HED:Precise cause of disease remains mystery



HED:Precise cause of disease remains mystery

By M. Scott Morris

Daily Journal

Doctors know how Parkinson’s disease operates. They just don’t know what causes it.

“Basically, Parkinson’s disease is an accelerated degeneration of the cells in the brain that are necessary for movement,” said Dr. Mark Fletcher, a Tupelo neurologist. “We’re just not sure what turns it on.”

Doctors do know that the average age of onset is 60 years old. Symptoms such as hand tremors and muscle stiffness are often mild when they first appear and their progression is usually slow.

“The unfortunate thing is Parkinson’s disease is a progressive disease. With time, it worsens in everyone who has it,” Fletcher said.

Though Parkinson’s disease is not fatal, symptoms progress until simple things like walking, smiling or holding a piece of paper become impossible.

Measure of control

There is good news. The loss of function can take place over decades, and drugs have been proven to slow the disease’s course.

“I don’t feel like I’m getting any worse. I feel like I’m staying the same,” said Opal Williams, 80, of Tupelo. “I feel like taking the medicine helps.”

Williams takes a drug called Sinemet, which is a combination of L-Dopa and carbidopa. The brain uses dopamine to initiate movement. L-Dopa enters the brain and is converted to dopamine, the chemical in the brain that is lost in Parkinson’s disease.

“There are also other drugs that imitate L-Dopa,” Fletcher said. “The brain recognizes the chemicals as L-Dopa.”

At their best, Parkinson’s drugs slow the course of the disease. At their worst, they can cause side effects such as hallucinations, confusion and random jerking or squirming movements.

Prescribing the right dosage of drugs can provide a challenge for physicians.

“As Parkinson’s progresses, you become highly sensitive to even small fluctuations in the level of chemicals (in the brain),” Fletcher said.

That can cause patients to go from rigidity to hyper-movement and back to rigidity in the course of an hour or less. Williams has experienced these “on/off” times.

“I can get the vacuum cleaner out and run it on the floor sometimes, and sometimes I can’t do it to save my life,” she said.

Researchers continue to look into possible genetic causes of Parkinson’s disease in the hopes of finding a cure.

“We don’t know what turns it on, but there’s got to be some degree of genetics involved,” Fletcher said.

Controversial research suggests placing cells from aborted fetuses into Parkinson’s patients can improve their conditions. Fletcher said those results have not been successfully verified by other researchers.

Though no cure, surgery has been shown to improve patients’ functions, Fletcher said.

Stereotactic surgery involves creating a lesion in the areas of the brain affected by Parkinson’s. The lesion serves to “interrupt the circuit” that causes the symptoms.

Another procedure based on the same theory involves placing a tiny electrode stimulator in the brain.

“The stimulator appears to be the new hot thing,” Fletcher said.

According to the scientific journal Nature Medicine, a study at the University of Toronto showed that eight of nine patients had an immediate improvement in the rigidity and slowness of movement that accompany Parkinson’s after undergoing the stimulator surgery.

Though technology is readily available to perform the stereotactic and stimulator surgery, many Parkinson’s patients shy away from the prospect, Fletcher said.

“There’s a stigma about brain surgery,” said Fletcher, adding that at least one of his patients has benefited greatly from stereotactic surgery.

“This is giving people back some of the quality of their life,” Fletcher said.

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