Pain measurement: Visual Analogue Scale (VAS) and Verbal Rating Scale (VRS) in clinical trials with OTC analgesics in headache

Abstract

This study shows that the VRS categories cannot be presented in an equidistant manner on the VAS, and that contrary to previous assumptions, the pain intensity descriptors are less clear and can have different meanings in different languages. Therefore, both in the 3rd edition of the International Headache Classification (ICHD-III) and in the guidelines for clinical trials of patients with headache illnesses, rather than a 4-grade VRS, a 6-grade or higher level VRS or a VAS should be recommended, with correspondingly broadly defined anchor points.