Teenagers aren’t necessarily tuning
out adults. They simply might not be able to hear them.
The proportion of teens in the
United States with slight hearing loss has increased 30 per cent in the past 15
years, and the number with mild or worse hearing loss has increased 77 per
cent, according to researchers.
One in every five teens now has at
least a slight hearing loss, which can affect learning, speech perception,
social skills development and self-image. One in every 20 has a more severe
The authors of the report in the
Journal of the American Medical Association eliminated ear infections and
exposure to loud noises in the environment as causes for the hearing loss, but
could not identify a specific cause. A recent Australian study, however, found
a 70 per cent increased risk of hearing loss associated with the use of
headphones to listen to portable music, and many experts suspect they are the
primary cause of hearing loss in teens.
Hearing loss and high frequencies
Personal stereos are the most
important change in the culture in the last 15 to 20 years,” said Tommie
Robinson Jr., president of the American Speech-Language-Hearing Association.
“Everybody has their own little device now, and how many times have you passed
somebody and could hear their music?”
Even the relatively low level of
damage found in the study can create problems.
“Just because a hearing loss is
slight does not mean it is insignificant, particularly when it is in the high
frequencies,” said Alison Grimes, manager of the audiology clinic at Ronald
Reagan- UCLA Medical Center.
In English, soft high-frequency
sounds such as “s,” “f,” “th” and “sh” “carry a great deal of meaning, and are
very important sounds to be able to discern,” Dr. Grimes said. But those are
the first to be lost, especially in a noisy environment like a classroom.
“We know children have more
difficulty learning and keeping up academically” when they can’t hear well, she
Hearing loss can also affect social
lives, because the teens may miss parts of conversations and punch lines, or
may have to keep asking others to repeat things. “It may seem like they are not
in touch, and kids are very aware when someone is a little different,” said
Gary C. Curhan of Brigham and Women’s Hospital in Boston, a coauthor of the
Dr. Curhan noted that there has
been a wealth of information about hearing problems in adults, but little about
such loss in teens. To remedy the situation, Josef Shargorodsky, an
otolaryngologist at the Harvard-affiliated Massachusetts Eye and Ear Infirmary,
and his colleagues used data from two separate editions of the National Health
and Nutrition Examination Survey, one conducted in 1988 to 1994 and a second in
2005 and 2006. The studies involved 2,928 and 1,771 teens, respectively, each
of whom underwent an audiology test to measure hearing.
Males are more at risk
The researchers found that the
proportion of teens with any hearing loss rose from 14.9 per cent in the first
national survey to 19.5 per cent in the second, while the proportion of mild or
worse hearing loss rose 77 per cent. Males were significantly more likely than
females to suffer loss, and teens living below the US-designated poverty level
were significantly more likely to have loss than those in areas with higher
income. There were no racial differences, however.
A variety of factors can increase
susceptibility to hearing loss, including genetics, certain medicines, head
trauma, very loud noises and the existence of hearing loss, which predisposes a
person to further loss. One example of genetics in action: For unknown reasons,
children with light blue eyes are more likely to suffer hearing loss than those
with other eye colours.
Some researchers have suggested
that genetics, at least in part, may account for the higher prevalence of
hearing loss among the disadvantaged. If parents have hearing loss, the argument
goes, they are less likely to get good jobs, which increases the chances that
their children will live in poverty. Poor people may also be less likely to be
treated for ear infections, which can damage hearing.
Hearing loss is permanent
Dr. Shargorodsky and his colleagues
were able to rule out multiple ear infections, as well as exposure to loud
noises in the environment, such as airplanes and gunshots. There was no data in
the national survey about the use of earphones, but that remains the prime
Most teens think they are
invulnerable, Dr. Curhan noted, and for most of them, the hearing loss is not
readily perceptible so they are not aware of the damage. But the bottom line
is, “Once there, the damage is irreversible,” he said.
“The message is, we’ve got to stop
what we are doing,” Dr. Robinson added. “We have to step back and say: OK, turn
down the volume on iPods and ear buds and MP3 players. Wear ear protection at
rock concerts or when you are exposed to loud noises for long periods of time,”
like when using a lawn mower.
“Once you lose your hearing, you
can’t get it back,” he said.