PainSA is a chapter of the International Association for the Study of Pain. Our mission is to improve all aspects of pain management in Southern Africa.

Reliability and responsivity of pain intensity scales in individuals with chronic pain

Prior research supports the validity and short-term test-retest stability of 4 commonly used scales for assessing pain intensity (Visual Analogue Scale [VAS], 6-point Verbal Rating Scale [VRS-6], Numerical Rating Scale [NRS-11], and Face Pain Scale-Revised [FPS-R]). However, the relative stability and ability of these measures to detect changes in pain intensity over longer time periods have not yet been examined. The 4 scales were administered to a Thai cohort of 250 chronic pain outpatients on 2 occasions to assess worst and average pain intensity 6 weeks apart. All 4 scales were found to be valid for detecting decreases in pain, and the VAS, NRS-11, and FPS-R evidenced the most validity for detecting increases in pain. Overall, the NRS-11 emerged as showing the most sensitivity and stability. This study adds to the body of knowledge the stability of pain intensity scales over the longer term.