That was the presentation that researchers from the University of Rochester Medical Center made last week in New Orleans at a meeting of the Association for Research in Otolaryngology.

Robert Frisina presented evidence of a feedback problem in the brain that diminishes our ability to hear. Previously, his group identified a timing problem that limits our hearing.

"Traditionally, scientists studying hearing problems started looking at the ear," says Frisina, a professor of otolaryngology at the university who got his doctorate in bioengineering from Syracuse University. "But we are finding patients with normal ears who still have trouble understanding a conversation. There are many people who have good inner ears who just don't hear well. That's because their brains are aging."

Hearing tests called audiograms can measure the ear's ability to hear, by asking people to respond to sounds. More sophisticated testing is available to measure deficiencies within the brain, examining how well a person hears a sentence amid babbling background noise.

The brain normally sorts through an onslaught of sensory information, separating the cooing baby sounds from the tires screeching on pavement. As its filtering capacity starts to wane, beginning in our 40s and 50s, the brain becomes less able to provide feedback to the ear. Without the filter, people can become overwhelmed with information and noise, and their ability to hear declines.

"The No. 1 hearing complaint among the elderly is that they have trouble hearing speech because of background noise. Someone might hear fine in a quiet environment like their home, but when they go to a restaurant or a meeting or a party, it sounds like chaos to them," Frisina says. "That's partly because the feedback system is failing."

His neuroscience team is investigating the role of a breakdown in calcium regulation in the brain stem and whether that throws off the way nerve cells talk to each other.x

Six years ago, the team reported finding a timing problem in the brains of some people who have trouble hearing some speech. The average person hears gaps in speech that are up to two milliseconds apart, but someone with a timing problem may not be able to detect such gaps. For them, words run together, and they may not be able to discern cat from fat or rat.

Frisina is part of the International Center for Hearing and Speech Research, which researches age-related hearing loss using money from the National Institutes of Health in Rochester.

The center continually recruits volunteers for various hearing studies. Right now, the group is looking at whether hearing loss is inherited. If your family includes multiple generations with hearing loss, learn about participating in research by calling (585) 475-7025.

By Amber Smith