Deep Brain Stimulation (DBS) - What is it? (#1 in DBS series)
I am about to enter a new phase in my journey living with and Challenging Parkinson's. I will be having surgery to implant a Deep Brain Stimulator (DBS). I will be taking time to document my journey as well as helping to "de-mystify" DBS and what it is like to go through the process.
How long has DBS been used in PD?
DBS was first developed in Grenoble, France in the late 1980s. (Ironically, I visited Grenoble many times during my career as the company I worked for had a major facility in Grenoble. It is a beautiful city.) DBS was not approved for use in the US until 2002. The most recent numbers I found show over 160,000 people with PD have had the surgery, and those numbers are from 2019, so I think it is safe to say there are somewhere between a quarter of a million and half of a million people that have already done what I am about to do.
Given that estimates range from 5-8 million people live with PD, it is still a relatively low percentage of people living with PD who have DBS.
What makes up DBS?
Basically, DBS consists of a "pacemaker", often called the battery or neurostimulator, which controls the frequency and the strength of the electrical signal sent to the brain and one or two leads that carry the signal to the brain.
This control center is most often placed near the collar bone under the skin (like a pacemaker). Wires from the battery are then run under the skin of the neck and skull to the entry point for the lead(s). A bore hole is drilled through the skull and each lead is placed into the brain through this hole. Depending on the types of symptoms (DBS can also be used to treat Epilepsy, Tourette's and even depression), a specific spot in the brain is targeted for the lead(s). The lead in the left side of the brain controls symptoms on the right side and vice-versa. Some people only get a unilateral DBS (one side) because they only have symptoms on one side. I will be getting a bilateral DBS (both sides).
A controller is the final piece, where programing can be changed by the Movement Disorder Specialist and minor daily adjustments can be made by the person living with PD and the unit can be turned off or on by the user.
How does it work?
While that may seem an easy question, the short answer is that it is not fully understood exactly HOW DBS works. There are several theories that range from blocking signals from neurons, to interrupting synapses of the neurons. What is known is that high frequency electrical stimulation is needed. In fact, low frequency electrical stimulation can make PD symptom worse.
What kinds of hardware are available?
For many years, there was basically one choice available for people looking to have DBS. The device was developed and marketed by Medtronoics. The device worked very well and was popular.
Starting in the late 2010s, other options started becoming available from Medtronics as well as other manufacturers. Currently, there are a few options from Medtronics and there are units available from Boston Scientific and Abbott,
Most of the units available today have advanced significantly from the original Medtronics unit. Possibly the biggest improvement comes from each lead having multiple outputs that can each be adjusted by the Movement Disorder Specialist in programing the device. This allows a more focused stimulation pattern, helping to avoid some side effects that were harder to control in the original units.
Specifically, speech was often hindered by the original DBS units. Today, with the more flexible programming, stimulation can be tuned down or off near the area in the brain where speech is controlled. Some people have multiple programs that they can use ... one where movement is maximized, but speech is impacted and one where movement is not optimal, but speech is impacted less, for example.
Boston Scientific originated a rechargeable battery unit (Medtronics also has a unit that is rechargeable). WIth a fixed life battery, it needs to be replaced every 3-5 years, requiring a surgery to implant a new unit in the chest while rechargeable units can last 15 years.
Abbott brought remote programming to market. Since many people living with PD are not near a Movement Disorders Specialist, this can be particularly helpful in tele-medicine. Patients and doctors no longer need to be in the same location to program the device.
Medtronics brought a new unit in 2020 that not only broadcasts the stimulation to the brain, but receives signals from the brain that can be downloaded and analyzed during programming sessions with the Movement Disorder Specialist. Longer term, these signals from the brain may be able to be used to automatically adjust the stimulation based on what the brain needs at any point in time (closed loop), but currently this is not available.
In addition to more units being powered by rechargeable batteries in the future, there are two exciting developments in the pipeline.
The first I mentioned above is closed loop. In this scenario, the brain communicates the symptoms (currently tremor, dystonia and dyskenesia frequencies are known) to the unit and the unit determines the type of stimulation needed and provides it. It also has the ability to turn down or off stimulation when it is not needed. Currently, the stimulator provides the programmed level unless fully turned off or adjusted by the user (only minor adjustments can be made without a Dr present). This could extend battery life and potentially significantly reduce the amount of stimulation a person is exposed to.
The second is a new type of battery (neurostimulator) that would be located in the skull rather than in the chest, as pictured below compared to a current system.
In my next entry, I will discuss how I decided DBS was right for me