More MS news articles for Oct 2001

Vital stimulation

Pacemaker-type device stops tremors with electric pulses to the brain

http://www.jsonline.com/alive/news/oct01/brain22102101.asp

Oct. 21, 2001
By KAWANZA L. GRIFFIN
of the Journal Sentinel staff

About seven years ago, Jack Christenson began to notice a slight tremor in his body when he laughed. But then it got progressively worse.

His hands began to shake uncontrollably, making it hard for him to write, and he soon found himself becoming frustrated because he was unable to do something as simple as lift a spoon.

"I would try to put a straw through a hole and it would take me 45 minutes to do what it should have taken 30 seconds to do," Christenson said.

Christenson was diagnosed with Parkinson's disease and initially took medications to replace dopamine, the brain chemical whose deficiency leads to the condition. At first that allowed him to control his tremors enough to continue his daily activities.

But the effect of the drugs began to diminish over time and his symptoms worsened. So Christenson decided to take another step. Doctors implanted two pacemaker-like devices in his body. The devices shoot electric pulses into his brain, blocking the signals that caused his arms and hands to shake.

The surgery was worth it, says Christenson.

"Parkinson's disease itself doesn't hurt," he said. "It's just the constant motion that drives you up a wall."

Approved in 1997
The deep brain stimulator device was approved by the federal Food and Drug Administration in July 1997 as a way of stimulating the thalamus, the region of the brain that processes and relays information before it goes to the muscles, to help control tremors in people with essential tremor or Parkinson's disease.

About 2 million Americans have essential tremor, a disorder that causes violent shaking. Another 1.5 million have Parkinson's, a neurological disorder characterized by progressive muscle rigidity, tremors and difficulty in moving. The decision to approve the device came after a study found that it reduced tremors by 58% in essential tremor and 67% in Parkinson's.

According to a report in the New England Journal of Medicine, thalamic stimulation works better than conventional thalamotomy in controlling severe tremors from Parkinson's and other diseases because it has fewer adverse effects and results in a greater improvement in function.

Thalamotomy is a decades-old operation that destroys overactive, tremor-causing nerve cells by burning or freezing a pea-size spot in the brain. But it leaves many patients with speech problems, weakness or numbness. Actor Michael J. Fox had a thalamotomy for Parkinson's.

Despite the study, not everybody is sold on deep-brain stimulation. Paul A. Nausieda, medical director of the Regional Parkinson Center at Aurora Sinai Medical Center, said that although the procedure seems to be gaining popularity across the nation, many physicians are hesitant about the it because its ability to improve quality of life remains to be determined.

"Just because the patient doesn't die and doesn't have a tremor doesn't necessarily mean that they're better," he said.

Nausieda, one of the leading national experts on the disease, said he has seen patients who are frustrated after having the procedure because they still have symptoms of the disease besides tremors. He believes that for many patients, a combination of medications and "psychological discussion" is more beneficial.

Deep brain stimulation "is an aggressive procedure in a disease that's not fatal and one that has other treatment alternatives," he said. "If used for tremors, it's not a bad treatment. But do you want to treat someone with a surgery that is so limited and so expensive?"

Ali R. Rezai, co-director of the Center for Functional and Restorative Neuroscience, and an associate professor in the department of neurosurgery at The Cleveland Clinic Foundation, is more enthusiastic about the procedure.

"This technology is safer than what's already out there . . (and) the outcomes are pretty good."

Rezai, who is considered one of the leading national figures on the procedure, said that the system could even provide a treatment alternative for patients with tremor due to multiple sclerosis, epilepsy, chronic pain or some psychiatric disorders.

"We're just at the tip of the iceberg now," he said.

How it works
The stimulation device, known as the Activa Tremor Control System, was developed by Medtronic Corp. of Minneapolis and consists of an electrode, an electronic device called the neurostimulator that provides the electric pulse and an extension wire to connect the two parts. When activated, the device sends a continuous flow of electrical pulses to the brain, blocking the brain signals that cause tremor. The patient is able to raise or lower the amount of stimulation by holding a magnet over the stimulator for one or two seconds.

The reason deep brain stimulation seems to work has not yet been determined.

Marshfield Neurosciences, a service of St. Joseph Hospital and the Marshfield Clinic, was one of 20 sites nationwide picked initially to offer the device, and the only one in Wisconsin. The procedure is now being offered at other state and local hospitals, including the University of Wisconsin Hospital and Clinics in Madison, Froedtert Memorial Lutheran Hospital in Wauwatosa and St. Luke's Medical Center in Milwaukee.

"As it becomes more accepted by the medical community and the results keep coming, word will get out that it works and more (doctors) will offer it," said Brad Hiner, director of the movement disorder clinic at Marshfield. "However, it isn't a cure. . . . It can help patients who are taking more and more medications but getting less and less benefits or experiencing more side effects."

Hiner, who treated Christenson, said that patients who have had the procedure tend to decrease their medications over time. But, he said, it is uncertain how long the benefits of stimulation last, because patients have been followed for only about six years.

So far, Christenson is convinced.

"My hand stopped dead still, just that fast," Christenson said. "I've got to tell you, it causes an emotion that's really strong. I even shed a tear or two."

Christenson said he decided to undergo the procedure twice because he "wanted to live like a human again" and that being able to do so has made the numerous 500-mile round trips from Crookston, Minn., to Marshfield worth every cent of his gas.

"I feel very fortunate," he said.

Implanting the device
To perform the procedure, surgeons first locate their target in the brain with magnetic resonance imaging (MRI) or computed tomography (CT) scans, then tightly attach an external head frame with a coordinate system to help them visualize the brain's internal structures. After numbing the skin, an incision of about an inch is made in the top of the head just behind the hairline and a nickel-sized hole is drilled through the skull.

The surgeon then attaches microelectrodes on the thalamus, located in the deeper layers of the brain. While taking readings of brain activity, the surgeon monitors how well the patient can answer questions and follow directions. Extreme caution is taken because an incorrect placement could cause double vision, tingling in the arms or legs, or a stroke.

"You know you're in the right spot because the hand stops shaking," said P. Charles Garell, director of the functional neurosurgery program and an associate professor of neurological surgery at UW Medical School. "The response is immediate."

Once correct placement is determined, the microelectrodes are removed and permanent electrodes are locked in place.

The patient is then anesthetized and the surgeon makes a 2-inch incision just below the collarbone to implant a neurostimulator, which contains the battery. A half-inch incision is made behind the ear to connect it to the electrode. Insulated wire is surgically passed under the skin of the head, neck and shoulder.

Possible complications include infection and bleeding, Garell said. The surgery takes about four hours, and patients go home as early as the next day.

Garell said that placing the device on the left side of the brain controls tremors and other symptoms on the right side of the body, and that some people may opt to have the surgery twice.

He warned that the surgery is fairly expensive because each stimulator costs $10,000, though health insurance generally covers the procedure.

Shaking stopped
Tammie Ward is another patient who had success with the procedure.

"I saw my hand completely stop shaking," said Ward, 35, of Black Creek. "I was ecstatic."

Ward, a kindergarten teacher, had tremors so severe on her right side that she couldn't do lesson plans or feed her small children. As with many people diagnosed with essential tremor, medications did not improve her symptoms.

Since she had thalamic stimulation in June in Madison, Ward says her life has completely changed and she has regained the confidence that she had lost.

"I can eat and drink with my right hand and I feel alot better," she said. "I'm now back to doing crafts and decorating, and putting on makeup is a whole lot easier and takes less time."

Who is taking advantage of deep-brain stimulation?

"The procedure is becoming more popular . . . and the technology is well-developed but medication failure is the reason for going ahead with this approach in a person," said Norman C. Reynolds, associate professor of neurology at the Medical College of Wisconsin and practicing neurologist at Froedtert and Zablocki Veterans Affairs Medical Center.

Reynolds said that although it is considered safe for patients of all ages, those who are older or who have other medical complications, such as heart problems, are at an increased risk for complications during the procedure.

He said that anyone thinking about any type of surgical procedure needs to weigh the risks and benefits of each option to determine what's best for them.

Ablation, or lesion, surgery, such as thalamotomy, irreversibly destroys an area of the brain and has a greater risk of bleeding or stroke than deep brain stimulation, but the stimulator can cause infection and has to have the battery replaced, meaning another minor surgery every five years, he said.

"This approach is relatively new, and the profession is carefully assessing who the best candidates for surgery are," Garell said. "But we are all encouraged that many patients will now have an option that is reversible and which they can largely control on their own."

Although deep brain stimulation won't replace traditional medications, it will be adjunct therapy, he said.