How DBS Works
DBS is an innovative surgical technique that can relieve the symptoms of different movement disorders..
The DBS system is similar in many ways to a cardiac pacemaker. It is an implanted system that delivers mild electrical stimulation to discrete areas of the brain near the electrode(s). The exact mechanism of how DBS reduces the symptoms of PD is an area of active research. We think that there is abnormal firing in circuits in the brain important for initiating movement. When these circuits do not work or abnormal signals resonate within these circuits, people can develop tremor, rigidity, difficulty initiating movement and increased tone in opposing muscles that can even be painful. As early as 1890, these circuits were interrupted by removing or burning holes in discrete areas of the brain to interrupt these abnormal circuits. More recently, DBS has been used to modulate these abnormal circuits without destroying parts of the brain. The FDA approved Medtronic’s Activa DBS system for tremor in 1997, for Parkinson’s disease in 2002 and for dystonia in 2003. It is believed that DBS disrupts abnormal firing patterns present in movement disorders and replaces them with more regularized firing. It is likely that the specific mechanism(s) by which DBS exerts its effects varies between diseases and the target area of the brain.
The DBS electrode has four electrode contacts. Depending on the disorder and/or the target, one may use variable sized contacts with different spacing arrangements.
Each contact can be activated utilizing monopolar or bipolar stimulation, and multiple settings can be adjusted for individual patient needs. These settings include the pulse width (how long the stimulation is), frequency (how often the stimulation is delivered), and amplitude (the strength or force) of stimulation.
The DBS lead is placed into a brain target, and is attached to an extension wire and a programmable pulse generator. The pulse generator or neurostimulator is placed below the clavicle. The pulse generator is connected to the DBS lead by the extension wire that travels behind the ear.
The system is turned on and off with a small, hand-held magnet. Once the DBS system has been activated, symptom reduction may occur within seconds to minutes. The benefits can be maximized through simple adjustments to the DBS system made by the movement disorder specialist during office visits.