According to Jason Lee Gerrard, MD, PhD, assistant professor of neurosurgery and neuroscience and section chief of Central Nervous System Radiotherapy, deep brain stimulation is the process of “taking a circuit in the brain that has been thrown out of whack, and trying to return it to a normal state by modulating the activity of other neurons in the brain."
This is achieved by surgically implanting a three-part system into the patient.
First, one or two electrodes are placed in areas of the brain believed to be causing a patient difficulty. In the case of a patient with Parkinson’s disease, this could be the subthalamic nucleus—a part of the brain that controls motor skills.
A stimulator, which resembles a pacemaker, is then implanted in the patient’s upper chest and connected to the electrodes with a wire.
Programmed by a movement
disorder expert working closely with the patient, the stimulator
determines the frequency and intensity of electrical impulses to the
patient’s brain. Though patients may not be able to feel, hear or see
any evidence of these impulses, they help regulate the abnormal
electrical activity that causes impaired motor functions or other
For patients with Parkinson’s-related tremors, results can be immediate and dramatic.
“The patient is able to turn the device on or off,” says Dr. Gerrard. “When they turn the device on, they often go from having quite marked tremor to, within several seconds, having almost no tremor. It’s amazing to see the difference.”