Abstract
INTRODUCTION: The Nijmegen Questionnaire assesses hyperventilation syndrome (HVS), but a validated Vietnamese version is lacking. This study investigates the cross-culture validity, structural validity, and reliability of the Vietnamese Nijmegen questionnaire (VNQ) for screening HVS in primary healthcare settings. METHODS: Following Beaton's guidelines, translation and adaptation involved two independent expert panels for content validity. Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) examined the VNQ's structure. Reliability was assessed via Cronbach's alpha, intraclass correlation coefficients, Bland-Altman analysis, and linear regression. RESULTS: Content validity was excellent (all I-CVIs > 0.79 and all S-CVIs > 0.8). EFA revealed a four-factor structure, including the original three NQ factors and a new "psychology" factor, confirmed by CFA. Cronbach's alpha and ICC values exceeded 0.7 and 0.8, respectively, indicating good internal consistency and test-retest reliability. Bland-Altman analysis showed low systematic error, and linear regression revealed no proportional bias (P > 0.05). CONCLUSION: The VNQ demonstrates excellent content validity, acceptable structural validity, and reliable psychometric properties for HVS screening in primary healthcare settings.