Meditations on Methodological Issues in Clinical Investigations of "Central Sensitization" (Jonah XII).

This perspective paper addresses five methodological concerns in clinical investigations across the field of pain research and the paradigm of central sensitization. The first is the conflation of the phenomenon and the measurement tool: a patient reported outcome questionnaire called "Central Sensitization Inventory" is given as an example. Second, instruments that are used for measuring central sensitization (and its severity) are not validated to measure the phenomenon of central sensitization. The third is conceptual ambiguity regarding the theoretical framework of central sensitization and nociplastic pain, perpetuating the perception of central sensitization/nociplastic pain as both a phenomenon and a mechanism at the same time. The fourth is the conflation of clinical reasoning with scientific thinking, where in the former jumping from the mechanism to the phenomenon and vice versa is natural. The fifth is terminology issues such as "central-sensitivity syndromes" and "central sensitization-associated symptoms" when referring to fibromyalgia and similar conditions. In summary, by clinician-researchers confusing empirics with theory and theory with empirics and using clinical reasoning instead of scientific thinking, central sensitization becomes an axiom instead of a paradigm to be investigated according to hypothesis-driven studies. The failure to be aware of and clearly distinguish between these cognitive frameworks can lead to flawed research designs, inappropriate interpretations of findings, groundless mechanistic conclusions, and ultimately compromised clinical decision making.