ID 181 – Does high-pass filtering proposed for concentric needle electrode recording affect the calculated neuromuscular jitter in myasthenia gravis?

• Published in: Clinical neurophysiology Vol. 127; no. 3; p. e89
• Main Authors: Görkem Şirin, N, Kocasoy Orhan, E, Durmuş, H, Barış Baslo, M, Deymeer, F
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2016
• Subjects: Neurology
• ISSN: 1388-2457; 1872-8952
• DOI: 10.1016/j.clinph.2015.11.298

Purpose To compare the jitter values of the potential pairs acquired with 1 kHz high-pass filtering to ones acquired with 2 kHz, during the voluntarily contraction of extensor digitorum (EDC) and frontalis (FR) muscles. Methods Patients with Myasthenia Gravis (MG) whom referred from our neuromuscular clinic between August 2014 and January 2015 were enrolled. During the voluntarily contraction of target muscle, 20 single-fiber like potentials were recorded by using 25 mm concentric needle electrode both with 1 and 2 kHz high-pass filtering. The calculated mean consecutive difference was accepted as jitter. The mean jitter values as well as the number of high jitters according to accepted criteria for each filter setting were calculated. Any significant difference was questioned. Results Mean MCD values for EDC muscle with 1 and 2 kHz high-pass filtering were 50.5 ± 34.9 μs and 52.7 ± 42.4 μs respectively and for FR muscle 83.9 ± 81.1 μs and 84.1 ± 72.3 μs respectively ( p ⩾ 0.05). The ratio of the number of abnormal jitters in EDC and FR muscles were 47.1% and 57.1% for 1 kHz, 42.6% and 61.5% for 2 kHz ( p ⩾ 0.05) respectively. Conclusion For MG patients, mean MCD values and ratio of abnormal jitters did not show any significant change while different frequencies were chosen for high-pass filtering.