About 1 in every 8 teenagers show signs of hearing loss by the time they reach 18, a new study says.

About 13% of teens show signs that noise has damaged their hearing by 18, and 6% have suffered some permanent hearing loss, researchers report.

"These findings highlight the importance of early monitoring and prevention, as even mild changes in hearing during adolescence may have long-term consequences,” lead researcher Dr. Stefanie Reijers, an otorhinolaryngologist with Erasmus University Medical Center in Rotterdam, The Netherlands, said in a news release.

Loud noises can damage the delicate hair cells in the inner part of the ear that converts sound energy into electrical signals for the brain, researchers said in background notes.

Once damaged, these hair cells can’t regrow, resulting in permanent hearing loss, researchers said.

For the study, researchers gave more than 3,300 Dutch teenagers hearing tests at ages 13 and 18.

Results showed that hearing “notches” — a dip in the ability to hear specific frequencies of sound — had become more common among the teens during the five years between hearing tests.

Further, teens who showed high-frequency hearing loss at 13 were more likely to have significantly deteriorated hearing by 18, researchers said.

Researchers noted that teenagers are frequently exposed to sounds above 85 decibels, the threshold at which noise can cause temporary or permanent hearing loss:

• Earphones, headsets and music speakers are often played at 100 decibels and can produce a maximum of 115 decibels.

• Live music concerts can reach 90 to 122 decibels.

• Fireworks, motorcycles and sirens produce 95 to 150 decibels.

“Adolescents are among the groups with the highest levels of exposure (to recreational noise) worldwide, which increases their risk of noise-induced hearing loss due to the cumulative effects of prolonged exposure to unsafe listening activities,” researchers wrote.

Even mild hearing loss as a teen can disrupt the ability to communicate and interact with others, impair academic performance, and accelerate the likelihood of age-related hearing loss later in life, researchers said.

Identifying teens at risk for hearing loss and regularly checking their hearing could help catch problems before they worsen, researchers added.

The team also called for more research into how specific recreational noise sources might have a cumulative effect on hearing health, and why some teens appear more susceptible to hearing damage than others.

The new study appears in the journal Otolaryngology–Head and Neck Surgery.