How in the name of John Phillip Sousa could hearing loss be as common for random children as it is for members of the University of Minnesota marching band?

That paradox encouraged researchers at the U of M to look critically at two oft-cited studies about child hearing loss. What they found, according to a newly published report, is that the age-old test for hearing loss is fraught with errors and is overestimating the share of children who suffer from it.

Published estimates that 15 percent of children suffer noise-induced hearing loss could be off by 10 percentage points, they say.

"People who show hearing loss on one measurement don't show it on the next," said Bert Schlauch, a professor of speech, language and hearing sciences. The conventional "raise-your-hand-when-you-hear-the-beep" test can be distorted by many things, he said, including how tightly the headphones are placed on people's heads.

In a year-long study of marching-band members, U of M researchers found that 15 percent showed signs of hearing loss on a first test. On follow-up tests, however, the majority of them showed no signs of disability.

Applying the same logic to recent studies in Pediatrics and the Journal of the American Medical Association, the U of M researchers re-analyzed the data and concluded that published estimates of child hearing loss were excessive.

Schlauch said one estimate involving children under 12 is particularly suspect, because those children don't have much exposure to intense noise and certainly aren't exposed to pounding drums and roaring brass every day.

Many children with apparent hearing loss reported problems in only one ear, which Schlauch said wouldn't be the case if loud noise were the cause.

"Unless they're shooting guns," he noted.

Schlauch's critiques were published this month in the Journal of Speech, Language, and Hearing Research.

The takeaway message shouldn't be for children and teens to crank up the tunes, Schlauch warned.

He said he hopes his study will encourage development of more accurate tests for early signs of hearing loss so help goes to those who could benefit from early intervention. As it stands, the high rate of false positives makes it difficult to identify those with real hearing problems, he said.

"Then," he said, "we're not getting attention to the people who really need it."

Jeremy Olson • 612-673-7744