- When Dr. Mahlon DeLong began studying neurology, scientists
thought that the brain worked like a funnel, sending impulses in a
straight path to the cerebral cortex to control movement and other
functions.
But in the past 30 years, that theory has evolved as experts have
learned more about how the brain functions, DeLong said.

"We came to the realization that there was not a funnel but a series
of loops that connect the cortex with [other parts of the brain],"
he said.

That's important because researchers can single out the parts of the
brain that correspond to various medical disorders, such as
Parkinson's disease, he said.

"Parkinson's is largely a movement disorder, and it's a disturbance
in the motor circuit [that causes the disease]," he said.

DeLong, a professor of neurology at Emory University, was a keynote
speaker Friday during the Texas Brain and Spine Institute's annual
neuroscience symposium.

More than 75 people attended the general public session on
Parkinson's.

Parkinson's disease is characterized by uncontrollable tremors, slow
movement, a shuffling gait and a marked face, DeLong said.

"The diagnosis of Parkinson's is the easiest to make for those
attuned to it," he said. "You recognize it when you see it."

But other symptoms make the disease more complex and difficult to
treat, he said, noting that there is no cure for the condition.

Many forms of the disorder are caused by a reduction in the
production of dopamine, a hormone and neurotransmitter, in the
brain, DeLong said. Therefore, some Parkinson's patients can be
treated with drugs to increase dopamine production in the body, he
said.

But some patients develop a tolerance for those drugs, and their
symptoms return, he said.

"The side effects of the medication can interfere with the benefits
of the medication," he said.

There are two surgical remedies for the symptoms of Parkinson's
disease, DeLong said.

Doctors can remove the subthalamic nucleus, the part of the brain
where the tremors and other symptoms originate, he said. The
downside of that procedure is that it is permanent.

The second, and better, solution is to implant a probe in the
subthalamic nucleus that emits pulses and eliminates the tremors and
other symptoms, DeLong said.

The probe is connected to a device that is placed in the patient's
chest, as a pacemaker would be, he said. That device controls the
pulses sent to the brain. When it is shut off, symptoms immediately
return, he said.

By undergoing the "deep brain penetration" surgery, patients are
able to live normal lives, he said.

"It replaces the peaks and valleys, the ups and downs, and gives the
patient control," he said. "This has been a godsend for patients."

ARENA WELCH
September 15, 2007 (Eagle