Multiple Sclerosis and Deep Brain Stimulation
Deep brain stimulation (or DBS) is a variation of an old surgery that may be used to treat tremors in people with conditions such as multiple sclerosis (MS), Parkinson's disease, and essential tremor. In the 1960s, surgery was used to destroy a small area deep in the brain called the thalamus (thalamotomy) or another part of the brain called the globus pallidus (pallidotomy).
These surgeries are still done today, although less frequently because of the availability of deep brain stimulation. These surgeries carry significant risks: both thalamotomy and pallidotomy require purposeful destruction of the brain. If the surgeon is off by even a fraction of an inch, the surgery may not be effective and severe complications such as paralysis, loss of vision, or loss of speech can result.
Deep brain stimulation is a way to inactivate parts of the brain without purposefully destroying the brain. Therefore, the risks are much lower. In deep brain stimulation, the tip of an electrode is placed in the thalamus (for tremor and multiple sclerosis) or in the globus pallidus or subthalamic nucleus (for Parkinson's disease).
The electrode for deep brain stimulation is left in the brain. It is connected by a wire to a pacemaker-like device that is implanted under the skin over the chest. The device generates electrical shocks.
What Are the Advantages of Deep Brain Stimulation?
Deep brain stimulation offers many advantages. The electrical stimulation is adjustable, whereas surgical destruction is not. The electrode has four metal contacts that can be used in many different combinations. Even if one electrode contact is not in the exact location, it is likely that one of the others or some combination of the electrical contacts will be closer to the proper target. As the patient's response to surgery changes over time, the stimulation can be adjusted without requiring a repeat operation.
Another significant advantage of deep brain stimulation relates to future treatments. Destructive surgery, such as thalamotomy or pallidotomy, may reduce the patient's potential to benefit from future therapies. With deep brain stimulation, the stimulator could be turned off if other therapies were to be tried.