Psychometric validity and reliability of the thai version of the Neuropathic Pain Symptom Inventory

Objective: The aim of this study was to evaluate validity and reliability of the Thai version of the Neuropathic Pain Symptom Inventory (NPSI-T) in Thai patients with neuropathic pain. Although the Thai version of Neuropathic Pain Symptom Inventory (NPSI-T) has been linguistically validated, the tool has to be psychometrically validated before applying to neuropathic pain patients in daily practice. Material and Method: Forty Thai patients with diagnosis of neuropathic pain were enrolled to the study and were evaluated by visual analog scale (VAS), the Thai version of Neuropathic Pain Diagnostic Questionnaire (DN4-T) and NPSI-T questionnaires. Four hours later, the patients were asked to perform retest NPSI-T and to evaluate the understanding of each NPSI-T question. Results: The total score of NPSI-T questionnaire was statistically correlated to visual analog scale (VAS) (Spearman’s correlation coefficient = 0.599, p<0.001) and neuropathic pain diagnostic questionnaire (DN4-T) (Spearman’s correlation coefficient =0.695, p<0.001). The reliability was determined by Intraclass correlation coefficient (ICC), an excellent interobserver agreement (ICC >0.8) and good agreement (ICC 0.6-0.8) were presented in 30% and 70% of the questionnaire, respectively. Conclusion: The study demonstrated validity and reliability of the NPSI-T for assessing the neuropathic pain in Thai patients.