Functional electrical stimulation (FES) facilitates ambulatory function after paralysis by activating the muscles of the lower extremities. Individuals with incomplete spinal cord injury (iSCI) retain partial volitional control of muscles below the level of injury, necessitating careful integration of FES with intact voluntary motor function for efficient walking. The FES-assisted stepping can be triggered automatically at a fixed rate (autotrigger), by a manual switch (switch-trigger), or by an electromyogram-based gait-event-detector (EMG-trigger). It has been postulated that EMG may be a more natural command source than manual switches, and therefore will enable better coordination of stimulated and volitional motor functions necessary during gait. In this study, the above stated hypothesis was investigated in two volunteers with iSCI during the over-ground FES-assisted gait initiation. Four able-bodied volunteers provided the normative data for comparison. The EMG-triggered FES-assisted gait initiation was found to be more coordinated and dynamically more stable than autotriggered and switch-triggered cases. This highlighted the potential of surface EMG as a natural command interface to better coordinate stimulated and volitional muscle activities during gait.

1.
Kobetic
,
R.
,
Triolo
,
R. J.
,
Uhlir
,
J. P.
,
Bieri
,
C.
,
Wibowo
,
M.
,
Polando
,
G.
,
Marsolais
,
E. B.
,
Davis
,
J. A.
, Jr.
,
Ferguson
,
K. A.
, and
Sharma
,
M.
, 1999, “
Implanted Functional Electrical Stimulation System for Mobility in Paraplegia: A Follow-Up Case Report
,”
IEEE Trans. Rehabil. Eng.
1063-6528,
7
(
4
), pp.
390
398
.
2.
Hardin
,
E.
,
Kobetic
,
R.
,
Murray
,
L.
,
Corado-Ahmed
,
M.
,
Pinnault
,
G.
,
Sakai
,
J.
,
Nogan
,
S.
,
Ho
,
C.
, and
Triolo
,
R.
, “
Ambulation After Incomplete Spinal Cord Injury With an Implanted FES System: A Case Report
,”
J. Rehabil. R. D
0742-3241,
44
(
3
), pp.
333
346
.
3.
Graupe
,
D.
,
Kohn
,
K. H.
,
Basseas
,
S.
, and
Naccarato
,
E.
, 1983, “
Patient Controlled Electrical Stimulation Via EMG Signature Discrimination for Providing Certain Paraplegics With Primitive Walking Functions
,”
J. Biomed. Eng.
0141-5425,
5
, pp.
220
226
.
4.
Triolo
,
R. J.
, and
Moskowitz
,
G. D.
, 1989, “
The Theoretical Development of a Multichannel Time-Series Myoprocessor for Simultaneous Limb Function Detection and Muscle Force Estimation
,”
IEEE Trans. Biomed. Eng.
0018-9294,
36
(
10
), pp.
1004
1017
.
5.
Graupe
,
D.
, 1989, “
EMG Pattern Analysis for Patient-Responsive Control of FES in Paraplegics for Walker-Supported Walking
,”
IEEE Trans. Biomed. Eng.
0018-9294,
36
(
7
), pp.
711
719
.
6.
Graupe
,
D.
, and
Kordylewski
,
H.
, 1995, “
Artificial Neural Network Control of FES in Paraplegics for Patient Responsive Ambulation
,”
IEEE Trans. Biomed. Eng.
0018-9294,
42
(
7
), pp.
699
707
.
7.
Kordylewski
,
H.
, and
Graupe
,
D.
, 2001, “
Control of Neuromuscular Stimulation for Ambulation by Complete Paraplegics Via Artificial Neural Networks
,”
Neurol. Res.
0160-6412,
23
(
5
), pp.
472
481
.
8.
Dutta
,
A.
,
Kobetic
,
R.
, and
Triolo
,
R. J.
, 2005, “
EMG Based Triggering and Modulation of Stimulation Patterns for FES Assisted Ambulation—A Conceptual Study
,”
20th Congress of the International Society of Biomechanics
, Cleveland, OH, Aug.
9.
Dutta
,
A.
,
Kobetic
,
R.
, and
Triolo
,
R.
, 2008, “
Ambulation After Incomplete Spinal Cord Injury With EMG-Triggered Functional Electrical Stimulation
,”
IEEE Trans. Biomed. Eng.
0018-9294,
55
, pp.
791
794
.
10.
Miller
,
C. A.
, and
Verstraete
,
M. C.
, 1996, “
Determination of the Step Duration of Gait Initiation Using Mechanical Energy Analysis
,”
J. Biomech.
0021-9290,
29
(
9
), pp.
1195
1199
.
11.
Winter
,
D. A.
,
Quantbury
,
A. O.
, and
Reimer
,
G. D.
, 1976, “
Analysis of the Instantaneous Energy of Normal Gait
,”
J. Biomech.
0021-9290,
9
, pp.
253
257
.
12.
Hurmuzlu
,
Y.
, and
Basdogan
,
C.
, 1994, “
On the Measurement of Dynamic Stability of Human Locomotion
,”
ASME J. Biomech. Eng.
0148-0731,
116
, pp.
30
36
.
13.
Hurmuzlu
,
Y.
,
Basdogan
,
C.
, and
Stoianovici
,
D.
, 1996, “
Kinematics Dynamic Stability of the Locomotion of Post-Polio Patients
,”
ASME J. Biomech. Eng.
0148-0731,
118
(
3
), pp.
405
411
.
14.
Dingwell
,
J. B.
,
Gu
,
K. H.
, and
Marin
,
L. C.
, 2007, “
The Effects of Sensory Loss and Walking Speed on the Orbital Dynamic Stability of Human Walking
,”
J. Biomech.
0021-9290,
40
, pp.
1723
1730
.
15.
Kobetic
,
R.
, and
Marsolais
,
E. B.
, 1994, “
Synthesis of Paraplegic Gait With Multichannel Functional Neuromuscular Stimulation
,”
IEEE Trans. Rehabil. Eng.
1063-6528,
2
(
2
), pp.
66
79
.
16.
Kobetic
,
R.
,
Triolo
,
R. J.
, and
Marsolais
,
E. B.
, 1997, “
Muscle Selection and Walking Performance of Multichannel FES Systems for Ambulation in Paraplegia
,”
IEEE Trans. Rehabil. Eng.
1063-6528,
5
(
1
), pp.
23
29
.
17.
Winter
,
D. A.
, 1991,
The Biomechanics and Motor Control of Human Movement
,
2nd ed.
,
Wiley
,
New York
.
18.
Angeloni
,
C.
,
Riley
,
P. O.
, and
Krebs
,
E. D.
, 1994, “
Frequency Content of Whole Body Gait Kinematic Data
,”
IEEE Trans. Rehabil. Eng.
1063-6528,
2
(
1
), pp.
40
46
.
19.
Dutta
,
A.
, and
Triolo
,
R.
, 2006, “
Stability Analysis of Functional Electrical Stimulation (FES)-Assisted Overground Gait in an Incomplete Spinal Cord Injured Subject
,”
J. Biomech.
0021-9290,
39
, p.
S113
.
20.
Johnson
,
R. A.
, and
Wichern
,
D. W.
, 2002,
Applied Multivariate Statistical Analysis
,
Prentice-Hall
,
Englewood-Cliffs, NJ
.
21.
Bianchi
,
L.
,
Angelini
,
D.
,
Orani
,
G. P.
, and
Lacquaniti
,
F.
, 1998, “
Kinematic Coordination in Human Gait: Relation to Mechanical Energy Cost
,”
J. Neurophysiol.
0022-3077,
79
(
4
), pp.
2155
2170
.
22.
Jolliffe
,
I. T.
, 1986,
Principal Component Analysis
,
Springer
,
New York
, pp.
44
48
,
269
296
.
23.
Carletti
,
T.
,
Fanelli
,
D.
, and
Guarino
,
A.
, 2006, “
A New Route to Non Invasive Diagnosis in Neurodegenerative Diseases
,”
Neurosci. Lett.
0304-3940,
394
, pp.
252
255
.
24.
Mah
,
C. D.
,
Hulliger
,
M.
,
Lee
,
R. G.
, and
O’Callaghan
,
I. S.
, 1994, “
Quantitative Analysis of Human Movement Synergies: Constructive Pattern Analysis for Gait
,”
J. Motor Behav.
0022-2895,
26
, pp.
83
102
.
25.
Friedman
,
P. J.
,
Richmond
,
D. E.
, and
Baskett
,
J. J.
, 1988, “
A Prospective Trial of Serial Gait Speed as a Measure of Rehabilitation in the Elderly
,”
Age Ageing
0002-0729,
17
(
4
), pp.
227
235
.
26.
Popovic
,
M. R.
,
Thrasher
,
T. A.
,
Adams
,
M. E.
,
Takes
,
V.
,
Zivanovic
,
V.
, and
Tonack
,
M. I.
, 2006, “
Functional Electrical Therapy: Retraining Grasping in Spinal Cord Injury
,”
Spinal Cord
1362-4393,
44
, pp.
143
151
.
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