Stimulation of External Carotid Artery Circulation

Inclusion Criteria: * Age ≥18 * Chronic migraine or status migrainosus, or craniofacial pain refractory to maximal medical therapy who are undergoing MMA IA lidocaine infusion. * Subject has provided informed consent. Exclusion Criteria: * Known allergies to lidocaine * Seizure disorder, history of seizures, or increased seizure susceptibility * Intracranial vascular malformations or dural AVF * Hemodynamic instability, any condition where brief hemodynamic shifts may pose risk * Previous MMA intervention or craniotomy that could result in MMA occlusion * Any implanted electronic device (pacemaker, ICD, DBS, VNS, cochlear implant, spinal cord stimulator) * Significant cardiovascular disease (unstable angina, severe arrhythmias, recent MI) * Severe autonomic dysfunction * Active systemic infection * Vulnerable populations (i.e. pregnant individuals, children, prisoners, individuals lacking decision-making capacity, persons with cognitive impairment, those unable to provide informed consent)