Devices, systems and methods are disclosed that allow a patient to self-treat a medical condition, such as migraine headache, by electrical noninvasive stimulation of a vagus nerve. The system comprises a stimulator that is applied to the surface of the patient's neck. The device housing transmits data to a patient interface device such as a mobile phone or computer relating to the status of a stimulation session. The interface device in turn may communicate with a database contained within other computers, via a network or the internet. The system is designed to address problems that arise particularly during self-treatment, when a medical professional is not present.