Cranking up noise levels in theaters could damage children’s hearing
Kids can be noisy, especially in movie theaters, where they talk and laugh loudly, slurp drinks and kick the seats in front of them. The volume had better be up if anyone is going to hear the movie. That’s easy to do with new technology that produces high volume that surrounds the audience, with no distortion.
But are movies getting too loud?
With the help of audiologists from Hennepin County (Minn.) Medical Center, we used a docimeter (an instrument that measures sound as perceived by the ear) to record sound levels at five movies rated G, PG and PG-13.
The upshot? “These levels are not healthy for ears,” said audiologist Amy O’Keefe.
Just how unhealthy is difficult to gauge, however. There’s no question that noise exposure damages hearing, but the only safety standard is set by the federal Occupational Safety and Health Administration (OSHA) and it’s for adults in the workplace over an eight-hour shift, O’Keefe said.
There is no standard for children.
Yet, children can be at greater risk. Ear canals in children under age 3 take in more sound than adults, and it’s potentially more damaging, said audiologist Janet Hansen. In addition, damage from exposure to loud sounds is cumulative. The younger it starts, the sooner hearing can be affected.
The American Academy of Audiology says Americans are losing their hearing at younger ages. One percent of school-age children already have some degree of hearing loss from noise exposure, said one researcher.
And the problem is more than not hearing well. Tinnitus – an intermittent or constant ringing, fizzing or roaring in the ears – is directly related to noise exposure.
These effects, called noise-induced hearing loss (NIHL), begin when waves from loud sounds enter the ear, pushing down tiny hair cells deep inside. If it’s not too loud, the cells recover when the noise stops, and hearing is unaffected, O’Keefe said.
This bend and recovery happens repeatedly over the years, but eventually it can stop, Hansen said. The hair cells break or stay bent and the result is hearing loss, tinnitus or both, and the damage is permanent and irreversible, hearing experts say.
That probably didn’t occur to the mother who brought her lap baby to the movie “XXX.” Babies are easy. They often fall asleep in movies, even the loud shows. But the sound is still getting into their ears and causing damage, said O’Keefe.
With the docimeter reading of 78.9 (max 98.4), the movie “is definitely too loud,” she said.
“It’s possible that this one exposure caused some hearing loss,” O’Keefe said, “but that might not be known until the preschool hearing screen detects the loss.” Meanwhile, the baby won’t show any outward sign of the damage, she said. He or she won’t cry in pain.
But linking any hearing loss to movies would be difficult. NIHL can be caused by exposure to one very loud noise (gunshot or firecracker) and from repeated loud sounds over time. Children typically are surrounded by noise: loud toys, music and the racket of household equipment
By the time they are teens, they’re used to it. Living with loud noise can become a habit, experts say.
It would help if the ear would show injury by bleeding so damage could be halted, experts say, but it doesn’t. By the time symptoms show (hearing loss or tinnitus), the damage is usually extensive and permanent.
It’s the length of exposure, the volume and the type of the noise working together that produce damaging effects. That makes it hard to judge what’s too loud.
The movie “Signs,” for example, leaves the impression that it’s a loud movie, yet its overall noise score is low. Long periods of silence interrupted by quick bursts of extremely loud sounds is scary and memorable, but not necessarily damaging. However, it’s difficult to know for sure.
Genetics makes some people more susceptible to noise-related damage than others. Exposure to the same noise can affect one person and not another, Hansen said. It’s as individual as, say, eye color. Studies indicate that people with light-colored eyes (blue, green, hazel) are more susceptible to hearing loss from noise than are people with dark eyes.
Loud movies would be less troubling if they were the only exposure of the day, audiologists say. But noise assaults often continue throughout the day as children play with noisy toys, plug into personal stereos, mow the lawn, practice musical instruments or attend sporting events and rock concerts.
“It all adds up as you go along in life,” O’Keefe said.
The solution is prevention. NIHL is the only hearing loss that’s totally preventable, she said. Children and adults should avoid unnecessary exposure to loud sound whenever they can, even at the movies.
(Distributed by Scripps Howard News Service, http://www.shns.com.)