What Is Deep Brain Stimulation (DBS)?
Deep brain stimulation (DBS) is a surgical procedure used to treat a variety of debilitating neurological symptoms common to movement disorders such as Parkinson’s disease (PD), essential tremor, and dystonia. It’s important to understand that DBS is not a cure for the underlying condition, but rather it can be an effective treatment for some of the motor symptoms associated with the condition.
The literal “deep brain stimulation” at the center of DBS treatment comes from an electrode (also called a lead) that is positioned within a specific brain area, depending on the movement disorder that’s being treated. The DBS system has three components — the implanted electrode, an implantable pulse generator (IPG) which is the “battery pack,” and an insulated wire connecting the two called the extension.
At Neurology Solutions, we work with DBS devices made by Medtronic, Boston Scientific, and Abbott.
How Does Deep Brain Stimulation Work?
In DBS, thin insulated wires called electrodes are implanted into one or both sides of the brain to stimulate areas of the brain that control movement. These areas—the motor cortex, premotor cortex, and sensory areas—pass through the basal ganglia and help modulate muscle tone, the smoothness of voluntary movement, and the involuntary “positional sense” (the subconscious ability to know where our body is at all times).
The DBS device has three components: a DBS electrode that is permanently implanted into the target structure in the brain, an Implanted Pulse Generator (IPG) placed beneath the collarbone, and an insulated wire connecting the two.
Following implantation, the electrodes are connected to the IPG, also known as a “stimulator.” An external programmer is used to communicate with the IPG to program the delivery of electrical signals through a wire to a small brain region to block the signals that cause some Parkinson’s symptoms. DBS is a relatively complex therapy that requires consistent monitoring by your doctor and battery replacement every 3-5 years on average.
The DBS procedure, a form of stereotactic brain surgery, is performed with a computer system that integrates previous imaging performed a few days before the surgery that provides a 3-dimensional image of the brain. The surgeon will use this image and instruments that provide audio/visual monitoring of the brain during surgery to guide the trajectory and target where the DBS wire will be placed.
Micro Electrode Recording (MER) and Micro Electrode Stimulation (MES) are instruments to identify the surgical site for implantation of the wire more precisely. The MER allows the surgical team to visualize and hear brain electrical activity along the trajectory to the planned target. MER helps measure the size and shape of specific structures expected along the trajectory to the target. MES allows for test stimulation in different locations along the planned trajectory to determine benefits and risks for side effects before the team commits to the placement of the larger permanent lead. If MER and MES do not suggest the most optimal placement for the permanent lead, the data is analyzed to determine which direction and distance to move the microelectrode to achieve the most optimal placement possible. Ideally, the attending neurologist, or neurophysiologist, typically provides this analysis and feedback to the neurosurgeon during the procedure.
Patients are under light to moderate sedation during some parts of the deep brain stimulation surgery to allow the neurosurgeon and attending neurologist to monitor electrical activity in the brain during the procedure. The team will also perform testing of the area after permanent lead placement to decide the best depth for the deepest contact and to affirm expected benefits without side effects at reasonable stimulation parameters.
A few days after placement of the DBS implantable pulse generator (IPG), the patient returns to the neurologist’s office for initial training and testing. The neurologist’s programming team adjusts more complex IPG settings with a wireless programmer. The patient will have a simpler handheld remote controller with limited settings, including amplitude and turning the DBS system on and off. The stimulation settings—size, shape, and field intensity—can be adjusted as a patient’s condition changes over time. The patient will likely see their neurologist 2-3 times per month for the first few months and every 2-3 months in subsequent years to adjust and monitor the effectiveness of DBS settings.
Secure remote WiFi telemedicine options are now available, connecting the neurologist’s programming team to the patient’s home or practically anywhere in the world.
Unlike other brain surgeries to address movement disorders, such as pallidotomy or thalamotomy, DBS does not damage the brain tissue. Thus, if better treatments develop in the future, the DBS procedure can be reversed.
Why Should a Movement Disorder Patient Consider DBS?
Many more movement disorder patients qualify for a deep brain stimulation surgery than actually go through with the procedure. But why is that?
For starters, DBS is literally brain surgery, and for many people, that is simply a bridge too far. While DBS is generally considered a safe procedure, DBS can nonetheless have potentially serious side effects, such as bleeding or a stroke during the surgery itself. Less serious side effects can result from the device needing an adjustment.
On the other hand, DBS can be extremely effective at helping the patient control their symptoms. One study has shown that 87% of the individuals who had undergone DBS showed improvement in motor control within one year after surgery. Also, DBS has been shown to reduce the need for medications in movement disorder patients — a benefit that’s over and above what it can do for the inherent motor symptoms.
But it’s important for people to understand that DBS is not a cure. The goal is to help manage a patient’s symptoms, and perhaps, to slow the progression of some movement disorders.
Who Is an Ideal Candidate for DBS?
An ideal candidate for DBS surgery is under 80 years old, is in good health, and is not presenting with any major cognitive symptoms. Patients who fluctuate between “on” and “off” medication states are usually good surgical candidates, as are those who have troublesome dyskinesias.
At Neurology Solutions, patients considering the DBS procedure must first complete a formal evaluation to determine if they are a proper candidate for the surgery. The evaluation will include neurological, behavioral, and cognitive testing, and an MRI. Formal neuropsychiatric testing is sometimes needed to further evaluate cognitive and/or behavioral decline that may contraindicate DBS surgery. An appointment with a neuropsychologist to ensure you are mentally and emotionally prepared for the procedure is an additional requirement.
Once you decide to move forward with the procedure you will consult with the neurosurgeon followed by an MRI brain scan used for surgical planning.
The Case for Doing DBS Sooner Rather Than Later
In many cases, movement disorder patients only turn to DBS after their medications are no longer working as well as in the past. However, at Neurology Solutions, our position is that movement disorder patients who qualify for DBS should consider getting the procedure done sooner rather than later.
There are a few good reasons why doing DBS earlier might be beneficial, including:
- The brain stimulation inherent to DBS is potentially beneficial to the patient (over and above strictly helping to manage the symptoms).
- A successful DBS procedure may allow the patient to substantially reduce their medications thus reducing potential long-term toxicity.
- Studies have shown that performing DBS earlier helps the patient have a better long-term outcome.
Which Movement Disorders Can Be Treated With DBS?
DBS treatment can be highly effective for patients with Parkinson’s disease, essential tremor (and other types of tremor), and dystonia.
DBS for Parkinson’s Disease
When patients first start taking their Parkinson’s disease (PD) medicines, the benefits usually last throughout the entire day. However, as PD worsens, the patient may notice that the benefit from the medication doesn’t last until the next dose; this is called “wearing off.”
When the medicine wears off, PD symptoms such as tremor, slowness, and difficulty walking may reappear. Then, the symptoms improve once again when the medication is retaken with the next dose. In this scenario, the good period is called an “ON” period, while the bad period is called the “OFF” period. Patients may also develop involuntary movements (twisting and turning) called dyskinesias, which may be troublesome.
Sometimes, your doctor can adjust your medication dose and the timing of the medications to try to reduce OFF periods and dyskinesias. But in other cases, adjusting the medication doesn’t alleviate the OFF periods and/or dyskinesias. It’s those PD patients that tend to benefit the most from DBS.
DBS for Essential Tremor
DBS is a highly effective therapy for patients with essential tremor, often resulting in an 80% decrease in tremor that lasts for several years. In essential tremor cases, the electrode is placed into the thalamus. The electrical signals from the DBS device improve the tremor by reducing abnormal brain activity in the thalamus. DBS can be used to treat both sides of the body for essential tremor patients.
DBS for Dystonia
Primary, generalized, and segmental dystonias respond best to DBS. (Primary dystonia (DYT1) describes a case in which dystonia is the only neurological disorder that the person has and is generally considered to be due to hereditary or genetic influences.)
Secondary dystonias that occur from head trauma, stroke, infection, or Multiple Sclerosis are less likely to benefit from deep brain stimulation surgery.
Follow-Up Care for DBS Patients — Programming Your Device Is Essential
Brain surgery, implanted devices, treating complex neurological disorders — frankly, this is not simple stuff. The surgical procedures (in three stages) to implant the device components are just the first steps in a long road ahead for DBS patients. It is crucial for DBS patients to have their DBS device programmed and adjusted by a skilled expert in order to achieve the best possible results.
At Neurology Solutions, we typically see our new DBS patients twice a week for about a month, then once a week for another month or so, then every other week for a month or so, and so on.
Dr. Izor and his team typically want to see all of their patients at least once every 4-6 weeks to optimize DBS, as well as maximize medical, metabolic, and neuroprotective therapies.
Troubleshooting Evaluation for your DBS device
The team at Neurology Solutions offers troubleshooting evaluations for new patients with already-implanted DBS devices to assess any problems or failures they may be experiencing. This evaluation is a quintessential “second opinion,” except that we can actually take the next step and work with the patient to correct the problems we discover in the evaluation.
Patients who have been implanted with DBS for Parkinson’s, essential tremor or dystonia will receive an initial 1-1/2 hour medical consultation with an experienced DBS programmer, including 15 minutes of analysis and supervision by Neurology Solutions Medical Director Dr. Robert Izor. Multiple visits with the Neurology Solutions team may be necessary until optimal results are achieved. Brain scans and surgical reports may be required to allow a complete assessment.