1. A method comprising: controlling a medical device to deliver peripheral nerve field stimulation to a region of a body of a patient in which the patient experiences pain via at least one electrode implanted in the region; receiving, with a processor, a first signal indicative of a physiological parameter of the patient in the region of the body in which the patient experiences pain, wherein the signal is generated by a sensing module, and wherein the signal indicates a response of the patient to the peripheral nerve field stimulation; receiving, with the processor, a control physiological signal indicative of the physiological parameter of the patient outside of the region of the body in which the patient experiences pain, wherein the control physiological signal changes as a function of the physiological parameter of the patient outside of the region of the body in which the patient experiences pain; comparing, with the processor, the first signal to the control physiological signal; and controlling, with the processor, the delivery of the peripheral nerve field stimulation by the medical device based on the comparison of the first signal and the control physiological signal.