After reviewing the historic differentiation between migraine and tension-type headache, the authors note that the similarities between these two types of primary headaches outweigh the differences, and so hypothesize that these headaches share a common pathophysiology. The convergence hypothesis for primary headaches links the clinical features of an evolving headache to current pathophysiological models. The authors suggest that successive symptoms experienced clinically reflect an escalating pathophysiological process, beginning with the premonitory period and progressing into tension-type headache and, if uninterrupted, finally into migraine. The clinical manifestations of other headache types, such as so-called sinus headache or temporomandibular headache, may also be explained by this model. A convergence hypothesis for primary headaches has important implications for earlier recognition, diagnosis, and treatment.

Objective.-This multi-center pilot study compared the efficacy of onabotulinumtoxinA with topiramate (a Food and Drug Administration approved and widely accepted treatment for prevention of migraine) in individuals with chronic migraine (CM).Methods.-A total of 59 subjects with CM were randomly assigned to one of 2 groups: Group 1 (n = 30) received topiramate plus placebo injections, Group 2 (n = 29) received onabotulinumtoxinA injections plus placebo tablets. Subjects maintained daily headache diaries over a 4-week baseline period and a 12-week active study period. The primary endpoint was the Physician Global Assessment, which measured the treatment responder rate and indicated improvement in both groups over 12 weeks. Secondary endpoints, measured at weeks 4 and 12, included headache days per month, migraine days, headachefree days, days on acute medication, severity of headache episodes, Migraine Impact & Disability Assessment, Headache Impact Test, effectiveness of and satisfaction with current treatment on the amount of medication needed, and the frequency and severity of migraine symptoms. At 12 weeks subjects were re-evaluated and tapered off oral study medications over a 2-week time period. Subjects not reporting a >50% reduction of headache frequency at 12 weeks were invited to participate in a 12-week open label extension study with onabotulinumtoxinA. Of these, 20 subjects, 9 from the Topiramate Group and 11 from the OnabotulinumtoxinA Group, volunteered for this extension from weeks 14 to 26.Results.-This study demonstrated positive benefit for both onabotulinumtoxinA and topiramate in subjects with CM. Overall, the results were statistically significant within groups but not between groups. By week 26, subjects had a reduction of headache days per month compared with baseline. This was a significant within-group finding.Conclusion.-OnabotulinumtoxinA and topiramate demonstrated similar efficacy for subjects with CM as determined by Global Physician Assessment and supported by multiple secondary endpoint measures.

Sumatriptan nasal spray, 20 mg, restored migraine-related cognitive function and clinical disability.

This pilot study is the first to document a significant drop in cognitive functioning during migraine and recovery after administration of a migraine-specific medication.