Deep Brain Stimulation
What is deep brain stimulation?
Deep brain stimulation (DBS) is a type of therapy that uses electrical stimulation to treat Parkinson’s disease (PD), essential tremor, multiple sclerosis, and certain other neurological conditions. DBS can be effective in treating movement problems such as tremors, stiffness, difficulty in walking, and slowed movement.
Doctors may use DBS when medications have become less effective and/or when side effects of the medications interfere with daily activities.
DBS does not cure PD or other conditions, but it can ease symptoms and decrease the amount of medications you need to treat the symptoms, thus improving your quality of life.
How does DBS work?
Movement-related symptoms of PD and other neurological conditions are caused by faulty electrical signals in the areas of the brain that control movement.
Unlike earlier surgical procedures that destroyed brain tissue in order to eliminate the faulty signals, DBS does not damage brain tissue. Instead, it blocks the faulty signals that cause tremors and other movement symptoms.
In DBS, a lead, or electrode, is placed inside the brain. In some cases, two leads may be placed. The lead is connected with an insulated wire extension to a very small neurostimulator (electrical generator) implanted in your chest or abdomen. Electric current from the neurostimulator is delivered to the electrode and passed into brain tissue at a carefully mapped location.
The parts of the brain most often involved in DBS are located in the cerebrum, at the front of the brain.
Some surgeons implant the lead and neurostimulator at the same time. Other surgeons implant the lead during one procedure and the neurostimulator in a separate procedure days to weeks later.
After the neurostimulator is implanted, it is programmed to deliver an electrical signal. Programming is usually done a few weeks after the neurostimulator is implanted. Neurostimulator programming is adjusted over a period of weeks or months in order to obtain the most effective results.
Reasons for the procedure
One of the primary uses of DBS is to treat PD symptoms. Medications are the first-line treatment for PD, but eventually the drugs become less effective, and movement problems worsen. In addition, medications can have their own side effects after long-term use. Not all people with PD are candidates for DBS.
DBS may also be used to treat:
Essential tremor, a condition that causes a rhythmic trembling of the hands, head, voice, legs, or trunk
Multiple sclerosis, a chronic disease that affects the central nervous system—the brain, spinal cord, and optic nerves—and that is often disabling
Intractable pain, pain that can’t be relieved by usual medical and/or surgical treatment
Dystonia, a movement disorder in which muscles contract involuntarily
Psychiatric conditions such as obsessive-compulsive disorder, anxiety, and depression that don’t respond to medications or other treatments
Your doctor may have other reasons to recommend DBS.
Risks of the procedure
As with any surgical procedure, complications can occur. Possible complications include:
Hemorrhage (bleeding) in the brain
Leaking of cerebrospinal fluid into brain tissue; this clear fluid is found in the brain and spinal cord
Pain and/or swelling at the surgery site
Movement of the electrode from the original location
Allergic reaction to one or more parts of the implanted device
Side effects that may occur after the surgery include:
Temporary tingling in the face and limbs
Problems with speech or vision
Jolting or shocking sensation
Dizziness and/or loss of balance
Difficulty with concentration
There may be other risks, depending on your specific medical condition. Be sure to discuss any concerns with your doctor before the procedure.
Before the procedure
DBS is not recommended for all people with PD or essential tremor. You should talk with a neurologist who specializes in movement disorders to determine if you are a good candidate for DBS.
These are factors that may exclude you from having a DBS procedure:
Your main disabling symptom is difficulty with balance, walking, or “freezing,” and medication is providing minimal improvement
Your primary symptom is speech difficulty, and medication is providing minimal improvement
You have confusion and problems with memory and thinking on a routine basis
You have a psychiatric condition such as depression or anxiety that has not improved or stabilized with other treatment
You have another condition that increases the risk for surgery complications
The National Parkinson Foundation lists these criteria for the ideal PD candidate for DBS:
PD symptoms for at least five years
“On/off” fluctuations in the effect of PD medications, with or without dyskinesia (involuntary jerking motions, especially in the arms and head)
Continued good response to PD medications, although the medication effects may wear off sooner than they have in the past
Has tried several different combinations of PD medications while under the supervision of a neurologist specializing in movement disorders
Has PD symptoms that interfere with daily activities
DBS requires a commitment to participate in evaluations, procedures, and consultations before and after the procedure. If you do not live close to a medical center that offers DBS procedures, you may need to spend significant time to travel. The procedure, as well as the pre-op evaluation and post-op follow-up, is expensive. DBS for PD treatment is approved by the FDA, so it is covered by Medicare. Many private insurers cover the procedure, but the extent of coverage will depend on your individual policy.
It is also important for you to have realistic expectations about DBS results. Although DBS can improve movement symptoms of PD, you will not experience a return to “near-perfect” health.
What tests are done before the procedure?
If you have PD, you may have a special assessment, called the Unified Parkinson Disease Rating Scale (UPDRS). This is generally done by a movement disorders neurologist while you are on your medications, then again when you are off them.
You may need other tests to evaluate memory and thinking. A psychiatrist may examine you to determine if you have a condition such as depression or anxiety that requires treatment before the DBS procedure.
During the procedure
Implantation of a DBS lead generally requires a hospital stay of one day or longer. Procedures may vary depending on your condition and your doctor's practices. The lead and neurostimulator may be implanted at the same time, or the neurostimulator may be implanted in a separate procedure after the lead is implanted.
Generally, surgery for DBS follows this process:
Implantation of lead
You will be asked to remove any clothing, jewelry, or other objects that may interfere with the procedure.
Numbing medication will be injected into your scalp for placement of a head frame. The head frame will be attached to the skull with screws. Once the head frame is attached, it will remain in place during the entire procedure. This is to keep your head in proper position during the procedure.
A computed tomography scan or magnetic resonance imaging (MRI) scan will be taken to locate the target site in the brain for the electrode.
You will remain awake during the surgery, as you will be asked to move certain parts of your body as the lead is being placed.
After more numbing medication is injected into your scalp, the neurosurgeon will drill a small hole in the skull to insert the lead.
Recordings will be taken as the lead is moved through the brain tissue are taken to help pinpoint the exact placement for the lead. You may be asked to move your face, arm, or leg at certain times while the recordings are being taken.
Once the precise location for the lead has been determined, it will be attached to an external neurostimulator. Electrical stimulation will be administered through the lead for a short period of time to determine if symptoms improve. Side effects may be deliberately induced with electrical stimulation to verify placement of the lead.
The lead will be attached after it is in the proper location. A wire to connect the lead to an extension to the neurostimulator will be placed under the scalp.
The hole in the skull will be closed with a plastic cap and stitches.
Placement of the neurostimulator (this may or may not be done at the same time the electrode is placed)
You will receive general anesthesia so that you are asleep during the procedure.
The neurostimulator will be inserted into a “pocket” under the outer layers of skin tissue. The surgical site is usually just under the collarbone, but may be in the chest or abdomen.
An extension wire will be attached to the neurostimulator and to the brain lead.
After the procedure
In the hospital
You will be watched for complications such as seizures. In general, the hospital stay after a DBS procedure is 24 hours; however, your stay may be prolonged if complications develop. Before you are discharged from the hospital, arrangements will be made for a follow-up visit with your doctor. He or she will also give you instructions for home care.
Once you are home, it’s important to keep the incisions clean and dry. Your doctor will give you specific bathing instructions. If stitches were used, they will be removed during a follow-up office visit. If adhesive strips are used, they should be kept dry and generally will fall off within a few days.
Programming the neurostimulator
After the DBS lead and neurostimulator have been implanted, the neurostimulator will be programmed for the best response from the electrical stimulation. Programming generally begins a few weeks after surgery, although some doctors activate the neurostimulator before you are discharged from the hospital after surgery.
Programming is a process that occurs over time. You will most likely return several times for adjustment to the neurostimulator settings. In addition, your medications will be adjusted. The goal is control your symptoms with the most appropriate amount of electrical stimulation and medication.
Once your “best” settings have been determined, you will need to return periodically for checkups. Your doctor will determine your follow-up schedule based on your particular situation.
You will be given a magnet to turn the neurostimulator on or off under conditions prescribed by your doctor.
The neurostimulator is powered by a long-lasting battery that generally lasts three to five years. When the battery begins to wear out, the neurostimulator will be replaced with a new one in an outpatient procedure.
Long-term effects of DBS
DBS can help people with PD improve their symptoms of tremors, stiffness, slowness, and dyskinesias. It can also help with medication therapy by decreasing the dose needed. Decreasing the dose of medication can ease side effects of long-term medication use.
Researchers continue to follow patients after DBS. They have found that many people continue to have improvements in their symptoms for several years after the procedure. They are able to perform basic activities, such as eating, toileting, and dressing. Memory, thinking, and mood may or may not be affected.
PD is a progressive disease, so later complications can develop. These complications include:
If these complications develop, the gains obtained from DBS may eventually be lost.
The following precautions should always be considered. Discuss the following in detail with your doctor:
Always carry an ID card that states you have a DBS neurostimulator. In addition, you may want to wear a medical identification bracelet indicating that you have a neurostimulator.
Let airport security screeners know you have a neurostimulator before going through the airport detectors. In general, airport detectors are safe for pacemakers, but the small amount of metal in the neurostimulator may set off the alarm. If you are selected for additional screening by hand-held detector devices, politely remind the screeners that the detector wand should not be held over your neurostimulator for longer than a few seconds, as these devices contain magnets and thus may affect the function or programming of your neurostimulator.
You may not have certain MRI procedures.
You should avoid places with large magnetic fields such as power generators and automobile junkyards that use large magnets.
Avoid using heat in physical therapy to treat muscles.
Avoid high-voltage or radar machinery, such as radio or television transmitters, electric arc welders, high-tension wires, radar installations, or smelting furnaces.
If you are scheduled for a surgical procedure, tell your surgeon that you have a neurostimulator well before the operation. Also ask your doctor's advice on whether anything special should be done before and during the surgery, as the electrocautery device that controls bleeding may interfere with the neurostimulator.
When participating in a physical, recreational, or sporting activity, protect yourself from causing trauma to the pacemaker. A blow to the chest near the pacemaker can affect its functioning. If you are hit in that area, you may want to see your doctor.