VOA常速英语:Study: Electric Brain Stimulation Alleviates Some Disorders

HOUSTON — Modern medicine relies mainly on drugs to cure or alleviate disorders, but for some conditions doctors apply electrical stimulation. The pacemaker, for example, helps weak hearts maintain a steady beat. Scientists are now using electrical pulses in the brain to relieve symptoms of Parkinson's disease. With such advances, electrical stimulation may soon be used for a variety of other conditions.

Just being able to walk and interact with people is a great gift for David Dewsnap.

His Parkinson's disease was resistant to standard treatments, so doctors planted electrodes deep in his brain.

The Deep Brain Stimulation System developed by the Medtronic Corporation consists of two parts: thin wires implanted in the region of the brain associated with movement and a battery pack that produces electrical pulses.

Before the implants, Dewsnap says he could not even take a short walk.

"It has given me my life back. This procedure has been just amazing for me. Without seeing me before, you don't really understand what it was like. The left side of my body, I could not use it really," says Dewsnap.

At Rice University, electrical engineer and neuroscientist Caleb Kemere has been using brain stimulation in experiments on rats.

But while he knows this treatment works, he says researchers still are not sure how.

"We are probably making it work not as it is supposed to work, but in a new way that allows movements to happen faithfully or for a tremor to go away," he says.

Kemere says the electrical stimulation may trick the brain by mimicking the function of the chemical dopamine in controlling motor activity.

To attack other disorders, Kemere wants to develop a brain stimulation system that would work with a feedback loop to adjust its own output.

"We propose to take this and then expand into something that has a much more complicated processor like the one that is found in your cell phone that can process incoming signals that we actually would be getting from the brain in real time, understand what is going on and then modulate the brain stimulation in response to that," says Kemere.

He says such a system could help people with epilepsy, depression, bipolar disorder and other problems,. But Kemere says, first, researchers need to overcome a couple of small problems.

"We don't know what signal to use, and we don't know how to do that modulation," admits Kemere.

In trying to answer those questions, Caleb Kemere is being helped by a grant from the National Science Foundation. He believes within five years there could be experimental devices to alleviate some mental disorders, just as a stimulation device helped David Dewsnap walk again.