Help for High-Frequency Hearers

A new "translator"device brings sound within range

After a bout with measles, three-year-old Karyl Ann Mirmelstein of Newport News, Va., seemed strangely unresponsive. Her mother consulted a number of doctors, who variously attributed the child's behavior to sibling rivalry with her baby sister, a learning disability, and even mental retardation. "I knew this couldn't be true," says Rona Mirmelstein. "I could see that Kam was very bright, perhaps more so than most children." Yet it was not until Kam was six that doctors acknowledged that her problem was her hearing. The results of an elaborate series of auditory tests were perplexing. While Kam could hear the sharp sound of a telephone ringing or a door slamming, she did not respond to subtler noises. A standard hearing aid was recommended, but Kam refused to wear it, relying instead on lipreading. Eventually, she graduated from college, married a lawyer from Long Island, N.Y., and resigned herself to being an "audiological enigma."

Then, at age 27, she met Charles I. Berlin, an audiologist who heads the Kresge Hearing Research Laboratory of the South in New Orleans. Using special equipment, Berlin was able for the first time to provide a precise diagnosis of Kam's problem: "ultra-audiometric" hearing, that is, the capacity to hear, but only at extremely high frequencies.

People with ultra-audiometric hearing, says Berlin, are usually born with full-range hearing, but become deaf in the lower registers after suffering a high fever, virus or meningitis in childhood. Some have an extended upper auditory range and can hear dog whistles or the shrill hiss of a department-store electronic security system. Their problem, as in Kam's case, generally goes undetected because of inadequate testing. Most testing devices do not produce sounds above a certain frequency, Berlin says, "and it is precisely at this cutoff that ultra-audiometric patients begin hearing." Worse still, ultra-audio-metrics may lose what hearing they have if they use conventional hearing aids, says Berlin. "The aids can cause overstimulation or acoustic trauma."

Kam's case was one of several that prompted Berlin to begin developing a hearing device that would "translate" low-frequency sounds into the range at which ultra-audiometrics could hear them. With help from engineers at the Illinois firm of Knowles Electronics, he produced a miniature magnetic earphone with two channels. One channel amplifies high-pitched sounds; the other shifts lower pitches upward into the range heard by ultra-audiometrics. The earphone is wired to a battery pack and microphone.

For Kam, the device opened up a bustling world, both raucous and musical.

Recounting her first exposure in her diary, she wrote: "All voices sounded like jabberwocky because they were so different," As she adjusted, however, she found that "I was able to understand my cousin despite the fact that he has a low voice and a mustache." Later, she rediscovered music: "I put Exodus on the stereo. So stirring was the music that I suddenly began to cry in an almost hysterical way. The beauty of the sound was almost torture--I simply couldn't get enough of it."

There are about 20 million hearing-impaired Americans, and Berlin guesses that as many as 20,000 could be helped by his device. To find them, he has begun testing students in schools for the hearing-impaired. In addition, eight free ultra-audiometric testing centers have been established across the country, along with a collect-call hot line (301-897-8682) to field questions about the condition. So far, Berlin and his colleagues have uncovered 167 potential patients, 37 of whom have received translators paid for by contributions to a fund started by Kam's mother. None is more delighted than Kam, who, at 32, has become a teacher of hearing-impaired adolescents: "My hearing aid has given me a chance to have a profession. I never could have done it without one."

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