Table 1: Subject inclusion/exclusion criteria. Potential subjects, naïve to upper cervical chiropractic care, demonstrated between ten and twenty-six headache days per month self-reported over the previous four months. Requisite was at least eight headache days per month, where intensity reached at least four, on a zero to ten Visual Analog Scale (VAS) pain scale.

Exclusion criteriaInclusion criteria

Presence of
() Any medical or psychiatric condition which in the opinion of the screening investigator would make the subject unsuitable for enrolment, because of inability to comply with study requirements or possible confounding of the results
() More than twenty-six headache days a month
() Acute medication overuse as defined by the International Classification of Headache disorders
() Pregnancy or lactation
() Severe cervical spine degeneration as assessed by cervical spine X-ray
() Claustrophobia
() A history of cardiovascular disease, cerebrovascular disease, brain surgery, or other central nervous system disorders
() Other chronic pain disorders which might interfere with headache assessment or study procedures
() A history of significant hypo- or hypertension as determined by the investigator
() Subjects on a beta-blocker, calcium channel blocker, or another medication which the investigator considers might alter cerebral vascular regulation. Triptans are allowed but must not be taken within 24 hours (frovatriptan 48 hours) before a PCMRI study
() A history of substance abuse or dependence within one year
() Current participation in a research study or within the last thirty days
() Any spinal chiropractic care outside of the study protocol is prohibited during the baseline and treatment period
Subject must be or have
() Male or female, 21 to 65 years of age
() Signed written informed consent
() Naïve to upper cervical chiropractic care
() Migraine with or without aura according to the International Classification of Headache Disorders
() Had ten to twenty-six headache days per month over the last 4 months (self-reported)
() At least 4 separate headache episodes per month, with episodes separated by at least 4 hours of pain-free time
() At least 8 days per month with pain of levels of ≥4/10 for part of the day
() At least eight headache days per month meeting migraine diagnostic criteria, or where headache is successfully treated with a migraine specific medication
() Suitable candidates for therapeutic intervention as assessed by NUCCA investigator
() Subjects on acceptable pharmacological prophylaxis must either remain on a stable dose throughout the study, or stop the prophylactic medication one month before entering the baseline period