A treatment called deep brain stimulation has proven effective in controlling Parkinson’s disease symptoms, but doctors have long debated which areas of the brain should be stimulated to produce the best results.
Now a small study suggests the stimulation of two distinct brain regions can each bring about good outcomes, with the best choice varying patient to patient.
Parkinson’s disease falls into the category of diseases known as motor system disorders. The main symptoms are trembling and stiffness in extremities and face; slowness of movement; and impaired balance and coordination. As these symptoms worsen, patients experience difficulty walking, talking, or other simple tasks. Parkinson’s is chronic and progressive, but is not contagious and usually not inherited.
Treatment consists of controlling symptoms with the drug levodopa, which replaces depleted levels of the brain chemical dopamine. As the disease progresses, levodopa can lose its effectiveness, however. When this happens, deep brain stimulation (DBS) can be brought in to help maintain motor function.
DBS consists of a multi-electrode lead implanted into the brain. The lead is connected to a pulse generator implanted under the skin in the chest. The pulse generator produces a high-frequency, pulsed electric current, conducted by the electrode to the brain. This electrical stimulation appears to block tremors.
“The whole idea of DBS therapy for Parkinson’s is a bit toward the cutting edge,” explained lead researcher Valerie C. Anderson, an associate professor and director of clinical research at Oregon Health and Science University. “One of the issues is where should we implant stimulators to get the best response.”
Earlier studies have shown that stimulation of two brain centers — the globus pallidus interna (GPi) or the subthalamic nucleus (STN) — can be done safely with effective results. While both sites have been approved for electrode implantation by the U.S. Food and Drug Administration (FDA), STN has been the preferred target among neurosurgeons.