Expanded and Independent Spanish Validation of the MDS-Non Motor Rating Scale

Area of Science:

• Neurology
• Movement Disorders
• Parkinson's Disease Research

Background:

• The Movement Disorder Society-sponsored Non-motor Rating Scale (MDS-NMS) is crucial for evaluating the severity and disability associated with non-motor symptoms (NMS) in Parkinson's disease (PD).
• Standardized assessment tools are essential for consistent clinical evaluation and research in PD.

Purpose of the Study:

• To formally document the process of creating the first official non-English version of the MDS-NMS (Spanish).
• To validate the Spanish MDS-NMS according to the International Parkinson and Movement Disorder Society (IPMDS) Translation Program protocol.

Main Methods:

• The translation program involved rigorous steps: translation, back-translation, cognitive pre-testing, and field testing.
• Confirmatory factor analysis (CFA) was used to compare the Spanish version's factor structure to the original English scale, requiring a Comparative Fit Index (CFI) ≥0.90 for official designation.
• The Spanish MDS-NMS was tested across seven countries with 364 native Spanish-speaking PD patients.

Main Results:

• The Spanish MDS-NMS achieved a CFI ≥0.90 for nine eligible domains in 349 patients, meeting the criterion for an Official Translation.
• Negligible missing data and acceptable item homogeneity were observed.
• A moderate floor effect was noted for the Non-Motor Fluctuations subscale, and domain correlations with related constructs were acceptable (r ≥ 0.50).

Conclusions:

• The Spanish version of the MDS-NMS successfully adhered to the IPMDS Translation Program protocol.
• The Spanish MDS-NMS has been officially approved and is now accessible on the MDS website.
• This validated Spanish version will facilitate the assessment of NMS in Spanish-speaking Parkinson's disease populations.