An emerging treatment technique for Parkinson’s involves the use of deep brain stimulation to reduce tremors.
Dr. Douglas Anderson a professor of neurological surgery at Loyola University Chicago Stritch School of Medicine has treated approximately 50 Parkinson’s patients with the therapy, known as DBS.
His first patient was a middle-aged woman who used a wheelchair due to her Parkinson’s. Dr. Anderson implanted an electrode that delivered mild electrical signals deep in her brain. This stimulation reorganized her brain’s electrical impulses. The treatment worked so well the patient was able to walk down the aisle as a bridesmaid at her friend’s wedding.
“DBS can quell or eliminate tremors,” Dr. Anderson said. “It increases the percentage of time that a patient is functional. It also improves a patient’s ability to move arms and legs in a more coordinated fashion. And there is a lessoning of bradykinesia.”
Dr. Anderson also has used deep brain stimulation to treat patients for obsessive-compulsive disorder, body dysmorphic disorder and debilitating headaches.
DBS has been called a “pacemaker for the brain.” It is an approved treatment for Parkinson’s patients who no longer benefit from drugs, or who experience unacceptable side effects. DBS is not a cure, and it does not stop the disease from progressing. But in the right patients, DBS can significantly improve symptoms, especially tremors. DBS also can reduce rigidity and dyskinesias.
About 40,000 patients worldwide have undergone DBS. The cost of the device and surgery can total more than $50,000. Medicare, Medicaid and private insurers generally cover the treatment.
Dr. Anderson said that although patients’ response to treatment may vary, overall he is pleased with the results. “Patients are more mobile and can move more freely,” he said. “Occasionally their medications can be reduced.”
DBS is among the treatments offered at Loyola University Health System’s new Movement Disorders Clinic. In addition to Parkinson’s disease, specialists at the clinic treat essential tremor, dystonia, Huntington’s disease and tic disorders.
“This treatment is an adjunct, not a substitute, for medications,” cautions Dr. Anderson, who believes collaboration with neurologists is vital to the overall successful treatment plans for patients with movement disorders.
Brain surgery for Parkinson’s disease dates to the 1940s. Using electrodes, surgeons would heat tissue and destroy small parts of the brain responsible for abnormal movements. These surgeries produced moderate benefits, but at the risk of causing neurologic deficits or hemiballismus.
In the 1980s, French neurosurgeon Alim-Louis Benabid, MD, discovered it was not necessary to destroy tissue; tremors instead could be stopped with electrical signals. His discovery lead to DBS, and in 1997, the Food and Drug Administration approved DBS for essential tremor and tremor in Parkinson’s disease.
In the procedure, the neurosurgeon drills one or two dime-size holes in the skull and inserts one or two electrodes about four inches into the brain. A connecting wire from the electrode runs under the skin to a battery implanted near the collarbone. Surgical risks include infection, hemorrhage and stroke. Adverse effects of electrical stimulation, which are reversible, include jolting sensation, numbness or tingling in the face or hand, dizziness, dyskinesia, muscle spasms, slurred speech, double vision and depression.
A pivotal 2001 study in the New England Journal of Medicine found that DBS significantly improved symptoms in Parkinson’s patients who could not be further improved with medications.
The clinical trial was conducted by the Deep Brain Stimulation for Parkinson’s Disease Study Group, an international collaboration.
Researchers performed a prospective, double-blind crossover study in 134 patients. Investigators compared scores on the motor portion of the United Parkinson’s Disease Rating Scale when the device was randomly turned on or off. Three months after the procedure, stimulation of the subthalamic nucleus was associated with a median improvement in the motor score of 49 percent, compared to when the device was turned off.
During the first six months, the percentage of time during the day patients had good mobility without involuntary movements increased from 27 percent to 74 percent. Similar improvements were seen with stimulation of the pars interna of the globus pallidus. Seven patients had intracranial hemorrhage, and the leads had to be removed from two patients because of infection.
The FDA approved DBS for advanced Parkinson’s disease motor symptoms in 2002 and for the humanitarian use of DBS for primary dystonia in 2003. DBS is being studied for several psychiatric conditions, including depression and obsessive-compulsive disorder (OCD).
In 2003, Dr. Anderson and a colleague published a case report about DBS treatment on a 35-year-old obsessive-compulsive patient. The woman had received minimal benefit from antidepressants, cognitive therapy and electroconvulsive therapy. Before surgery, her behaviors included repeated urges to pull her hair out and checking her mailbox 20 times a day. She was unable to work and scored 34 of a possible 40 on the Yale-Brown Obsessive Compulsive Scale.
Three months after surgery, her OCD score had dropped to 7. At 10 months, she was able to “return to the workforce and all compulsions had abated,” Dr. Anderson wrote in the Journal of Neurosurgery.
At the 2008 meeting of the American Society for Stereotactic and Functional Neurosurgery, Dr. Anderson presented case reports about two patients. One patient was treated for body dysmorphic disorder and the other was treated for debilitating headaches.
Body dysmorphic disorder is excessive preoccupation with minor or imagined flaws in appearance. Dr. Anderson’s patient was a 20-year-old man who obsessed on perceived flaws with his nose and other facial features. He had attempted suicide once, and described his life as a “living hell.” Eight months after DBS surgery, the patient reported mild depression and obsessive compulsive disorder, but no symptoms of body dysmorphic disorder.
“While this is a single case report with all the limitations inherent as such, the patient has reported steady psychological progress, the absence of body dysmorphic disorder symptoms, increased activity and energy — confirmed by both family members and his psychiatrist,” Dr. Anderson reported.
The second patient was a 43-year-old woman who suffered paroxysmal hemicrania headaches around the orbit of her right eye. She would typically get 10 to 20 attacks per day, each lasting 2 to 20 minutes. The headaches did not respond to either medications or a nerve block. But as soon as the DBS device was turned on, the woman reported the pain went away.
A year after surgery, she remained headache-free. Anderson said this was the first reported case of DBS for refractory chronic paroxysmal hemicranias. A limitation was the lack of neuroimaging during attacks. More study is needed to determine the potential of DBS for managing refractory headaches.
The concept of psychosurgery still makes many people uneasy. It often brings to mind the inappropriate or indiscriminate use of frontal lobotomy, such as the operation depicted in the novel and 1975 movie One Flew Over the Cookoo’s Nest. But psychosurgery today is nothing like the Hollywood depiction.
“The benefits of DBS for intractable psychiatric conditions outweigh the risks,” Dr. Anderson said.
“The great advantage of DBS over earlier surgical treatments is that it’s reversible,” Dr. Anderson said. “If there are side effects, we can turn the device off and reverse them.”
Source: Loyola University Health System