Dr Cathy Stephenson: Hearing loss - 4 May
What is noise?
Noise is unwanted sound. It is all around us. It causes the ear to age faster. The World Health Organisation has labelled noise a "serious health issue".
What are the effects of noise?
Noise is the leading cause of preventable hearing loss in the modern world. The hearing loss is gradual, so is often not noticed until it is too late. It is irreversible. Hearing loss affects education, socialisation, employment and general well-being of many New Zealanders, and leads to frustration, anger and social withdrawal in sufferers. 1 out of 10 people in New Zealand has a hearing loss, and this number is increasing dramatically. It is estimated that 30 school children per 1000 have a hearing loss; 1 in 12 thirty year olds; and 1 in 3 sixty five year olds.
Noise can cause tinnitus - a ringing or buzzing noise in the ear. This can be a warning sign for early damage to the ear.
Noise can also cause sleep disorders, mental fatigue, high blood pressure and poor concentration.
How does noise cause hearing loss?
Sound waves are transmitted through the funnel-like outer ear
(the "pinna), via the ear canal to the ear drum ("tympanic
membrane"). The sound waves vibrate the drum, which transmits them
to the middle ear. The middle ear ("ossicles") amplifies the sound
and transfers the waves to the inner ear. The inner ear ("cochlea")
contains microscopic hair cells that vibrate and send electrical
impulses to the brain allowing us to hear. Too much noise, or too
loud, damages these hair cells, which are unable to regenerate. The
damage affects high frequency sounds first, but will affect lower
pitch sounds too over time.
What are the worst noises?
Workplace - employers have a responsibility to reduce noise exposure, and provide effective hearing protection. If you work in a noisy environment, try to have regular breaks and reduce the amount of time you are exposed to the noise if possible. Make sure you wear adequate ear protection - proper ear muffs are by far the most effective, and don't require ongoing adjustment. Ear plugs can be effective for less intense noise, but need to be properly fitted and regularly checked. Get regular hearing tests.
Stereos - portable music players are creating a generation of
young people with hearing loss in their 20's and 30's. Ear "buds"
cause more damage than head phones. If you listen to music for long
periods, try to take regular breaks and reduce the volume - some
systems come with automatic volume limiters that keep the volume at
a safe level. If you can't hear people talking when you are wearing
your headphones, the volume is too loud - turn it down!
DIY - a recent National Foundation for the Deaf survey has revealed
that up to 700,000 New Zealanders are at risk of damaging their
hearing through DIY. Sustained noise of 80 decibels or above can
cause permanent damage to hearing. Some common DIY activities
include:
Lawnmower 95dB
Hammering nails into wood 127dB
Chainsaw 110dB
Electric drill 80dB.
Hearing protection should be worn for all these tasks, and in any
high noise environment.
Is there any treatment?
Prevention! Noise damage is 100% preventable. Follow the advice:
E - earplugs
A - avoid loud sounds
R - Reduce sounds/turn down the volume
S - shorten the exposure time (less than 30
minutes if possible).
Once permanent damage is present, the only treatment is a hearing aid. Most hearing loss can be substantially improved with the use of an aid. Aids are now highly advanced, and can be tailored to the individuals needs. They can be expensive but there are lots of different funding options including a basic government subsidy available to all New Zealanders (every 5 years); ACC funding (for accidental or work-related hearing loss); funding from ENABLE New Zealand; or obtaining a cheaper/free aid from a Hearing Aid "Bank" via the Audiological Society.
How do I get tested?
There are screening questionnaires available on-line which can help you assess whether or not you have a hearing difficulty. If you do, or your family or workmates are concerned, contact an audiologist for further evaluation. Visit the MNZAS website to find an audiologist in your area, or ask your doctor for a referral within the public sector.
Useful websites:
Audiologist's
website. List of services in your area, and advice on testing,
hearing aids etc.
National Foundation for the
Deaf. Hearing quiz, resources, education and support, as well
as funding advice.
