The hoopla around digital technology, some audiologists say, obscured a fundamental truth: Some people with hearing problems simply don't need sophisticated sound processing to function well.

And determining who should pay for those extra features isn't easy, because the sale of hearing aids is driven more by marketing and trial-and-error than by solid scientific studies, some audiologists say.

"We really don't have good independent, verifiable research to show us that these particular features may be good," said Dennis Van Vliet, a California-based audiologist with HearUSA, a national hearing aid sales company. "We just have to go ahead and work with the patients and try them and see what kind of success we have. . . . It really seems like a backwards way to do things."

Today's situation can be traced to not-so-reputable early days of hearing aids, when they were sold door-to-door like encyclopedias or vacuum cleaners. Now, hearing aids can be bought only through audiologists, who have degrees in the field, or hearing aid dealers, who are licensed by the state. But the top-down, sales-oriented approach persists, leaving consumers vulnerable at a time when there is an ever wider array of features to choose from.

About 16 out of every 1,000 US adults use hearing aids, which pick up sound through a microphone, amplify it, and feed it directly into a person's ear. While traditional analog aids amplified all sound waves indiscriminately, digital hearing aids convert the waves to zeros and ones that are processed by a microchip, amplifying certain frequencies and muting others.

That means a digital hearing aid can have preprogrammed sound levels, much like equalizer settings on a hi-fi system, that fluctuate to compensate for the amount of background noise -- more sensitive in quiet rooms and less sensitive at parties. Digital hearing aids also can reduce background noise, cancel out feedback, and use more sophisticated directional microphones that tune out competing sources of sound.

For some, those features are a godsend. Kimberley Shaw, a library assistant at Wellesley College, struggled for years with analog aids because they are designed for the majority of hearing-impaired people who have trouble with higher frequencies. Shaw, on the other hand, struggled to hear lower frequencies until getting digital aids a couple of years ago.

"They are so much better," she said. ''They only amplify what I need."

The Better Hearing Institute, a nonprofit organization funded largely by the hearing aid industry, says customer satisfaction is rising as more users -- now nearly 50 percent -- get digital devices. An institute study this year showed that 77 percent of people with digital hearing aids expressed overall satisfaction with the devices, compared with 66 percent of people with analog aids.

"The scientists, the engineers who have designed hearing instrument technology, are making them better and better," said Sergei Kochkin, the institute's executive director. "I can only judge by what the consumers are saying."

But the type and severity of hearing loss varies greatly from one person to the next, as do lifestyles. Younger people who find themselves in a lecture hall one moment and a crowded bar an hour later might need more options than an elderly person who rarely leaves the house.

"The person who's just sitting in the nursing home watching TV all day, I don't want to sell her a high-end expensive hearing aid that has a lot of technology in it that they're not going to be using," said Michael Skrip, manager of the Hearing Aid Center of the Massachusetts Eye and Ear Infirmary.

The extra features can double or triple the price of hearing aids to as much as $6,000 a pair -- a cost that is borne largely, if not entirely, by the user, because most health insurance plans, as with eyeglasses, don't contribute more than a few hundred dollars. A bill pending in the Massachusetts legislature would require insurance companies to pay 85 percent of the cost.

And that extra cost has little hard science behind it. Few rigorous studies have conclusively shown that digital hearing aids are helping people hear better, Skrip and others said.

"When you make a recommendation, you should be able to refer to some objective research that supports your recommendation," said Mark Ross, a retired audiology professor at the University of Connecticut who writes a column for Hearing Loss magazine. "And under that kind of standard, many of the recommendations that are made for these bells and whistles wouldn't hold up."

The state of hearing aid science is so rudimentary that the Journal of the American Academy of Audiology devoted an entire issue last summer to making the hearing aid industry more "evidence-based" -- a notion taken for granted in most other fields of medicine. Van Vliet, writing in that issue, said, ''The distinction between sales and science is often blurred for the consumer and practitioner alike."

In a recent interview, Van Vliet said he doesn't blame hearing aid manufacturers for the lack of objective data, saying they do "whatever they need to do as a manufacturer to, in their mind, prove some goodness about these features they put on the hearing aids." But unlike pharmaceutical companies, which must put new drugs through a rigorous battery of clinical trials to test their safety and effectiveness, hearing aid companies don't have to meet those same exacting standards, he said.

Back in 1993, the FDA did warn six major manufacturers to stop making inflated claims about their technology. And that was before digital technology came along, introducing an array of new but largely untested features.

The exaggerated claims can be especially effective on senior citizens, said Paul Gambina, who has assisted hearing-impaired people.

"A lot of the elderly get sucked into that," he said. ''They're not educated about digitals and how they work."

Last year, the state Attorney General's Office required a Chelmsford dealer to pay $40,000 in restitution for deceiving consumers, many of them elderly. Among the alleged abuses were the dealer's failure to properly size hearing aids, and misrepresenting the type of hearing aids being sold. This year, the office received 21 complaints about hearing aids, most of them through its Elder Hotline.

Gambina, who is hearing-impaired, too, has decided to stick with what he knows -- an old-fashioned analog device. "My brain is used to the sound I get from analogs," he said. "If I got digital, I would have to retrain myself to hear again. . . . I don't need too many options."

But when that pair gives out, he may have no choice but to go digital.

Hearing aid companies are expected to abandon analog aids because digitals are so much easier to manufacture and repair. The good news for consumers, audiologists say, is that manufacturers, aware of backlash over rising prices, are introducing "entry-level" digital aids that lack many of the newer features and cost about the same as analogs.

By Brian Kladko
http://www.boston.com/news/globe/health_science/articles/2006/01/09/hearing_aids_digital_isnt_always_better/