Reliability and Validity of Cross Culturally Adapted Punjabi Version of NDI (NDI-P) in Patients with Neck Pain: A Psychometric Analysis

Abstract

Background: Neck disability index (NDI) is one of the commonest patient-reported outcome measures used to evaluate disability related to neck pain. Its application to non-English-speaking Punjabi population is limited as a validated and cross-culturally adapted Punjabi version of NDI is not available. The purpose of the study was to analyze the psychometric properties of Punjabi version of neck disability index (NDI-P) in patients with neck pain. Materials and Methods: The translation and cross-cultural adaptation of Punjabi version of NDI was done according to well-recommended guidelines. The pre-final version was tested on a set of 15 patients and suitable modifications were made. The final version was administered to 100 patients with neck pain of more than 2 weeks duration. Psychometric properties comprising internal consistency, test–re-test reliability, construct validity and factorial structure of the questionnaire were determined. Results: The developed NDI-P showed excellent internal consistency (Chronbach alpha of NDI-P is 0.87), test–re-test reliability (ICC 0.840) and construct validity (Spearman correlation coefficient with VAS 0.547). Factor analysis proved the questionnaire to be having a 2-factor structure with a total variance of 56.58%. Conclusion: NDI (P) is a reliable and valid instrument for measurement of disability related to neck pain in Punjabi population. It can be used both in research and clinical care settings in future.