Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

M/RMS: an EMG method for quantifying upper motoneuron and functional weakness

J F Haughton1, J W Little, R K Powers

  • 1Department of Rehabilitation Medicine, University of Washington, Seattle.

Muscle & Nerve
|August 1, 1994
PubMed
Summary
This summary is machine-generated.

Related Concept Videos

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Acute Postoperative Pain Due to Dental Extraction in the Adult Population: A Systematic Review and Network Meta-analysis.

Journal of dental research·2023
Same author

Umbilical Cord-derived Mesenchymal Stem Cells for COVID-19 Patients with Acute Respiratory Distress Syndrome (ARDS).

CellR4-- repair, replacement, regeneration, & reprogramming·2021
Same author

Implementing a declination form programme to improve influenza vaccine uptake by staff in Department of Veterans Affairs spinal cord injury centres: a pilot study.

The Journal of hospital infection·2015
Same author

Noise analysis and performance comparison of low current measurement systems for biomedical applications.

IEEE transactions on biomedical circuits and systems·2013
Same author

Lack of resveratrol neuroprotection in developing rats treated with kainic acid.

Neuroscience·2012
Same author

Applications of accelerator MS in pediatric drug evaluation.

Bioanalysis·2012
Same journal

Targeted Muscle Reinnervation for Intuitive Prosthetic Control.

Muscle & nerve·2026
Same journal

Urinary Dysfunction in Myasthenic Syndromes: A Scoping Review of Clinical Features and Treatment-Related Associations.

Muscle & nerve·2026
Same journal

Join AANEM.

Muscle & nerve·2026
Same journal

Targeted Muscle Reinnervation for Management and Prevention of Symptomatic Neuroma.

Muscle & nerve·2026
Same journal

AANEM News & Insights.

Muscle & nerve·2026
Same journal

Fat-Fraction Quantification Using Three-Point Dixon Technique in Duchenne Muscular Dystrophy and Its Correlation With Clinical Progression and Genotypic Characteristics: A Single Centre One-Year Prospective Study.

Muscle & nerve·2026
See all related articles

A novel EMG method quantifies upper motoneuron (UMN) weakness. An elevated M/RMS ratio effectively identifies UMN weakness in stroke and spinal cord injury patients, distinguishing it from peripheral nerve injury.

Area of Science:

  • Neurology
  • Electromyography
  • Motor Neuron Diseases

Background:

  • Quantifying upper motoneuron (UMN) weakness is crucial for diagnosing neurological disorders.
  • Standard electromyography (EMG) methods often lack specificity in differentiating UMN lesions from other causes of muscle weakness.
  • Existing methods like twitch occlusion can be complex and time-consuming.

Observation:

  • A new method using standard EMG equipment was developed to quantify UMN weakness.
  • Measurements included force, EMG, and twitch force during isometric contractions.
  • Two key ratios were analyzed: elicited CMAP amplitude (M)/voluntary-root-mean-square EMG activity (RMS) and voluntary contraction twitch force (Ti)/resting twitch force (Tmax).

Findings:

  • Both log M/RMS and Ti/Tmax ratios correlated linearly with force in control subjects.

Related Experiment Videos

  • The log M/RMS ratio was significantly elevated in weak muscles of stroke and incomplete spinal cord injury (SCI) patients.
  • This ratio remained normal in muscles weakened by peripheral nerve injury (PNI), indicating specificity for UMN dysfunction.

    • Implications:

    • The elevated M/RMS ratio shows potential for quantifying deficient supraspinal activation characteristic of UMN weakness.
    • This new EMG-based method offers a more accessible and potentially more accurate way to assess UMN lesions.
    • Distinguishing UMN weakness from PNI has significant diagnostic and therapeutic implications for neurological rehabilitation.