Reliability of the diaphragmatic compound muscle action potential evoked by cervical magnetic stimulation and recorded via chest wall surface EMG

• Published in: Respiratory physiology & neurobiology Vol. 243; pp. 101 - 106
• Main Authors: Welch, Joseph F., Mildren, Robyn L., Zaback, Martin, Archiza, Bruno, Allen, Grayson P., Sheel, A.William
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.09.2017
• Subjects: Adult; Analysis of Variance; Biophysics; Cervical magnetic stimulation; Compound muscle action potential; Diaphragm; Diaphragm - physiology; Electric Stimulation; Electromyography; Evoked Potentials, Motor - physiology; Female; Functional Laterality; Humans; Magnetics - methods; Male; Medical Education; Neural Conduction - physiology; Phrenic nerve; Pulmonary/Respiratory; Reaction Time - physiology; Reliability; Reproducibility of Results; Sex Characteristics; Thoracic Wall - cytology; Thoracic Wall - physiology; Young Adult; CMAP; CMS; ICC; LHD; RHD; Cervical magnetic stimulation; CV; Phrenic nerve; ANOVA; Compound muscle action potential; Diaphragm; Reliability; EMG; Intraclass correlation coefficient; Right hemi-diaphragm; Coefficient of variation; Left hemi-diaphragm; Electromyography; Analysis of variance
• ISSN: 1569-9048; 1878-1519; 1878-1519
• DOI: 10.1016/j.resp.2017.05.011

•Diaphragm CMAPs may be reliably evoked within and across testing sessions conducted on different days.•Cervical magnetic stimulation combined with chest wall surface EMG provides an effective means of evaluating phrenic nerve conduction in healthy young subjects.•Maximal phrenic nerve stimulation can be achieved in the majority of subjects using cervical magnetic stimulation. Stimulation of the phrenic nerve via cervical magnetic stimulation (CMS) elicits a compound muscle action potential (CMAP) that allows for assessment of diaphragm activation. The reliability of CMS to evoke the CMAP recorded by chest wall surface EMG has yet to be comprehensively examined. CMS was performed on healthy young males (n=10) and females (n=10). Surface EMG electrodes were placed on the right and left hemi-diaphragm between the 6–8th intercostal spaces. CMAPs were analysed for: latency, duration, peak-to-peak amplitude, and area. Reliability within and between experimental sessions was assessed using intraclass correlation coefficients (ICC). Bilateral (right-left) and sex-based (male-female) comparisons were also made (independent samples t-test). All CMAP characteristics demonstrated high reproducibility within (ICCs>0.96) and between (ICCs>0.89) experimental sessions. No statistically significant bilateral or sex-based differences were found (p>0.05). CMS is a reliable and non-invasive method to evaluate phrenic nerve conduction.