Deep brain stimulation (DBS) involves placement of an electrode into the brain to "jam a circuit," and works like a pacemaker for the brain. It treats conditions like Parkinson's disease, essential tremor (shaking of the hands, head, voice, etc. which typically runs in families), and dystonia (involving stiffness of certain muscle groups).
It is under investigation for some other disorders like obsessive compulsive disorder, headaches, depression, Tourette's, or even obesity. Different targets in different areas of the brain are used for different problems.
At present, the procedure is used only for patients whose symptoms cannot be adequately controlled with medications.
Before the procedure, a neurosurgeon typically uses an MRI or CT scanning to identify and locate the exact target within the brain where electrical nerve signals generate the PD symptoms.
DBS does not damage healthy brain tissue by destroying nerve cells. Instead the procedure blocks electrical signals from targeted areas in the brain. Stimulation from the neurostimulator is easily adjustable—without further surgery—if the patient's condition changes. Some people describe the stimulator adjustments as "programming."