Deep brain stimulation (DBS) for Parkinson’s disease

Deep brain stimulation (DBS) supports drug treatment for Parkinson’s disease. It is particularly effective in the treatment of tremor, one of the most common and distressing symptoms in Parkinson’s patients. DBS is usually used when the tremor or stiff muscles do not respond sufficiently to drug therapy. The additional electrical stimulation of targeted brain regions can then provide significant relief, which can lead to a noticeable improvement in quality of life.

Deep brain stimulation is an innovative therapy that requires surgical intervention. The aim is to alleviate the motor symptoms of Parkinson’s disease through targeted electrical stimulation of specific brain regions using implanted electrodes. However, even with this procedure, it is not possible to cure the disease. In this article, you will find out how deep brain stimulation works, who it is suitable for, what benefits and risks it entails and exactly how it works.

What is deep brain stimulation (DBS)?

Deep brain stimulation (DBS) is a surgical therapy method that is used for the neurological disease Parkinson’s disease, among others. Electrodes (probes) are implanted in certain regions of the brain to alleviate the motor impairments associated with Parkinson’s, such as tremors, muscle stiffness (rigor) and slowness of movement (bradykinesia). These electrodes are connected to a neurostimulator (generator), which is usually implanted under the skin in the chest area. The neurostimulator continuously sends electrical impulses to the brain, which help to alleviate the symptoms of Parkinson’s disease.

How does deep brain stimulation work?

Deep brain stimulation works by specifically stimulating certain areas of the brain that are involved in the regulation of movement. This “brain pacemaker” is primarily intended to stimulate two target structures in the brain of Parkinson’s patients:

• Subthalamic nucleus (STN): This is the most frequently stimulated region in Parkinson’s disease. Stimulation in this area can significantly improve motor symptoms and reduce the need for medication.
• Globus pallidus internus (GPi): Stimulation of this area is particularly important for patients with severe dyskinesia (involuntary movements).

DBS positively influences the electrical activity in these brain regions, which has changed due to the dopamine deficiency in Parkinson’s disease. As a result, DBS can help to improve movement control and reduce uncontrolled movements such as the annoying tremor, i.e. involuntary shaking.

Deep brain stimulation: procedure

Deep brain stimulation (DBS) surgery is a highly precise procedure that usually takes between four and six hours, depending on the patient’s individual situation. In many cases, the operation is performed under local anesthesia as an “awake operation”, in which patients remain awake for around six hours. In the first step of the operation, the electrodes are implanted in the target regions of the brain. This allows the surgical team to ensure the correct placement of the electrodes based on direct feedback from the patient.

The following day, a two-hour procedure is performed under general anesthesia. It involves the implantation of a neurostimulator, which is placed under the skin in the chest area and connected to the electrodes.

It is now also possible to perform a DBS completely under general anesthesia, as offered as standard by the Inselspital in Bern, for example. The operation takes six to seven hours and also enables extremely precise implantation of the electrodes without the need for a stressful awake operation.

Deep brain stimulation Indication: Who is the method suitable for?

Deep brain stimulation is not the right therapy for all Parkinson’s patients. A specialized team of neurologists, psychologists and neurosurgeons uses strict criteria to carefully weigh up who should and should not be implanted with the probes. The surgical procedure is aimed at the following people:

• Patients for whom drug therapy is no longer sufficiently effective
• Patients for whom the medication causes severe side effects
• People who suffer from strong motor fluctuations within a day or involuntary muscle movements (dyskinesia)
• Affected persons without severe cognitive impairment or pronounced depression, as these can impair the success of DBS
• Patients who still have a certain degree of independence and mobility despite advanced Parkinson’s disease

Advantages of deep brain stimulation

Although DBS cannot cure Parkinson’s, the procedure can improve the quality of life of those affected. Deep brain stimulation offers numerous advantages for suitable patients:

• Improved mobility: DBS can significantly reduce the motor symptoms of Parkinson’s, including tremors, stiffness and slowness of movement, and counteract the progressive worsening of symptoms. Many sufferers report a significant improvement in their mobility and quality of life.
• Reduced need for medication: By stimulating certain areas of the brain, the need for Parkinson’s medication can often be reduced. This in turn can reduce the side effects that can occur as a result of the medication.
• Control of dyskinesias: DBS can lead to a significant improvement in patients suffering from severe dyskinesias, especially if these are triggered by the medication used. Fluctuations in effect (fluctuations in the effectiveness of medication) can also be mitigated with this procedure.
• Long-term effectiveness: Studies have shown that deep brain stimulation can remain effective over long periods of time, making it a valuable treatment option for advanced Parkinson’s patients.

Risks and side effects: Disadvantages of deep brain stimulation

As it is a surgical procedure, there are also risks and possible side effects with deep brain stimulation – as with all operations. We have compiled the most common risks for you.

Infections due to THS

As deep brain stimulation is a surgical procedure in which foreign bodies are introduced into the body, there is a possibility of bacteria entering the surgical wound and causing an infection. Such infections can occur on the skin around the implantation site or spread to deeper tissue layers and the brain. To minimize the risk of infection, strict antiseptic measures are taken during surgery and post-operative care, and patients often receive preventive antibiotic treatment. Nevertheless, it is important that patients and their relatives inform the attending doctor if they notice any signs of infection such as redness, swelling or pain.

Bleeding due to THS

Another serious risk associated with deep brain stimulation is the possibility of bleeding in the brain that can occur during the surgical procedure. These bleedings, also known as intracranial bleedings, occur when blood vessels in the brain are injured by the implantation of the electrodes. Although such complications are rare, they can have serious consequences, such as strokes, neurological deficits or, in extreme cases, even life-threatening conditions.

Modern neurosurgical techniques and precise imaging procedures such as magnetic resonance imaging (MRI) and computer tomography (CT) help to minimize the risk by enabling precise planning and execution of the operation.

Hardware complications due to THS

The implanted devices themselves also pose a certain risk. For example, the electrodes can slip out of place unintentionally, a cable can break or the neurostimulator can develop malfunctions. Such problems can lead to the electrical stimulation no longer working optimally, resulting in a recurrence of Parkinson’s symptoms or undesirable side effects. In some cases, surgery may be required to repair or replace the hardware. Regular follow-up examinations are therefore important to monitor the proper functioning of the system and to be able to react to potential problems at an early stage.

Side effects of DBS

Side effects of deep brain stimulation (DBS) can occur despite the overall high effectiveness and safety of the method. The most common side effects include motor impairments such as muscle twitching, visual disturbances, speech disorders, muscle weakness or balance disorders, which can be caused by the electrical stimulation itself. Cognitive or emotional changes such as depression, anxiety or impulse control disorders are also possible. In many cases, these side effects can be alleviated or eliminated by adjusting the stimulation parameters.

What is the success rate of deep brain stimulation for Parkinson’s disease?

The success rate of deep brain stimulation (DBS) in the treatment of Parkinson’s disease is high overall, with around 70 to 90 percent of patients experiencing a significant improvement in their motor symptoms such as tremor, rigor or bradykinesia. Many sufferers also report that they are able to reduce the dose of their medication thanks to DBS. This in turn reduces the potential side effects of medication, meaning that deep brain stimulation can make life with Parkinson’s more pleasant again overall.

Does health insurance cover the costs of deep brain stimulation?

Yes, the costs of deep brain stimulation (DBS) are generally covered by statutory and private health insurance companies if certain medical requirements are met. These include, for example, that medication alone does not provide the desired treatment success and patients are severely impaired in their everyday lives by Parkinson’s symptoms.

Deep brain stimulation: duration of the operation

However, the duration of DBS surgery can vary depending on the individual situation and the procedure (with or without awake surgery).

• With awake surgery: about six hours, plus surgery the next day under general anesthesia: about 2 hours.
• Without awake surgery: completely under general anesthesia: about six to seven hours.