Explanation:
Hearing loss is more common than ever before. About 16% of American adults have an impaired ability to hear speech, and more than 30% of Americans over age 20 — an estimated 55 million people — have lost some high-frequency hearing, according to a new study published Monday in the Archives of Internal Medicine. The finding has got experts — and concerned parents — wondering anew: Does listening to loud music through headphones lead to long-term hearing loss? Brian Fligor, director of diagnostic audiology at Children's Hospital Boston, explains how much damage your headphone habit might cause — and how to mitigate your risk.
Q: How much hearing loss does an iPod cause?
A: It depends on the person, it depends on how long you're listening, and it depends on the level at which you're setting your iPod.
If you're using the earbuds that come with an iPod and you turn the volume up to about 90% of maximum and you listen a total of two hours a day, five days a week, our best estimates are that the people who have more sensitive ears will develop a rather significant degree of hearing loss — on the order of 40 decibels (dB). That means the quietest sounds audible are 40 dB loud. Now, this is high-pitched hearing loss, so a person can still hear sounds and understand most speech. The impact is going to be most clearly noted when the background-noise level goes up, when you have to focus on what someone is saying. Then it can really start to impair your ability to communicate.
This would happen only after about 10 years or so or even more of listening to a personal audio device. One patient I had used his headphones instead of earplugs when he was on his construction job. He thought as long as he could hear his music over the sound of his saws, he was protecting his ears — because he liked the sound of his music but didn't like the sound of the construction noise. He had a good 50 dB to 55 dB of noise-induced hearing loss at 28 years old. We asked a few pointed questions about when he was having difficulty understanding people, and his response was classic. "When I'm sitting at home with the TV off, I can understand just fine," he said, "but when I go out for dinner, I have trouble."
There is huge variation in how people are affected by loud sound, however, and this is an area where a number of researchers are conducting studies. Certainly a huge part of this is underlying genetics. We know how much sound causes how much hearing loss based on studies that were conducted in the late '60s and early '70s, before employers were required to protect workers' hearing in noisy work environments. What was found is that when people are exposed to a certain level of noise every day for a certain duration, they're going to have a certain degree of hearing loss on average. But the amount of hearing loss might differ by as much as 30 dB between people who had the toughest ears and those with the most tender ones — a huge variation. Unfortunately, we don't know who has the tougher ears and who has the tender ones until after they've lost their hearing. So, as a clinician, I have to treat everyone as if they had tender ears.
