Deep brain stimulation (DBS) uses one or two surgically implanted medical devices called neurostimulators, similar to cardiac pacemakers, to deliver electrical stimulation to precisely targeted areas on each side of the brain. DBS is used mainly to treat people with advanced Parkinson’s as well as other movement disorders such as essential tremor and dystonia.
A stereotactic head frame is used to keep the patient's head still during surgery and the neurosurgeon uses special imaging techniques, such as magnetic resonance imaging (MRI) or computed tomography (CT), to map the brain and locate the site to be stimulated: either the subthalamic nucleus (STN) or the internal globus pallidus (GPi). The patient remains awake through out as it is important that they can give feedback regarding the sensations they experience as the surgeon establishes the exact site for the implant. As the brain itself has no pain receptors this is not painful, although the lengthy surgery can be demanding and tiring.
Stimulation appears to block the signals that cause disabling motor symptoms and so helps provide greater control over movement. Once the leads are implanted in the brain, extensions are fitted down through the neck to an Implantable Pulse Generator (IPG) which controls the delivery of neuro-stimulation, and is placed under the skin in the chest. A hand held device is used to programme and to switch the IPG on and off so stimulation can readily be adjusted.
Unlike lesioning, DBS does not cause permanent damage to the brain and the stimulation it provides can be adjusted as frequently as necessary, allowing for some change in symptoms over time.
