Psycho-Vox: A Polish Questionnaire for the Differential Diagnosis of Muscle Tension Dysphonia

Objective: The aim of the study was to devise and validate a new questionnaire-Psycho-Vox-for diagnosis of muscle tension dysphonia and develop normative data for Polish-speaking adults. The tool was designed to measure 10 key psychological and social dimensions that have a bearing on functional voice disorders (FVDs), namely perseverance, coping with stress style (task-oriented or avoiding-oriented), mental well-being, resilience, burnout, family and social relationships, and tendency to project a positive self-image, tendency to exaggerate symptoms. Methods: The validation study involved 164 participants (46.3% were patients with muscle tension dysphonia and 53.7% were in good health; 92.7% were women). Their ages ranged from 18 to 76 years (M = 40.2; SD = 13.1). The Psycho-Vox questionnaire comprised 80 items, which participants rated on a 5-point Likert scale. Construct validity was tested using factor analysis with principal component rotation and confirmatory factor analysis. Reliability was determined using Cronbach's α, and linguistic comprehension was assessed using the Flesch Reading Ease Score (FRES, Polish version) and the Jasnopis indicator. Sten norms were developed for the entire sample. Results: Factor analysis confirmed the 10-factor structure of the questionnaire, consistent with theoretical assumptions (KMO = 0.734; χ²(3160) = 8643.41; p < 0.001), with 89.2% classification agreement. Cronbach's α for individual scales ranged from 0.705 to 0.837, confirming high internal reliability. The results of the FRES and Jasnopis tests indicate that the tool is understandable to adults with secondary or higher education. Significant differences were found between the patient group and the control group in terms of family relationships (p < 0.001), social capital (p = 0.003), mental well-being (p = 0.007), tendency to project a positive self-image (p = 0.004), and tendency to exaggerate symptoms (p = 0.005). A logistic regression model (χ²(10) = 62.27; p < 0.001; Hosmer-Lemeshow χ²(8) = 5.00; p = 0.757) showed that belonging to the patient group was positively associated with higher scores on the scales of family relationships, mental resilience, mental well-being, tendency to project a positive self-image, and symptom exaggeration, while negatively associated with perseverance and task-oriented coping with stress. The classification accuracy of the model was 73.2%. Sten norms were developed for all diagnostic scales. Conclusions: The Psycho-Vox questionnaire is characterised by good construct validity, high reliability, and practical clinical usefulness. The tool can be used in the differential diagnosis of muscle tension dysphonia and in monitoring the progress of treatment and rehabilitation.