Diverse paths of phenotypic evolution in functional movement disorders: A longitudinal perspective

Area of Science:

• Neurology
• Movement Disorders
• Clinical Neuroscience

Background:

• Functional Movement Disorders (FMD) present with a variable clinical course.
• Understanding FMD phenotype evolution is crucial for prognosis and natural history insights.

Purpose of the Study:

• To investigate the longitudinal changes in FMD phenotypes.
• To identify clinical predictors of FMD phenotype modification over time.

Main Methods:

• Retrospective analysis of 112 FMD patients from a tertiary movement disorders clinic (2011-2024).
• Comparison of clinical and demographic data between patients with and without phenotype changes from initial to last consultation.
• Logistic regression analysis to identify predictors of phenotype modification.

Main Results:

• 13.2% of patients exhibited a phenotype change from initial to last consultation, predominantly shifting towards mixed FMD.
• Phenotype modification was associated with family dysfunction, within-phenotype variability, symptom migration, and poorer patient-reported status.
• Functional dystonia at initial assessment predicted phenotype modification, even after adjusting for variability.

Conclusions:

• FMD phenotypes frequently change over time, with a trend towards mixed presentations.
• Specific clinical features, such as functional dystonia, can predict these longitudinal changes.
• Continuous patient follow-up is essential for managing evolving FMD.