One in five teens has already experienced a slight hearing loss, and the problem has increased substantially in recent years, according to a national study published in the Aug. 18 Journal of the American Medical Association.
Scientists at Brigham and Women's Hospital in Boston looked at data on 12 to 19-year-olds across the U.S., which showed that one in five teenagers already shows signs of hearing loss.
"What we're seeing is a significant jump in the occurrence of hearing loss in a very short period of time," said Otolaryngolost Wayland Wong, M.D. "This study has found a 30 percent increase in minimal levels of hearing loss since the mid-1990s, among children ages 12 to 19. In addition, the study showed a 77 percent increase in more serious hearing problems, which are those where obvious communication difficulties can be observed.
"Most of the hearing loss found in the study was categorized as 'slight,' which means that a person is not able to hear sounds at 16 to 24 decibels. This includes sounds like a person whispering, water dripping or rustling leaves.
"Some parents may think that their teenagers aren't listening, but it may be that they are not clearly hearing what is said to them. Those with slight hearing loss will hear vowel sounds clearly during a conversation, but might miss some of the consonant sounds, such as t, k and s. Although speech will be detectable, it may not be fully understandable."
While the study's researchers didn't single out iPods, MP3 players or specific electronic devices for blame, they found a significant increase in high-frequency hearing loss, which may indicate that noise caused the hearing loss problems. And, they cited a 2010 Australian study that linked use of personal listening devices with a 70 percent increased risk of hearing loss in children.
Too Loud? Too Long?
Loud music isn't new, and each generation of teenagers has found a new technology to play their loud music - from the bulky headphones of the 1960s to the handheld Sony Walkmans of the 1980s. According to the Consumer Electronics Association, the first MP3 player went on sale in the U.S. in 1998, and today it is projected that MP3 players will outsell all other home audio products for the sixth consecutive year in 2010.
"It is very likely that listening for hours on end with earbuds has contributed to the alarming rate of hearing loss," Dr. Wong added. "Today's young people are listening to music for periods of time that are more than twice as long as previous generations. In addition, older technology had a limited battery life and limited music storage. Nowadays, teens have the option of being plugged into an electronic listening device all day and all night."
Researchers, who study hearing loss in the workplace, have found that a person who is exposed to noise levels at 85 decibels or higher for a prolonged period of time is at risk for hearing loss. Many devices that children use today have noise levels much higher than 85 decibels. For example, an MP3 player at maximum level is roughly 105 decibels. In addition, regular exposure to sounds at 110 decibels for more than one minute risks permanent hearing loss.
Some young people turn their digital players up to levels that would exceed federal workplace exposure limits, and an informal study of 200 New York college students, showed that more than half listened to music at 85 decibels or louder, which is about as loud as a hair dryer or a vacuum cleaner.
"There are small sensory hair cells in the inner ear that convert sound energy into electrical signals that travel to the brain," Dr. Wong advised. "When a person is exposed to harmful noise, such as sounds that are too loud or that last a long time, these sensitive structures can be damaged, causing noise-induced hearing loss or NIHL. Habitual listening at high noise levels can turn these microscopic hair cells into scar tissue. Once they are damaged, they cannot grow back.
"NIHL is related both to the decibel level of a sound and to the amount of time a person is exposed to it. The distance you are from the sound also matters. If you are far away from the sound, its intensity and its potential to cause damage are much lower. In addition, the impact of noise adds up over a lifetime. If you are exposed to loud sounds on a regular basis, your risk for permanent damage adds up as you age.
"Symptoms of NIHL will increase gradually, and the person may not even be aware that hearing loss is occurring. However over time, sounds may become distorted or muffled, and it may become difficult to understand speech. Once a person's hearing is gone, it is gone for good. This is a permanent situation, and to lose hearing at such a young age can be devastating for a lifetime."
What Parents Can Do
For parents who are concerned, there are things you can do. "If you're giving your child an iPod, one proactive thing you can do is set the volume limit on the device," Dr. Wong suggested. "For example, Apple provides detailed instructions on how to do this on its website. Parents can also teach their children to know when loud is too loud and turn down their music."
It's too loud if...
- You must raise your voice to be heard.
- You have difficulty understanding someone who's an arm's length away.
- You have pain, ringing or buzzing in your ears after exposure to loud sounds.
- Speech sounds muffled or dull after noise exposure.
Appointments with Dr. Wong can be scheduled by calling Salem Ear, Nose and Throat, at 330-337-4900. Dr. Wong's office is located on the second floor of the Salem Medical Center across from Salem Community Hospital, at 2094 East State Street, Suite A, in Salem.