Single fiber EMG and repetitive stimulation of the same muscle in myasthenia gravis.

Journal Article

We performed RNS and SFEMG studies of the same muscle in 46 patients with myasthenia gravis. Maximum decrement to 3-5-Hz stimulation before and after maximum voluntary exercise, percentage of action potential pairs with increased jitter and blocking, and mean MCD in each study were compared. A significant decrement (> 10% decrease in CMAP area or amplitude between the first and fourth response) was never found without increased jitter and impulse blocking on SFEMG. Increased jitter, blocking, and mean MCD were each correlated with maximum decrement (r > 0.61, P < 0.0001). We conclude that decrement to RNS and impulse blocking on SFEMG result from the same physiologic phenomenon, and that SFEMG is more sensitive at detecting disordered neuromuscular transmission given its ability to detect impulse blocking at levels below the resolution of RNS and increased neuromuscular jitter when there is not blocking.

Full Text

Duke Authors

Cited Authors

  • Gilchrist, JM; Massey, JM; Sanders, DB

Published Date

  • February 1994

Published In

Volume / Issue

  • 17 / 2

Start / End Page

  • 171 - 175

PubMed ID

  • 8114786

International Standard Serial Number (ISSN)

  • 0148-639X

Digital Object Identifier (DOI)

  • 10.1002/mus.880170207

Language

  • eng

Conference Location

  • United States