“It’s definitely a combination of sound level as well as duration,” said Dr. Brian Fligor, director of audiology at Children’s Hospital, who argues that popular new devices such as iPods haven’t been around long enough to let experts definitively determine whether they cause hearing loss.

“We’ve had a few patients who have subtle hearing losses, although it’s not obvious,” he said. “It’s definitely not proof, but I’m suspicious that their use of a personal stereo has contributed.”

A study released last year estimated 12.5 percent of children ages 6 to 19 - or about 5.2 million - have noise-induced hearing loss. This compares with 10 percent of the general population, and experts say the hearing problems among children are on the rise.

A phone survey of 301 high schoolers by Zogby International released last month found that more than half of respondents experienced at least one symptom of hearing loss associated with using an MP3 player or other portable device.

Fligor said some lovers of loud music may experience signs of tinnitus, or ringing in the ears, and voices sounding muffled in about five to 10 years.

But not everyone will experience the symptoms, “even if their ear is getting whacked with some pretty high sound,” he said.

Apple recently released volume-control software after one Louisiana man filed a lawsuit claiming the company does not provide safe listening levels despite a warning in the owner’s manual that high-volume noise can cause hearing loss.

Apple has sold more than 42 million iPods since they went on sale in 2001, making it the most popular portable MP3 player. But experts agree its ability to cause hearing loss isn’t unique.

“It happens to be the most popular, and that’s why it gets all the attention,” Fligor said. “It’s the same problem it’s always been, but more people than ever are using them so the danger is greater than ever.”

Apple did not return calls seeking comment.

Fligor suggested listeners keep their volume at 85 decibels. At that level, most people can handle listening for about eight hours. Any volume above 90 decibels pumped directly into the ear canal via ear buds is only safe for one hour, he said.

By Jenna Wolf
http://news.bostonherald.com/localRegional/view.bg?articleid=134266