Chewing, talking or singing might potentially help protect your hearing, suggests an Australian researcher.
These simple actions may activate the tiny muscles in your ear to muffle loud sounds, says Dr Andrew Bell from the Research School of Biology at the Australian National University.
In a paper published in the Journal of Hearing Science, Dr Bell suggests conventional models of hearing do not explain why contracting the muscles of the ear – which some people do voluntarily – can reduce sound by 30 decibels.
The answer, he says, lies in a discarded 19th-century theory that suggests the middle ear muscles work like a hydraulic pump.
This theory may explain why some people seem to have “tough” ears that are impervious to hearing loss while others are more sensitive, he says.
“The sound of an opera singer singing can be 100 decibels, so why doesn’t an opera singer go deaf?,” Dr Bell said.
“The explanation is that when an opera singer sings, the middle ear muscles contract.”
The middle ear consists of three tiny bones – including the smallest bone in the body – two miniature muscles and tendons.
“If you close your eyes tightly you’ll hear a fluttering sound and that’s your middle ear muscles at work,” Dr Bell said.
Under current theories of how the ear muscles work, the muscles and bones of the middle ear stiffen up in reaction to a loud noise, dampening sound waves that travel into the cochlea where fine hairs detect the vibration.
“Obviously [the bones and muscles of the middle ear] have got some sound control function because they’re activated when the sound gets loud,” Dr Bell said.
“But that doesn’t quite tell you about the fact that when you close your eyes or activate your middle ear muscles you can get a 30-decibel or 1,000 times change in the amount of sound that goes through.
“If you do the model of how that process works in terms of sound conduction, the best you can get is about 100 times. So that doesn’t quite seem to be a good explanation of what is going on,” he said.
Instead, the pressure theory proposes the middle ear muscles work like a hydraulic pump, pushing the last bone into the cochlea and increasing the pressure of the watery fluid that fills it. In turn, that pressure squeezes the sensing cells inside and reduces their sensitivity.
Dr Bell says better understanding of this mechanism could help prevent hearing loss.
“We might be able to find ways of making the middle ear muscles more activated. Even if you’re chewing or singing along to music you’re actually doing something that might encourage middle ear muscle activity that might give you more protection than otherwise,” he said.
It is an issue he says is very important in an age where use of mp3 players is causing hearing loss but people do not heed the warnings.
“Jimi Hendrix sounds awesome when it’s loud and people don’t want to turn it down,” he said.
“Here we have the middle ear with this natural inbuilt protective mechanism.”
“I think it’s worthwhile to open up the question and see what all the options are given that things are going to get steadily worse if we don’t do something.”
In the meantime, Dr Bell advocates taking precautions such as limiting exposure to loud music and using over-the-ear ear phones with noise cancellation instead of bud-style ear phones to help prevent hearing loss.
If you have any questions about hearing loss contact Hidden Hearing.