Diagnostic utility of Niigata Persistent Postural-Perceptual Dizziness (PPPD) Questionnaire (NPQ) for PPPD in comparison to dizziness handicap inventory

BackgroundPersistent postural-perceptual dizziness (PPPD) is a common yet challenging functional vestibular disorder. The Niigata PPPD Questionnaire (NPQ) is a simple diagnostic tool developed to assess the severity and presence of PPPD.ObjectiveTo validate the Korean version of the NPQ and to evaluate its reliability and diagnostic performance in differentiating PPPD from other vestibular disorders in comparison to Dizziness Handicap Inventory (DHI).MethodsWe recruited 255 patients, 150 with PPPD, 64 with peripheral vestibular disorders, and 41 with central vestibulopathy at a tertiary dizziness center in South Korea from January to December 2024. The NPQ was translated into Korean with a forward-backward translation procedure. In addition, all participants completed DHI, the Beck Depression Inventory-II (BDI-II), the State-Trait Anxiety Inventory (STAI), and the Perceived Stress Scale (PSS) to assess dizziness-related disability and psychological symptoms. Internal consistency was assessed using Cronbach's alpha. Discriminative ability was evaluated through between-group comparisons, correlation analyses, and receiver operating characteristic (ROC) curve analyses.ResultsThe Korean NPQ demonstrated excellent internal consistency (Cronbach's α = 0.93). The total and subscale scores of the NPQ were significantly higher in PPPD than in other vestibular disorder groups. ROC analysis yielded an area under the curve of 0.670 with a cut-off score at 15.5 (sensitivity 59.3%, specificity 71.4%). The visual stimulation subscale showed the highest AUC (0.703). A logistic regression combined model using NPQ visual stimulation and dizziness handicap inventory (DHI) emotional subscales achieved the best diagnostic accuracy (AUC = 0.756). The NPQ total score was moderately correlated with the DHI (ρ = 0.65) and modestly correlated with psychological symptoms.ConclusionThe Korean NPQ is reliable and provides acceptable diagnostic utility for distinguishing PPPD. Combining NPQ and DHI subscales enhances diagnostic accuracy, supporting its use as a screening tool in diverse clinical settings, including telemedicine.