TY - JOUR
T1 - A multiple-layer finite-element model of the surface EMG signal
AU - Lowery, Madeleine M.
AU - Stoykov, Nikolay S.
AU - Taflove, Allen
AU - Kuiken, Todd A.
N1 - Funding Information:
Manuscript received July 27, 2001; revised December 31, 2001. This work was supported in part by the Whitaker Foundation under a biomedical engineering research grant, in part by the National Institute of Child and Human Development under Grant #1K08HD01224-01A1, and in part by the National Institute of Disability and Rehabilitation Research under Grant #H133G990074-00. Asterisk indicates corresponding author. *M. M. Lowery is with the Rehabilitation Institute of Chicago and in the Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, IL 60611 USA (e-mail: [email protected]).
PY - 2002
Y1 - 2002
N2 - The effect of skin, muscle, fat, and bone tissue on simulated surface electromyographic (EMG) signals was examined using a finite-element model. The amplitude and frequency content of the surface potential were observed to increase when the outer layer of a homogeneous muscle model was replaced with highly resistive skin or fat tissue. The rate at which the surface potential decreased as the fiber was moved deeper within the muscle also increased. Similarly, the rate at which the surface potential decayed around the surface of the model, for a constant fiber depth, increased. When layers of subcutaneous fat of increasing thickness were then added to the model, EMG amplitude, frequency content, and the rate of decay of the surface EMG signal around the limb decreased, due to the increased distance between the electrodes and the active fiber. The influence of bone on the surface potential was observed to vary considerably, depending on its location. When located close to the surface of the volume conductor, the surface EMG signal between the bone and the source and directly over the bone increased, accompanied by a slight decrease on the side of the bone distal to the active fiber. The results emphasize the importance of distinguishing between the effects of material properties and the distance between source and electrode when considering the influence of subcutaneous tissue, and suggest possible distortions in the surface EMG signal in regions where a bone is located close to the skin surface.
AB - The effect of skin, muscle, fat, and bone tissue on simulated surface electromyographic (EMG) signals was examined using a finite-element model. The amplitude and frequency content of the surface potential were observed to increase when the outer layer of a homogeneous muscle model was replaced with highly resistive skin or fat tissue. The rate at which the surface potential decreased as the fiber was moved deeper within the muscle also increased. Similarly, the rate at which the surface potential decayed around the surface of the model, for a constant fiber depth, increased. When layers of subcutaneous fat of increasing thickness were then added to the model, EMG amplitude, frequency content, and the rate of decay of the surface EMG signal around the limb decreased, due to the increased distance between the electrodes and the active fiber. The influence of bone on the surface potential was observed to vary considerably, depending on its location. When located close to the surface of the volume conductor, the surface EMG signal between the bone and the source and directly over the bone increased, accompanied by a slight decrease on the side of the bone distal to the active fiber. The results emphasize the importance of distinguishing between the effects of material properties and the distance between source and electrode when considering the influence of subcutaneous tissue, and suggest possible distortions in the surface EMG signal in regions where a bone is located close to the skin surface.
KW - Finite-element analysis
KW - Mathematical model
KW - Surface EMG
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U2 - 10.1109/10.995683
DO - 10.1109/10.995683
M3 - Article
C2 - 12002176
AN - SCOPUS:0036108844
SN - 0018-9294
VL - 49
SP - 446
EP - 454
JO - IEEE Transactions on Biomedical Engineering
JF - IEEE Transactions on Biomedical Engineering
IS - 5
ER -