The Brio(TM) deep brain stimulator is the world's smallest rechargeable neurostimulator approved to treat the symptoms of Parkinson's disease. Slightly larger than the typical man's watch, the device is usually implanted near the collarbone and sends mild electrical pulses to specific targets in the brain. The Brio deep brain stimulation system is not approved for use in the U.S. (Photo: St. Jude Medical, Inc.)