Parkinson's Disease causes progressive neurological decline. Characteristic symptoms of the condition include tremors, rigid muscles and extremely slow movements. Although there are medications to treat Parkinson's Disease, also referred to as PD, patients eventually decline to a point where they cannot care for themselves. In the United States, about one percent of people over the age of 65 have the disease. Rose Hoban reports on an effort to identify people who will develop PD early enough to delay or slow the condition's onset.

There are no blood or laboratory tests to diagnose PD, says Dr. Kapil Sethi from the Medical College of Georgia. And many of the early signs of the illness are often explained away as the normal effects of aging.

But Sethi says patients who develop Parkinson's Disease look back and realize they had certain traits long before they were diagnosed.

"They don't have a very good sense of smell," he reports. "Frequently, when they look back after the diagnosis of Parkinson's Disease has been made? years before that, they [realized they had] lost their smell discrimination ability."

Sethi says PD patients also report having drunk less coffee before they got sick than other individuals. They often were non-smokers before developing the disease.

But Sethi says it's unlikely that smoking or drinking coffee somehow protects people from developing Parkinson's Disease What's more likely, he suggests, is that patients who are slowly developing PD start losing their sense of smell or develop an aversion to coffee and cigarettes. Sethi calls these "soft" signs that might be early clues to PD.

He says there are other soft signs, related to neurological changes. For example, he says some people display a sleep disorder called REM Behavior Disorder in the years before being diagnosed with PD. People who have this disorder act out their dreams.

"They often shout like they're fighting demons in the middle of the night," Sethi says. "Sometimes they kick, and they're trying to kick somebody in their dream, but they end up kicking their spouse or they end up falling out of bed, and injuring themselves." Sethi says about half of them develop Parkinson's disease or some other degenerative disease of the brain from three to ten years after being diagnosed with REM Behavior Disorder.

Sethi says doctors would like to know if these neurological changes actually do signal the development of PD. He says if that were the case, it would give doctors a window of opportunity to intervene early and arrest its development.

"I think intervening early is really good because giving the patients three extra years up front is much more important than trying to prolong their life in the end for three more years," Sethi says. "Because the quality of life is never going to be the same. So it's better to delay PD."

Sethi is studying people all over the United States who might be at risk for developing Parkinson's. He's asking family members of people who have the condition to allow him to follow their health. He's also going to sleep clinics and neurologists' offices to look for patients willing to be studied to see if they develop Parkinson's Disease.

He expects his research to take up to 10 years to find any answers.