点击显示 收起
June 22, 2010 -- Blasting your iPod or another portable music player may cause temporary hearing loss, according to new research in the June issue of the Archives of Otolaryngology-Head & Neck Surgery.
“These devices are potentially harmful,” conclude the study authors, who were led by Hannah Kempler, MS, of Ghent University in Ghent, Belgium. “Further research is needed to evaluate the long-term risk of cumulative recreational noise exposures.”
Occupational noise exposure can lead to noise-induced hearing loss, but less is known about the long-term and short-term effects of recreational noise -- including exposure to loud music at a concert, on your iPod, or at noisy sporting events including the World Cup where revelers regularly blow, buzz, or hunk their vuvuzela horns.
Excessive noise produces changes in the ear’s organ of Corti, which is the organ in the innerear that contains hair cells. Outer hair cells are more vulnerable to noise than inner hair cells.
In the new study, 21 participants listened to an MP3 player for a maximum of six sessions at varying volume levels using either earbuds or more traditional earphones. Researchers evaluated the participants’ hearing before and after the experiment via two standardized hearing measurements. They found that participants showed temporary changes in their hearing after listening to one hour of pop-rock music on their portable music devices.
“This paper shows without question that if you are using these devices at a high level for a long period of time, you increase your risk for temporary hearing loss,” says Brian Fligor, director of diagnostic audiology at Children's Hospital in Boston, who was familiar with the data before its publication.
“These short-term changes are reversible, but it’s the shot across the bow and there is potential to do permanent damage,” he says.?
Warning signs of iPod-induced hearing loss may include ringing in the ears (tinnitus) and difficulty hearing what people are saying in a noisy room, he says. By the time the latter occurs, the damage is usually done, he tells WebMD.
“Noise-induced hearing loss sneaks up on you big time,” he says. “It’s tragic because it is completely avoidable.”
There are safe ways to enjoy your music on these portable devices, Fligor says. “You could listen to your iPod for an hour and a half at 80% (or a volume of level eight) and not increase your risk for hearing loss.” And, “If you keep it at six or below, you can listen all day long,” he says. These safe settings were verified by the new study.
Today’s portable music devices are capable of holding thousands of songs, and they have a much longer battery life than older devices, says Michael Rothschild, MD, director of ?pediatric otolaryngology at Mount Sinai Medical center in New York City.