Some 20 million people in the United States suffer from a hearing impairment, according to the Better Hearing Institute, a trade group.

Although hearing problems affect people of all ages, they are most prevalent among adults over 65; one of every three people in that group has a hearing impairment.But many people still fail to recognize their problem or deny it. "Denial is one of our biggest problems," says Robert Briskey, staff audiologist at Beltone Electronics Corp., manufacturers of hearing aids and diagnostic equipment.

"Usually family members get tired of hearing, `What did you say?' They persuade the person to come in for testing. And the best way to find out if you have a hearing loss that warrants assistance is to simply get your hearing tested by a hearing health professional," says Briskey.

He notes some warning signs of hearing loss:

- People seem to mumble more frequently.

- You hear, but have trouble understanding.

- You find telephone conversation increasingly difficult.

- You no longer hear the ringing of a doorbell.

- You have been told that you speak too loudly.