Many Parkinson’s patients suffer greatly from their symptoms. Brain surgery with a pacemaker can alleviate it. However, many do not dare to approach it. Jens Volkmann, who helped to establish this method in Germany, explains who deep brain stimulation is suitable for and how it brings about a “second honeymoon”.

“After the skull surgery, tremors and other symptoms seem to have disappeared,” reports Parkinson’s patient Max Gruber in an interview with FOCUS online. The neurologist Jens Volkmann operated on him. The director of the neurological university clinic in Würzburg has already been able to help hundreds of Parkinson’s patients with a brain pacemaker. He was one of the first to work with it in this country. He has been researching deep brain stimulation (DBS) in the treatment of movement disorders for decades, which is why he co-founded the Parkinson Foundation. Its task is to act as a link between research and patients/interested people to provide up-to-date and verified information about Parkinson’s. His practical experiences with DBS and the most important questions about this technology.

FOCUS online: The option of THS surgery has been around for a good 40 years and has revolutionized the treatment of Parkinson’s. How many are estimated to be carried out in Germany?

Jens Volkmann: In Germany, around 800 to 1000 implantations are carried out every year. The number has been constant for years and has even declined slightly since Covid. In view of the approximately 350,000 people affected by Parkinson’s, of whom a conservative estimate is around ten to 15 percent, there is an indication for deep brain stimulation (DBS), very little. Unfortunately, the knowledge of this therapy is still insufficient for many doctors and Parkinson’s sufferers. And because of ignorance, there are reservations, so that well-suited patients are informed about this alternative too late or not at all and referred to suitable centers.

For which form of Parkinson is DBS suitable as a therapy?

Volkmann: Many of the symptoms of Parkinson’s disease, such as movements that are too small and slow, sluggish gait, tremors or muscle stiffness, are an expression of a lack of dopamine, a chemical messenger in the brain. The lack of dopamine leads to a signal disruption in brain networks that control movement.

Deep brain stimulation uses mild electrical impulses to correct network activity, mimicking the effect of dopamine. It is therefore suitable for all patients whose symptoms respond well to treatment with dopamine substitutes, but who suffer from side effects of the medication or an unreliable response over the course of the day, the so-called on-off fluctuations. This affects about half of all Parkinson’s patients after five to six years of drug therapy.

What can this patient group expect from DBS?

Volkmann: Deep brain stimulation is then able to restore a state of continuous, good mobility, as it was at the beginning of drug treatment. This is called the second “honeymoon” in suitable patients. The aim is to maintain the quality of life of those affected for as long as possible through a phase of optimal symptom control.

And who is it not suitable for?

Volkmann: If Parkinson’s disease is too advanced and characterized by symptoms that do not respond adequately to medication, such as dementia, even deep brain stimulation can no longer help. Although there is no formal age limit, many centers are cautious about the indication beyond the age of 70 to 75 because the benefits decrease and the risks increase.

What exactly happens during the operation?

Volkmann: Deep brain stimulation is a minimally invasive intervention on the brain. A thin and flexible probe is inserted through small drill holes in the skull into a deep core of the brain, which is important for controlling movement. Today, the intervention is planned with millimeter precision using high-resolution nuclear spin images of the brain, and the probes are inserted with high precision using a frame or robot system. It is a routine procedure that has been refined over the years and is now also offered under general anesthesia at many centers.

The technology is a bit similar to a pacemaker?

Volkmann: The technology behind brain pacemakers actually comes from heart pacemakers. However, a cardiac pacemaker only needs to deliver about one electrical pulse per second, while a brain pacemaker delivers 100 to 200 pulses per second. That is why a brain pacemaker also has a much larger battery or accumulator capacity. In other respects too, stimulating nerve tissue is much more demanding than stimulating the heart. Modern deep brain stimulation systems are ultimately brain-computer interfaces that specifically promote movement and can avoid side effects by delivering highly complex stimulation patterns.

How long does the procedure take on average?

Volkmann: The duration of the operation is now just a few hours, but it is not the crucial point. Patients need to know that the full effect of the stimulation will only come after a slow adjustment of the stimulation parameters and an equally careful adjustment of the medication. For this you have to calculate a few weeks or months after the procedure.

And how risky is the operation?

Volkmann: Of course, many patients are very concerned about the possible risks of brain surgery. But you can really calm down here. The risk of suffering permanent damage from the operation is well below one percent. For comparison: The risk of suffering a stroke during an operation to narrow the carotid artery is around three percent. It takes place outside the brain and is perceived by most people as less “dangerous”. This description should not belittle the fact that in very, very rare cases, tragically, serious complications can also occur with deep brain stimulation, but the operation has now become a routine intervention with a very high level of safety.

It is amazing that my patient Max Gruber does not and did not have a headache, not even when the electrodes were placed in the brain, although he was awake.

How successful is DBS in Parkinson’s? Do all patients experience this so-called second “Honymoon” with significantly fewer symptoms than our patient?

Volkmann: We would not operate on a patient in whom we do not see the prospect of a far-reaching improvement after a detailed examination. Basically, our goal is to almost completely replace the effect of dopamine drugs with well-placed stimulation. Of course, we cannot cure Parkinson’s.

If the patients are well selected and the operation is performed with precision, it is a success in almost all cases. Only very rarely is it necessary to correct a probe that has deviated from the planned target point. But even then, the desired result can usually be achieved through operational repositioning.

This positive effect lasts for many years, as a recent study shows?

Volkmann: The effect of deep brain stimulation generally lasts for many years or even decades. However, Parkinson’s disease progresses and may require adjustment of stimulation over time. Over time, some patients also develop symptoms that no longer respond well to medication or deep brain stimulation, so that how long a patient can live largely unaffected by Parkinson’s problems after the operation depends heavily on the course of Parkinson’s disease.

Of course, age also plays a major role. Younger patients simply have a longer life span ahead of them in which to benefit from DBS while remaining in good general health.

Who can Parkinson’s patients contact about DBS?

Volkmann: All centers that specialize in the treatment of Parkinson’s patients on an outpatient or inpatient basis can advise on deep brain stimulation. The operation is offered at over 30 locations in Germany, but patients should inquire about the number of procedures performed, as a certain level of routine on the part of the team is beneficial for good treatment quality.