PREPRINT: Assessing chronic pain processes longitudinally: Part 1 - Validation of the German “Assessing Chronic Pain Processes” (ProCEss) item set

Background. Ecological Momentary Assessment (EMA) has become increasingly feasible with technological advances, enabling the capture of dynamic fluctuations in symptoms and processes. EMA is ecologically valid and can reduce recall biases. However, there is a lack of thoroughly validated items. This study seeks to validate a set of items to assess key psychological processes in chronic pain in EMA. Methods. The “Prozesse Chronischer Schmerzen ErfaSSen” (ProCEss; engl. „Assessing Chronic Pain Processes”) item set was developed for an EMA coverage model, i.e. a broad range of the day shall be captured instead of single momentary experiences. In multiple studies, practitioners (n = 18 + n = 12) and affected persons (n = 12 + n = 12) contributed to establishing content validity through an adapted Discriminant Content Validity Method and cognitive interviews. Findings from these studies informed the development of written and audio-visual comprehension aids, designed and evaluated in a healthy sample (n = 128) to replace extensive participant instruction procedures.Results. Across studies, both affected persons and practitioners rated the items positively with regard to content validity and clinical utility. Feedback of affected persons contributed to item refinement, and the item set was reduced from 29 to 25 items. The evaluation of the comprehension aids supported the comprehensibility of the item set.Conclusions. The ProCEss item set is among the first validated instruments for assessing chronic pain processes using EMA in German. The current study supports its content validity. Other forms of validity have to be established in future research.