Determining the Optimal Position of Surface Electrodes for Diaphragm Electromyography: A Cross-Sectional Study

TL;DR

This study identifies the best electrode placement for measuring diaphragm muscle activity using surface electromyography.

Contribution

The study empirically determines the optimal electrode positions for maximum signal amplitude and shortest duration in diaphragm EMG.

Findings

Electrodes placed 5 cm superior to the xiphoid process and 16 cm away on the sixth intercostal space provided maximum amplitude and shortest duration.

The position on the sixth intercostal space had a mean amplitude of 232.35 and duration of 7.316 milliseconds.

This placement outperformed positions on the seventh and eighth intercostal spaces in signal quality.

Abstract

Background: Placing electrodes on different aspects of the chest determines the motor firing from the diaphragm. The electrode placement close to the extent of the muscle gave promising readings as compared to the ones that were placed away. The position with the maximum amplitude and least duration was chosen. Positions of the electrodes were decided as per the extent of the muscle. The aim is to determine the appropriate position of surface electrodes for surface diaphragm electromyography (EMG).

Material and methodology: Thirty healthy individuals of age ranging from 21 to 45 years were included in the study. Participants were made to lie down in a supine position and different positions like G1 (recording electrode) 5 cm superior to the tip of the xiphoid process and G2 (reference) 16 cm along the costal margin from G1, G1 over the xiphoid tip and G2 at the seventh intercostal space at the costochondral junction and G1 over the xiphoid tip and G2 at the eight intercostal space at the costochondral junction were used for assessing maximum amplitudes and durations were observed by using a Octopus New Wave EMG machine (Octopus Medical Technologies, Vadodara, IND). After observing all the positions, an optimum position for maximum amplitude and least duration was analyzed.

Results: As per the study, out of the four positions, the electrode placements on the tip of the xiphoid process and 16 cm away diagonally on the sixth intercostal space showed maximum amplitude and the least duration with maximum mean amplitude and less mean duration of 232.35 and 7.316. On the seventh intercostal space it was 199.15 and 7.887 and on the eighth intercostal space was 176.055 and 8.639. The tip of the xiphoid process and 16 cm away diagonally on the sixth intercostal space is chosen as the appropriate position for electrode placement for EMG of the diaphragm.

Conclusion: We conclude that the best electrode position was when the electrodes were placed 5 cm superior to the xiphoid process, i.e., G1, and 16 cm away from the recording electrode on the costochondral junction, i.e., G2, at the sixth intercostal space. Ground electrode placement is the nearest bony prominence, i.e., xiphisternum.

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