Median averaging of electromyographic motor unit action potentials: comparison with other techniques


Journal Article

A technique of extracting individual motor unit action potentials (MUAPs) from EMG signals by median averaging, a modification of an existing method, is presented. To compare different techniques of MUAP extraction, 89 MUAPs were recorded with a concentric needle electrode in the brachial biceps muscle of normal subjects and patients with nerve and muscle diseases. MUAPs were also extracted by another method, called split-sweep median averaging, in which alternate MUAP discharges are averaged independently in two computer buffers until the two averaged signals appear equal on visual inspection by the operator. The amplitude, area, area: amplitude ratio, duration and number of phases and turns of each extracted MUAP were determined by each technique. Overall, there was a strong correlation between all features of the MUAPs extracted by median and splitsweep averaging, although the latter method required, on average, twice as many MUAP discharges to produce acceptable signals. We thus conclude that median averaging is a fast and accurate method that requires relatively few MU discharges to extract MUAP signals from spurious background signals. © 1989 IFMBE.

Full Text

Duke Authors

Cited Authors

  • Nandedkar, SD; Sanders, DB

Published Date

  • November 1, 1989

Published In

Volume / Issue

  • 27 / 6

Start / End Page

  • 566 - 571

Electronic International Standard Serial Number (EISSN)

  • 1741-0444

International Standard Serial Number (ISSN)

  • 0140-0118

Digital Object Identifier (DOI)

  • 10.1007/BF02441637

Citation Source

  • Scopus