Deep Brain Stimulation (DBS) for Parkinson's Disease

Contents:

• How It Works
• Symptoms Treated
• Risks and Side Effects
• What to Expect
• Frequently Asked Questions

Overview:

Deep brain stimulation is a surgical intervention performed in order to reduce the major symptoms of Parkinson's disease. These three major symptoms include stiffening of muscles, slowness of movements, and shaking. Although DBS doesn't cure Parkinson's, it can greatly improve symptoms that medications cannot adequately control, leading to more "on" time during the day where patients feel better.

How Does Deep Brain Stimulation for Parkinson's Work?

Deep brain stimulation works by modifying abnormal electrical activity in the brain. It was approved in 1997 for the treatment of Parkinson's tremors but has evolved over the years into a standard procedure for the management of other motor symptoms of Parkinson's disease.

The three main parts to a DBS:

• Leads: Electrodes implanted in the areas of the brain controlling movement.
• Implantable Pulse Generator (IPG): A small, battery-operated device, about the size of a stopwatch, implanted in the chest or abdomen.
• Extension: A thin, insulated wire connecting leads to IPG, conducting electrical stimulation from the pulse generator into the brain.

First, the MRI or CT scan is used to locate the target area in the brain. After that, the leads are implanted via small openings drilled into the skull. This minimally invasive surgery is done in the operating room under local anesthesia and generally requires an overnight stay.

The IPG is implanted in a separate procedure a week or so later. Weeks later, programming of the device by a neurologist begins and can take several weeks to months. Once programmed, patients can control the device with a hand-held remote control.

The mechanism of action of DBS is not fully understood, though it is believed that it works by the electrical impulses blocking or interfering with abnormal signals in the brain that are related to Parkinson's disease. Those faulty signals are, in fact, the result of loss of dopamine in cells of the brain that control movement.

DBS electrodes can be implanted in three different brain regions. Those include the subthalamic nucleus, globus pallidus internus, and the ventral intermediate nucleus of the thalamus.

Stimulation of the subthalamic nucleus and globus pallidus internus helps with motor symptoms, while the stimulation of the ventral intermediate nucleus primarily controls tremors.

The Symptoms That DBS Treats

DBS is mainly utilized to treat the motor symptoms of Parkinson's disease, which vary depending on the site of implantation. These include the following symptoms:

Slowed movements (bradykinesia)

Tremors

Stiffness or rigidity

Abnormal movements, dyskinesias, which are often an adverse effect of Parkinson's medications

Although deep brain stimulation is often indirectly beneficial to walking due to improvements in symptoms, it typically does not help symptomatic balance problems or nonmotor symptoms such as cognitive changes, mood disorders, or sleep problems. Generally, the benefits of DBS are similar to the response to levodopa; in general, symptoms that respond to levodopa tend to also respond to DBS.

DBS can reduce the amount of levodopa needed to control Parkinson's symptoms, which can decrease involuntary movements  and "off" time, improving quality of life.

Who May Benefit from Deep Brain Stimulation?

There are several criteria that have been identified which define candidate selection for DBS. These include patients who:

• Have had Parkinson's disease for at least five years
• Have symptoms that cannot be controlled by medications
• Respond to Parkinson's medications such as levodopa, although benefit fluctuates
• Have an impaired quality of life due to lack of symptom control
• No severs impairment of cognition
• Although there is no age limit to DBS, the effectiveness decreases with older age

Sites of Deep Brain Stimulation and Symptom Control

Both STN and GPi sites of stimulation lead to optimal motor symptoms such as bradykinesia and rigidity control, but in some studies discrepancies have been noted.

• STN Stimulation: Increased ability to reduce more medications.
• GPi stimulation: This is more effective in reducing dyskinesias and may improve quality of life, speech fluency, and depression symptoms. DBS directed at the ventral intermediate nucleus mainly helps alleviate tremors.

Deep Brain Stimulation: Risks and Side Effects

DBS is surgery, and as such, it holds its risks and side effects, though the permanent damage to the brain is not significant. The risks include:

• Bleeding (brain hemorrhage)
• Stroke
• Infection
• Incorrect placement of the lead or inadequate benefit despite correct placement
• Seizures
• Confusion
• Pain or swelling at the implantation sites

Hardware complications: this can manifest as malfunction, erosion, migration, or failure of the battery. In a series of over 1000 DBS procedures, complications were rare. Less than 2% had long-term hardware-related complications, and these generally did not need further surgery.

Side effects are typically mild and reversible. Side effects associated with the surgery include:

• Headache
• Exacerbation of emotional symptoms

Side effects due to stimulation, which occur with device programming, include:

• Paresthesias
• Involuntary muscle contractions or tightness
• Speech or language disturbances
• Visual problems
• Dyskinesias
• Lightheadedness
• Balance problems
• Mood changes
• Worsening of gait or balance
• What to Expect After DBS

The typical length of stay in the hospital is overnight for lead implantation, whereas IPG implantation is performed as an outpatient. Recovery includes wound care, showering, and activity restrictions .

Patients return two to four weeks later for device programming, which will occur over the course of several weeks to fine-tune stimulation settings. Follow-up visits are important to adjust the device to ensure continued symptom control.

Living With a DBS Device

Batteries generally last somewhere between three to five years, but in some cases, rechargeable ones function for as long as 15 years. Furthermore, there are necessary precautions to take regarding electrical and magnetic devices; however, in most circumstances, household electronics will not cause a disturbance with the stimulator. Carry the stimulator identification card with you everywhere because it's possible you'll need it when going through security checks at airport entrances and thus that goes for entering a variety of retail shops and other businesses that have high security detectors.

Medical issues include: avoiding some types of MRI techniques, heat issues, and surgical issues with cautery. Occupational-based issues involve: avoiding big magnetic fields and high-voltage surroundings.

Deep brain stimulation is a surgical treatment that uses implantable devices to sends electrical signals to the brain. These implanted devices help control movement symptoms of Parkinson's, including tremors, stiffness, and slowness, thus allowing for a reduction in medication doses and recovery in the quality of life of patients. DBS has no effects on the natural course of developing Parkinson disease or the reduction of non-motor functioning symptoms and cannot be detected, although the benefits of DBS on movement tendencies can be significant.

A Word From Verywell

DBS affords long-term correction of stiffness, tremors, and slow movements in individuals who qualify for treatment. It does not influence the progression of Parkinson's or manage non-motor symptoms, but DBS is still an important means of managing the frustrating motor manifestations until more effective treatments can emerge.