Conversion between NMSS and MDS-NMS in Parkinson's Disease

Area of Science:

• Neurology
• Clinical Assessment
• Parkinson's Disease Research

Background:

• Parkinson's disease (PD) significantly impacts patients through non-motor symptoms.
• Two key scales, the Non-Motor Symptoms Scale (NMSS) and the International Parkinson and Movement Disorder Society Non-Motor Rating Scale (MDS-NMS), assess these symptoms but differ in structure and scoring.
• This disparity hinders direct comparison of data across studies utilizing different scales.

Purpose of the Study:

• To develop reliable conversion formulas for transforming scores between the NMSS and MDS-NMS.
• To enable direct comparison and enhance data comparability for non-motor symptoms in Parkinson's disease research.

Main Methods:

• Utilized data from 402 Parkinson's disease patients from the primary MDS-NMS validation study.
• Assessed the association between domain and total scores of both scales using Spearman rank correlation and Kendall's W concordance coefficient.
• Constructed weighted linear regression models to derive equations for score transformation.

Main Results:

• Spearman rank correlations indicated moderate to strong associations between corresponding domains of the MDS-NMS and NMSS (0.39–0.88).
• Developed a formula to convert NMSS total scores to MDS-NMS total scores: MDS-NMS = 11.629 + 1.624 × NMSS (R² = 0.748).
• Developed a formula to convert MDS-NMS total scores to NMSS total scores: NMSS = 2.475 + 0.495 × MDS-NMS (R² = 0.771).

Conclusions:

• The derived conversion equations provide a robust method for interchanging scores between the NMSS and MDS-NMS.
• Facilitates enhanced data comparability across diverse research studies assessing non-motor symptoms in Parkinson's disease.
• Supports more integrated analysis and meta-analyses in the field of movement disorder research.