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Single fiber electromyography.

Publication ,  Journal Article
Juel, VC
Published in: Handb Clin Neurol
2019

Single fiber electromyography (SFEMG) is a highly selective technique that permits assessment of individual muscle fiber action potentials (MFAPs). This selectivity is achieved with a specialized concentric needle electrode with a 25-μm diameter recording surface located in a side port 3mm from the needle tip. Additional selectivity is achieved with 500-Hz low-frequency filtering. An oscilloscope with a trigger and delay line enables identification of time-locked MFAPs within the same motor unit. SFEMG techniques allow assessment of two important features of the motor unit: jitter and fiber density (FD). Neuromuscular jitter is a direct measure of neuromuscular transmission and reflects the temporal variation in end-plate potentials reaching threshold to elicit a MFAP. SFEMG may be used to assess paired jitter with voluntary activation or by axonal stimulation of motor nerve branches to individual end plates. SFEMG is the most sensitive clinical test for neuromuscular junction disease and is often abnormal in clinically unaffected muscles in patients with myasthenia gravis (MG) and Lambert-Eaton myasthenia (LEM). Normal jitter findings in a clinically weak muscle exclude neuromuscular junction disease as a cause for weakness in that muscle. FD measurements assess the local concentration of muscle fibers within a motor unit and provide a sensitive in vivo assessment of reinnervation.

Duke Scholars

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Published In

Handb Clin Neurol

DOI

ISSN

0072-9752

Publication Date

2019

Volume

160

Start / End Page

303 / 310

Location

Netherlands

Related Subject Headings

  • Synaptic Transmission
  • Neurology & Neurosurgery
  • Nervous System Diseases
  • Muscle Fibers, Skeletal
  • Humans
  • Electromyography
  • Action Potentials
  • 3209 Neurosciences
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Juel, V. C. (2019). Single fiber electromyography. Handb Clin Neurol, 160, 303–310. https://doi.org/10.1016/B978-0-444-64032-1.00019-9
Juel, Vern C. “Single fiber electromyography.Handb Clin Neurol 160 (2019): 303–10. https://doi.org/10.1016/B978-0-444-64032-1.00019-9.
Juel VC. Single fiber electromyography. Handb Clin Neurol. 2019;160:303–10.
Juel, Vern C. “Single fiber electromyography.Handb Clin Neurol, vol. 160, 2019, pp. 303–10. Pubmed, doi:10.1016/B978-0-444-64032-1.00019-9.
Juel VC. Single fiber electromyography. Handb Clin Neurol. 2019;160:303–310.
Journal cover image

Published In

Handb Clin Neurol

DOI

ISSN

0072-9752

Publication Date

2019

Volume

160

Start / End Page

303 / 310

Location

Netherlands

Related Subject Headings

  • Synaptic Transmission
  • Neurology & Neurosurgery
  • Nervous System Diseases
  • Muscle Fibers, Skeletal
  • Humans
  • Electromyography
  • Action Potentials
  • 3209 Neurosciences