The XI Congress of the International Headache Society (IHC) provided useful feedback for a wide range of disciplines for all scientists involved in basic and applied research concerning headaches.

World Headache Alliance members were among the 2,000 delegates from around the world to meet in Rome, Italy for the XI Congress of the International Headache Society(IHS). The biennial Congress provides a launch platform for new research and strategies that further the understanding of headache disorders. The meeting is open to clinicians, scientists, sufferers or caregivers whose objective it is to help patients affected by primary headache, or to help identify the underlying disease in the case of secondary headache.

The Presidential Symposium, which anticipated the scientific sessions, provided the most updated knowledge regarding neuroimaging, neuropsychological and potential clinical implications of the activation of brainstem structures as well as the dependency of cortical events on this activation during migraine attacks. The results of the strenuous work carried out from autumn 1999 to 2003 of an International Committee of headache experts, presided by J. Olesen, reached its peak with the presentation of the new International Headache Classification ICHD-II. There are many relevant changes in the new classification, even though the basic structure and the most important criteria, such as those for migraine without aura and tension-type headache, have been maintained. Several new entities have been added including chronic migraine for patients having migraine ge 15 days/month.