What is (are) Deep Brain Stimulation for Parkinson's Disease ?
Deep brain stimulation (DBS) is a surgical procedure used to treat several disabling neurological symptomsmost commonly the debilitating motor symptoms of Parkinsons disease (PD), such as tremor, rigidity, stiffness, slowed movement, and walking problems. The procedure is also used to treat essential tremor and dystonia. At present, the procedure is used only for individuals whose symptoms cannot be adequately controlled with medications. However, only individuals who improve to some degree after taking medication for Parkinsons benefit from DBS. A variety of conditions may mimic PD but do not respond to medications or DBS. DBS uses a surgically implanted, battery-operated medical device called an implantable pulse generator (IPG) - similar to a heart pacemaker and approximately the size of a stopwatch to - deliver electrical stimulation to specific areas in the brain that control movement, thus blocking the abnormal nerve signals that cause PD symptoms.
                
Before the procedure, a neurosurgeon uses magnetic resonance imaging (MRI) or computed tomography (CT) scanning to identify and locate the exact target within the brain for surgical intervention. Some surgeons may use microelectrode recording - which involves a small wire that monitors the activity of nerve cells in the target area - to more specifically identify the precise brain area that will be stimulated. Generally, these areas are the thalamus, subthalamic nucleus, and globus pallidus. There is a low chance that placement of the stimulator may cause bleeding or infection in the brain.
                
The DBS system consists of three components: the lead, the extension, and the IPG. The lead (also called an electrode)a thin, insulated wireis inserted through a small opening in the skull and implanted in the brain. The tip of the electrode is positioned within the specific brain area. 
                
The extension is an insulated wire that is passed under the skin of the head, neck, and shoulder, connecting the lead to the implantable pulse generator. The IPG (the "battery pack") is the third component and is usually implanted under the skin near the collarbone. In some cases it may be implanted lower in the chest or under the skin over the abdomen.
                
Once the system is in place, electrical impulses are sent from the IPG up along the extension wire and the lead and into the brain. These impulses block abnormal electrical signals and alleviate PD motor symptoms.