Can’t hear? No harm.

Q: My dog is bothered by a sound my espresso machine makes that I cannot hear. And then there is that cell-phone ring tone that kids can hear but older people cannot. Can your hearing be harmed by a loud, high-frequency noise you cannot hear?

A: “No,” said Dr Joseph Montano, director of hearing and speech at NewYork-Presbyterian Hospital/Weill Cornell Medical Center. “If you can't hear it, it can't cause damage, as far as we know.

“Testing of sensitivity to ultra-high-frequency sound is not routinely done,” he continued, “because it is outside of the normal hearing range and doesn't contribute significantly to communication.” But he did cite a recent study by researchers in Switzerland that looked at rock musicians and the effect of loud music on hearing.

The study found a decrease in hearing for “normal” frequencies (250 to 8,000 hertz, or cycles per second) but no evidence of change in ultra-high frequencies (8,000 to 14,000 hertz).

“What happens naturally as we age is that we lose high-frequency hearing, but we lose the ultra-high ranges before we lose the ones that we use for communication,” Montano said. “Usually the first ones to show loss are around 4,000 hertz. Then as noise exposure continues, it affects other frequencies as well. But the damage comes from the loudness, not the frequency, and the real concern is the increasing amount of noise pollution we live with every day.”

The New York Times