nVNS, CBD, and SoC for Persistent Post-Traumatic Headache

INCLUSION CRITERIA 1. Between the ages of 18 and 75 years inclusive 2. Participated in competitive sports at high school level or beyond or, in the case of sports without interscholastic competition, as per investigator 3. Persistent headache attributed to traumatic injury to the head in accordance with the ICHD-3 criteria (including "Headache persists for \>3 months after its onset") 4. Experiences 4-25 (inclusive) headaches days per month (during the 28-day baseline period), with at least 4 of them being moderate or severe in intensity 5. Completed at least 80% (23 of 28 days) on 28-day baseline headache diary 6. Agrees to refrain from initiating or changing the type, dosage, or frequency of any preventive headache medications whether for headache prevention or for indications other than headache that, in the opinion of the clinician may interfere with the study objectives (e.g., antidepressants, anticonvulsants, beta-adrenergic blockers, etc.) 7. Agrees to be randomized to nVNS, CBD or SoC 8. Agrees to use nVNS, CBD, or SoC as intended, follow all of the requirements of the study including Follow-up Visit requirements, and record required study data in the subject e-diary 9. Able to provide written informed consent EXCLUSION CRITERIA 1. Body weight at screening of less than 40 kg 2. Other severe pain condition (e.g., cancer pain or trigeminal neuralgia) that, in the discretion of the investigator, may confound the study assessments 3. Known or suspected severe cardiac disease (e.g., symptomatic coronary artery disease, prior myocardial infarction, congestive heart failure), neurologic disease (history of intracranial aneurysm, intracranial hemorrhage, or brain tumor), moderate to severe hepatic impairment, history of cervical surgery (e.g. cervical vagotomy) that in the judgment of the investigator would interfere with the study, or other major medical problems at the discretion of the investigator 4. Psychiatric, substance abuse, or cognitive disorder and/or behavioral problems that, in the opinion of the investigator, may interfere with the study. 5. Belongs to a vulnerable population (e.g., developmentally disabled, prisoner) or has any condition such that his or her ability to provide informed consent, comply with the follow-up requirements, or provide self-assessments is compromised at the discretion of the investigator 6. Currently takes prescription opioids more than 4 days per month for any indication 7. Patients receiving PREEMPT protocol onabotulinumtoxin injections, nerve blocks (occipital or other), steroid injections, radiofrequency ablations, and/or trigger point injections in the head or neck injections within the prior 12 weeks must continue receiving this procedure on a regular schedule at the discretion of the investigator during the course of the study. Patients who experience "wear-off" effects or increases in headache days during the last two weeks of their procedural cycles will be excluded from the study 8. Currently implanted with a cardiac defibrillator 9. Allergy to CBD or other components of Cannabis sativa L. (including hemp or cannabis) 10. Previously used gammaCore or high-dose CBD (\>100mg/day) for PPTH 11. Used medical marijuana, cannabis, hemp or CBD-based product within 30 days prior to the study 12. Unwilling to discontinue use of medical marijuana, cannabis, hemp or CBD-based product during the study 13. Patients using medications that can interact with the study drug and/or its safety profile throughout the study and for at least five half-lives after the last dose of investigational product, including clobazam and valproic acid and other drugs according to the drug-drug interaction (DDI) risks as described in the Epidiolex USPI. 14. Patients who are pregnant, breastfeeding, or not using acceptable methods of contraception during the course of the study and for three months thereafter. 15. Male patient's partner is of childbearing potential; unless willing to ensure that they (male patients) or their partner(s) are using acceptable methods of contraception during the course of the study and for three months thereafter. 16. Participating in any other therapeutic clinical investigation or has participated in a clinical trial in the preceding 30 days 17. A relative of or an employee of the Investigator or the clinical study site 18. Presence of any implantable device that may interfere or interact with gammaCore, any history of cardiac arrhythmias or conduction defects, and any other medical history that, in the opinion of the investigator and/or based on the labeling of gammaCore, may increase the risk of using the gammaCore device.