Related Experiment Video
Updated: Jan 13, 2026
09:18
Measurements of Motor Function and Other Clinical Outcome Parameters in Ambulant Children with Duchenne Muscular Dystrophy
Published on: January 12, 2019
10.8K
Development and Evaluation of Upper Extremity Movement Quality Outcome Measures for Individuals With Functional
Garrett Weidig1,2, Tamara Reid Bush3
1Mechanical Engineering Department, Michigan State University, East Lansing, MI 48824-1226.
Journal of Biomechanical Engineering
|January 6, 2026
Summary
Researchers developed Summed Centripetal Acceleration (SCA), a new objective measure for assessing Functional Movement Disorder (FMD) symptoms. SCA shows promise for clinical use in tracking patient improvements in movement quality.
Area of Science:
- Neurology
- Biomedical Engineering
- Movement Science
Background:
- Functional Movement Disorder (FMD) impacts movement quality, with symptoms varying from tremors to jerks.
- Objective assessment tools for FMD movement quality are currently lacking in clinical practice.
- Existing methods struggle to quantify the spectrum of FMD-related upper extremity movement abnormalities.
Purpose of the Study:
- To develop and validate a novel movement-quality outcome measure for quantifying upper extremity FMD symptoms.
- To compare the efficacy of the new measure against existing metrics using data from healthy participants exhibiting simulated FMD movements.
Main Methods:
- Healthy participants performed reaching and retrieving movements emulating four FMD symptom types.
- Four movement-quality outcome measures were calculated: Number of Peak velocities (NoP), Log-Dimensionless Jerk (LDLJ), Spectral Arc Length (SPARC), and Summed Centripetal Acceleration (SCA).
- The newly developed SCA measure was designed to capture hyperkinetic movement based on position and velocity profiles.
Main Results:
- Summed Centripetal Acceleration (SCA) demonstrated strong correlations (r² > 0.5) with key movement aspects in three geometries and moderate correlations (0.25 ≤ r² ≤ 0.5) in one.
- SCA outperformed NoP, LDLJ, and SPARC in its correlation with movement characteristics and its ability to order movement types by quality.
- The developed SCA measure offers a potentially more objective and comprehensive assessment of FMD-related movement abnormalities.
Conclusions:
- Summed Centripetal Acceleration (SCA) is a promising novel outcome measure for objectively assessing upper extremity movement quality in Functional Movement Disorder (FMD).
- This measure has the potential to significantly aid clinicians in objectively evaluating FMD symptoms and monitoring treatment progress.
- Further validation in clinical populations is warranted to fully establish SCA's utility in patient care.
