Deep brain stimulation may have a big impact on tremors, quality of life

Movement Disorders affect more than 2.5 million people in the United States. For many of them, medications keep their tremors under control. But when drug therapies fail or side effects become unbearable, a surgical option — offered at Baylor University Medical Center at Dallas beginning this year — may help some patients. This option is known as deep brain stimulation.

Bob Morrison of Sulphur Springs, Texas, says deep brain stimulation has eliminated his tremors and dyskinesia — involuntary movements often associated with medications taken to treat Parkinson's disease. "I'm walking straight as any other person. No one can tell I have any problem," he says.

Diagnosed with Parkinson's disease nine years ago, Morrison, 74, had tried different combinations of medications, which helped for a while. But by last summer, he could hardly walk, stumbling and staggering due to pronounced stiffness. That's when Jorge Romero, MD, a neurologist on the medical staff at Baylor University Medical Center at Dallas, suggested deep brain stimulation and referred him to another facility that performed the procedure. Now Baylor offers the procedure, providing comprehensive care for movement disorders.

"Deep brain stimulation is an implantation of a pacemaker, but instead of pacing the heart, it paces the brain," says Cole A. Giller, MD, PhD, a neurosurgeon on the medical staff at Baylor Dallas. "We know that stimulation is effective in helping the symptoms of movement disorders, such as tremor, essential tremor and Parkinson's disease."

During the procedure, the surgeon makes a small incision in the top of the head, creates a nickel-sized opening in the skull and threads a wire containing electrodes deep into the brain. The wires may be placed on the left, right or both sides of the brain, depending on the patient's symptoms. The surgeon tunnels the remaining wire under the skin to the pacing device, which is tucked in a pocket under the chest skin.

Electrical impulses generated by the device continually stimulate the precise area of the brain responsible for the tremors, tempering the activity. Imaging studies, such as MRIs, help surgeons guide the wire and electrodes to the right spot.

"There are very specific targets within the brain that must be reached by the electrode to be effective," Giller says. "Hitting one of these targets is similar to sinking a basket on a basketball court when you are three-quarters of the way down the court."

After the surgery, the patient returns to the neurologist, who turns on and adjusts the frequency and intensity of the stimulation of the individual electrode terminals to obtain the optimal response, Romero explains.

"At the same time, we start trying to reduce the medications," Romero says. "One of the goals is to reduce the amount of medication the patient requires to limit side effects."

The procedure primarily benefits people with Parkinson's disease or essential tremor whose movement disorder affects their quality of life. In addition, deep brain stimulation may help decrease the repetitive muscle contractions of dystonia and relieve tremors associated with multiple sclerosis.


Neurosurgeons began performing surgery for Parkinson's disease about 50 years ago. Back then, doctors would create a small hole in the brain tissue to destroy the tissue where the movements originated. As Sinemet^® (a drug known generically as levodopa) became available in the 1960s, surgical treatment lost favor. However, over time, levodopa's effect wears off or dyskinetic side effects cause additional movement problems. In the late 1980s and early 1990s, physicians again began looking toward surgical solutions.

"It was good for helping people reaching the limit of using Sinemet," Giller says. "At the same time we had the huge leaps in technology. Imaging got better. Pacemakers got better, and the idea of stimulation, rather than placing a hole in the brain, came about."

A primary advantage of using an electrode to stimulate nerve cells is that it does not destroy brain tissue. In addition, patients do not suffer medication side effects or rapid flip-flops between rigidity and dyskinesia.

A decision about surgery requires a complete workup to ensure that the diagnosis is proper; that other conditions, such as dementia, would not interfere with results; and that medications are not working. The process involves serious collaboration with a movement disorders neurologist and neurosurgeon. Indications for deep brain stimulation procedures vary, depending on the disease.

With essential tremor or dystonia, Giller considers surgery when the condition hampers a patient's lifestyle and cannot be medically controlled. Patients with Parkinson's rigidity, altered gait and tremors are prime candidates. With Parkinson's, patients must show some response to medication, even if it lasts only for a short period of time. The area of the brain has to be capable of responding.

"In general, most neurologists feel if the patient is doing well with medication, he or she does not need the surgery," Romero says. "However, that is changing. There is increasing interest in treating people with this modality earlier in their course of illness, but those criteria [for doing so] are not well-defined yet."

Romero explains that in addition to improvements with tremors, patients receiving deep brain stimulation often experience fewer problems with stiffness, rigidity and gait, leading some physicians to suggest surgery sooner. A French study, reported last August in The New England Journal of Medicine, found after six months that deep brain stimulation was more effective for improving a number of areas than medications alone: mobility, activities of daily living, emotional well-being and other aspects of advanced Parkinson's disease.

As with any medical therapy or surgery, deep brain stimulation carries some risk. The most serious, although rare at 1 percent to 3 percent, is the chance of bleeding as the neurosurgeon pushes the wire through the brain. This can produce a stroke, with the associated disability or death. Infection, seizures and an adverse reaction to anesthetic also are possible.

"This is an operation designed for the Parkinson's population, most of them older, so people usually tolerate it pretty well," Giller says.

Long-term, if the brain cannot accept the stimulation, patients may develop memory problems.

Patients with essential tremor typically notice improvement as soon as the neurologist activates the stimulator. Parkinson's patients also respond fairly quickly. In fact, Giller often tests patients in the operating room, turning on the stimulator and watching as the patient's rigid extremities loosen up.

"The operation helps the symptoms of Parkinson's, but it does not help the cause or cure it," Giller says. "This will not slow the progression, but it will make life better."

For multiple sclerosis, it may take a few weeks for the patient to notice a difference, and with dystonia, results may not be noted for six months to one year and will benefit only about half of patients.

Morrison does not notice any buzzing in the head and is unaware of the stimulation. Occasionally, patients may feel a tingling or rigidity, but usually the neurologist can adjust the electricity, so it is not bothersome. The battery on the stimulator will require changing every few years, a surgery that is done on an outpatient basis.

People typically enjoy the benefits and improved quality of life for a long time. Another French study, published in 2003 in The New England Journal of Medicine, found that patients with advanced Parkinson's experienced marked improvement in motor function if off medication, and dyskinesia if on medication, during the five years after implantation. Disease progression, noted by changes in gait, speech and thinking ability, were consistent with the natural history of Parkinson's.

"If results are good, in the right place and the brain accepts it, the response is durable and can last for years," Giller says.

Morrison is happy he had the procedure and would do so again.

"It lets me do what I want to do," Morrison says. "I'm 100 percent of what I wanted from it."  : :



For information on deep brain stimulation, click here.