Listen up - hearing health is vital
Pete Townsend of the band The Who, is a legend in the rock and roll industry, and has made millions of dollars during the course of his long career. But one thing that all his money cannot buy him is normal hearing: because Pete Townsend is almost deaf.
Hearing problems and deafness affects a huge number of people in this country and can affect a wide spectrum of peoples across all ages. It’s a sense that we all have and use on a daily basis to communicate, to enjoy life and as a warning sensor for dangers that lurk nearby. Most of us think that our ears are merely there for hanging our sunnies on, or for the more decorative personality, to pierce with fashionable pieces of metal. Our ears are much more than that and comprise the external part of our auditory apparatus, a highly complex structure without which our lives would be much more limited and much more challenging.
The auditory apparatus is divided for convenience into three distinct parts:
The Outer Ear comprises the swirled, cartilaginous structures we sport on either side of our head, plus the ear canal itself which funnels sound waves from the outside world down toward the ear drum.
The Middle Ear is the space behind the eardrum that contains the tiny bones - the stapes, hammer and the anvil - which amplifying the sound waves received by the drum, and transmit them into the cochlear. This space is connected to the back of the nose by the eustachian tube, and allows the air pressure to be equal on both sides of the eardrum: otherwise the drum couldn’t vibrate properly and all sounds would be muffled. This is the area that commonly gets blocked and infected when little children get bad head colds and leads to the condition known as otitis media - or a middle ear infection.
The Inner Ear refers to the cochlear which converts mechanical sound waves into electrical impulses through the movement of minute hair cells. These hair cells are activated when the sound waves transmitted from the “three small bones”, are transferred into the fluid medium within the cochlear and which bath these tiny hair cells. The nerves that are triggered by these hair cells then combine to form the auditory nerve that relays the “sounds” we hear to the hearing centre in the brain.
Damage to any of these structures, or to the linkages within this chain, will result in impaired hearing. So:
Block the external canal with anything - for example, in infants this can be a tiny toy or even a miniature battery:
whilst at the other end of the age spectrum, a buildup of wax is the common culprit - and the sound waves will fail to reach the eardrum and hearing is reduced. Luckily, both these scenarios are easily reversed and normal service is resumed!
Damage the drum with a large hole or perforation and it won’t work properly. The most dramatic example of this is that after a terrorist explosion the most obvious feature of the survivors is that they are very quiet. The reason is not just the terrible experience but that their eardrums have been blasted open and they literally can’t hear anything! Simple perforations are much more common and are a frequent consequence of middle ear infections in children. In the vast majority of these cases, these perforations will heal of their own accord, or for the more persistent, can be fixed with simple surgical procedures.
Damage to the stapes, hammer or anvil means that sound cannot be augmented and hearing is greatly reduced. This can be an age related problem or even simple arthritis can affect them. Surgery is an option in these cases.
Damage to the hair cells in the cochlear is one of the most frequent causes of hearing impairment and is the one that most older folk may face. It’s also the one that can be an occupational hazard due to chronic exposure of sounds - think of people who use electrical saws, chainsaws, those employed in the construction industry and a more modern phenomenon, those involved in the music industry such as Pete Townsend. Finally, amongst this growing group are those who use ipods with a high volume setting: if you can’t hear someone speaking to you when you’re listening to your music then the volume is too high and could well be in the dangerous range.
One of The Who’s greatest hits was called “My Generation” and these days Pete Townsend can be heard talking about just that - speaking about the dangers to hearing as a result of chronic exposure to loud music both at home and at concerts. He’s learned his lesson the hard way: let’s hope our generation will learn from his mistakes.
Sound levels of common noises:
Decibels Noise source
60 Normal conversation
70 Washing machine
85 to 90 Heavy city traffic, power lawn mower, hair dryer
100 Hand drill
110 Chain saw, rock concert
120 Ambulance siren
140 (pain threshold) Jet engine at takeoff
165 12-guage shotgun blast
180 Rocket launch
Adapted from National Institute on Deafness and Other Communication Disorders, 2008; the National Institute for Occupational Safety and Health, 2009; and American Tinnitus Association, 2009