Hearing experts advise people to listen to personal music players at a moderate volume. (Paul Sancya/Associated Press)

Teenage girls who listen to personal music players too long or too loudly risk a type of hearing loss, U.S. researchers have found.

The study examined 8,710 girls from low-income families with an average age of 16. They had their hearing tested when they entered a residential facility in the northeastern United States.

High-frequency hearing loss — a common result of excessive noise exposure — increased from 10.1 per cent in 1985 to 19.2 per cent in 2009, audiologist Abbey Berg of Pace University in New York reported in Tuesday's online issue of the Journal of Adolescent Health.

"Not surprisingly, what I noticed was that the adolescent girls with high-frequency hearing loss also used personal listening devices for longer periods of time per day and they also had more tinnitus, which is ringing in the ear," Berg said.

High-frequency hearing adds clarity to speech, aiding in hearing sounds like "s," "sh," or "ch," particularly in noisy environments. Teens with high-frequency hearing loss might have difficulty in the classroom, said Berg. Adolescent hearing loss could also have implications as girls age, reducing their ability to locate sound in space or follow rapid speech, Berg noted.

Between 2001 and 2008, use of personal music players among the girls increased from 18.3 per cent to 76.4 per cent.

But the study's findings don't necessarily mean there is a cause-and-effect link between listening to personal music players and hearing loss. Berg suspects personal listening devices play a role, but says other factors, such as poverty or substance abuse, might also contribute.

Hearing experts advise people to listen to personal music players at a reasonable volume — conversational or slightly louder — without overworking the ear.

A similar study released two weeks ago in the Journal of the American Medical Association estimated one-fifth of U.S. teens have lost some hearing. Most of this hearing loss was "slight," defined as inability to hear at 16 to 24 decibels — sounds such as a whisper or rustling leaves.

In 2008, the Hearing Foundation of Canada said 30 per cent of 145 students surveyed listened at levels of 91 decibels or higher for an average of 2.9 hours a day. Long-term damage can occur from such exposure to sound, hearing experts say.