A Simplified Version of the Psychogenic Movement Disorders Rating Scale: The Simplified Functional Movement Disorders...

Area of Science:

• Neurology
• Psychiatry
• Movement Disorders

Background:

• The Psychogenic Movement Disorders Rating Scale (PMDRS) is a potential objective assessment tool for clinical research.
• Existing PMDRS has limitations, prompting the development of a simplified version (S-FMDRS).

Purpose of the Study:

• To assess the inter-rater reliability, concurrent validity, and sensitivity of the simplified Functional Movement Disorders Rating Scale (S-FMDRS).
• To evaluate the S-FMDRS as an improved objective assessment for functional movement disorders (FMD).

Main Methods:

• Fifty-two videos of patients with FMD were rated using the original PMDRS and the S-FMDRS by three neurologists.
• Inter-rater reliability was measured using intraclass correlation coefficient (ICC) and Light's kappa.
• Concurrent validity was assessed using Spearman's correlation; sensitivity was evaluated in a physiotherapy feasibility study.

Main Results:

• The S-FMDRS demonstrated high inter-rater reliability (ICC=0.85), comparable to the original scale (ICC=0.84).
• Concurrent validity was strong (Spearman's correlation 0.84-0.95).
• The S-FMDRS showed good sensitivity to change (effect size 0.79) and high reliability between physiotherapists and neurologists (ICC=0.85).

Conclusions:

• The S-FMDRS exhibits high inter-rater reliability and good sensitivity to change, making it a valuable tool for FMD research.
• Lower agreement on specific classifications with the original scale supports the utility of the simplified version.
• Further psychometric validation of the S-FMDRS is recommended.