The popularity of personal music devices like iPods and other MP3 players and their lack of sound-limiting controls has a Harris Health System ear specialist concerned. These devices, when combined with attached ear buds and headphones, can generate sound levels up to 115 decibels, well above the highest level of 85 decibels recommended by most hearing experts.

"Unfortunately, children who suffer noise-induced hearing loss from these devices are risking permanent damage that will affect them as adults and for their entire lives," says Dr. Sancak Yuksel, otorhinolaryngologist, Harris Health Lyndon B. Johnson Hospital, and assistant professor, The University of Texas Health Science Center at Houston (UTHealth).

According to the National Institute on Deafness and Other Communication Disorders, about 28 million Americans suffer partial or permanent hearing loss and another 30 million are exposed to dangerous noise levels daily.

Signs of potential hearing loss:

    Raises voice to talk
    Complains of ringing in ear
    Turns up TV or radio volume
    Fails to understand conversations in large gatherings
    Feels people are mumbling or talking too quickly
    Gets up close or sits in front to listen

Hearing loss occurs when the hair cells in the inner ear are damaged. Sudden or prolonged damage can lead to permanent hearing loss or complete deafness.

"Aside from the intensity of the sound or a noise, my concern is how long the person is exposed to that sound or noise," Yuksel says.

While everyone is susceptible to hearing loss, Yuksel worries that children risk more long-term issues when they don't fully complete their speech and learning development. He estimates 15 percent of children under age 18 suffer some sort of noise-induced hearing loss.

Recommendations for using ear buds or headphones:

    Adjust volume of device in quiet environment
    Use sound-limiting controls
    Take periodic breaks of 15-20 minutes when listening to loud music to allow ears to recover
    Use loose-fitting ear buds or headphones to minimize intensity of sound

"Basically, everyone should avoid noises that are too loud, too close or last too long," he says.

Common decibel readings:

    Refrigerator -- 45 decibels
    Normal conversation -- 60 decibels
    Heavy traffic noise -- 85 decibels
    Vacuum cleaner -- 85 decibels
    Rock concerts -- 115-120 decibels
    Motorcycles, firecrackers -- 125 decibels
    Jet engine -- 130 decibels

People who attend a rock concert for longer than an hour at a sustained 115-decibel level can suffer damage to the inner ear. The result could be a temporary threshold shift (a brief loss of hearing) or tinnitus (a ringing in the ears). Most individuals tend to recover from these conditions; however, those with prolonged damage could suffer permanent hearing loss or ear ringing.

Yuksel suggests using ear plugs to minimize the effects of loud sounds. Some ear plugs can reduce sound by 20-30 decibels, while more expensive headphones can reduce sound even more.

For more information on hearing loss, visit the National Institute on Deafness and Other Communication Disorders (http://www.nidcd.nih.gov/).