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Study Suggests Body Controlled By One Side of Brain

Posted on: Wednesday, 5 October 2005, 00:00 CDT

A Charleston doctor says his theory could not only influence how surgery is used to cure seizures, but also the general understanding of how the brain functions.

Dr. Iraj Derakhshan suggests that only one side of the brain controls movement. Doctors currently claim that each side of the brain controls the opposite side of the body: For instance, the left side, or hemisphere, controls the right side of the body and so on.

His study will appear this month in the academic journal Neurological Research.

"Up to now, we were assuming we were riding in a car with two drivers," Derakhshan said. "My studies show the driver sits in one hemisphere."

A person with a dominant left-brain is not necessarily lugging around a useless mass on the right side of their head, of course.

The non-dominant side serves as a kind of telegraph station, Derakhshan explained. According to his theory, if a person's left- brain is dominant, or the driver, it will move the right hand through a direct signal, as doctors now think, he said.

But the left-side driver also controls the left hand by sending a message through the right side of the brain. Current medicine says the right brain can do this independently. Of course, without the non-dominant, or passenger, side of the brain the driver could not voluntarily control one side of the body, he added; it would have no way to communicate with it.

"[The passenger's] importance cannot be underestimated, but it does things at the behest of the dominant hemisphere," he said of the submissive brain portion.

A person may ask how with all the brain-monitoring equipment available someone didn't notice such a connection before. Derakhshan said that most equipment fails to pick up such details, but simple tests support his theory.

Because of the extra step from driver to passenger, a person's body should move slower on the side not directly connected to the dominant brain, he concluded.

Volunteers were asked to tap two letters on a computer keyboard at the same time: One with a left finger and the other with a right. One left-handed volunteer discovered that her right hand was the fastest. The right hand fell first on 69 out of 81 key taps, or about 88 percent of the time. When the subject crossed her hands, the right hand again beat out the left, 60 to 21.

Although the patient would have been thought of as right-brain dominant, her cerebral driver was in fact on the left, he said: "It really has nothing to do with right or left. It has to do with how you're wired."

So, what does this have to do with seizure?

Surgeons operate on seizure patients under the belief that movement - even involuntary - can begin anywhere in the brain, Derakhshan said. If he is correct, however, then surgery will only work on the driver-side brain, while cutting into the passenger side is virtually useless.

He proffers that roughly 30 to 40 percent of the nearly 2,000 seizure surgeries performed each year are on the wrong side of the brain.

He assumes that surgeries are performed evenly on the right and left sides. But the common conception is that about 80 percent of people are left-side dominant. Therefore, if movement originates only in the left side for most people as Derakhshan says, then a large proportion of seizure surgeries done on the right side are done on the wrong side.

Derakhshan began working on his theory in 1979. At that time, the most common surgical cure for seizure was to partially cut the hunk of nerves connecting the left and right halves of the brain. The bundle of fibers is known as the corpus callosum.

By following these patients at the Cleveland Clinic, Derakhshan noticed that they could not move one side of their body voluntarily if the callosum was cut completely. In some cases, patients who had the bundle cut partially were temporarily paralyzed.

Derakhshan's theory has yet to meet scrutiny from the medical field at large, said Dr. Manuel Dujovny, a neurosurgeon and editor- in-chief of Neurological Research.

The journal operates on peer-review, meaning that Derakhshan's article was read and edited by two or three experts, Dujovny said. They decide if the paper is sound for publishing.

"Certainly, it's a contribution to the medical knowledge. The potential is that it is significant, but it needs to be analyzed very carefully like all new findings," Dujovny said.

"This is how science and technology have grown up in the 14,000- years of civilization."

Derakhshan's upcoming paper is similar to a speech made last year at the Cleveland Clinic. For more information, visit Derakhshan's Web site www.mimickingman.com.

To contact staff writer Morgan Kelly, use e-mail or call 348- 1254.

Source: Charleston Gazette, The

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