An Overview of Deep Brain Stimulation (DBS) for Parkinson’s

Deep brain stimulation (DBS) is a common surgical treatment for Parkinson’s disease symptoms like stiffness, slow movements, and tremors.

DBS will not cure the disease, but it may improve the symptoms that medicine for Parkinson’s is not adequately treating. It may result in more “on” time (a longer duration of feeling good) during the day.

This article will discuss how deep brain stimulation works for Parkinson’s, the symptoms it treats, benefits and risks, and what to expect after this surgery.

How Does Deep Brain Stimulation for Parkinson’s Work?

Deep brain stimulation works by modifying abnormal electrical activity in the brain. It was first approved for Parkinson’s tremors in 1997 and has become an established treatment to control additional motor (movement-related) symptoms of Parkinson’s disease.

DBS involves three main components:

• Leads: Leads (electrodes) are implanted in the brain in a region responsible for motor (muscle) activity.
• Implantable pulse generator (IPG): A separate procedure is performed to implant a battery-operated device (roughly the size of a stopwatch) in the chest (under the collarbone) or in the abdomen. An IPG is similar to a pacemaker for the heart and has been coined by some as a “pacemaker for the brain.”
• Extension: A thin, insulated wire is passed beneath the skin between the leads and implantable pulse generator to deliver the electrical stimulation from the pulse generator to the leads.

The target area in the brain is first identified by magnetic resonance imaging (MRI) or computed tomography (CT). Then, the leads are placed via small holes that a surgeon drills in the skull.

This is considered a minimally invasive surgery that is done in the operating room with local anesthesia. It usually requires an overnight stay.

The IPG is inserted in a separate surgical procedure in the operating room roughly a week later.

After a few weeks, a neurologist begins to program the unit. This process can take several additional weeks to months. When this is completed, people are able to manage (turn on and off) the device with a handheld remote control.

It’s not known exactly how DBS works. The impulses from the generator are thought to interfere with or block abnormal electrical signals (faulty firing of nerve cells) in the brain that are associated with Parkinson’s disease.

These abnormal electrical signals, which have been referred to as “noise” by some neurologists, are thought to result from the loss of dopamine in brain cells that control movement. Dopamine is a chemical that transmits messages between nerves.

There are three different regions in the brain where the electrodes may be implanted:

• Subthalamic nucleus
• Globus pallidus internus
• Ventral intermediate nucleus of the thalamus

DBS of both the subthalamic nucleus and globus pallidus can help with the motor symptoms of Parkinson’s disease, while DBS of the ventral intermediate nucleus is primarily done to control tremors.

The Symptoms That DBS Treats

Deep brain stimulation is used primarily to treat the motor (muscle-related) symptoms of Parkinson’s disease, but this can vary somewhat between the different placement sites. Symptoms treated include:

• Slowed movements (bradykinesia)
• Tremors
• Stiffness (rigidity)
• Abnormal movements (dyskinesias): Dyskinesias are often a side effect of medications for Parkinson’s disease and include involuntary movements such as twisting, head bobbing, squirming, and more.

DBS is not usually helpful with walking problems or balance, though improvements in the symptoms above can indirectly affect walking. It also does not provide significant benefits for non-motor symptoms of Parkinson’s such as cognitive changes, mood changes (such as depression or anxiety), or problems with sleeping.

The benefits of DBS can be estimated by looking at how a person responds to levodopa. Symptoms that respond to levodopa will often respond to DBS (usually to roughly the same degree). But symptoms that are not changed with levodopa are unlikely to be improved by DBS.

DBS often allows for a reduction in the dosage of levodopa, which in turn can result in fewer involuntary movements (dyskinesias) and a reduction in “off” time. The result is often improved quality of life.

Who May Benefit from Deep Brain Stimulation?

A number of criteria can help identify people who are good candidates for deep brain stimulation. This includes people who:

• Have been living with Parkinson’s disease for at least five years, though the procedure was approved for early symptoms in 2016 and is now being evaluated to see if it offers benefits for people earlier in the disease
• Have symptoms that are not well controlled on medications
• Are responding to Parkinson’s medications (levodopa): The procedure should only be done for people who are responding to this treatment, but the medication effects fluctuate during the day and the effectiveness of the medication is getting shorter.
• Find that the uncontrolled symptoms are lowering their quality of life
• Are doing relatively well cognitively (no significant dementia)

At the current time, there is no set age limit for DBS, but the effectiveness may be lower in older people.

Sites of Deep Brain Stimulation and Symptom Control

While both subthalamic nucleus (STN) and globus pallidus internus (GPi) stimulation help improve the motor symptoms of Parkinson’s disease, studies have found a few differences.

DBS of the third target, the ventral intermediate nucleus, can be beneficial for controlling tremors but does not work as well at addressing the other motor symptoms of Parkinson’s disease.

In a Canadian study, targeting the subthalamic nucleus allowed people to reduce the doses of their medications to a greater degree, while targeting the globus pallidus internus was more effective for abnormal movements (dyskinesias).

In another study, STN deep brain stimulation also led to a greater reduction in medication dosages. However, GPi stimulation resulted in greater improvement in quality of life, and also appeared to help with the fluency of speech and depression symptoms.

Side effects of DBS can sometimes include subtle cognitive changes (a decline). A different study compared these effects with regard to these different areas.

GPi showed smaller neurocognitive declines (looking at things such as attention and memory) than STN, though the effects were small with both. On a positive note, both procedures seemed to reduce symptoms of depression following surgery.

Risks and Side Effects of Deep Brain Stimulation

Like any surgery, deep brain stimulation can have side effects, and it carries potential risks. It’s also important to consider the complications and side effects of medications you take since their dosages can often be reduced following surgery.

While DBS may cause side effects, it may also reduce side effects from medications.

Risks

The risks of deep brain stimulation can be broken down into those that involve the surgery and those that involve the devices and connections. It’s important to note that DBS does not appear to cause any significant permanent damage to the brain.

In addition to general risks of surgery and anesthesia, complications may include:

• Bleeding (brain hemorrhage)
• Stroke
• Infection
• Inaccurate placement of the leads or lack of benefit even with proper placement
• Seizures
• Confusion
• Pain or swelling at the site where the leads are implanted or where the battery is placed

Hardware problems may include malfunction, erosion, migration, or fracture of the leads, or battery failure.

In a review of over a thousand people who underwent DPS for movement disorders, complications were uncommon. Though close to 4% experienced asymptomatic bleeding into the ventricles or cortex of the brain, only 1% had symptoms of a brain hemorrhage. Another 0.4% suffered a stroke.

Long-term complications related to the hardware were seen in less than 2% of people and did not require additional surgery. It was also noted that the most common complications could be avoided to at least some degree with careful planning and technique.

Side Effects

Side effects are common but tend to be relatively mild. They can also be broken down into those related to the surgery and those related to stimulation.

It’s noteworthy that, unlike other surgical procedures for Parkinson’s disease, any side effects that occur with stimulation can be reversed by simply turning off the device.

Side effects related to surgery may include a headache or a worsening of emotional symptoms.

Side effects related to stimulation occur for nearly everyone while the device is being programmed, and this process can take several weeks. These can include:

• Numbness or tingling sensations (paresthesias)
• Involuntary muscle contractions, tightness, freezing (feeling like your feet are glued to the floor), or the sensation of muscles being pulled
• Speech or language disturbances
• Double vision or other visual problems
• Unwanted movements (dyskinesias)
• Lightheadedness
• Loss of balance
• Mood changes (depression, anger, anxiety)
• Worsening of gait or balance with walking

What to Expect After DBS

Surgery to implant the leads generally entails an overnight stay, while the IPG is usually implanted as same-day surgery. During recovery, your surgeon will talk to you about caring for your wounds, when you can shower, and any activity restrictions. It’s usually recommended that any heavy lifting be avoided for a few weeks.

After another two to four weeks, you’ll return to have your device programmed. This process will continue for several weeks to ensure the stimulation settings are optimal to control your symptoms. During these visits, you will be shown how to turn the device on and off with the handheld device and check the battery level.

Once the programming has been completed, you will have regular follow-up visits to check and adjust the stimulation to maintain the most benefit for your symptoms.

Living With a DBS Device

Batteries most often last three to five years, but this can vary. Rechargeable batteries may last up to 15 years.

There are several precautions related to electrical/magnetic devices that are important, but usually easy to accommodate. Items such as cell phones, computers, and home appliances do not generally interfere with the stimulator. Keep your stimulator identification card handy when you are out and about, in your wallet or purse.

Theft Detectors

Be aware that some devices may cause your transmitter to turn on or off. This includes security monitors (theft detectors) that might be found at the library and retail shops.

If this occurs accidentally, it is not usually serious, but may be uncomfortable or result in your symptoms worsening if the stimulator is turned off. When you visit stores with these devices, you can ask to bypass the device by presenting your stimulator identification card.

Home Electronics

Keep the magnet used to activate and deactivate the stimulator at least 12 inches away from televisions, computer disks, and credit cards, as the magnet could potentially damage these items.

Air Travel/Metal Detectors

Talk to TSA personnel when traveling by plane, as the metal in the stimulator may set off the detector. If you are asked to go through additional screening with a detector wand, it’s important to talk to the person screening you about your stimulator.

Since the stimulator contains magnets, holding a handheld detection device over the stimulator for more than a few seconds could interfere with the monitoring of the device. Other techniques, such as a pat down, are an option. Again, it’s important to have your stimulator identification card with you when you fly.

Medical Diagnosis and Treatment

Certain types of MRI can be done with the device, but you always have to check with your doctor regarding the compatibility of your device. Alternatives, such as CT, are usually recommended in case you cannot have MRI. The use of heat therapy for painful muscles, whether done during physical therapy or with a heating pad, should be avoided.

During surgery, the use of cautery (burning small bleeding blood vessels) should be avoided, so it’s important that your physicians are aware that you have a stimulator in place. Additional treatments that may interfere with the device include therapeutic ultrasound, lithotripsy (for kidney stones), and radiation therapy.

Occupational Electromagnetic Concerns

Situations that entail exposure to large magnetic fields, radar machinery, or high-voltage currents should be avoided. This can include being near electric power generators, electric substations, ham radio antennas, arc welders, transmission towers, and microwave communication towers.

Most of these potential exposures are occupational, so it’s important to talk to your doctor about your work setting before returning to work.

Summary

Deep brain stimulation is a procedure in which implantable devices deliver electrical impulses to the brain. It can be used to relieve motor symptoms of Parkinson’s disease in some patients. It has some risks, and there may be mild side effects. It often allows the person to use less levodopa and have a better quality of life.

A Word From Verywell

Deep brain stimulation can result in long-term control of stiffness, tremors, and slow movements in people with Parkinson’s disease who meet the criteria for treatment. Unfortunately, DBS does not affect the natural history (progression) of the disease, nor does it control non-motor symptoms such as cognitive changes or mood issues.

At least until we have better treatments that address the underlying process of Parkinson’s disease rather than treat symptoms alone, DBS offers an additional option to help people cope with the very frustrating symptoms of the disease.