Imploding and Exploding Migraine Headaches: Comparison of Methods to Diagnose Pain Directionality

Background The study aims to compare methods of determining headache directionality (imploding, exploding, and/or ocular headaches) in women with migraine, investigate the concordance between physician assignment and patient self-assignment of pain directionality, and evaluate whether patients assigned their headaches to the same direction when queried using different methods. Directionality of migraine headache pain (imploding, exploding, or ocular) may reflect differences in the underlying pathogenesis of individual migraine attacks among and within individuals. Emerging evidence suggests that directionality of pain in migraine sufferers may predict response to onabotulinumtoxin A. The best method of determining headache directionality in migraine sufferers has not been systematically explored. Methods We conducted a prospective cross-sectional survey study of 198 female patients with migraine presenting to a Women's Health Clinic. Patients determined the directionality (imploding, exploding, and/or ocular) of their own migraine pain by choosing among 3 pictures graphically representing directionality and also by responding to a written question regarding directionality. Clinicians then classified directionality of migraine pain using structured interviews. Concordance between clinician assignment of directionality and patient self-assignment was determined with Kappa coefficients. Results Subjects were females between the ages of 18 and 77 years (mean 48 years). According to patient selection of representative pictures, 62 (31.6%) had imploding headaches with or without ocular pain, 36 (18.4%) had exploding headaches with or without ocular pain, 78 (39.8%) had ocular pain only, and 20 (10.2%) had imploding and exploding headaches with or without ocular pain. Two subjects did not respond. According to patient responses to a written question, 80 (41.0%) had imploding headaches with or without ocular pain, 53 (27.2%) had exploding headaches with or without ocular pain, 46 (23.6%) had ocular pain only, and 16 (8.2%) had imploding and exploding headaches with or without ocular pain. Three subjects did not respond. For physician assignment, 69 (34.9%) subjects had imploding headaches with or without ocular pain, 89 (45%) had exploding headaches with or without ocular pain, 14 (7.1%) had ocular pain only, and 26 (13.1%) had imploding and exploding headaches with or without ocular pain. The concordance (Kappa coefficient) between physician assignment of headache directionality with patient response to the written question was 0.33 (weak agreement), between physician assignment and patient assignment via selection of representative pictures was 0.35 (weak agreement), and between patient assignment via written question and via selection of representative pictures was 0.35 (weak agreement). Conclusions The assignment of headache directionality varied substantially depending upon the method of determination. The concordance between clinician assignment, patient-self assignment via answering a written question, and patient self-assignment via choosing a representative picture was weak. Improved methods of determining pain directionality are needed.