single fiber electromyography
Also written as: SFEMG — single fiber electromyography
A specialized EMG technique measuring individual muscle fiber action potentials and neuromuscular transmission.
Full Definition
Single fiber electromyography (SFEMG) is a highly specialized electromyographic technique that records action potentials from individual muscle fibers using a specialized electrode with a small recording surface. The test measures jitter, which reflects the variability in neuromuscular transmission time, and fiber density, which indicates muscle fiber innervation patterns. SFEMG is the most sensitive test for detecting neuromuscular junction disorders, particularly myasthenia gravis, where increased jitter occurs before clinical weakness becomes apparent. The technique requires significant technical expertise and patient cooperation, as voluntary muscle contraction must be carefully controlled during recording.
Usage
Usage note: Hyphenate 'single-fiber' when used as compound adjective.
In Context
- "Single fiber electromyography revealed increased jitter in the extensor digitorum communis muscle, consistent with myasthenia gravis." — Specialized EMG report
- "SFEMG testing requires a cooperative patient able to maintain minimal voluntary contraction." — Technical procedure note