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Deep brain
stimulation restores quality of life for end-stage Parkinson's patients
March 2, 2004 - A tiny
electric wire deep in Carlene Morehead's brain constantly sends signals
that tame overactive neurons, restoring her ability to walk, talk and
enjoy time with her family.
Mrs. Morehead, 67, has
had Parkinson's disease for 20 years. Little more than a year ago, her
motor skills rapidly declined after her response to medications began to
change, causing her to oscillate between having too little mobility and
having excessive, uncontrolled movements. She opted to undergo a
surgical procedure called deep brain stimulation.
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Carlene Morehead is examined by Dr.
Padraig O'Suilleabhain. Mrs. Morehead is one of his patients who
have benefited from deep brain stimulation monitored by UT
Southwestern physicians. |
Dr. Cole Giller,
associate professor of neurological surgery and radiology at UT
Southwestern Medical Center at Dallas and one of only three surgeons in
Dallas who performs the operation, placed two tiny electrodes in the subthalamic
nuclei on either side of Mrs. Morehead's brain and wired them to
pacemakers implanted in the chest wall just below her collarbones. The
electrodes deliver continuous, high-frequency electrical stimulation to
cells in areas of the brain that control movement. The treatment results
in marked improvement in stiffness, slowness, tremors, weakness and
other disabling symptoms.
"The goal of this is to
trade electricity for medication, because the electricity can be
delivered at a steady rate that can be adjusted in small steps to
produce the greatest benefits and the least side-effects," Dr. Giller
said. "The pacemaker is actually turned on by the same doctor who has
been managing the drug therapy of the Parkinson's patient."
After her recovery from
surgery, Mrs. Morehead's neurologist, Dr. Padraig O'Suilleabhain,
assistant professor of neurology at UT Southwestern, activated the
pacemakers and made a series of adjustments in the following weeks.
During this time, with adjustment of medication and stimulation, she
recovered the ability to function without limitation and without the up
and down response she had been experiencing. Mrs. Morehead now visits
the clinic once every few months for adjustments.
"I'll come in, and I'll
be having trouble with my speech, and he'll tweak it a little bit, and
I'll start speaking more clearly," she said.
Dr. O'Suilleabhain said
the surgery has significantly improved the quality of life for 80
percent of his patients who opted to have it, with dramatic improvements
in some.
"Some of the effects of
stimulation occur in the first minute after adjustment. A severe tremor
can disappear right before your eyes," Dr. O'Suilleabhain said.
Deep brain stimulation
was originally approved for use in the early 1990s to provide electrical
stimulation of the thalamus in patients with disabling tremors. In the
last few years, neurological surgeons have found that placement of the
electrodes just under the thalamus - in the subthalamic nucleus - not
only improves tremors, but is effective in managing the slowness and
stiffness and involuntary movements seen in Parkinson's disease.
Researchers have found that the electrical stimulation continues to
provide significant improvements in quality of life for at least five
years after implantation. Balance and mental abilities, which can be
impaired by Parkinson's disease in some people, are usually not helped
by the stimulation.
The surgery is not a
cure for Parkinson's disease. The gradual loss of nerve cells in the
affected part of the brain continues despite the functional
improvements.
Deep brain stimulation
is replacing surgical procedures known as pallidotomy and thalamotomy,
in which the surgeon actually creates holes in specific areas of the
brain. Unlike the older procedures, deep brain stimulation is
reversible, adjustable and poses less risk.
Dr. Giller has
developed a unique method of pinpointing the location of the structure
in the brain targeted for electrode implantation. He inserts a wire with
a tiny flashlight on the tip to illuminate the area of the brain and
then analyze its optical properties. Dr. Giller has used the optical
probe to guide his placement of the electrode in 130 deep brain
stimulation procedures, including Mrs. Morehead's.
"We can distinguish
gray matter from white matter very elegantly," Dr. Giller said. "It is
very easy, very quick, and we are the only ones in the world to use
optical technology to do this."
Eleven months after
Mrs. Morehead's surgery, she and her husband, Randall, had a glimpse of
what life might have been without it. Two days before Christmas, a
magnetic device in a department store shut off one of the pacemakers in
her chest. Within hours, she could not walk or talk.
"By dinner time that
night, I was crawling," she said. "My husband had to carry me into the
doctor's office," she said.
Dr. O'Suilleabhain
reactivated the pacemaker, and she was able to walk within an hour.
Mr. and Mrs. Morehead,
who met in high school in Paradise, have been married 43 years. The
couple has five children and 12 grandchildren. The way Mrs. Morehead
sees it, enjoying time with her husband and family is what life is all
about.
"We have been very
pleased with the way this turned out," Mr. Morehead said.
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