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1.3 PHYSICAL SCIENCES
Several experiments were designed and carried out in order to compare the performances of five commercially available EMG surface electrodes. The aim was to identify the optimal surface recording electrode from the samples examined. The particular interest was to assess the comparative performance of the electrodes routinely used in our hospital Neurophysiology laboratory. It is envisaged that the conclusions from the study might be applied to improve the quality and reproducibility of nerve conduction techniques use din our department. A literature survey was carried out to identify some of the factors that influence the recording of evoked potentials from peripheral nerve and muscle. CMAP amplitude was used as a means of comparing the electrode performance. Conclusions were drawn fro the experimental results regarding which electrode performed best overall with respect to quality of signal, convenience of application and general ease of use. Results showed that there was no statistically significant difference in the size of CMAP amplitude provided the electrodes were used in a comparative fashion. It was possible to get bigger amplitudes from the variable cathode-anode distance electrodes if the anode was on tendon and not on muscle. However, it was found to be more convenient to search for the largest size amplitude signals with the fixed 2.3 cm anode-cathode distance bipolar pad electrode. Conclusion This project indicates that for the routine nerve conduction studies carried out in our department, the re-usable bipolar round electrode is the preferred option. Its fixed cathode-anode distance is an advantage in repeat studies. Ideally, temperature should be routinely measured and recorded in NCSs and electrode placement should be applied according to know anatomical correlates. A search should be attempted by moving the cathode subtly on the muscle to achieve optimum placement for maximum CMAP amplitude. As an alternative, the disposable pre-gelled stick-on electrode is a favourable option for neuromuscular junction testing.
Augustine, J. (2006). An investigation of the effect of variation in surface electrode type and placement on action potentials elicited by peripheral nerve simulation. Masters dissertation. Technological University Dublin. doi:10.21427/D7HW3Z