Using Deep Brain Stimulation to Treat Brain-Related Disorders

Relief Possible for Parkinson's Disease, Tremor, and Dystonia

Doctors reviewing brain imaging on tablet

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Deep brain stimulation is a neurosurgical procedure that involves the placement of an implanted system that will send electrical signals to specific regions of the brain to help restore dysfunctional circuits that impact movement symptoms. People affected by movement disorders usually improve their symptoms by using drug therapies. Although, in some cases, drug therapies are not effective or fluctuate in effectiveness over time. Some individuals diagnosed with Parkinson’s disease, essential tremor, or dystonia who inadequately respond to conventional medications may be good candidates for deep brain stimulator placement.

What Is Deep Brain Stimulation?

Deep brain stimulation (DBS) is a surgical procedure used as a form of therapy for symptoms associated with certain neurological movement disorders. This procedure involves the placement of electrodes at specific sites in the brain and the implantation of a pacer in the chest, which is responsible for controlling the electrical stimulus of the electrodes.

While the mechanism of DBS is not fully understood, the general consensus believes that the released electrical signals affect certain cells (and associated chemical messengers) in the brain and aids in modulating communication between certain regions of the brain. This, in turn, reduces symptoms associated with movement disorders and eases the ability to generate movement.

The most common areas of the brain that are targeted include: 

  • Ventralis intermediate nucleus of the thalamus
  • Globus pallidus pars interna
  • Subthalamic nucleus

Over 16,000 people worldwide have undergone this procedure, and the numbers are only rising. DBS was first approved by the U.S. Food and Drug Administration (FDA) in 1997 for the treatment of essential tremor.

DBS has been the standard of care for those diagnosed with Parkinson’s disease, essential tremor, and dystonia when medications fail to control symptoms.

In some cases, DBS is also used as a form of therapy for those dealing with focal epilepsy and multiple sclerosis that is not responding to first-line medical treatment.

Components of the DBS System

There are three components to the DBS system that are implanted in a patient: 

  1. The first component is the electrode (also called a lead). The electrode is a thin, insulated wire that is inserted through a small opening in the skull and implanted in the brain. Some patients receive two electrodes, one on each side. This bilateral procedure may be done to help control symptoms affecting both sides of the body.
  2. The second component is another wire, often called an extension, which is passed under the skin of the head, neck, and shoulders to the implanted pulse generator⁠—the final component.
  3. The internal pulse generator (IPG) is responsible for controlling the level of stimulus released by the electrode.

While many patients experience clinically significant improvements, this form of treatment is not guaranteed to work for everyone. It is important to consider the purpose of the treatment and the evaluation that must occur prior to surgery.

Purpose of DBS in Specific Conditions

While DBS can improve motor symptoms (those associated with the initiation and control of movements), not all symptoms associated with the diagnosed underlying neurological disorder may be relieved by this treatment.

  • For patients diagnosed with multiple sclerosis, DBS is primarily used to control arm tremors.
  • For patients diagnosed with dystonia, DBS is effective for treating symptoms of torsion dystonia. This refers to sudden and involuntary muscle tightening. In fact, it happens to be more effective for those diagnosed with primary dystonia rather than secondary dystonia.
  • For patients diagnosed with focal epilepsy, DBS can aid to reduce the number of seizures and associated symptoms over time.
  • For patients diagnosed with Parkinson’s Disease, DBS can help alleviate motor symptoms like stiffness, slow movements, and tremor. It does not reduce non-motor symptoms, like psychosis, sleep problems, imbalance, and the sudden inability to move while walking (called freezing).

Evaluation Before the DBS Procedure

Before someone can undergo this procedure, they must talk with a team of medical experts to determine eligibility. This team includes a movement disorder specialist, often a fellowship-trained neurologist, and a brain surgeon (neurosurgeon) who specializes in DBS procedures. This level of expertise may require evaluation at a major academic medical center, often associated with a university that has a medical school.

In meeting with the team, the experts will review your use of disease-modifying medications. It is important to evaluate the severity of your symptoms, both when taking and without the medications.

Comprehensive testing will include multiple brain imaging scans (such as an MRI scan) and psychological tests to evaluate memory and thinking abilities. During your evaluation, you will also go over the potential benefits of DBS placement, based on the underlying neurological disorder, and the possible surgical risks. Based on the information obtained from this in-depth evaluation, the experts will decide the best sites within the brain for placing the DBS electrodes. 

For patients diagnosed with Parkinson’s Disease, there are set criteria that must be met before DBS can be considered as a form of treatment. Parkinson’s disease must have been diagnosed for at least three years, and two or more of the hallmark symptoms, like tremor or stiffness, must be present. In addition, either dyskinesia must be present or prior but now incomplete responsiveness to medications, like levodopa, must be demonstrated

Generally, when medical therapy with the use of standard medications begins to fail, especially at maximal doses and with combination drug therapy, DBS may be considered. Symptoms may become difficult to manage, impairing quality of life and daily function, leading to the need to escalate the treatment provided.

People with dementia are not generally eligible for the procedure, as it may worsen thinking, hallucinations, and memory abilities.

What to Expect During and After the Surgical Procedure

During surgery, patients receive conscious sedation and are awake in order to assess brain function and response to the procedure. You may be asked to perform certain tasks, such as holding a glass of water, to ensure correct placement and resolution of the bothersome symptoms.

Electrical stimulation of the targeted brain region will lead to an immediate improvement in symptoms, proving that it is effectively placed.

The placement of the leads is painless due to the brain’s inability to perceive and relay pain signals. The neurosurgeon will determine the precise locations for placement using computerized brain-mapping. This technique visualizes the function and physical structure of the brain using high-quality imaging and recording equipment, like magnetic resonance imaging (MRI) and computed tomography (CT) scanning. Although uncommon, some centers may rely on these technologies alone to perform the procedure while the patient is fully asleep.

The internal pulse generator (IPG) component, which is similar in size to a cardiac pacemaker (significantly smaller than a pack of playing cards), is typically implanted under the skin near the collarbone. It can also be placed in the chest or under the skin above the abdomen.

A few weeks following the surgery, the IPG will be programmed by your doctor to specific settings that will optimally treat your symptoms. In addition to adjusting these DBS stimulation parameters, the doses (or ongoing use) of prior medications will be altered.

Typically, a handheld magnet that serves as a control device will be given to you in order to adjust the stimulation parameters of the IPG at home. It will be possible to control the level of stimulation released at the electrode, providing the ability to relieve breakthrough symptoms.

Risks and Side Effects

DBS is a minimally invasive procedure, however, there are several risks and potential side effects that should be considered.

The placement of the DBS includes the following risks:

  • Allergic reaction to the implant
  • Temporary tingling involving the face or limbs
  • Temporary pain and swelling at the site of the implantation
  • Headaches
  • Moderate paralysis (inability to move)
  • Vision impairment
  • Speech problems
  • Difficulties with coordination
  • Impaired concentration
  • Imbalance
  • Bleeding (hemorrhage)
  • Infection

There is a 2% to 3% risk of brain hemorrhage that either has no impact or may cause other conditions such as paralysis, speech impairment, and stroke. It is possible for the placement of the DBS to lead to a leak of cerebrospinal fluid, which may cause positional headaches or infections called meningitis or encephalitis. Lastly, although there is a risk of acquiring an infection from the implant; once treated the infection will not cause any long-term effects. 

Aside from these potential risks, there have been cases reported that involve the movement (called migration) of the electrodes from the site of implantation. Some patients have even experienced the onset of seizures in the post-procedure period.

It is possible, over the long term, for the effectiveness of the stimulation to cease which may lead to symptoms returning and worsening over time.

It is important to note that as with most surgeries, surgery may be of higher risk in certain populations or in those with specific conditions:

  • Advanced age
  • High blood pressure (hypertension)
  • Morbid obesity
  • Smokers
  • Diabetes
  • Clotting or bleeding disorders
  • Immune system compromise

As always, review your medical history with your physician and consider the potential risks of these and other chronic medical conditions that may make surgery more risky in your case. 

Estimated Costs of DBS

It should not be ignored that the DBS procedure is an expensive proposition, and its expenses should be fully discussed with your physician and insurance provider.

The costs⁠—including the device, surgical procedure and associated anesthesia, hospital fees, and other physician fees⁠—can range from $35,000 to $50,000. Bilateral procedures may double the prices, leading to costs that range from $70,000 to $100,000.

Health insurance may cover some or all of these costs, and your benefits will vary depending on your deductible and other policy details. Because the procedure is FDA-approved for the treatment of drug-resistant Parkinson’s disease, Medicare and many private insurance companies will cover most, if not all, of the cost of the procedure.

During your evaluation, it is recommended that you request a meeting with a financial counselor to get a full understanding of the costs associated with the procedure and ongoing management.

Long-Term Benefits of DBS

While DBS may not be the right treatment in some cases, when it works there are many long-term benefits associated with the procedure.

Stimulation can be constant, rather than needing to be optimally timed like when taking medication. Therefore, DBS can better regulate symptoms that are continuous throughout the day. For patients with Parkinson’s disease, if effective, the need for dopamine replacement therapy is reduced by 50% to 70%.

Over time, the stimulation parameters can be adjusted to minimize side effects.

When the battery needs to be replaced, years later, the procedure is fairly simple and can be done in an outpatient clinic.

If ineffective, the procedure is reversible, and the system can be removed if necessary.

Research and Development of DBS

Ongoing research, including new potential applications involving deep brain stimulation, continues.

While refinement of the best evaluation and techniques to optimize the effectiveness in treating symptoms associated with Parkinson’s disease, essential tremor, and dystonia is still debated, early research has indicated that DBS may also have a role to improve mood and psychiatric disorders. Symptoms like depression, anxiety, and compulsions associated with obsessive-compulsive disorder may be improved with DBS when medications fail. Further research is required to investigate its effectiveness in treating those with medication-resistant psychiatric disorders.

Researchers also continue to investigate the areas of the brain that should be targeted to most effectively reduce symptoms, as well as ways to treat other symptoms like walking and balance issues that are not presently improved by DBS placement.

On a similar note, research on possible biomarkers that can explain why certain patients have better clinical outcomes with reduced symptoms compared to other patients continues to be done in the field. Researchers are also testing out stimulation parameters that might be most effective, as well as how early after diagnosis a patient should ideally undergo DBS placement.

Finally, DBS is also used as a scientific tool to investigate the physiological mechanisms behind dysfunctions affecting the brain. Information from DBS placement benefits the field in developing further technological innovation, expanding safety measures, and enhancing clinical outcomes.

Technological innovations, such as smaller IPGs that may be placed in the skull or IPGs with a rechargeable battery that does not require replacement, continue to help expand the use and safety of DBS placement.

A Word From Verywell

Deep brain stimulation can be a great alternative for those dealing with symptoms from movement disorders that are no longer responsive to standard drug therapies. When medications fail, surgery may become necessary. DBS is minimally invasive and can be beneficial, however, this treatment may not be effective for all who seek it and is associated with a number of risks and side effects that can further impact the quality of life.

If you deal with Parkinson’s disease, dystonia, or essential tremor, and believe that DBS might be a good option to treat your symptoms, talk with your doctor and seek the evaluation of a neurologist. Openly discuss benefits, risks, and costs to determine if DBS is right for you.

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Article Sources

  1. Lozano AM, Lipsman N, Bergman H. Deep brain stimulation: current challenges and future directions. Nat Rev Neurol. 2019;15(3):148-160. doi:10.1038/s41582-018-0128-2

  2. American Association of Neurological Surgeons. Deep Brain Stimulation. (n.d.)

  3. Okun MS, Zeilman PR. Deep Brain Stimulation: A Practical Guide for Patients and Families.

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