Objective pain assessment by electrical stimulation

Background and Objectives: Pain estimation remains a difficult medical problem. Many subjective and objective methods were tried. Subjective methods depend on personal difference to a good extent and cannot be accurate. The aim of this work was to evaluate the validity of using electrical stimulation (ES) as an objective and valid method in quantitating the pain intensity and, consequently, the intensity of needed treatment. Methods: Twenty chronic low back pain (LBP) patients with sciatica and 20 normal subjects participated, and they were compared in this study. Electrical threshold and pain tolerance were recorded from the most painful site in the study group and from the corresponding matching site in the control group. Blood analysis for β-endorphin was done to objectively determine the intensity of pain as well as the objectivity and validity of ES in the assessment of pain. Pain intensity was also recorded by the visual analogue scale for each subject. Results: Significant differences between both groups regarding the threshold and pain tolerance to electrical current were noted. A significant positive correlation was also observed between β-endorphin level as well as the threshold and pain tolerance intensity in the patient group. Non-significant correlation was also observed between the visual analogue scale and β-endorphin level. Conclusion: ES is an objective and valid method, whereas visual analogue scale is a subjective method in the assessment of pain intensity in chronic LBP patients.