Adaptation and validation of the Niigata PPPD questionnaire in Turkish: A clinical study

ObjectiveThis study aimed to translate and cross-culturally adapt the Niigata Persistent Postural-Perceptual Dizziness Questionnaire (NPQ) into Turkish and evaluate its psychometric properties, including reliability, validity, and diagnostic accuracy, in Turkish-speaking patients with Persistent Postural-Perceptual Dizziness (PPPD).MethodsThis prospective case-control study included 114 participants: 36 PPPD patients, 40 with other vestibular disorders, and 38 healthy controls. Participants completed the Turkish version of the NPQ (T-NPQ) and the Dizziness Handicap Inventory (DHI). Internal consistency was assessed using Cronbach's alpha, and test-retest reliability was evaluated over 14-30-day interval. Construct validity was tested through confirmatory factor analysis (CFA) to test the hypothesized three-factor structure (Upright Posture/Walking, Movement, and Visual Stimulation), while convergent validity was examined by correlating T-NPQ scores with DHI scores. Diagnostic accuracy was assessed using Receiver Operating Characteristic (ROC) curve analysis.ResultsThe T-NPQ demonstrated excellent internal consistency (Cronbach's α = 0.919) and strong test-retest reliability (r = 0.832, p < .001). CFA supported the hypothesized three-factor structure and showed good model fit (χ²/df = 1.47, CFI = 0.964, RMSEA = 0.064). T-NPQ total scores strongly correlated with DHI total scores (r = 0.709, p < .001). The T-NPQ discriminated PPPD patients from other vestibular patients with an Area Under the Curve (AUC) of 0.746. The optimal cut-off score of 27.5 showed sensitivity of 86.1% and specificity of 57.5%.ConclusionThe Turkish version of the NPQ is a reliable and valid tool that may be useful for assessing symptom severity in PPPD patients. It has the potential to be effective for screening and measuring outcomes in clinical practice and research in Turkey.