What is deep brain stimulation (DBS)?
Deep brain stimulation (DBS) is a surgical procedure that involves implanting electrodes in the brain, which deliver electrical impulses that block or change the abnormal activity that cause symptoms.
The deep brain stimulation system consists of four parts:
- Leads (thin insulated wires) that end in electrodes that are implanted in the brain
- A small pacemaker-like device, called a pulse generator, that creates the electrical pulses
- Extension leads that carry electrical pulses from the device and are attached to the leads implanted in the brain
- Hand-held programmer device that adjusts the device’s signals and can turn the device off and on.
In deep brain stimulation, electrodes are placed in the targeted areas of the brain. The electrodes are connected by wires to a type of pacemaker device (called an implantable pulse generator) placed under the skin of the chest below the collarbone.
Once activated, the pulse generator sends continuous electrical pulses to the target areas in the brain, modifying the brain circuits in that area of the brain. The deep brain stimulation system operates much the same way as a pacemaker for the heart. In fact, deep brain stimulation is referred to as “the pacemaker for the brain.”
How is deep brain stimulation (DBS) used to treat Parkinson’s disease?
Deep brain stimulation (DBS) delivers electrical impulses to a targeted area of the brain that is responsible for the movement symptoms (also called motor symptoms) caused by Parkinson’s disease. The electrical impulses disrupt the abnormal activity that occurs in the brain’s circuitry, which is causing the symptoms.
There are three areas in the brain that can be targets for deep brain stimulation in patients with Parkinson’s disease. They are the subthalamic nucleus, the globus pallidus internus, and the ventral intermediate nucleus of the thalamus. Each of these areas plays a role in the brain’s circuitry that is responsible for the control of movement.
The specific area in the brain to target in an individual with Parkinson’s disease depends on symptoms that need to be treated. For example, deep brain stimulation of subthalamic nucleus is effective for all major movement symptoms of Parkinson's disease, such as tremor, slowness of movement (bradykinesia), stiffness (rigidity), and problems with walking and balance. Deep brain stimulation of globus pallidus is another effective target for a wide range of Parkinson's symptoms. The thalamic target is sometimes selected for patients with tremor symptoms. The recommended target for each patient is made collaboratively with the neurologist, neurosurgeon and other caregivers involved in the decision making process.
How do I know if I’m a candidate for deep brain stimulation (DBS)?
Before being considered a candidate for deep brain stimulation (DBS), patients with Parkinson’s disease must undergo an extensive evaluation process. Ideally, a multidisciplinary team of specialists in the area of movement disorders will assess the patient. This clinical team typically includes a neurologist, neurosurgeon, neuropsychologist and psychiatrist.
If patients are well managed on medications, DBS is not considered. Candidates for DBS are patients who meet one or more of the following criteria:
- Symptoms are not well controlled despite receiving the appropriate dose of levodopa and other medications.
- Symptoms are significantly reducing patients’ quality of life.
- Abnormal or uncontrolled involuntary movements (dyskinesia) or motor fluctuations are not improving despite adjustments in medications.
- Four or more doses of levodopa are required a day.
- Tremors that have not been able to be controlled by medications.
Levodopa response test
Patient’s response to a single dose of levodopa is another test physicians use to identify which patients are likely to benefit from DBS. In this test, patients stop taking levodopa for 8 to 12 hours and then receive a single dose. Patients are likely to benefit from DBS if they have a clear positive response after receiving the single dose of levodopa.
For many patients, the response to DBS will be similar to levodopa but without the symptoms fluctuations. In addition to this, DBS is still effective for tremor in Parkinson’s disease that may not be responsive to levodopa and will also help reduce dyskinesia related to medication use.
How is deep brain stimulation performed?
Before the actual procedure begins, for most patients, a head frame (stereotactic head frame) is positioned on your head, which keeps your head still during brain imaging and is used to deliver the electrode to the target in the brain. Surgical pins or screws are used to secure the frame to your head. Sedation is typically given during this portion of the procedure.
Your neurosurgeon will implant the deep brain stimulation system in one to three stages.
First, a small hole is made in the skull. The leads, which have electrodes at the ends, are passed through this hole and surgically implanted in the areas of the brain identified as the site(s) responsible for the movements caused by Parkinson’s disease.
Most people with Parkinson's disease will require one lead placed on each side of the brain unless symptoms are mostly one-sided (then only one lead on one side of the brain would be needed). Each side (hemisphere) of the brain controls the opposite side of the body, so each lead is inserted on the opposite side of where symptoms are occurring. Sometimes this procedure is done in stages; one lead is placed at one time followed by another surgery for the other side. In other patients, both leads are placed during the same operation. Many times patients are awake during lead insertion. An intraoperative MRI is also sometimes used to image the lead location.
In a separate operation approximately 1 week later, one or two battery-powered pulse generator devices (one per lead) are implanted just under the skin in your upper chest area below your collarbone. An extension wire is attached to the lead already positioned in the brain, then tunneled under your skin behind your ear and down your neck to the pulse generator device.
You will return for an office visit about 2 to 4 after the implant surgery. The implanted pulse generator is turned on by a hand-held device and the electrical pulses are adjusted until symptoms improve. (The device sends electric pulses to the brain through these leads.) The hand-held device can also check the battery level and can turn the device on and off.
Several follow-up programming visits will be needed to fine-tune the stimulation sent to the brain to best relieve symptoms. Then regularly scheduled longer-term follow-up visits will be needed to continue to check to make sure the system is working properly, adjust the stimulation as needed to continue to best control symptoms and to check the battery life of the device.
How does the neurosurgeon know where to place the electrodes in my brain?
Positioning the electrodes in the brain is the most critical step. The electrodes have to be placed in an exact location in the brain to improve symptoms. Computed tomography (CT) or magnetic resonance imaging (MRI) scans are taken before and/or during the procedure to pinpoint the exact areas to target and guide the lead and electrode placement. Many times an electrode may be used to record brain cell activity at the target site to improve lead placement.
Will I be asleep during the entire procedure?
You will be sedated or receive local anesthesia for part of the procedure, may or may not be awake for lead and electrode placement, and will be asleep when the impulse generator is implanted. To provide more details:
- A local anesthetic is applied to areas of the head where pins or screws are used to secure the head frame and sedation is given.
- You will be sedated during the beginning of the procedure, while the surgical team is opening the skin and drilling the opening in the skull for placement of the lead.
- Most patients will be awake for lead and electrode placement. This part of the procedure is not painful, as the brain does not feel pain. Being awake allows the surgical team to interact with you when testing the effects of the stimulation. However, some patients who cannot tolerate the procedure while awake can have the electrode and lead placed under general anesthesia. The lead placement is guided in real time by magnetic resonance imaging. The procedure is performed in a special MR-equipped operation room.
- Implantation of the pulse generator in the chest and connection of the leads from the device to the lead in the brain is usually done under general anesthesia.
Risks / Benefits
What are the advantages of deep brain stimulation (DBS)?
Deep brain stimulation (DBS) has many advantages:
- DBS does not cause permanent damage in any part of the brain, unlike thalamotomy and pallidotomy, which surgically destroy tiny areas of the brain and therefore is permanent and not reversible.
- The electrical stimulation is adjustable and reversible as the person's disease changes or his or her response to medications change.
- Because DBS is reversible and causes no permanent brain damage, use of innovative not-yet-available treatment options may be possible. Thalamotomy and pallidotomy result in small, but permanent changes in brain tissue. A person's potential to benefit from future therapies may be reduced if undergoing these procedures.
- The stimulator can also be turned off at any time if DBS is causing excessive side effects without any long-term consequences.
What are the risks and complications of deep brain stimulation (DBS)?
As with any surgical procedure, there are risks and complications. Complications of DBS fall into three categories: surgery complications, hardware (device and wires) complications, and stimulation-related complications.
- Surgical complications include brain hemorrhage, brain infection, wrong location (misplacement) of the DBS leads, and less than the best location (suboptimal placement) of the leads.
- Hardware complications include movement of the leads, lead failure, failure of any part of the DBS system, pain over the pulse generator device, battery failure, infection around the device and the device breaking through the skin as the thickness of skin and fat layer change as one ages.
- Stimulation-related complications occur in all patients during the device programming stage. Common side effects are unintended movements (dyskinesia), freezing (feet feel like they are stuck to the floor), worsening of balance and gait, speech disturbance, involuntary muscle contractions, numbness and tingling (paresthesia), and double vision (diplopia). These side effects are reversible when the device is adjusted.
Recovery and Outlook
How effective is deep brain stimulation for Parkinson’s disease?
Deep brain stimulation provides excellent relief for most patients’ symptoms including tremor, stiffness (rigidity), slowed movement (bradykinesia), freezing of gait (feet seem to stick to the floor) and dyskinesias. Long-term studies have shown continued improvement in tremor, bradykinesia, and dyskinesia. Many patients are able to reduce their medications and maintain their level of function including independent participation in activities of daily living required to care for oneself. One of the distinct advantages, is that after DBS, patients on average improve their daily ‘on time’—when they are at their best, without troublesome dyskinesia—by half a day.
Does deep brain stimulation cure Parkinson’s disease?
Deep brain stimulation does not cure Parkinson’s disease and its tremor. However, it may significantly improve motor symptoms, which improves a patient’s function and quality of life.
Will I still need to take medications after deep brain stimulation?
Yes. However, your dosage may be greatly reduced over time.
When will I be able to go home after the deep brain stimulation procedure?
The average hospital stay following implantation of the DBS leads is 1 to 2 days. Most patients are able to return home on the same day that their battery is placed.
How should I care for the surgical area once I am home?
- Your stitches or staples will be removed 10 to 14 days after surgery.
- Each of the four pin sites should be kept covered with band aids until they are dry. You will be able to wash your head with a damp cloth, avoiding the surgical area.
- You may only shampoo your hair the day after your stitches or staples are removed, but only very gently.
- You should not scratch or irritate the wound areas.
Will I have to limit my activity following deep brain stimulation surgery?
- You should not engage in light activities for 2 weeks after surgery. This includes housework and sexual activity.
- You should not engage in heavy activities for 4 to 6 weeks after surgery. This includes jogging, swimming, or any physical education classes. Anything strenuous should be avoided to allow your surgical wound to heal properly. If you have any questions about activities, call your doctor before performing them.
- You should not lift more than 5 lbs. for at least 2 weeks.
- You should not raise your arms above your shoulders or over bend or stretch your neck.
- Depending on the type of work you do, you may return to work within 4 to 6 weeks.
When to Call the Doctor
When would I need to call my doctor?
Call your doctor immediately if you experience any of the following symptoms:
- Severe and persistent headaches.
- Bleeding from your incision.
- Redness or increased swelling in the area of the incision.
- Loss of vision.
- A sudden change in vision.
- A persistent temperature of 101 degrees Fahrenheit or higher.
How long does the battery in the impulse generator device last?
Batteries can last 3 to 5 years in non-rechargeable devices and up to 15 years or even longer in rechargeable battery devices. However, these times may vary significantly. A simple outpatient procedure is needed to replace the battery. Rechargeable battery devices can be charged daily (for about 30 minutes) or every 10 to 14 days (for about 4 hours). Your doctor will discuss how often you should recharge your battery based on your therapy settings.
Can I use electrical devices?
While you should be able to use most electronic devices, you should be aware that:
- Some devices, such as theft detectors and screening devices, like those found in airports, department stores, and public libraries, can cause your neurotransmitter to switch on or off. Usually, this only causes an uncomfortable sensation. However, your symptoms could get worse suddenly. Always carry the identification card given to you. With this, you may request assistance to bypass those devices.
- You will be able to use home appliances, computers, and cell phones. They do not usually interfere with your implanted stimulator.
- You will be provided with a magnet to activate and deactivate your stimulator. This magnet may damage televisions, credit cards, and computer discs. Always keep it at least 1 foot away from these items.
Is deep brain stimulation for treatment of Parkinson’s disease covered by insurance?
Most insurance companies and many – but not all – state Medicare programs are providing coverage for deep brain stimulation for Parkinson’s disease. It is best to speak with your insurance representative directly to determine the extent of coverage your policy provides.