May 8 (HealthDay News) -- For millions of Americans, including thousands of Iraq War veterans, ringing in the ears is a condition that is annoying at best and disabling at worst.

Now, a researcher says he hopes to find a cure in a very unusual place -- a fish.

Ernest Moore, an audiologist and cell biologist at Northwestern University, said the zebrafish seems to have the ability to suffer from the condition, known as tinnitus. Treatment with drugs appears to help restore electrical activity in the fish's inner ear to normal.

"If they work in clinical trials in humans, this might offer a cure," Moore said. "What we're hoping is that we could perhaps help individuals who have this intractable problem."

Moore himself is one of those people. He suffers from tinnitus, and said the cause may date back to the years when he hunted for possum with his grandfather without using ear protection.

Later, he worked as an audiologist in the U.S. Army Reserves and remembers "listening to stories about ringing in the ears and telling people why we didn't really have a cure."

Moore describes his tinnitus as sounding a bit like white noise. Others, he said, hear a pure tone in a middle frequency.

The American Tinnitus Association says many people suffer from the condition 24 hours a day. William Shatner, the "Star Trek" actor, describes his own case as creating "agonizing screeching in my head," according to the association.

"Some people have it all the time, and some people have it intermittently," Moore said. "Some people only recognize it at night, when it's quiet. You have it in one ear, and you put that ear on the pillow, and you can hear it."

Causes of tinnitus appear to include noise exposure and genetic susceptibility. The use of some pharmaceutical drugs can cause it, too.

Treatments include the use of devices that mask the noise and surgery, Moore said. Some people find relief through drugs like aspirin and steroids, he said.

Researchers have tried to study tinnitus by looking at the rat, which can develop the condition. Moore turned to the zebrafish, a tropical fish that's often found in aquariums.

Fish, like humans, have two ears, he said, and electrical activity allows the fish to hear. Moore is giving different drugs to the fish and testing how they affect neuronal activity involving hearing.

Moore said he's submitted a grant proposal to the Department of Defense, which is spending money to support research into tinnitus.

Anthony Cacace, a professor of communications sciences and disorders at Wayne State University, said the key to any research in animals is to determine that they actually hear tinnitus. Research suggests that rats and mice do, he said.

"You have to know if they have tinnitus before you treat it with drugs," he said.

Research has progressed over just the last couple of years, Cacace said, as scientists have learned new ways to gauge the effectiveness of treatments by doing a better job of monitoring the nervous systems of animals.

SOURCES: Ernest Moore, Ph.D., audiologist and cell biologist, Northwestern University, Chicago; Anthony Cacace, Ph.D., professor, communications sciences and disorders, Wayne State University, Detroit