television ads, can cause hearing
damage, the biggest concern for most people should be their personal music devices.
"A colleague of mine in New York who studies tinnitus (ringing in the ears) and hearing
loss has found a large number of test subjects amongst undergraduates who ride the city's subway with their iPods cranked up," she says. "It doesn't take as much as you might
To process sound, the human ear has to interpret the sound waves it receives. Approximately 30,000 hair cells attached to the basilar membrane, found within the inner
ear, move when hit by the waves. When displaced, they trigger neural impulses in the
auditory nerve - creating the signal that goes to the brain.
"Those hair cells are most often damaged after noise trauma or aging," Becker says. "The
hairs should be in nice, neat rows, like the bristles of a hair brush. But when they're
damaged, they look as though someone's come along and stomped on them."
She says hearing damage can begin when sounds reach more than 90 decibels - the noise
level of truck traffic or a lawnmower.
Becker is part of the team that developed the NeuroCompensator hearing aid technology.
Traditional hearing aids generally amplify sounds based on the frequencies the user is
having trouble hearing. Instead, the NeuroCompensator uses a model of the human ear to
reinforce sound based on what the damaged parts of the user's hearing would have heard.
This technology aims to take into account the interference of multiple sound frequencies,
aiming to improve hearing aid performance in noisy situations, such as crowds, where
traditional hearing aids have difficulty.