Publication: Effect of reference electrode position on the compound muscle action potential (CMAP) onset latency
Issued Date
2002-06-11
Resource Type
ISSN
0148639X
Other identifier(s)
2-s2.0-0036263207
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Mahidol University
Rights Holder(s)
SCOPUS
Bibliographic Citation
Muscle and Nerve. Vol.25, No.6 (2002), 816-821
Suggested Citation
Gulapar Phongsamart, Jacqueline J. Wertsch, Mohammed Ferdjallah, John C. King, D. Terrence Foster Effect of reference electrode position on the compound muscle action potential (CMAP) onset latency. Muscle and Nerve. Vol.25, No.6 (2002), 816-821. doi:10.1002/mus.10119 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/20061
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Title
Effect of reference electrode position on the compound muscle action potential (CMAP) onset latency
Abstract
Compound muscle action potential (CMAP) onset latency is interpreted to reflect the arrival time at the muscle of impulses in the fastest-conducting motor nerve fiber. However, we have observed that the position of the reference or indifferent electrode (E2) affects CMAP onset latency. Motor nerve conduction studies (NCS) of the median, ulnar, and deep ulnar motor (DUM) nerves on 20 normal hands were performed using both traditional bipolar and experimental monopolar (referenced to the contralateral hand) montages. As the position of E2 was altered, the CMAP onset latency varied 0.1-0.5 ms for the median NCS, 0.1-0.3 ms for the ulnar NCS, and 0.1-1.5 ms for the DUM NCS. This study demonstrates that E2 recorded potentials are significant and vary with positioning, affecting motor onset latency. This has implications both for reference values and the physiologic interpretation of the CMAP waveform. © 2002 Wiley Periodicals, Inc.