DBS targets one of three areas in the brain. When placed in the thalamus, the treatment reduces only tremor. In the globus pallidus or the subthalamic nucleus, DBS can reduce tremor, rigidity, bradykinesia and/or gait problems. DBS is a very effective treatment for some patients. It can reduce the need for medication and control the incidence of symptoms. But it doesn't work for everyone.
Researchers say DBS is best for people who have had a good response to medication and are otherwise in good health. There are some risks associated with the surgery - most notably bleeding (which can lead to a stroke, occurring in about two percent of patients) and infection (affecting 4 percent of patients). The National Parkinson Foundation says patients typically have had the disease for at least five years before they are considered for brain stimulation.
Now, researchers at Vanderbilt University want to find out if DBS can be useful in early stages of Parkinson's, when symptoms are still very mild. David Charles, M.D., a Neurologist with Vanderbilt University Medical Center, says the FDA has issued an investigational device exemption to enable doctors to perform a small pilot study of DBS in 30 patients with early stage Parkinson's. Half the participants will receive the surgery plus medication; the other half will get only medication. Patients will be followed for two or more years and their symptoms and outcomes will be compared.
Just recently, French researchers announced their results of DBS for a group of 20 Parkinson's patients with early-stage disease. After 18 months, daily medication dose in those receiving surgery was reduced by 59 percent. Severity of symptoms during "off medication" periods decreased by 69 percent and levodopa-induced motor complications decreased by 83 percent. On the other hand, patients who only received medication (no surgery) had a 12 percent increase in medication dose, 29 percent increase in symptoms during "off medication" times and a 15 percent increase in motor complications.