Correlation between compound muscle action potential amplitude and duration in axonal and demyelinating polyneuropathy.

To get a better understanding of pathophysiology in polyneuropathies (PNPs) by correlating compound muscle action potential (CMAP) amplitude with duration. A total of 145 motor nerve conduction studies (MNCS) in 53 axonal and 132 MNCS in 45 demyelinating PNPs were analyzed. Peroneal and tibial MNCS were done by surface stimulation while for median and ulnar nerves near nerve or surface stimulations were used. CMAP amplitude and duration were compared in axonal and demyelination PNPs. Relationships between amplitude and duration of distally and proximally evoked CMAP were examined using regression analysis. CMAP amplitude was lower and duration was increased in all examined nerves in demyelinating PNPs than in axonal PNPs. In demyelinating PNPs, an inverse linear correlation between amplitude and duration was seen in distally and proximally evoked CMAP in all examined nerves. In axonal PNPs, there was no correlation in any of the nerves neither in distally nor in proximally evoked CMAP. Distal CMAP duration and the relationship between CMAP amplitude and duration show supplementary electrodiagnostic potential in demyelinating PNPs. More knowledge about the relation between amplitude and duration in axonal lesions and demyelination may help to reveal the pathophysiology in PNPs. Significant correlation between amplitude and duration in demyelination may suggest that the severe decrease in amplitude in demyelinating PNPs is probably due to the increase in duration secondary to temporal dispersion. Copyright © 2012 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Citation

Hatice Tankisi, Marit Otto, Kirsten Pugdahl, Birger Johnsen, Anders Fuglsang-Frederiksen. Correlation between compound muscle action potential amplitude and duration in axonal and demyelinating polyneuropathy. Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology. 2012 Oct;123(10):2099-105

Mesh Tags

PMID: 22560637

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