Concentric needle single fiber electromyography: normative jitter values on voluntary activated Extensor Digitorum...

Area of Science:

• Neurology
• Neurophysiology
• Clinical Electrophysiology

Background:

• Single fiber electromyography (SFEMG) is highly sensitive for neuromuscular junction disorders like myasthenia gravis.
• Published normal values for SFEMG jitter exist, but data for concentric needle electrodes (CNE) is limited.
• Concentric needle electrodes (CNE) offer a potential alternative for jitter analysis in clinical neurophysiology.

Purpose of the Study:

• To explore the feasibility of analyzing jitter using concentric needle electrodes (CNE).
• To determine normal jitter values for the Extensor Digitorum Communis muscle with disposable CNE.
• To provide reference values for CNE-based jitter analysis in clinical settings.

Main Methods:

• Fifty healthy subjects (16 male, 34 female; age 19-55) were studied.
• Jitter was measured using disposable concentric needle electrodes (CNE) on the Extensor Digitorum Communis.
• Mean Consecutive Difference (MCD) was calculated from 20 analyzed potential pairs per subject.

Main Results:

• The mean MCD for jitter was 24.2 ± 2.8 µs (95% confidence limit: 29.8 µs).
• The overall mean jitter across 1000 potential pairs was 24.07 ± 7.30 µs, with a practical upper limit of 46 µs.
• Mean Interpotential Interval (MIPI) was 779 ± 177 µs, with no impulse blocking observed.

Conclusions:

• Concentric needle electrodes (CNE) are suitable for jitter analysis in neuromuscular disorders.
• This study provides normative jitter values for the Extensor Digitorum Communis using CNE.
• Findings align with existing literature, supporting CNE's utility in clinical neurophysiology.