OBJECTIVESAssessment of pain is challenging given its subjective nature. Standard pain assessment tools have limitations. We aimed to compare the verbal numeric rating scale (NRS) and Grasp, a novel ...handheld electronic device that reports pain by squeezing.METHODSTo compare Grasp and NRS, healthy adult volunteers were invited to undergo two subsequent standardised tests of cold-triggered pain using a cold pressor test (CPT) at a temperature of 3°C. Pain intensity was in a randomised manner reported by NRS (scale 0-10) or by squeezing Grasp (0-3 V) during the two CPTs. A third CPT was performed 1 to 14 days later where subjects reported pain by Grasp a second time in order to study the association of repeated Grasp measurements. Acceptable association was a priori considered as mean Kendall's τ-b coefficient (τ-b) ≥ 0.7. The subjects reported their experience of using Grasp in a purpose-made questionnaire.RESULTSIn total, 102 subjects were included, and 96 subjects (56 females) completed all three tests. The association of pain intensity reported by Grasp and NRS was moderate with a mean τ-b of 0.53 (95% confidence interval CI 0.47-0.58). The association between the repeated Grasp measurements was weak with a mean τ-b of 0.43 (95% CI 0.37-0.48). Most subjects reported that Grasp was intuitive and easy to use.CONCLUSIONSPain intensity reported by squeezing Grasp did not show acceptable association with pain intensity reported by NRS during CPTs. The association between pain intensity reported by Grasp during two CPTs on separate days was weak. Further improvements of the Grasp ball are needed before use in clinical settings.
