Muscle fiber conduction velocity in situ revisited: A new approach to an ancient technique

Author(s)

Kouyoumdjian, Joao Aris ; Graca, Carla Renata

• Document type: Journal article
• Source: FRONTIERS IN NEUROLOGY; v. 14, p. 10-pg., 2023-02-23.

Abstract

The aim of this study was to measure the muscle fiber conduction velocity (MFCV) in situ in the tibialis anterior muscle in healthy subjects. A total of 36 subjects matched for age and sex were studied. The MFCV was measured with a concentric needle by intramuscular monopolar needle electrical activation at a distance of 50 mm. The mean consecutive difference (MCD) of <5 mu s was obtained after a median of 62 muscle fiber action potentials (MFAPs), confirming a direct muscle fiber activation. The measuring latency was at the median point of ascending depolarizing line of the MFAP. The calculated MFCV from 784 MFAPs was 4.10 +/- 0.66 m/s, 3.99 +/- 0.57 for female subjects (95%, 2.85 to 5.13), and 4.20 +/- 0.73 for male subjects (95%, 2.74 to 5.67). The MFCV was 5.22% faster in male subjects. The calculated fast-to-slow MFCV ratio (F/S ratio) was 1.47 for female subjects (95%, 1.27 to 2.54) and 1.67 for male subjects (95%, 1.31 to 3.74). Aging significantly increased the F/S ratio. As the MFCVs mainly depend on the muscle diameter, their assessment is a quick and helpful tool for estimating it. Its variability by the F/S ratio is also a powerful tool in the follow-up of some neuromuscular disorders. (AU)

• FAPESP's process: 22/02291-1 - Electrophysiological evaluation of jitter and muscle fiber conduction velocity in situ post COVID-19
• Grantee: João Aris Kouyoumdjian
• Support Opportunities: Regular Research Grants