Systems and methods for delivering vagal therapy

A method, comprising:

• delivering intermittent vagal nerve stimulation (VNS) therapy, the intermittent VNS therapy including a plurality of stimulation bursts, each stimulation burst including a plurality of neural stimulation pulses, and successive neural stimulation bursts are separated by a time without neural stimulation pulses;
• recording physiological parameter values, including:
• recording first population data, the first population data including evoked response (ER) values corresponding to the evoked physiological responses to stimulation bursts;
• and
• recording second population data, the second population data including reference values that include no effect (NE) values corresponding to physiological parameter values that are not evoked physiological responses to stimulation bursts;
• calculating an evoked response metric (ERM) to quantify a relationship between the first population data and the second population data;
• determining if the stimulation bursts are evoking desired physiological responses, wherein determining includes analyzing the ERM to indicate if the stimulation bursts are evoking the desired physiological responses;
• and
• when it is determined that the stimulation bursts are not evoking the desired ERM, adjusting the intermittent VNS therapy to produce the desired ERM.