Deep brain stimulation (DBS) is a surgical procedure used to treat a variety of neurological symptoms that can become disabling. It is most commonly used as a treatment for motor symptoms in Parkinson’s disease patients who suffer from tremors, stiffness, walking problems, rigidity or slowed movement.
Caring for someone with Parkinson’s disease brings a daily and continual challenge for understanding, treatment and general caregiving. Among the many special challenges is the exploration of treatment options in middle stages. While there is currently no cure for Parkinson’s, the various treatments should be discussed with a physician and compared with the individual’s symptoms. This article attempts to give a basic outline and understanding of one of the surgical treatments available, DBS.
While there are several available surgical methods, including brain lesioning, the most common method for this surgery is a DBS procedure. It involves placement of an electrode in the brain to "jam a circuit," and works like a pacemaker for neurological processes. Usually while the patient is awake using local anesthesia or occasional sedation. This neurostimulator is about the size of a stopwatch; It treats conditions like Parkinson's disease, essential tremor (shaking of the hands, head, voice, etc. which typically is common within families), dystonia (involving stiffness of certain muscle groups), and bradykinesia due to long-term usage of dopaminergic drugs. Its primary function is to stop the abnormal nerve signals. This is accomplished through electrical impulses that are sent from the neurostimulator into the brain, blocking the electrical signals that cause PD symptoms.
Most patients have symptoms on both sides of the body and require both sides of the brain to be implanted for maximal benefit. DBS on one side of the brain mainly affects the symptoms on the opposite side of the body.
This treatment is under investigation for some other disorders like obsessive compulsive disorder, headaches, depression, Tourette's or even obesity. Targets in different areas of the brain are used for different problems.
Typically, the procedure is used only for patients whose symptoms cannot be adequately controlled with medications. However, only patients who do improve to some degree after taking medication for Parkinson’s benefit from DBS. The main benefit of DBS surgery for PD is it makes movement in the off-medication state more like the movement in the on-medication state.
Before the procedure, a neurosurgeon typically uses magnetic resonance imaging (MRI) or computerized tomography (CT) scanning to identify and locate the exact target within the brain where electrical nerve signals generate the PD symptoms.
The DBS system has three components:
- the lead or electrode, which is implanted in the brain;
- the extension, an insulated wire, that connects the lead to the neurostimulator; And,
- the neurostimulator itself, the “battery pack.”
There are three target site choices approved by the U.S. Food and Drug Administration for use in Parkinson’s disease and these should be tailored specifically to the patient’s individual needs. These sites are small clusters of nerve cells that play critical roles in the control of movement. Many studies will remain ongoing, as this is an exciting procedure, but still a field of study with many questions and possibilities.
DBS does not damage healthy brain tissue by destroying nerve cells. Instead, the procedure blocks electrical signals from targeted areas in the brain. Stimulation from the neurostimulator is easily adjustable, without further surgery, if the patient's condition changes. To achieve maximum relief of symptoms, the stimulation can be adjusted during a routine office visit by a physician or nurse using a programming computer held next to the skin over the pulse generator. Some people describe the stimulator adjustments as "programming." Improvement in PD symptoms may take a few hours or few days to respond following a programming change. Some problems may respond more quickly than others.
Following surgery, the patient normally is given a Medtronic Access Review unit. This is a hand held battery-operated unit that determines if the device is on or off and allows the user to check battery life. Some new models allow the patient some control over the stimulation level. Normally the device remains on at all times. If necessary, the implanted pulse generator can be removed and the DBS procedure can be halted.
During the first few days after surgery, it is normal to experience some temporary swelling around the electrode and the eyes. It may produce no symptoms initially, or it may produce mild disorientation, sleepiness, or personality change that can last to one to two weeks.
Most patients experience considerable reduction of their PD symptoms and are able to reduce their medications. Being able to reduce dosages leads to great reduction of side effects. The procedure does carry risks, and it is currently estimated to carry about a one to three percent risk of infection, stroke bleeding, and other complications associated with anesthesia.
Additional post-operative restrictions for the first few days or weeks include:
- no flying in commercial aircraft;
- keeping incisions dry;
- avoiding tight-fitting clothing or hats.
Other than these brief precautions, the patient may return to normal activities rather quickly.
The National Parkinson Foundation has published solid information resulting from their research. Their list of characteristics for determining potential candidates for DBS includes the following:
- Intact intellectual function and memory;
- PD symptoms for a minimum of five years;
- fluctuations with and without dyskinesia;
- good response to PD medications;
- realistic expectations;
- patient age;
- degree of disability;
- previously tried different combinations of levodopa/carbidopa and dopamine agonists under the supervision of a movement disorder neurologist;
- little results from other pd medications such as entacapone, tolcapone, selegiline or amantadine; and
- PD symptoms interfere with daily activities; and the
- ability to remain calm and cooperative.
The National Institute of Neurological Disorders and Stroke is a part of the National Institutes of Health and supports research in DBS to determine its safety, reliability, and effectiveness as a treatment for PD. Researchers are continuing to study and develop ways for improving DBS. Continued development and testing have improved implantable pulse generators and have helped medical professionals and researchers to better understand the therapeutic effects of neurostimulation on neural circuitry and brain regions affected in PD.
Always discuss procedures like DBS thoroughly with your physicians and specialists, and gather as much information as possible when considering any treatment option.