Comparison of migraine with left- versus right-sided headache: A cross-sectional study

ObjectiveThe goal of this study was to clarify whether clinical differences exist between patients with migraine who experience headache that is typically left-sided ("left-migraine") versus right-sided ("right-migraine") during attacks.BackgroundMigraine has been associated with unilateral headache for millennia and remains a supportive trait for the clinical diagnosis of migraine of the International Classification of Headache Disorders. It is currently unknown why headache in migraine is commonly unilateral, and whether headache-sidedness is associated with other clinical features.MethodsThis is a cross-sectional study comparing left- versus right-migraine using all available intake questionnaires of new patients evaluated at an academic tertiary headache center over a 20-year period. Eligibility was based on patient written responses indicating the typical location of headache during attacks. In our analyses, the side of headache (left or right) was the predictor variable. The outcomes included various migraine characteristics and psychiatric comorbidities.ResultsWe identified 6527 patients with migraine, of which 340 met study eligibility criteria. Of these, 48.8% (166/340) had left migraine, and 51.2% (174/340) had right migraine. When comparing patients with left- versus right-migraine, patients with left migraine experienced 3.6 fewer headache-free days (95% confidence interval [CI] 1.3-5.9; p = 0.002) and 2.4 more severe headache days (95% CI 0.8-4.1; p = 0.004) in the previous 4 weeks. No significant differences in age, sex, handedness, migraine characteristics, or psychiatric comorbidities were identified between the two groups.ConclusionsPatients with migraine with typically left-sided headache during attacks reported a higher burden of headache frequency and severity than those with typically right-sided headache during attacks. These findings may have implications for our understanding of migraine pathophysiology, treatment, and clinical trial design.Plain Language SummaryIn this study, we wanted to learn if patients with migraine who typically experience left-sided headache during attacks show differences in migraine features or psychiatric comorbidities compared to patients who typically experience right-sided headache during attacks. We reviewed the intake questionnaires of all new patients diagnosed with migraine at an academic headache center over the last 20 years. Our main finding was that patients with typically left-sided headache reported more headache days and more severe headache days than patients with typically right-sided headache. In this study, we wanted to learn if patients with migraine who typically experience left-sided headache during attacks show differences in migraine features or psychiatric comorbidities compared to patients who typically experience right-sided headache during attacks. We reviewed the intake questionnaires of all new patients diagnosed with migraine at an academic headache center over the last 20 years. Our main finding was that patients with typically left-sided headache reported more headache days and more severe headache days than patients with typically right-sided headache.