Teens asked by their peers to turn their iPods down actually turn them up, finds a new study that reveals other odd habits. Among the most disconcerting revelations: Teens who express the most concern about the risk for and severity of hearing loss from iPods actually play their music at higher levels than their peers.
The study concerns researchers because prolonged exposure to loud music in headphones or earbuds can lead to hearing loss. Among the more famous cases is rocker Pete Townshend, who says loud headphones caused his profound hearing loss and ringing in his ears.
The new study, focusing on about 30 volunteers from the Denver-Boulder area, also found:
- Teenage boys listen louder than girls.
- Teens play their music louder than young adults.
- Teens may inaccurately perceive how loud they are playing their music.
"We really don't a have good explanation for why teens concerned about the hearing loss risk actually play their music louder than others," said study leader Cory Portnuff, an audiologist and doctoral candidate at the University of Colorado at Boulder. "But we do know that teens who knew what the benefits were of listening at lower levels had less hearing loss risk, which is why we believe targeted education is the key."
The findings, announced today, were presented at the annual Hearing Conservation Conference held in Atlanta last week.
Risky volume levels
Other research has shown that the widespread and increasing use of headphones and of earbuds has been shown to induce hearing loss in young people. The ultimate effect of earbuds may not be known for years, when studies can be done on those who have used them over time. Already there are signs, however.
"We're seeing the kind of hearing loss in younger people typically found in aging adults," Dean Garstecki, a Northwestern University audiologist, said in 2006. "Unfortunately, the earbuds preferred by music listeners are even more likely to cause hearing loss than the muff-type earphones that were associated with the older devices."
Portnuff said the new study indicated a relatively small percentage of teens — somewhere between 7 and 24 percent — listen to their iPods and MP3 players at risky levels. "We don't seem to be at an epidemic level for hearing loss from music players," he said. In fact, volumes are similar to those found in studies of young people using Walkmans 20 years ago.
"One of the concerns we have today is that while Walkmans back then operated on AA batteries that usually began to run down after several hours, teenagers today can listen to their iPods for up to 20 hours without recharging them," he said.
A 2006 study by Portnuff and a colleague indicated a typical person can safely listen to an iPod for 4.6 hours per day at 70 percent volume using stock earphones. But listening to music at full volume for more than five minutes a day using stock earphones increased the risk of hearing loss in a typical person. Further, people can safely listen to iPods for 90 minutes a day with stock earphones if the volume is at 80 percent of maximum levels without greatly increasing the risk of hearing loss, he said.
Your results may vary
Loud music can potentially damage delicate hair cells in the inner ear that convert mechanical vibrations, or sound, to electrical signals that the brain interprets as sound, said Portnuff. "Over time, the hair cells can become permanently damaged and no longer work, producing hearing loss."
Everyone does not share the same risk of hearing loss, he said. Some people are born with "tougher ears" that allow them to listen to music relatively safely for longer periods. In contrast, those with "tender ears" may suffer ear damage even if they follow MP3 listening recommendations. "There is really no way of knowing which people are more prone to damage from listening to music," he said.
"Damage to hearing occurs when a person is exposed to loud sounds over time," said Portnuff. "The risk of hearing loss increases as sound is played louder and louder for long durations, so knowing the levels one is listening to music at, and for how long, is extremely important."