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1 in 6 youths in Singapore at risk of noise-induced hearing loss; everyday sounds and their noise levels

Published on Mar 27, 2014 3:48 PM
Sony changed lifestyles way before Apple came along with its iPod and iPhone. -- ST FILE PHOTO: DESMOND FOO

Sony changed lifestyles way before Apple came along with its iPod and iPhone. In the late, 1970s, the Japanese electronics giant introduced the Walkman to the world, forever changing the way personal music is consumed.

There was no turning back.

These days, personal music players (PMPs)are in the spotlight for a totally different reason: There is increasing concern that noise-induced hearing loss (NIHL) is prevalent in users, especially children and teenagers.

A recent study by a group of biomedical engineering students from Temasek Polytechnic, published in the Singapore Medical Journal this year, revealed that at least one in six youths here are at risk of NIHL caused by high volumes from their portable music players. A total of 1,928 Temasek Polytechnic students participated in the survey. Out of the group, 16.4 per cent listened to PMPs at more than 85dB for eight hours daily. Gender-wise, male students tended to listen to music at louder volumes than female students,

What is NIHL, exactly? Here are three things to know about NIHL:

What is NIHB?
NIHL is the only type of hearing loss that is completely preventable.

Sounds that are too loud or that last a long time may cause sensitive structures in the inner ear to be damaged. When this happens, the result is NIHL.

According to American Speech-Language-Hearing Association, sound levels are harmful when:

* In a noisy area, you must raise your voice to be heard.
* You can't hear someone 1m away from you.
* Speech around you sounds muffled or dull after you leave the noisy area.
* You have pain or ringing in your ears - also known as "tinnitus" - after exposure to noise.

What causes NIHL?
A few studies have implied that “pleasant” sound is less likely to cause NIHL than noxious sounds. But generally, noise hazard is based on level and duration, which means both a one-time exposure to an intense “impulse” sound, like an explosion, as well as continuous exposure to loud sounds over a long period of time, can cause NIHL.

What are some recreational activities that can put you at risk for NIHL?
The National University of Singapore's Saw Swee Hock School of Public Health highlights using earphones "for more than three minutes at maximum volume, with portable media players (PMPs) as the main culprit among the younger population".

In the United States (US), target shooting and hunting, snowmobile riding, playing in a band, attending loud concerts and of course, listening to PMPs at high volume through earbuds or headphones are listed as activities to be mindful of,

Background story

How loud is loud? 
Sound is measured in decibel (dB) units.

The magic number to take note of is 85dB. Long or repeated exposure to sounds at or above 85dB can cause hearing loss, and the louder the sound, the shorter the amount of time it takes for NIHL to happen, warned the US National Institute on Deafness and Other Communication Disorders.

Conversely, any sound level less than 75dB, regardless of length of exposure, is relatively safe.

Here are the average dB ratings of some common sounds:

Siren =- 120dB

Extremely loud
PMP at maximum volume = 110dB
Hand drill = 100dB
Sound of motorcycle engine = 95dB
Concert = 94dB

Very Loud
Hair dryer/kitchen blender/food processor = 80-90dB 
Vacuum cleaner = 70dB

Normal conversation/clothes dryer = 60dB 
Moderate rainfall = 50dB
Refrigerator hum = 45dB
Quiet room = 40dB

Whisper/quiet library = 30dB

Figures culled from the American Speech-Language-Hearing Association, National Institute on Deafness and Other Communication Disorders and 3M.