Related Experiment Video
Updated: May 23, 2026
Stimulated Single Fiber Electromyography (SFEMG) for Assessing Neuromuscular Junction Transmission in Rodent Models
Published on: March 8, 2024
Application of futility analysis to refine jitter recordings in myasthenia gravis
Pushpa Narayanaswami1, Norberto Pantoja-Galicia, Rebecca A Betensky
1Department of Neurology, Harvard Medical School, Beth Israel Deaconess Medical Center, TCC-8, 330 Brookline Avenue, Boston, Massachusetts 02215, USA. pnarayan@bidmc.harvard.edu
Introduction:
The current practice of single-fiber electromyography (SFEMG) requires that 20 fiber pairs with normal jitter be collected to exclude myasthenia gravis (MG). We applied principles of futility analysis from clinical trials in an attempt to reduce that requirement.
Methods:
We utilized conditional power futility analysis to assess the probability of an abnormal 20-pair SFEMG based on ongoing analysis of jitter as each pair is collected. Rules for early test termination in the presence of 0, 1, or 2 abnormal pairs were identified. These rules were then applied to previously collected SFEMG data.
Results:
SFEMG could be stopped at just 12 pairs if all are normal and at 17 pairs if 1 is abnormal. The rules successfully determined when SFEMG could be stopped in 104 of 106 (98%) studies originally reported to be normal.
Conclusions:
If the first 12 SFEMG pairs have normal jitter, the study can be terminated and interpreted as normal.
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