In 2007, in the middle of a 12-hour nursing shift at New York-Presbyterian Hospital in Manhattan, Rebecca Serdans noticed something was wrong. "It always starts with pain," she says — a hot, radiating pain growing from the base of her skull. Serdans suffers from a neurological disorder called dystonia that, when untreated, leaves her with debilitating muscle pain and movement problems. She keeps it in check with a deep brain stimulation (DBS) device. This pacemaker for the brain works by sending a steady electrical pulse into her globus pallidus. When it's functioning properly, this pulse lets her walk without tripping and move through the world without pain. Only now, years after it was installed, it wasn't working. She could feel it. Serdans began the surreal process of troubleshooting her electrically enhanced brain.