Faculty Collaboration Database

Suppression of stimulus artifact contaminating electrically evoked electromyography. NeuroRehabilitation 2014;34(2):381-9

Date

01/15/2014

Pubmed ID

24419021

Pubmed Central ID

PMC4000584

DOI

10.3233/NRE-131045

Scopus ID

2-s2.0-84901919221 (requires institutional sign-in at Scopus site)   18 Citations

Abstract

BACKGROUND: Electrical stimulation of muscle or nerve is a very useful technique for understanding of muscle activity and its pathological changes for both diagnostic and therapeutic purposes. During electrical stimulation of a muscle, the recorded M wave is often contaminated by a stimulus artifact. The stimulus artifact must be removed for appropriate analysis and interpretation of M waves.

OBJECTIVES: The objective of this study was to develop a novel software based method to remove stimulus artifacts contaminating or superimposing with electrically evoked surface electromyography (EMG) or M wave signals.

METHODS: The multiple stage method uses a series of signal processing techniques, including highlighting and detection of stimulus artifacts using Savitzky-Golay filtering, estimation of the artifact contaminated region with Otsu thresholding, and reconstruction of such region using signal interpolation and smoothing. The developed method was tested using M wave signals recorded from biceps brachii muscles by a linear surface electrode array. To evaluate the performance, a series of semi-synthetic signals were constructed from clean M wave and stimulus artifact recordings with different degrees of overlap between them.

RESULTS: The effectiveness of the developed method was quantified by a significant increase in correlation coefficient and a significant decrease in root mean square error between the clean M wave and the reconstructed M wave, compared with those between the clean M wave and the originally contaminated signal. The validity of the developed method was also demonstrated when tested on each channel's M wave recording using a linear electrode array.

CONCLUSIONS: The developed method can suppress stimulus artifacts contaminating M wave recordings.

Author List

Liu J, Li S, Li X, Klein C, Rymer WZ, Zhou P

Author

Xiaoyan Li PhD Assistant Professor in the Neurology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Arm
Artifacts
Electric Stimulation
Electromyography
Humans
Image Processing, Computer-Assisted
Muscle Contraction
Muscle, Skeletal
Software