Expanded and independent validation of the NoMoFA scale for Parkinson’s disease: the Italian version

Introduction: Non-motor symptoms (NMS) in Parkinson’s disease (PD) can fluctuate daily, impacting patient quality of life. The Non-Motor Fluctuation Assessment (NoMoFA) Questionnaire, a recently validated tool, quantifies NMS fluctuations during ON- and OFF-medication states. Our study aimed to validate the Italian version of NoMoFA, comparing its results to the original validation and further exploring its clinimetric properties. Methods: The scale underwent translation, back-translation, and cognitive pretesting before being administered to a calculated sample of > 200 PD patients. Each patient was assessed using a set of validated measures for assessing PD and cognitive state. We explored NoMoFA’s feasibility, acceptability, factorial structure, internal consistency, convergent validity, test–retest reliability (the latter performed on 50 patients after 14 days), and the precision of the scale. Results: 227 PD patients (mean age 65.34, disease duration 9.31 years) were included, with 100% data computability. The scale was free from floor and ceiling effects, and included 7 factors (59.2% of the variance). Cronbach’s alpha coefficient was 0.89, indicating strong internal consistency. The intraclass correlation coefficient (ICC) of 0.90 demonstrated satisfactory reproducibility. The NoMoFA Total score showed the strongest correlations with MDS-UPDRS Parts I (rS = 0.71) and II (rS = 0.60). Significant differences in NoMoFA scores were observed based on disease duration, H&Y score, and LEDD (p < 0.0001), but not age or sex. The Standard error of measurement (SEM) was 3.40 (for ½ SDpooled = 5.48). Conclusion: The Italian version of the NoMoFA scale demonstrated strong reliability, validity and precision, making it a robust tool for assessing non-motor fluctuations in PD.