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As people around the world live longer, maladies of old age are becoming more common. And that has doctors searching for ways to treat or prevent diseases like Parkinson's...a degenerative brain condition that usually develops after age 50, and that's known for its disabling physical tremors. Medications today can treat the symptoms of Parkinson's, but researchers are hopeful that soon, there will be a way to halt its devastating advance.

Sarah Taylor knew something was very wrong, but she never dreamed she had Parkinson's disease. "It was a shock. But it was a relief when I found out what was wrong with me, though," she recalled.

Five years ago, when Taylor came to Medstar Washington Hospital Center for treatment, she could hardly move. "When I first came here, it was awful. It was terrible. I couldn't stand up. I couldn't get up out of the chair. I was struggling," she stated.

Now she has only mild symptoms. She credits her improvement to following Dr. Mark Lin's advice -- from daily exercise to taking medications on a precise schedule.

Parkinson's disease develops when cells that make dopamine, a brain chemical that controls muscle movement, mysteriously die off. Scientists believe genetics could play a role in a small number of Parkinson's cases. A new U.N. study says man-made chemicals in everyday products are to blame. Other researchers say exposure to toxic chemical pesticides could trigger the disease.

Whatever its cause, the best way to control Parkinson's is to treat it as soon as a diagnosis is made -- usually after the onset of tremors and walking difficulties. But that can be too late, according to Dr. Hubert Fernandez at the Cleveland Clinic.

"By this time, though, a considerable amount of degeneration has already occurred in the brain," Fernandez explained. "Ideally, we would like to have a test that is specific for Parkinson's disease. And, ideally, we would like to have that test become positive even before we see the shaking.

There's currently no such test for Parkinson's, but at Northwestern University, researchers think they might have found a way to slow its progression.

"We looked at the cells in the brain that were most vulnerable to the disease. What we saw was they allowed lots and lots of calcium into their cell bodies," said Jim Surmeier, Physiologist who spoke to VOA by Skype.

The calcium eventually killed dopamine-producing cells and triggered Parkinson's symptoms. But the Northwestern University scientists found a drug that limits the brain cells' uptake of calcium, without harmful side effects. In a Skype interview, co-researcher Tanya Simuni told VOA another clinical trial is being planned. "The primary question to be answered in this study is whether the drug is effective in slowing the progression of Parkinson's disease disability," she said.

Current drugs used to control the tremors and walking difficulties work well for about five to ten years. If scientists could develop a new therapy that could double or triple that time, it would enable Sarah Taylor and the ten million other people living with Parkinson's disease around the world to lead much more normal lives.