DEEP BRAIN STIMULATION

Information courtesy of Medtronic Europe

Not everyone with Parkinson's disease is a candidate for deep brain stimulation (DBS) but even for those who are declared suitable by a team of professionals, the decision to undergo DBS is not an easy one. There are many considerations. Before you decide to go forward with DBS, the information within this page will inform you on the general aspects of DBS. Your neurologist and neurosurgeon will provide you with the details about the surgery, programming and the therapy itself.

How does deep brain stimulation (DBS) work?

Deep brain stimulation uses one or two surgically implanted medical devices called neurostimulators, similar to cardiac pacemakers, to deliver electrical stimulation to precisely targeted areas on each side of the brain. One of two areas may be stimulated: either the subthalamic nucleus (STN) or the internal globus pallidus (GPi). These structures are deep within the brain and involved in motor control. A neurologist and a neuro-surgeon decide whether to target the STN or GPi. Stimulation of these areas appears to block the signals that cause the disabling motor symptoms of the disease*. As a result, after DBS, many patients achieve greater control over their body movements. The entire system is implanted completely inside the body. Depending on which neurostimulator your doctor recommends, either one or two neurostimulators will be implanted to control symptoms which may effect both sides of the body.

* The Parkinson's disease motor symptoms are:

Rigidity: stiffness or inflexibility of the limbs and joints
Bradykinesia/akinesia: slowness of movement/absence of movement
Tremor: involuntary, rhythmic shaking of a limb, the head or the entire body

What are the components of the deep brain stimulation DBS system?

Neurostimulator - a pacemaker-like device that is the power source for the system. It's about 7.5 cm wide and 1.3 cm thick and contains a small battery and computer chip programmed to send electrical pulses to control Parkinson's disease symptoms.
	Lead - an insulated wire terminating in four electrodes. Extension - an insulated wire placed under the scalp and outside the skull that connects to the lead and runs behind the ear, down the neck, and into the chest below the collar- bone where it connects to the neurostimulator.

External components used with the DBS system include:

A programmer that the physician uses to non invasively program (transmit instructions to) the neurostimulator. People respond to deep brain stimulation in their own way and the program for your neurostimulator will be customized to your needs. A special controller or a handheld magnet that the patient uses to turn the neurostimulator on or, off.or to adjust the settings within limits set by the physician .

How is the DBS system implanted?

The system is implanted by a functional stereotactic neurosurgeon, that is, a neurosurgeon who specializes in treating central nervous system function disorders using stereotactic techniques. This means that a stereotactic head frame is used to keep the patient's head still during surgery and the neurosurgeon uses special imaging techniques such as magnetic resonance imaging (MRI) or computed tomography (CT) to map the brain and locate the site to be stimulated - either the STN or GPi.

There are two parts to the surgery: the procedure to implant the leads, and the surgery to implant the neurostimulator(s) and extensions. The details of the surgical procedure vary between centers, but the following is what you can expect in most centers.

For the first part the patient is awake during the placement of the leads so that dialogue with the surgeon can establish precisely which part of the brain is being passed. For the second part, when the surgeon runs the extensions and positions the neurostimulator (generally in the chest wall) the patient is fully anesthetised. The duration of the procedure and the specific steps involved may vary. The surgery time will depend upon whether one or two leads are to be placed in the brain.. Some surgeries last up to five hours or more. Discuss the procedure with your neurologist or neurosurgeon.

Although the prospect of surgery is somewhat intimidating because the patient is fully awake throughout the procedure, there is comfort in knowing that patients who have the DBS system usually describe the surgery as demanding and exhausting, but not painful. Fortunately, the brain itself has no pain receptors and feels no pain.

Benefits of Deep Brain Stimulation Deep brain stimulation achieves longer periods of symptom relief. Deep brain stimulation can provide hours of relief from the debilitating slowness, stiffness and/or shaking of Parkinson's disease every day. It can also reduce the duration of the abnormal, involuntary movements (dyskinesia) that are a common side effect of Parkinson's medications. In Medtronic multicenter clinical studies, neurostimulation leads were implanted in the subthalamic nucleus (STN) or internal globus pallidus (GPi). Deep brain stimulation increased periods of good motor function and symptom relief by an average of more than 6 hours per day at 12 months*. * Includes only patient data that were fully verified against medical records. Percentages have been rounded to the nearest whole percent. Data on file at Medtronic, Inc

Risks and side effects of Deep Brain Stimulation (DBS)

Potential side effects of deep brain stimulation

Side effects of deep brain stimulation may include the following:

• Tingling sensation (paresthesia)
• Worsening of symptoms
• Speech problems (dysarthria, dysphasia)
• Dizziness or lightheadedness (disequilibrium)
• Facial and limb muscle weakness or partial paralysis (paresis)
• Abnormal, involuntary muscle contractions (dystonia, dyskinesia)
• Movement problems or reduced coordination
• Jolting or shocking sensation
• Numbness (hypoesthesia)

Many side effects related to stimulation can be managed by adjusting the stimulation settings. Several follow-up visits may be necessary in order to find the right stimulation settings to optimize symptom control and minimize side effects.

Potential surgical risks

Implanting the DBS system carries the same risks associated with any other brain surgery. Risks may include:

• Paralysis, coma, death
• Intracranial hemorrhage
• Leakage of cerebral fluid surrounding the brain
• Seizure
• Infection
• Allergic response to implanted materials
• Temporary or permanent neurological complications
• Confusion or attention problems
• Pain at the surgery sites
• Headaches

Your neurologist can provide more information about these risks.

Did you Know?

Facts about Deep Brain Stimulation (DBS)

• Electrical stimulation of the brain has been used worldwide since 1987 to treat movement disorders.
• More than 30,000 people worldwide have benefited from DBS for Essential Tremor and Parkinson's disease since 1995.
• DBS is used as an adjunctive, or complementary treatment for the approximately 100,000 patients in advanced stages of the disease who still respond to the drug levodopa, but whose symptoms are not adequately controlled by medications.
• DBS for Parkinson's disease works by electrically stimulating targeted structures in the brain - either the subthalamic nucleus (STN) or the internal globus pallidus (GPi). These structures control movement and muscle function. A team of specialists including a neurologist, neurosurgeon, neurophysiologist and neuropsychologist determines which structure will be stimulated.
• DBS is used for Parkinson's patients in the advanced stages of the disease or in cases where medication has no effect. In most cases patients should be "levodopa responsive." This means the primary symptoms respond to the drug levodopa. A person's age or pre-existing medical condition does not necessarily exclude him or her from becoming a candidate for DBS. A team of specialists considers all factors before determining if a patient is a good candidate.
• A Parkinson's care team consisting of a neurologist, neurosurgeon and team of nurses is involved in caring for deep brain stimulation patients.
• Patients who have the DBS system usually describe the surgical procedure as demanding and exhausting but not painful. The brain itself has no pain receptors and feels no pain.
• The hospital stay is usually a few days for the pre-operative tests, implant surgery and recovery.
• Many people with a DBS system will not feel the stimulation at all. Some people may feel a brief tingling sensation when the therapy is first turned on.
• Deep brain stimulation is adjustable. This means that the stimulation can be changed over time to match the need for symptom control. To adjust the stimulation, a physician uses a programmer that communicates with the neurostimulator through radio frequency. It's completely non-invasive.
• In Medtronic studies, average improvement in periods of good motor function and symptom relief for treated patients was 6 hours per day*.

*Includes only patients whose data were verified against medical records. Data on file at Medtronic, Inc.

Is Deep Brain Stimulation (DBS) right for you?

Reasons to consider Deep Brain Stimulation

• It is a safe and effective treatment that can relieve many of the debilitating symptoms of Parkinson's disease.
• It can increase the duration and the quality of your periods with good motor function and symptom relief.
• The drugs are no longer working well and you are suffering from their side effects.
• Deep brain stimulation is reversible. If a cure for Parkinson's disease is developed, the therapy can be turned off and the system can be removed.

Am I a candidate?

Deep brain stimulation is used for patients:

• - Who suffer from advanced Parkinson's disease. Patients should be carefully screened for other movement disorders, which may not respond to Deep brain stimulation.
• Who have shown benefit from levodopa therapy. Deep brain stimulation has not been shown to improve symptoms that do not respond also to levodopa.
• Whose symptoms are not adequately controlled by medications.

Only a neurologist or neurosurgeon can determine if deep brain stimulation is right for you. Here are some factors which are considered:

• You must be physically able to endure the surgery, and must be able to cooperate by answering questions and following directions during the surgery.
• If you have significant cognitive decline or dementia, you may not be considered for this surgery.
• You must understand the nature of the therapy and be able to operate the neurostimulator controller (or magnet).
• You must be available for periodic follow-up visits.

The safety and effectiveness of this therapy has not been established for use in these patients:

• Patients with neurological disease origins other than idiopathic Parkinson's disease
• Patients with a previous surgical ablation procedure
• Patients who are pregnant
• Patients under the age of 18 years
• Patients over the age of 75 years
• Patients with dementia
• Patients with coagulopathies (blood disorders in which the blood does not clot properly)
• Patients with moderate to severe depression

Questions to ask your neurologist

Here are some of the questions you might ask. You can also request from your neurologist the Living with Activa Therapy brochure that provides more detailed information on deep brain stimulation before, during and after the surgery.

• Am I a candidate for this therapy? Why? Why not?
• What are the risks and potential benefits?
• What are the side effects?
• What are the surgical risks?
• What kinds of tests will be conducted before the surgery?
• What can I expect on the day of the surgery?
• How long does the surgery last? Is it painful?
• Is this procedure carried out using local or general anaesthetic
• How long will I need to be hospitalized?
• Will my condition improve immediately after surgery or will it take more time?
• What precautions will I need to take after surgery?
• How often will I need to return for follow-up visits?
• How many programming sessions can I expect?
• How often will I need to have the neurostimulator replaced?