Diagnostic lessons from the spectrum study.

Abstract

Neurology. 2002;58(9 suppl 6):S27‐S31.Migraine is a heterogeneous condition that causes symptoms that vary both among individuals and within individuals from attack to attack. We examined and reviewed several important lessons on the diagnosis of migraine learned from the distribution of headache types and patterns of treatment response in the Spectrum Study, including recruitment and diagnostic issues. The accuracy of an initial diagnosis, assigned by a clinician in the context of a clinical trial, was compared with the results of a final diagnosis, assigned by a neurologist, reviewing the initial evaluation as well as headache diaries for up to 10 attacks. Several lessons can be learned from the Spectrum Study. Recruitment difficulties teach us that disabling tension‐type headache is difficult to find, suggesting that it is rare. Examination of the final diagnosis given after diary evaluations suggests that a diagnosis of migraine can usually be confirmed for patients with disabling headache. After reclassification of the final sample of 432 subjects, 24/75 (32%) patients initially clinically classified as having disabling episodic tension‐type headache proved to have migraine or migrainous headache after a diary review. Among study participants, 90% of subjects with disabling headache (HIMQ score>250) had a migraine‐related disorder. Treatment response suggests that, in migraineurs, tension‐type headaches may have a pathophysiology similar to that of migraine. The diary data show that mild headaches in migraine often evolve into full‐blown migraine. The Spectrum Study supports the view that, for patients with disabling episodic headache, migraine is often the correct diagnosis. In clinical practice, the suspicion of migraine should be high for patients experiencing episodic disabling headache. Assessment of headache‐related disability may assist practitioners in making a diagnosis of migraine. Comment: The Spectrum Study (Lipton R, et al. Headache. 2000;40:783‐791) has proven to be one of the most important investigations to be reported in the modern clinical headache literature. The results, if accepted, constitute a shift in paradigm for the diagnosis of migraine, or, rather, a return to Neil Raskin's concept of the “continuum of benign recurring headache.” One conclusion of the study was that all headaches in patients with coexisting episodic tension‐type headache, migrainous headache, and migraine behaved the same in their response to sumatriptan. This suggests that the three headache types might all be manifestations of the same primary headache disorder, namely migraine, rather than representing three independent disorders, as currently suggested by the IHS classification system. Another finding of the Spectrum Study was that diary review often changed the diagnosis of headaches initially thought to be tension‐type to migraine, suggesting both that longitudinal data can be illuminating with respect to diagnosis, and that, as Richard Lipton notes, “for patients with disabling episodic headache, migraine is often the correct diagnosis.” SJT