What is deep brain stimulation?
In deep brain stimulation (DBS), a surgeon places a device under a person's skin. The device sends out electrical impulses to specific parts of the brain. The pulses can block abnormal signals that underlie several neurological conditions.
DBS works well for some people but not for all, and there may be a few adverse effects. A newer technology, known as adaptive DBS, shows promise for reducing some of the problems that occur with DBS.
What is DBS?
Research shows that DBS can help people with Parkinson's disease or essential tremor.
The DBS system involves three different components. A surgeon will implant the following:
A lead: This is a thin, insulated wire know as an electrode. The surgeon implants it in the target area of the person's brain.
An internal pulse generator (IPG): This usually sits under the skin near the collarbone.
An extension wire: This travels under the skin and connects the lead to the IPG.
The IPG will send out electrical signals that help to prevent unwanted movements and other reactions in the body. It runs on a battery, which sometimes needs replacing or recharging.
How does it work?
DBS changes brain activity in a controlled way, and its effects are reversible.
DBS may help the brain to release more adenosine triphosphate (ATP), an energy-carrying molecule that occurs in the cells of all living things. This release of ATP leads to a buildup of adenosine.
Activating the adenosine A1 receptor triggers a process that reduces both tremor and any adverse effects that DBS may cause. This works because the process dampens excitatory transmission in the thalamus.
The DBS procedure does not destroy any nerve cells or healthy brain tissue, but there can be some adverse effects.
This video, by Rajarshi Holder, shows briefly how DBS works.
DBS may be beneficial for people with the following conditions:
It can help to control tremor, which is a symptom of these conditions.
According to the American Association of Neurological Surgeons (AANS), DBS may help improve symptoms such as anxiety, mood, memory function, and compulsion in people with some psychiatric disorders.
These disorders include:
- depression that does not respond to other treatment
- obsessive-compulsive disorder (OCD)
Clinical trials are also underway to see how DBS can benefit people with many other health conditions, including:
- chronic dysphagia
- muscular dystrophy
- muscular atrophy
- Alzheimer's disease
- lower back pain
- focal dystonia
- multiple sclerosis
The AANS note that more than 35,000 DBS implants have been carried out around the world and that the technology has proven a safe and effective way of treating essential tremor.
Researchers who published an article in Experimental and Therapeutic Medicine put this number higher, at 80,000.
People mainly have DBS if their symptoms have not responded well to medications. Most individuals will continue to take medication alongside DBS, but many experience a significant reduction in their symptoms.
Surgery: What to expect
Most people who have DBS need two separate surgeries to implant the necessary equipment.
First, the surgeon will implant the electrodes in the brain. Special scanning equipment will guide them to the correct location.
The surgeon typically starts by fitting a stereotactic head frame to ensure that the person's head remains still during the procedure. They apply local anesthesia to numb the scalp,
Next, they implant a thin wire with electrodes into the brain, followed by a neurostimulator near the collarbone.
The person sometimes needs to be awake during the procedure, so that the neurologist and neurosurgeon can ask questions to monitor their brain function.
One day later, the surgeon implants a pulse stimulator in the person's chest during a second procedure involving chest wall surgery. The surgeon will make a small opening behind the ear, pass the extension wire under the skin, and connect it to the neurostimulator.
When the surgery is complete, the neurostimulator will send electrical pulses to the brain.
Benefits: What does the research say?
Researchers have looked at the benefits of DBS for various medical conditions.
In 2009, a study gave 255 people with advanced Parkinson's disease either DBS or the best alternative care doctors were able to recommend.
Those who had DBS saw an average increase of 4.6 hours a day of good symptom control, while the other group did not see this benefit. The DBS group also saw improvements in motor function and quality of life.
However, 40 percent of the participants who received DBS also had adverse effects, including infections from the surgery.
Following further investigations and clinical trials, the Food and Drug Administration (FDA) approved the use of DBS in 2015 for people who have had Parkinson's disease for at least 4 years with complications that medications cannot control.
In 2010, a team from the University of South Florida followed 34 people with essential tremor for an average of 56.9 months after DBS surgery.
Overall, participants showed an improvement of just over 80 percent on their tremor scores and nearly 70 percent on handwriting scores.
The researchers concluded that the treatment was safe and effective, but they warned that tolerance might develop in some people and symptoms could return.
In 2005, Canadian researchers found that using DBS to treat people with severe depression led to positive results, including mood improvement.
In 2014, doctors Sibylle Delaloye and Paul Holtzheimer of the Geisel School of Medicine at Dartmouth, Lebanon, NH, looked at some of the issues around treating depression with DBS.
They concluded that, while it may help, they needed to see more research before considering DBS safe and effective for depression.
They also stressed the importance of ethical concerns, and especially the issue of consent. A person with a severe mental health condition may not be able to give informed consent.
In 2017, Holzheimer and a team of researchers compared the effects of DBS and a sham therapy in 90 people.
The results, appearing in the Lancet, noted that the two groups showed similar results. In addition, 28 people experienced serious adverse effects, eight of which were likely due to the implanted device or the surgery. The researchers called for further studies.
A 2014 review of research findings suggested that DBS might help some people with alcohol addiction by impacting structures that are deep within the brain. However, the investigators also called for more research.
Mental health conditions
Investigations continue into DBS.
A review from 2018 concluded that DBS might be useful in treating a wide range of conditions, and especially those that doctors relate to mental health. The researchers also pointed out that other, less invasive techniques may also become available in time.
Risks and complications
DBS appears to be a safe procedure, but there is a risk of complications and adverse effects.
Possible adverse effects include blurry vision.
Possible adverse effects include:
- problems with coordination and balance
- difficulty focusing
- jolting or shocking sensations
- allergic reactions
- blurry vision
- tingling in the face or limbs
- pain and swelling at the treatment site
- slight paralysis
People who are more than 70 years old and those with existing medical conditions, such as cerebrovascular disease, may have a higher risk of complications than others.
Associated problems include:
- equipment malfunction or migration to another area
- symptoms return when treatment stops
- adjustment of the device by a specialist may be needed
- replacement of the battery is sometimes needed
Finally, while DBS has helped many people, not everyone will benefit from the introduction of this equipment.
Next generation? Adaptive DBS
In 2018, scientists tried a new technique that they called adaptive DBS, testing it on two people with Parkinson's disease.
As well as providing stimulation, the new version can monitor brain activity. Using this data, it can also vary the levels of stimulation, according to the person's needs.
As it only works when necessary, the battery may also last longer.
Clinical trials: Find out more
Trials are ongoing to test the safety and effectiveness of DBS for a range of medical conditions.
Anyone who may be interested in clinical trials that are taking place now can find information on the ClinicalTrials.gov website or the National Institute of Neurological Disorders and Stroke (NINDS) website.
My husband has advanced Parkinson’s disease, and his medications do not help. Is it easy to get DBS treatment, and will the insurance pay?
Insurance should cover DBS for Parkinson’s, if a person meets the typical criteria, such as becoming less responsive to medication over time, or having certain side effects from the medications. The FDA approval helped in this regard.Seunggu Han, MD Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.