The International Classification of Headache Disorders from the point of view of Thomas Kuhn: a reflection

Headaches are characterized by a sensation of discomfort or pain in the cephalicregion. Due to the large number of types and subtypes of headaches, the standardization of their approach is necessary through the International Classification ofHeadache Disorders (ICHD), a document that is currently in its 3rd edition (ICHD-3).The evolution of the ICHD follows the hypothetical-deductive model of science basedon Karl Popper's philosophy, which has a strong presence in the health sciences.The classification of headaches has evolved over time, incorporating and removingcriteria, reflecting the need to adapt the classification to constantly evolving scientificand clinical demands. However, some changes can generate discrepancies betweenclinical practice and the elaborated diagnostic tools. In this context, this article reflectson whether it would be advantageous to return to old principles and foundations ofobsolete classifications. The criterion of osmophobia, which is no longer in use inICHD-3, is highlighted. This reflection can be developed following Thomas Kuhn's(1922-1996) view on science. In his main work, "The Structure of Scientific Revolutions"(1962), Kuhn proposes a three-stage model for science: the adoption of a paradigm,normal science, and a period of crisis. Kuhn also proposes the principle of incommensurability to understand the limitations and complexities of science. The applicationof this principle allows headache specialists to recognize that different approachesto headache classification have their own limitations and complexities, encouragingthem to consider a variety of perspectives, paradigms, and theories in approachingclinical cases and conducting scientific studies. An integrative approach that combinesPopper's hypothetical-deductive model with Kuhn's principle of incommensurabilityallows headache specialists to have a broader and more critical understanding ofheadache classifications.