About 36 million Americans have some kind of hearing impairment, but about half have never had their hearing tested. Cost is an obstacle for some people. A full test of your hearing can run $75 to $150, and often it's not covered by insurance. Denial is another common problem. Some people will wait seven to 10 years from the time they first notice small hearing deficits, research shows, because let's face it, few things make you feel as old as getting a hearing aid.

A new program put together by two universities and a small company in Indiana is attempting to surmount these roadblocks by making screening for hearing loss as easy and inexpensive as possible. For the first time in the United States, you can have your hearing accurately screened over the phone, and the service is free.

To read instructions and take the test, go to the Web site here.

Funded by a two-year, $890,000 grant from the National Institutes of Health, a company called Communication Disorders Technology Inc., along with researchers from Indiana University in Bloomington and VU University Medical Center in The Netherlands, is offering the over-the-phone test, whose reliability they proved in earlier research. The technology is intended as an initial screening test, not as a replacement for a full test by an audiologist.

"The most novel thing about it is it’s over the telephone and it’s taken in the privacy of your living room, and no one has to know that you’re worried about your hearing, if that bothers you," said Charles Watson, professor emeritus of speech and hearing sciences at Indiana University and president of the company.

That's not as simple as it sounds. For many years, it was an article of faith that hearing couldn't be tested over the phone, Watson said, because hearing tests use a pure tone delivered at different frequencies. Testers had no way of knowing how much each person's telephone amplified the tone and therefore could never be sure of the results.

But in 2004, Dutch researchers showed that hearing could be effectively tested by having a recorded voice deliver a series of three-digit numbers obscured by background noise. They started using it in several European countries.

No matter how loud or soft the volume on your telephone, the voice saying "3-8-1" and the background static are delivered at the same level of clarity relative to each other. Listeners are asked to punch the numbers they hear into the telephone key pad. (The test should be taken with a land line, not a cell phone.)

The Dutch researchers, counterparts at IU and Watson's company joined forces to prove the test's reliability and market it in the United States. I took the test Thursday night at home. When I correctly identified a three-digit sequence and punched it into the keypad, the next number was buried in a little more background noise, making it slightly more difficult to hear. If I got it wrong, the subsequent number had a little less background noise, making it easier to detect. It took a little more than eight minutes for me to listen to 25 three-digit sequences per ear and punch what I was hearing into my phone. When it was over, Watson's recorded voice came on to tell me that I had slightly less than normal hearing in my right ear and normal hearing in my left. He advised that I see a professional for a full test.

I can't say I was suprised. I've noticed for a few years now that it's more difficult for me to hear someone speaking if there is background noise, such as water running in a sink. Watson said that is the most frequent complaint of people when they first seek a hearing test.

About 15 months ago, Watson said, the researchers began marketing the test in places where older people gather, such as senior centers, offering it for about $8. Almost no one would take it. They continued dropping the price until it reached zero, and changed their marketing strategy to focus on getting newspaper coverage for the test. Older people are the most reliable readers of printed newspapers, and newspaper health sections in particular. Since the group changed strategy, thousands of people in cities across the U.S. have taken the test, Watson said.

"To our amazement, in every town and city where a newspaper article on the test has run, there’s been an amazing spike of hundreds of calls on the day the article runs, and hundreds for several days thereafter," he said.

But it's not just people over 60 who should take the test, he said. Anyone who is frequently exposed to loud noise at work or elsewhere (such as in a band) should do it. And anyone who suspects they are beginning to have a hearing deficit should as well, he said. Signs include turning up the television louder than other people can stand it or more frequently asking people to repeat themselves.

"It can be a huge change in the quality of life if you get help for hearing loss instead of just learning to live with it," he said.