Adaptation and psychometric properties of the Italian version of the Non-Motor Symptoms Questionnaire for Parkinson’s disease

Although non-motor symptoms (NMS) of Parkinson’s disease (PD) are very common also in early stages of the disease, they are still under-recognized. Screening tools for non-motor symptoms, such as non-motor symptoms questionnaire (NMSQuest), help clinicians to recognize NMS and to evaluate if patients could require further assessment or specific treatments. To validate an adapted Italian version of NMSQuest and study its psychometric properties, Italian PD patients self-completed Italian NMSQuest, and then underwent a standard clinical evaluation including motor assessment (by Hoehn and Yahr staging, unified Parkinson’s disease rating scale part III) and non-motor assessment (by Montreal cognitive assessment, Beck depression inventory, neuropsychiatric inventory, Epworth sleepiness scale, scale for outcomes in Parkinson’s disease-Autonomic and movement disorder society-sponsored revision of the unified Parkinson’s disease rating scale part I). Somatic comorbidities were quantified using the modified cumulative illness rating scale (CIRS). Seventy-one subjects were assessed (mean age years 69.8 ± 9.6 SD; 31% women; mean duration of disease 6.3 ± 4.6 years; H&Y median 2). Italian NMSQuest showed adequate satisfactory clinimetrics in terms of data quality, precision, acceptability, internal consistency and reliability. A significant correlation was found between NMSQuest and most of non-motor assessment scales, while no significant correlation appeared with motor severity as well as with age of patients, disease duration, levodopa equivalent daily dose, l-DOPA/dopamine agonists assumption and CIRS total score. The Italian version of the NMSQuest resulted as a reliable instrument for screening NMS in Italian PD patients.