CHILDREN'S -GLUED- HEADPHONES : LIVING TECH

CONSTANT headphone use can damage children's ears. Volume is one problem but duration of exposure can be harmful.

With children inclined to listen with headphones for longer periods of time these days, we asked some experts about safe listening habits.

ARE CHILDREN'S HEADPHONES SAFE?

Not necessarily. Children's headphones are generally capped at 85 decibels, which helps. But there's more to it.
''Treating 85 decibels as a safe level makes no sense at all,'' said Rick Neitzel, a Ph.D., an associate professor of environmental health sciences at the University of Michigan.

''Expose is not just intensity - it is also how long it lasts and how frequently it occurs,'' he said.
''Ignoring the time is missing the point. This 85-decibel number has achieved mythical status, not because it is safe but because it is one of the few ways that occupational noise is regulated.''

What's more, some children's headphones - the ones with volume limits touting their safety - are marketed as having comfortable ear pads and a long battery life, so children can rock all day long. ''It is totally conflicting messaging,'' Dr. Nietzel said.

Turning up a favorite song is fine. It's constant exposure to much lower volumes that people don't realize is damaging.

A SAFE AMOUNTING OF LISTENING?

There is no one-size-fits-all answer. If forced to put numbers on such a complex concept, a safe limit for most headphone users for an unlimited amount of listening is 70 decibels, said Drs Neitzel and Fligor, who published a recent paper on recreational sound exposure.

Both are consultants to the World Health Organization's Make Listening Safe program, an initiative to raise awareness about noise-induced hearing damage.

For eight hours of daily exposure to noise, a ''more liberal'' limit is 83 decibels, but 75 decibels is a ''realistic compromise.''

There is no need to suck the joy out of music. ''When you impose some draconian maximum, you turn people off from what is an otherwise well-considered message,'' Dr. Fligor said.

For comparison, 70 decibels is the whir of a small canister vacuum and 85 is a powerful upright vacuum.

Noise, however, is not always steady. It includes peaks and troughs, as well as factors such as frequency harmonics and reverberation.

Furthermore, noise exposure is cumulative. If a headphone-loving child also practices the drums, mows the lawn or bangs on pots and pans every night at 7, the day's noise dose soars.

[For those activities, experts advise protective earmuffs. Earplugs can work for older children, but they are not especially user-friendly and they pose a choking
hazard for young ones.]

An unknown factor is individual susceptibility. It's imp;ossible to predict whose ears are tough and whose are tender.
''The same noise dose has no apparent impact on some and a life-altering impact on others,'' said Bryan Pollard, president of the nonprofit Hyperacusis research, which funds research about noise-induced pain.

Damage from constant low-level noise builds up little warning. People must decide for themselves how much risk they are comfortable with.

The honor and serving of the latest global operational research on Children's Habits and Health, continues. The World Students Society thanks author Joyce Cohen.