Overview of Deep Brain Stimulation (DBS)
It has been long understood that the brain is an electrical organ, and the first studies of electrical stimulation of the human brain date to the 1870’s. Modern Deep Brain Stimulation (DBS) was developed about a century later, in the 1970’s, initially for the control of pain. DBS was first used to treat Parkinson’s Disease in 1987. Today, DBS is a standard surgical treatment for Parkinson’s Disease, Tremor, and Dystonia.
Deep Brain Stimulation delivers electrical current to small areas of brain tissue near the brainstem. This electrical current changes, or “modulates”, the communication between nerve cells in the brain. The symptoms of disease, such as slowness of movement, stiffness or tremor, are caused by abnormal communication between nerve cells. Therefore, the DBS modulation will silence this abnormal communication and restore function that is closer to normal.
The electrical stimulation to the brain is delivered through a fine wire that is passed through brain tissue to reach its target deep in the brain. Outside of the brain, but underneath the skin, the wire is connected to an extension wire that goes to an implanted neurostimulator or “brain pacemaker” that is usually placed in the chest. The whole system is underneath the skin. The neurostimulator can be programmed to many different settings using a device that communicates with the neurostimulator through the skin.
Procedural details for Deep Brain Stimulation (DBS)
DBS surgery is usually divided into two stages. In stage 1, the DBS leads (brain wires) are placed into the brain. In stage 2, the neurostimulator device (brain pacemaker) is implanted and connected to the DBS leads with an extension wire.
Stage I: DBS lead placement
Goal: In this stage, the DBS leads that deliver the electrical current are implanted.
Parkinson’s Disease Medication: Patients need to be off all PD medication for at least 8 hours.
Anesthesia: Patients are wide-awake for most of the surgery, but may have mild sedation during certain times.
The success of DBS surgery depends on the accuracy of the placement of the DBS leads within a particular group of neurons (nucleus). Therefore, a Stereotactic frame guides surgery. This metal frame is a highly accurate measurement device that is attached to a patient’s head like a halo. Using this frame, any location within the brain may be targeted with millimeter precision.
In order to match the frame with the patient’s brain, and MRI scan must be performed with this MRI-compatible frame in place. In addition, location of the DBS wires in the brain is confirmed with microelectrode recording and test stimulation. Microelectrode recording is essentially “listening” to the brain activity. Different areas in the brain have characteristic firing patterns, which means they sound differently when we listen to them.
Finally, when we are confident in the brain location, we test stimulate to check for any side effects and benefits to the stimulation. After all this information is confirmed, the permanent DBS electrode is implanted in the brain, and the other end is tucked under the scalp for later connection to the neurostimulator. This procedure is usually performed on both sides of the brain during a single surgery.
Stage II: Neurostimulator implantation
Goal: Connect the DBS brain electrodes to an implanted pulse generator or “pacemaker”.
This stage is an outpatient surgery that is scheduled 1 to 3 weeks after the first surgery. This surgery is performed under a general anesthesia. A stimulator device is typically implanted on each side of the body in the upper chest, each of the two stimulators stimulating one side of the brain. It is possible to have a larger stimulator implanted only on one side that stimulates both sides of the brain. The decision between two smaller and one larger stimulator must be made before your first surgery. Currently, the stimulators contain a non-rechargeable battery that must be replaced every 4-5 years. In the future, there will be an option of using rechargeable batteries that are expected to last 10 years before replacement.
Medications for Deep Brain Stimulation (DBS)
After DBS surgery, patients are often able to reduce their medications in consultation with their Neurologist. Patients with Parkinson’s Disease should never abruptly stop taking their medications.
Considerations for Deep Brain Stimulation (DBS)
Patients with Parkinson’s Disease, Essential Tremor, or Dystonia whose medications are not effective or causing side effects.
Effectiveness of Deep Brain Stimulation (DBS)
This treatment is highly effective for certain movement related symptoms of Parkinson’s Disease such as slow movement, stiffness, and tremor. The treatment is highly effective for patients with tremor.
Urgency to have be treated or having Deep Brain Stimulation (DBS)
This is an elective surgery, so there's no urgency in seeking treatment.