Abstract
The Classification Committee of the International Headache Society aims to share issues key to the development of the fourth edition of the International Classification of Headache Disorders. The Committee met on 5th September at the 20th International Migraine Trust Symposium in London, UK. We report here our discussions so that interested healthcare professionals and members of the Society can participate by giving us their feedback, preferably based on scientific data, which could come from real-world studies, views and reviews.
The over-arching issues for the Committee at this stage are the underlying principles and some broad, important matters. These apply to much of the rest of the classification, so we have considered the need to address them early in the process. Among the pressing issues are:
Primary and a secondary headache disorder when phenotypes overlap. Post-traumatic headache and migraine were used as exemplars of the problem. We are developing a commentary, whose text could be used in the initial section of the classification, to clarify some principles. Tension-type headache. There is a notable apparent inconsistency, without any pathophysiological basis, between episodic and chronic tension-type headache with regard to associated symptoms, specifically nausea. ICHD-2 proposed alternative criteria for tension-type headache with no nausea, photophobia or phonophobia, and commented they would be more specific and less sensitive (1). These have field tested well (2). Research investigating tension-type headache, and clinical practice, would be well-served by moving the appendix criteria into the main section, and moving the current main section criteria to the appendix (3). This change would require some discussion concerning people with single sensitivities, such as just one of photophobia or phonophobia. Chronic migraine. The issue of demarcation of chronic migraine and the utility of the diagnosis of episodic migraine was discussed. Much has been written, and the Committee is mindful of the implications of change. This matter will be discussed at our next meeting.
Vestibular migraine was discussed. This diagnosis has the disadvantage of extracting vestibular symptoms from other forms of sensory sensitivity, such as photophobia or phonophobia. Being clinically pragmatic, as vestibular symptoms are often assessed in non-neurology settings, such as audiovestibular and otolaryngology practices, criteria for vestibular migraine in the main classification might improve the recognition of migraine in the round. We have initiated a stream of work in this area.
Medication-overuse headache was discussed, in terms of nomenclature and desirability of terminological change, and because the present criteria are not pragmatic. It is recognized that some find the term stigmatizing. There are also implications for the global burden of disease data. Additionally, there was discussion about the ICHD recognizing medication overuse, even in the absence of medication-overuse headache. This will be the subject of a discussion paper.
There was a discussion on how the classification criteria should be used in epidemiological studies and in experimental studies e.g., looking for biomarkers. This issue might be best addressed by comments in the next classification, such as who has “active” migraine.
In order to have a broad discussion, the Committee will run a workshop at IHC2025 in Sao Paulo (22nd International Headache Congress (IHC) - International Headache Society). Our initial plan is to set out areas that we judge need consideration, and then invite feedback from the International Headache Society constituency. The latter will take two forms. We invite members with proposals for changes to the Classification to submit to the Committee Secretary a one-page outline of the problem and the proposed solution with appropriate citations of supportive literature. The Committee will select the most developed proposals and will invite their authors, if they are present at IHC2025, to present them during the workshop. We will also have an open microphone session for comments from the floor.
Classification is not easy; change may bring unintended consequences and one's clinical experience may not align entirely with others. Our classification has many strong aspects, so the process of change needs to be measured.
Classification Committee of the International Headache Society, 4th edition
Peter J. Goadsby, Chair
Stefan Evers, Secretary (everss@uni-muenster.de)
Amy A. Gelfand
Richard B. Lipton
Arne May
Patricia Pozo-Rosich
Jean Schoenen
Todd Schwedt
Cristina Tassorelli
Gisela Terwindt
Shuu-Jiun Wang
Footnotes
Declaration of conflicting interests
The authors declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: P.J.G. reports, over the last 36 months, a grant from Kallyope, and personal fees for consulting from Aeon Biopharma, Abbvie, Aurene, CoolTech LLC, Dr Reddy's, Eli-Lilly and Company, Epalex, Linpharma, Lundbeck, Pfizer, PureTech Health LLC, Satsuma, Shiratronics, Teva Pharmaceuticals, Tremeau, and Vial, and personal fees for advice through Gerson Lehrman Group, Guidepoint, SAI Med Partners, Vector Metric, and fees for educational materials from CME Outfitters and WebMD, and publishing royalties or fees from Massachusetts Medical Society, Oxford University Press, UptoDate and Wolters Kluwer. S.E. None disclosed. A.A.G.: In the last 24 months, Dr Gelfand has received royalties from UpToDate (for authorship), and honoraria from Elsevier (for authorship), the American Academy of Neurology (for editing) and the Weill Cornell Neurology Department (for speaking). She receives a stipend from the American Headache Society for her role as Editor of Headache. She receives grant support from PCORI as a member of the Steering Committee for the REACH study and from the UCSF Resource Allocation Program as an investigator. R.B.L. None disclosed. A.M. reports no conflict of interest. In the past he has received personal fees from Novartis, Betapharm, TEVA and Ipsen for speaker activities or advisory boards. P.P.-R. has received, in the last 3 years, honoraria as a consultant and speaker from AbbVie, Amgen, Dr Reddy's, Eli Lilly, Lundbeck, Medscape, Novartis, Organon, Pfizer and Teva Pharmaceuticals. Her research group has received research grants from AbbVie, AGAUR, EraNet Neuron, FEDER RIS3CAT, Instituto Investigación Carlos III, MICINN, Novartis, and Teva Pharmaceuticals, and has received funding for clinical trials from AbbVie, Amgen, Biohaven, Eli Lilly, Lundbeck, Novartis, Pfizer and Teva Pharmaceuticals. She is the Honorary Secretary of the International Headache Society, is an associate editor for Cephalalgia and Neurologia. She is a member of the Clinical Trials Guidelines Committee of the International Headache Society. She has edited the Guidelines for the Diagnosis and Treatment of Headache of the Spanish Neurological Society. J.S. None disclosed. T.J.S. has received, in the last 36 months, consulting fees from AbbVie, Allergan, Amgen, Axsome, Collegium, Eli Lilly, Linpharma, Lundbeck, Salvia, Satsuma, Scilex, Theranica. Royalties from UpToDate. Research Grants from the American Heart Association, Flinn Foundation, Henry Jackson Foundation, National Headache Foundation, National Institutes of Health, Patient Centered Outcomes Research Institute, Pfizer, Spark Neuro, United States Department of Defense. And Stock Options from Allevalux, Aural Analytics, Nocira. C.T., in the last 36 months, has received an institution grant from Abbvie. She has received personal consulting fees from Abbvie, Eli Lilly, Dompe, Ipsen, Lundbeck, Pfizer, Medscape and Teva. She has received honoraria from Abbvie, Eli Lilly, Teva, Lundbeck and Pfizer. She has received support from attending meetings/travel from Abbvie, Eli Lilly, Dompe, Ipsen, Teva, Lundbeck and Pfizer. She is a PI in trials sponsored by Abbvie, Biohaven, Eli Lilly, Ipsen, Lundbeck, Pfizer and Teva and has received drugs for an investigator-initiated trial. G.T., in the last 36 months, reports institutional funding from the Dutch Brain Council, grant funding from the European Community, Dutch Heart Foundation, IRRF and Dioraphte. She has received royalties from Up to date (RVCL-S) and personal royalties from the Dutch Neurology Handbook. She receives consulting fees from Novartis, Lilly, Teva, Abbvie/Allergan, Lundbeck and Pfizer to her institution. She has received honoraria from Spring Media, Ashfield MedComms, Remedica and Cygnea, paid to her institution. She has patent planned, issued or pending for consultation of e-diary patient journey with Interactive Studios. She participates (unpaid) with CGRP Education and Research Forum. Has unpaid board, society, committee roles with Dutch Headache Society (Board Member), Dutch Headache Alliance (Advisory Member), National Headache Guidance for Neurologists (Chair), Clinical Trial Guideline Committee of the International Headache Society (Chair) and Women's Leadership Forum of the International Headache Society (Chair). S.J.W. None disclosed
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
