Evaluation of neuromuscular transmission by using monopolar needle electrode

Objective:  To evaluate the value of single-fibre electromyography (SFEMG) with monopolar electrode (MNPE) in revealing neuromuscular transmission dysfunction. Material and methods:  We examined the extensor digitorum communis muscle by using single-fibre electrode (SFE) and MNPE sequentially, in randomly assigned 20 healthy volunteers and in 17 patients with known myasthenia gravis (MG). The high-pass filter setting was 3 kHz for MNPE. Ten individual jitter values were calculated for each electrode in every muscle. Repetitive nerve stimulation (RNS) test on trapezius muscle was performed on 15 patients. Results:  In controls, the mean jitter values were 27 ± 9 (10–59) μs with SFE, and 21 ± 7.2 (9–56) μs with MNPE (P = 0.001). In the MG group, the mean jitter values were 52.4 ± 38 (12–221) μs with SFE, and 51.8 ± 34.7 (12–179) μs with MNPE. Both electrodes identified junction dysfunction in 14 patients. RNS revealed decrement in four patients but 11. Conclusion:  SFEMG with SFE is still the gold standard; however, SFEMG with MNPE is superior to RNS like SFEMG with SFE.