Pain Assessment Scale for Patients With Disorders of Consciousness: A Preliminary Validation Study

Background: Patients with acquired brain injury undergoing rehabilitation are often unable to verbalize pain because of disorders of consciousness. Hence, observational pain assessment instruments are warranted for these patients. Aim: The aim of this study was to study interrater agreement and sensitivity to change over time of an assessment scale developed for the evaluation of pain in severely brain-injured patients with disorders of consciousness. Methods: We developed a pain assessment scale based on scientific literature and clinical experience with severely brain-injured patients. It consists of four domains: physiological/autonomic, body language, verbal communication, and behavior. The domains consist of 27 items. Interrater reliability was tested through three experienced nurses who rated 26 patients with acquired brain injury. The patients were rated in two different situations: before and after repositioning in bed and before and after administration of analgesics. We used Cohen's kappa test for interrater reliability. Sensitivity to change was tested by Wilcoxon signed rank test. Results: Cohen's kappa for the presence or absence of each item was above 0.8 for 13 items, between 0.6 and 0.8 for eight items, and less than 0.6 for only three items. The sensitivity test showed a significant change from before to after repositioning (p =.004). Conclusion: It appeared that many of the pain assessment scale items held potential for inclusion in a new, more comprehensively developed and validated scale for the assessment of pain in patients with disorders of consciousness.