An assembly of battery-powered devices intended to apply periodic electrical stimuli to the vagus nerve to help control seizures and/or to help treat psychiatric disorder symptoms (e.g., depression). The vagus nerve stimulation (VNS) is provided through an implantable pulse generator, typically placed in the anterior chest wall, and leads that run subcutaneously to where their electrodes are implanted around the left vagus nerve. The system may be programmed externally following implantation.