Diagnosis

Movement disorders like Parkinson’s disease, tremor or dystonia respond poorly to drug treatment at an advanced disease stage. In these instances, the quality of life of the patient may substantially be reduced. In the case of dystonia, children can already be affected at a very young age. Treatment with deep brain stimulation can be of great value when the symptoms of Parkinson’s disease are subject to unpredictable fluctuations that can’t effectively be stabilised with medication or when for instance tremor respectively painful muscle cramps do not respond to drugs. Deep brain stimulation can also be helpful in rare cases of psychiatric disorders (obsessive-compulsive disorder), epilepsy or various pain syndromes (e.g. cluster headaches).

During a first non-binding consultation and clinical examination at the Centre for Deep Brain Stimulation (LuxSTIM), the patient is given a first diagnostic classification as well as therapeutic advice. This is important since many forms of Parkinson’s disease, tremor disorders and dystonia may respond better to treatment with deep brain stimulation.

The admission of the patient can then be organised if the diagnosis and predicted treatment response to deep brain stimulation look promising. The patient will then be comprehensively and carefully pre-examined before the deep brain stimulation procedure is performed. The implicated team comprises the colleagues from Neurosurgery (Dr. Hertel and colleagues), Neurology (Prof. Dr. Krüger) as well as the Psychiatry. The Neuropediatry (Dr. Scalais) and the Pain Therapy Department (Dr. Boeker) are also majorly involved in the deep brain stimulation treatment unit.

Following a comprehensive diagnosis and consultation with the treating colleagues at the ‘interdisciplinary indication conference for deep brain stimulation’, the patient is personally given a detailed therapy recommendation.

Therapy

In addition to classical drug therapy, deep brain stimulation represents a major advance in treatment options for movement disorders. In particular for patients, whose motor symptoms do not sufficiently respond to medication (anymore), deep brain stimulation represents a promising improvement of quality of life.

Recently, a large French-German Parkinson’s disease multicentre study (EarlyStim) has shown that deep brain stimulation majorly improves quality of life in comparison to mere medication therapy, especially an improved control of motor symptoms could be observed.

This study has shown for the first time that deep brain stimulation could already improve early fluctuations from medication therapy. On average, the patients that took part in the EarlyStim study were suffering from Parkinson’s disease for 7 years only.

In the later disease stages of Parkinson’s disease, walking disturbances become more prominent, which do not adequately respond to current treatment and can lead to limited mobility and risk of falls. The deep brain stimulation team from Tübingen, Germany, led by Prof. Krüger has developed an improved form of deep brain stimulation, which concurrently stimulates two neighbouring nerve cell structures. The refractory freezing gait may possibly be better treated than before using this simultaneous stimulation (STN+SNr). An additional study is under way in different centres in Luxembourg and Germany, which seeks to confirm therapeutic outcome of deep brain stimulation.

Procedure

Fig. 1 Trajectory planning for DBS of the left subthamalic nucleus

Fig.2 Computer-assisted navigation for frameless implantation of DBS electrode

Similar to cardiac pacemakers, deep brain stimulation employs one or two surgically implanted medical devices called neuro-stimulators. These conduct electrical impulses to precisely targeted regions on either side of the brain. 

During the surgery, the patient’s head is kept still and supported using a (stereotactic) head frame after the skin is anesthetised with a local anesthetic. Using special imaging techniques, including magnetic resonance imaging (MRI) or computerised tomography (CT), the brain can be mapped and the target area of stimulation exactly defined. For Parkinson’s disease essentially two brain regions can be targeted, namely the subthalamic nucleus (STN) or the internal globus pallidus (GPi). ­­

Once the thin electrode is implanted in the brain, extensions are connected to an implanted pulse generator (IPG), which controls the distribution of neuro-stimulation and is inserted under the skin below the collarbone. The IPG can easily be switched on and off and configured in order to adjust stimulation using a hand-held device.   The stimulation seems to block the signals causing the motor symptoms and therefore provides better movement control.

The therapy does not damage brain tissue, but reversibly changes the irregular function of the neuronal cells in the region of the stimulating electrode. As highly individualized therapy, deep brain stimulation may require some time and patience before optimisation of its effects