What can go wrong with a deep brain stimulation implant?

The most common malfunction of an implanted deep brain stimulation (DBS) device is spread of electrical current from the area we want targeted to other areas. For example, spread of current to centers that control speech can cause slurred speech instead of improving tremors. The huge advantage of DBS over pallidotomy is that we have four contact points on each DBS electrode (one on each side of the brain). If one of these contact points gives side effects we can choose one of the other three. In most cases we are able to find the sweet-spot electrode that gives the best control of symptoms with the least side effects. Another rare malfunction is lead breakage. If this happens the DBS will lose effect and symptoms can come back. After about three to five years the battery wears out and symptoms return. Replacing the battery is a relatively simple outpatient procedure. Infection can occur in about 5% of cases. Most often this can be treated with antibiotics, but in some cases the DBS will need to be removed.