DBS

What is deep electrical stimulation of the brain and how does it work?

Deep electrical stimulation of the brain is a treatment for Parkinson's disease, based on the application of current through electrodes to specific structures (nuclei) in the brain. An electrical stimulus with specific characteristics (intensity, frequency, range) restores a more normal function in neuronal circuits that have been shown to be affected in Parkinson's disease.

When and to which patients is deep electrical stimulation of the brain addressed?

Deep electrical stimulation of the brain is mainly for patients who, despite repeated adjustments, are no longer able to cope with medication (on-off) or have side effects due to it (e.g. hyperactivity). From the point, therefore, at which the scope for controlling the disease with drugs has been exhausted, surgical treatment should be recommended.

What does deep electrical stimulation of the brain offer the Parkinson's disease sufferer?

Deep electrical stimulation of the brain is particularly effective for symptoms such as tremor, stiffness, bradykinesia. In addition, it relieves patients from hyperactivity due to medication and also greatly reduces the strong fluctuations in their mobility (on - off phenomena) during the day. It is less effective in balance disorders or cognitive disorders. Overall, deep electrical stimulation of the brain can improve the functionality of patients to a considerable extent, giving them a very satisfactory quality of life.

Is deep brain stimulation an experimental form of treatment?

Deep brain stimulation is not an experimental form of treatment. It is a method whose effectiveness and safety have been proven through numerous studies. It is therefore a method that has been established as a treatment option for Parkinson's disease.

How are patients selected for surgical treatment with deep electrical stimulation of the brain?

Selection of a suitable patient requires the collaboration of the neurologist, neuropsychologist, psychiatrist and neurosurgeon. This team of doctors, through a certain pre-operative protocol involving a series of tests, identifies the set of patients who both genuinely need and will benefit from surgical treatment. The neurosurgeon assumes final responsibility and decides whether surgery is feasible and the type of operation.

Which patients with Parkinson's disease are candidates for surgical treatment with deep electrical stimulation of the brain?

The necessary criteria for selecting patients for surgical treatment with deep brain electrical stimulation are as follows:

• Diagnosis of idiopathic Parkinson's disease,
• Parkinson's disease,
• Severe motor problems (dyskinesias, severe on - off phenomena),
• Ineffective medication,
• Good response of the patient to dopamine (positive L-dopa test, >30%),
• Hoehn and Yahr disease stage 2 - 4 (moderate - severe disorder, patient can walk in on state),
• Age less than 75 years,
• Patient without cognitive impairment or untreated mental illness.

Which patients with Parkinson's disease are excluded from surgical treatment with deep electrical stimulation of the brain?

The criteria for excluding patients from surgical treatment with deep brain electrical stimulation are as follows:

• Secondary Parkinsonism (e.g., Supranuclear Ophthalmoplegia, Multiple System Atrophy, Vascular Parkinsonism, etc.),
• Limited response to dopamine (negative L-dopa test, <30%),
• Gait or speech disorders as the main symptom,
• Presence of significant cortical atrophy on preoperative MRI,
• Comorbidity (e.g. severe cardiac or pulmonary disease, uncontrolled arterial hypertension, coagulation disorders, malignant disease),
• History of dementia or medication-resistant depression,
• Patients or relatives who have difficulty cooperating with physicians.

What is the surgical procedure?

Most of the surgery, which includes stereotactic targeting and electrode implantation, is performed under local anesthesia with anesthesia present and the patient is awake to be in constant communication with the medical team. General anaesthesia is only required during the last phase of the procedure where the neurostimulator (battery) is placed in the anterior chest wall and connected to the electrodes.

What are the possible complications of the surgery?

The most important intraoperative or immediate postoperative complications of the surgery involve intracranial bleeding and inflammation of the stimulator, neck or skull. The risk is small and kept to a minimum by appropriate measures, but it is real.

How is postoperative planning shaped?

The electrodes are usually activated after a period of 10 days after surgery. Until then, patients receive their treatment as before surgery. When the electrodes are activated, the appropriate combination of current parameters, which may vary from patient to patient, is selected to achieve the maximum therapeutic effect without side effects. Initially, therefore, frequent visits to the doctor (the neurosurgeon or neurologist) are necessary for a period of time after the surgery in order to arrive at the ideal setting for each patient.

Is medication discontinued after surgical treatment with deep electrical stimulation of the brain?

The goal of surgery is to improve the patient's functionality, not to stop medication. Very often, however, after surgery there is a need to readjust or possibly reduce the medication to avoid adverse effects that may result from the synergy of the current and the drugs. In specific cases and always depending on the age of the patient and the severity of the disease, it is possible to reduce the total medication, so that in the future, in case of disease progression, more alternatives for symptom control can be offered in combination with the current.

What are the side effects of deep electrical stimulation of the brain?

The selection of suitable candidates and the control carried out during the surgery minimize in advance the possibility of side effects. It is, however, possible that various symptoms may occur as a result of the action of the current, such as, for example, disturbances in speech or vision, muscle twitching, hyperactivity, paresthesias, deterioration of balance, cognitive or behavioural problems. An important advantage of deep electrical stimulation of the brain is that it is a reversible method. Symptoms subside with the interruption of the current or after modulation of the parameters. After choosing the appropriate setting it is most likely that there will be no side effects at all and of course the best therapeutic effect will be ensured. In addition, this technology offers the possibility for the patients themselves to configure, obviously within a framework predetermined by the doctor, their setting so that it corresponds precisely to the needs of their daily life.

How long does the therapeutic effect of deep electrical stimulation of the brain last?

Experience to date has proven the long-term effectiveness of the method. As far as the lifetime of the materials is concerned, after about 5 years, the neurostimulator needs to be replaced by local anaesthesia.

Does surgical treatment with deep electrical stimulation of the brain "disappear" Parkinson's disease?

Surgical treatment with deep brain electrical stimulation, as well as the various pharmaceutical preparations, are symptomatic treatments. They relieve the patient of his symptoms, possibly to such an extent that he regains full functionality and leads a completely normal life, but the underlying disease still exists and progresses. Although it has been theorised that surgical treatment with deep electrical stimulation of the brain may play a protective role and to some extent halt the progression of the disease, this has not been proven. However, it is a fact that to date there is no form of causal treatment of the disease that is still in the experimental stage.

What other conditions other than Parkinson's disease can be treated by surgical treatment with deep electrical stimulation of the brain?

Apart from Parkinson's disease, surgical treatment with deep electrical stimulation of the brain is used in idiopathic tremor, dystonia, certain psychiatric conditions (depression, obsessive-compulsive disorder), epilepsy.