An implantable medical device for treating a medical condition in a patient comprises means for applying, during a first period, a primary mode of cranial nerve stimulation to a cranial nerve of a patient, and, during a second time period, applying a secondary mode of cranial nerve stimulation comprising an electrical signal characterized by having a number of pulses per microburst, an interpulse interval, an interburst period, and a microburst duration to a portion of a cranial nerve of said patient. At least one of the number of pulses per microburst, the interpulse interval, the microburst duration, or the interburst period is selected to enhance cranial nerve evoked potentials.
