View Full Version : EMG and electric stimulation - summary

06-19-2008, 08:17 PM
Dear Biomec-L subscriber:

A summary of the answers sent for the subject about "EMG and electric
stimulation" is below.

Thank you very much for:
- Young-Hui Chang
- Vera Talis
- Edmund Cramp
- Duncan Wood
- Anand Pandyan
- Paul Taylor
- Colleen Monaghan
- Kevin Kelleher - kevin.kelleher@strath.ac.uk
- Wayne Piekarski - Piekarski@worldviz.com

Best regards,

Wagner de Godoy
Gait Analysis Laboratory
AACD - Brazil


Original question:

I would like to know if to use an electric stimulation devices (FES and
Russian current) and to acquire EMG signals simultaneously is possible.
- is it possible to filter the interference of stimulation device?
- does some rehabilitation center develop researches with this configuration
of equipments?



I do not believe that there would be a safety issue but, as with any new
procedure, I would start with a pilot test on a normal volunteer.

Assuming that the frequency used by the Russian Current device is in the
2.5kHz range then the EMG system should be able to filter it out - unless
the Russian Current signal is large enough to interfere with the common mode
circuitry in the preamplifier. This means that the Russian Current applied
to the preamplifier inputs would need to be less than 4V ... higher levels
will not damage the preamplifier but would interfere with the CMRR circuitry
and cause interference - this interference would be impossible to filter

Edmund Cramp


We tried to collect EMG during FES, but because of many cross-talks the EMG
signal was corrupted.

Vera Talis


It depends if you want to close the loop and use the recorded EMG to drive
the FES or if you want to only record EMG and filter the data off-line.

Filtering off-line to measure voluntary activity is a simpler problem
(relatively speaking). We recently published a short technical letter on how
to do this using an optimum eigen filter (let me know if you want a
reprint): Yeom HJ, Park YC, and Chang YH. Eigen filter to detect volitional
EMG signals in autogenic EMG-controlled FES. Electronics Letters 43(25):
1410-1411, 2007.

A real-time, closed loop system is much harder, particularly with surface
EMG recording and stim. A common method to cancel the primary stim artifact
is to use a blanking circuit during the time of
stimulation (i.e., don't record when stim is on). However, this still leaves
residual stim artifacts along with the muscle response to the stim (M-wave),
which can cause problematic false negatives due to poor SNR.

A postdoc in my lab (Hojun Yeom) has developed a real-time closed loop
system for surface electrode FES using blanking circuits and an adaptive
filter that works reliably in real-time. We are currently
writing these results up, but he published the original concept paper back
in 2005 (Yeom et al. Gram-Schmidt M-Wave cancellor for EMG controlled FES.
IEICE Trans. Inf. & Syst. E88-D(9): 2213-2217).

A few groups have combined blanking circuits with comb filters with some
success. But, comb filters are finite impulse response (FIR) filters and
assume the artifacts to be deterministic signals, which
we have found to be more problematic compared to the adaptive filter

Young-Hui Chang


Quick note
take a trigger fro FES and only colllect EMG when FES is off - I think TMSi
and/or Delsys can do this

Anand Pandyan


What stimulation parameters will you use?

I used a 50Hz burst of 15 pulses from a stimulator made in our university
department (University of Twente). Then measured EMG with a TMI
International PortiLab EMG device. As you know, the stimulation will
generate stimulation artefact in your EMG signal, there is a paper on
stimulation artefact removal by O'Keefe et al. We made a Matlab file based
on their algorithm. Check out our article "Interaction of Artificial and
Physiological Activation of the Gastrocnemius During Gait. Monaghan, Colleen
C.; Hermens, Hermie J.; Nene, Anand V.; Tenniglo, Martin J. B.; Veltink,
Peter H. Neuromodulation, Volume 11, Number 2, April 2008 , pp. 135-142(8)".
This paper has details of the EMG equipment we used as well as containing
the reference of the paper for stimulus artefact removal and how we did it.
Hope this is useful.

Colleen Monaghan


It is possible to detect EMG while using electrical stimulation but
generally requires some method of blanking and filtering. Please find below
a reference list which was completed in 2004.

6. Kraft GH, Fitts SS and Hammond, MC. Techniques to improve function of
the arm and hand in chronic hemiplegia. Arch. Phys. Med. Rehabil. 1992; 73:

7. G Francisco, J Chae H Chawla, S Kirshblum, R Zorowitz, G Lewis and S
Pang. Electromyogram-triggerred neuromuscular stimulation for improving the
arm function of acute stroke survivors: a randomised pilot study. Arch Phys
Med Rehabil 1998.Vol. 79

8. J Heckmann, T Mokrusch, A Krockel, S Warnke, T von Stockert and B
Neundorfer. EMG-triggered electrical muscle stimulation in the treatment of
central hemiparesis after stroke. Eur j phys med rehabil 1997; 7 No 5

12. HJ Hollander, M Huber, G Vossius. An EMG controlled multichannel
stimulator. Advances in external control of human extremities IX Ed. Dejan
Popovic. Belgrade 1987 pp 291 - 295

13. J. Minzly, J. Mizrahi, N. Hakim, A. Liberson. Stimulation artefact
suppression for EMG recording during FES by a constant-current stimulator.
Med. & Biol. Eng. & Comput., 1993 31, 72-75

14. Timothy RD Scott, Kevin L Kilgore, and P Hunter Peckham. Assessment of
tri-state myoelectric control for bilateral upper extremity neuroprostheses.
Proc. 5th Vienna international Workshop on Functional Electrical
Stimulation. Aug 17-19 1995 ISBN 3-900928-03-7 p 343 - 346

15. S Saxena, S Nikolic, D Popovic An EMG-controlled grasping system for
tetraplegics. J.Rehabil Res & Dev Vol.32 No.1 1995

16. Thoresen R, Ferrarin R, Spadone R, Frigo C. An approach using Wrist
extension as control of FES for restoration of hand function in
tetraplegics. Proc. 6th Vienna international Workshop on Functional
Electrical Stimulation. Sep 22-24 1998 ISBN 3-900928-04-5 p 263 - 266

17. S Sennels, F Biering-Sorensen, OT Andersen and SD Hansen. Functional
neuromuscular stimulation controlled by surface elctromyographic signals
produced by volitional activation of the same
muscle: adaptive removal of the muscle response from recorded EMG signal.
IEEE Trans Rehabil Eng Vol 5 No 2 June 1997

19. Muraoka Y, Miyajima S, Tomita Y, Hona S, Tanaka N, Okajima Y.
EMG-Controlled hand opening for hemiplegia. Proc. 6th Vienna international
Workshop on Functional Electrical Stimulation. Sep 22-24
1998 ISBN 3-900928-04-5 p 255-258.

20. Rakos M, Freudenschub B, Grirsch W, Hofer C, Kaus J, Meiners T,
Paternostro T, Mayr W. EMG controlled FES treatment of the paralysed upper
extremity. Proc. 6th Vienna international Workshop on Functional Electrical
Stimulation. Sep 22-24 1998 ISBN 3-900928-04-5 p 259 - 262

21. Tepavac D, Medri E. Programmable functional electrical stimulator with
EMG feedback. Proc. 6th Vienna international Workshop on Functional
Electrical Stimulation. Sep 22-24 1998 ISBN 3-900928-04-5 p 267 - 270

22. Kimberley TJ, Lewis SM, Auerbach EJ, Dorsey LL, Lojovich JM, Carey JR.
Electrical stimulation driving functional improvements and cortical changes
in subjects with stroke. Exp Brain Res. 2004

23. Cauraugh J. Light K, Kim S. Thigpen M, BehramA. Chronic motor
dysfunction after stroke: recovering wrist and finger extension by
electromyography triggered neuromuscular stimulation. Stroke. 2000

29. Thoresen R, Spadne R, Ferrarin M. A pilot study of myolectrically
controlled FES of upper extremity. IEEE Trans Neural Syst Rehabil Eng. 2001

30. Thoresen R, Occhi E, Brccardi S, Ferrarin M. Tenonesis grip augmented by
EMG controlled FES. 9th IFESS conference, Bournemouth Sept. 2004. Accepted
for publication.

31. Muraoka Y. Development of an EMG recording device from stimulation
electrodes for functional electrical stimulation. Front Med Biol Eng.

32. Rakos M, Freudenschuss B, Girsch W, Hofer C, Kaus J, Meiners T,
Peternostro T, Mayr W. Electromyogram-controlled functional electrical
stimulation for treatment of the paralysed upper extremity. Artif Organs.
1999 May;23(5): 466-9

33. Popovic MB, Popovi DB, Sinkjaer T, Stefanovic A, Schwirtlich L.
Restoration of reaching and grasping promoted by functional electrical
therapy. Artif Organs. 2002 Mar;26(3):271-5

34. Chae J, Bethoux F, Bohine T, Dobos L, Davis T, Friedl A. Neuromuscular
Stimulation for Upper Extremity Motor and Functional Recovery in Acute
Hemiplegia. Stroke. 1998; 29:975-979.

36. Chae J, Fang ZP, Walker M Purmehdi S. Intramuscular elecromyographicaly
controlled neuromuscular electrical stimulation for upper limb recovery in
chronic hemiplegia. Am J Phys Rehabi 2001;80:935-941

37. Van Overeem Hansen G. EMG controlled Functional Electrical Stimulation
of the paretic hand Scand J. Rehab Med 1979.11:189-193

38. Taylor P, Chappell P. Variation in system gain when using voluntary EMG
to control electrical stimulation of the same muscle. 9th Annual Conference
of the International FES Society and 2nd
FESnet Conference, (ISBN 1-85899-191-9), pp. 126-128, Bournemouth, UK,
September 2004.

Paul Taylor

Duncan Wood