Damage from music is not always permanent, but some audiologists have seen mp3-inflicted issues so strong that hearing aids were needed
Portable music players may be contributing to permanent hearing loss among many casual listeners, gradually leading to the inability to discern speech. An iPod's maximum volume is more than 10 times as loud as the recommended listening setting, audiologists say, and the sensory damage caused by prolonged listening is irreversible.
Since the iPod was introduced in 2001, hearing loss has been an obvious problem among young patients of Brian Fligor, an audiologist at the Boston Children's Hospital.
"It depends on what you call major hearing loss, but there are a couple of cases (among children and teenagers) where using headphones contributed to a person's hearing loss that was enough that they needed to use hearing aids," Fligor said. These cases generally involved other factors contributing to the problem but were mainly music-related.
Hearing damage from loud music is not always permanent, but prolonged exposure to loud noise can lead to health problems such as hypertension and tinnitus, or ringing in the ears.
MUSIC-INDUCED HEARING LOSS
Noise-induced hearing loss occurs, simply, when sensitive cells in the inner ear are exposed to loud noises. These "hair cells," which convert sound energy into electrical impulses that are sent to the brain, can't grow back once they are damaged.
According to the National Institutes of Health, "long or repeated exposure to sounds at or above 85 decibels can cause hearing loss" -- noise louder than city traffic but not as loud as a lawnmower. The louder the sound, the shorter the time it takes to damage hair cells.
At maximum volume, an iPod reaches about 103 decibels, which can cause permanent hearing loss in a matter of minutes while listening through ear buds. In-ear headphones, like the earbuds that come with an iPod, send loud music straight into your ear and directly toward sensitive cells.
Noise-amplifying headphones, such as the kind DJs might use in clubs to hear over background club music, can produce louder sounds and take less time to cause irreversible damage. Just 15 minutes of listening at 100 dB can be harmful, according to the NIH.
Hearing loss among musicians can affect their abilities to discern pitch, perceive loudness, and recognize where sounds are coming from, according to Kathy Peck, executive director of Hearing Education and Awareness for Rockers. Peck said she has noticed a trend among DJs and hip-hop artists losing their ability to hear bass frequencies.
"If you lose your low end, that's like hearing a train go by, so that's very dangerous," Peck said, as opposed to losing the ability to detect high frequencies like birds chirping.
After years of performing, David Beltran has started to notice that he has trouble recognizing lower frequencies through his left ear, and deep voices sound muffled when he talks on the phone on his left side.
The 27-year-old Chicago DJ said that people in his industry often have no choice but to have their headphones at maximum volume for hours at a time -- and they often must stand near monitor speakers, adding to the problem.
"I know a lot of musicians who have experience with some form of hearing damage," said Beltran, who has tried to better monitor his own volume limit since noticing the problem. "When I'm working with other DJs, they'll have it as loud as possible. That to me is a sign that these older guys are going deaf."
PORTABLE MUSIC PLAYERS
For regular iPod users, the negative effects of loud listening might not be immediately noticeable.
"Noise-induced hearing loss or music-induced hearing loss happens very slowly over time," said audiologist Cory Portnuff. "I think in a few years we'll be able to see some effects of music players on hearing, but we're still easily five to 10 years away from seeing larger scale effects."
Portnuff has been studying the effect of portable music players on hearing loss as part of his doctoral dissertation at the University of Colorado. Studies on the hearing effects of portable music players have been around for decades, first looking at cassette and CD players. Portnuff's research is the first to use a monitoring device attached to participants' iPods to take away the unpredictability of self-reporting.
Consistent with previous research, his study found that people will increase their listening levels in proportion to background noise. But he said the most interesting or, rather, concerning result of the study was finding that 17 percent of the people monitored were putting themselves at risk for music-induced hearing loss from daily activities, exceeding the maximum allowable dosage for the day.
"It's a small but substantial group, about one in six people that are putting themselves at risk for hearing loss," Portnuff said. "That on its own is not a huge number, but when you think about the number of iPods in the world, we start to get a little concerned."
The biggest concern is that as hearing worsens over time, people may lose some ability to distinguish consonants and understand speech.
Most people are exposed to the problem throughout their lives, though the change is gradual. Some jobs require prolonged exposure to loud noises, such as those in factories or on construction sites. The Occupational Safety and Health Administration recognizes the risk, limiting workers to 40 hours per week while exposed to noise at 85 to 90 dBA. Even then, it's acknowledged that this doesn't necessarily protect against hearing damage.
As Beltran recognized a little too late, it's an occupational hazard for musicians. But going home and listening too loudly to a portable music player increases the risk.
"The best cure is prevention," Peck said. "We only have one set of ears -- there are no spare parts."
Portnuff recommended casual music listeners follow the "80-90 rule": listen at 80 percent volume (about 90 dBA) for 90 minutes, then let your ears rest. Sensitive cells are like batteries that need to recharge after a while.
"My car is capable of driving 120 miles an hour down the streets, but as a society we set speed limits because those are safer," he said. "We need to set some sort of speed limit for music listening."
Image: John T. Takai/Shutterstock.