Transcript Identification of innervation zone based on high-density EMG M-wave recordings in healthy and stroke subjects Sheng Li, MD, PhD Department of Physical Medicine and.

Identification of innervation zone based
on high-density EMG M-wave recordings
in healthy and stroke subjects
Sheng Li, MD, PhD
Department of Physical Medicine and Rehabilitation
University of Texas Health Science Center – Houston
Neurorehabilitation Research Laboratory
TIRR Memorial Hermann Hospital, Houston, TX
R24 Research Meeting, Chicago, 6.18-20, 2013
Introduction – Botulinum toxin injection for poststroke spasticity management
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Poststroke spasticity (PSS)-related disability is
emerging as a significant health issue for stroke
survivors. (Wissel et al. 2013)
Prevalence estimates of PSS were highly variable,
ranging from 20-40%, thus causing a significant
burden for survivors and caregivers (Zorowitz et al. 2013)
Botulinum toxin remains the first line treatment for
focal spasticity management
Wissel J, Manack A, and Brainin M. Toward an epidemiology of poststroke spasticity. Neurology 80: S13-S19, 2013.
Zorowitz RD, Gillard PJ, Brainin M. Poststroke spasticity: Sequelae and burden on stroke survivors and caregivers Neurology, 2013
80:S45-S52
Botulinum Toxin Mechanism of Action
Botulinum toxin blocks presynaptic release of Acetylcholine at the neuromuscular junction
Botulinum toxin blocks release of neurotransmitters
(Acetylcholine) from the presynaptic membrane of the
motor endplate at the neuromuscular junction.
Jahn 2006
Detection of Innervation zone using high-density
EMG recordings
Barbero M. Merletti R., Rainoldi A. (2012) Atlas of muscle innervation zones. Springer
Detection of Innervation zone using high-density
EMG recordings and M-wave
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IZ
Endplate-Targeted injection using high-density
EMG in healthy subjects
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10 U Dyspot to the endplates of EDB
10 U to contralateral side away from endplates
Measured by CMAP
Lapatki BG, van Dijk JP, van de Warrenburg BPC, and Zwarts MJ. Botulinum toxin has an increased effect when targeted toward the muscle's
endplate zone: A high-density surface EMG guided study. Clinical Neurophysiology 122: 1611, 2011.
Effectiveness decreases with distance from
Endplates: study vs. control side
Current clinical guidance is based on histological cadaver
studies: Motor points in cadavers using whole-mount actylcholinesterase (AchE) staining
Amirali A, Mu L, Gracies JM, and Simpson DM. Anatomical localization of motor endplate bands in the human biceps
brachii. Journal of clinical neuromuscular disease 9: 306-312, 2007.
Indication for botulinum toxin injection
MAS
0
1
1+
2
3
• Patients who have moderate to severe spasticity need injection;
• The goal of injection includes
• ROM, positioning, Pain management; Prevention of complications
• To improve functions: ADLs, mobility and motor control
Need to detect innervation zone for stroke patients
• Pathological changes in spastic muscles occur after stroke
• atrophy
• contracture etc.
• NO study on motor points/innervation zone for spastic muscles
• Patients with moderate to severe spasticity need injection usually have
minimum to no voluntary contraction of spastic muscles;
• Nerve stimulation is an alternative method to obtain EMG signals for
innervation zone detection (M-wave method).
Overall goal
• To develop a method based on high-density EMG Mwave recordings to identify and evaluate innervation
zone of spastic-paretic muscles in chronic stroke.
• The method could be used to improve targeting of
botulinum toxin injection to the innervation zone, thus
the efficacy of treatment.
Specific aims
• To identify and evaluate innervation zone in healthy
and stroke subjects
• To overcome technical difficulties (stimulation artifacts
during M-wave recordings)
• To optimize methods for automatic identification of
motor innervation zone
• To re-evaluate EMG-torque relations in chronic stroke
based on innervation zone analysis
IZ in healthy and stroke subjects
• Exp. Setting: as shown
• N = 11 healthy subjs.
• N = 10 hemiparetic stroke
subjects
• Both sides
• Two tasks:
• MVC
• M-wave
1 mV
Removal of stimulation artifact
10 ms
Stimulus artifact
(a)
(b)
Contaminated M wave
Reconstructed M Wave
(c)
Clean M wave
Reconstructed M-Wave
(d)
Clean M wave
Methods of IZ detection
6.77
6.72
7.91
7.89
9.32
8.19
9.90
9.70
10.87
12.27
9.46
1.61
9.37
13.64
13.44
13.90
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2
3
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Channel Index
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11
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0
10
20
30
Time (ms)
40
50
120
MNF (Hz) CORR
93
93
89
95
91
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99
108
132
113
105
104
100
100
0.97
0.99
0.99
0.99
0.99
1.00
1.00
0.99
0.99
0.98
0.48
0.75
0.99
0.99
1.00
Accuracy(%)
RMS (µV)
80
60
40
20
0
CORR
MNF
RMS
Automatic estimation method
RMS: root mean square amplitude,
MNF: mean frequency,
CORR: cross correlation
Sample trials from a healthy subject
M-wave trial
MVC trial
IZ
IZ location : 9
IZ
IZ location : 9
Sample trials from the nonimpaired side
M-wave trial
MVC trial
IZ
IZ
IZ location : 10
IZ location : 11
Sample trials from the impaired side
M-wave trial
MVC trial
IZ
IZ location : 10
IZ
IZ location : 10
Comparison of IZ in healthy subjects
Characteristics of stroke subjects
Impaired side
IZ location
(MVC)
Non-impaired side
IZ location (MStrength (in
wave)
IZ location
(MVC)
IZ location
(M-wave)
ID
Age
Gender
Paretic
MAS
Strength
(in Nm)
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57
F
right
1+
18
8
8
40
5
5
2
67
M
right
1+
25
10
8
73
8
7
3
61
M
right
0
36
12
10
31
9
10
4
89
M
left
1+
12
9
9
42
10
10
5
76
M
right
1
38
6
8
15
6
7
6
58
F
left
1
6.5
9
8
19
5
6
7
59
F
right
0
40
7
8
58
6
5
8
50
M
right
1
21
10
10
52
10
11
9
47
M
left
0
55
10
10
70
10
10
10
39
M
right
1
12
9
9
58
9
9
average
26.35
9
8.8
45.8
7.8
8
Nm)
Comparison of IZ in stroke subjects
No difference in IZ location using different
EMG methods and between two sides
10
9
8
7
6
impaired
5
non-impaired
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3
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1
0
MVC IZ
M-wave IZ
Re-evaluation of EMG-torque relations using highdensity EMG recordings
• Exp. Setting: as shown
• N = 10 hemiparetic stroke
subjects
• Both sides
• Tasks:
• MVC
• Submax at 10, 20, 30,
40, 50, 60, 70,
80%MVC
Sample EMG and torque signals
B: Impaired side
Torque (Nm) A: Non impaired side
50
40
30
20
10
0
0
EMG (µV)
800
600
400
200
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Time (sec)
0
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10
Sample EMG-Force relations in all channels
Slope
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6
4
2
0
Non impaired side
8
Impaired side
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2
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10
15
EMG Channel
20
Comparison of EMG-torque slope
Summary
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4.
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Global aver. Slope: non-impaired>impaired,
Highest slope: non-impaired>impaired
Lowest (on IZ channel): nonimpaired>impaired
consistent for all subjects
Summary
• Successful and reliable detection of IZ of biceps
in both healthy and hemiparetic stroke subjects;
• No difference in IZ location between impaired and
non-impaired sides;
• No difference in IZ detection using MVC and Mwave methods;
• Re-evaluation of EMG-torque relations using
high-density EMG
Future plan
• To develop a method based on high-density EMG Mwave recordings to identify and evaluate innervation
zone of spastic-paretic muscles in chronic stroke.
• To compare efficacy of botulinum toxin injections to
the innervation zone and using the traditional
approach, based on the M-wave method.
Project-specific publications
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Jie Liu, Sheng Li, Xiaoyan Li, Cliff Klein, William Z. Rymer, Ping Zhou (2013)
Suppression of stimulus artifact contaminating electrically evoked
electromyography. Neurorehabilitation (in press)
Jie Liu, Sheng Li, Faezeh Jahanrimi-Nezhad, William Z. Rymer, Ping Zhou
(2013) Automatic innervation zone detection of spontaneous motor units in
amyotrophic lateral sclerosis (under review)
Jie Liu, Minal Bhadane, William Z. Rymer, Ping Zhou, Sheng Li (2013)
Comparison of innervation zone based on high-density EMG and M-wave
recordings in healthy and stroke subjects (in preparation)
Minal Bhadane, Jie Liu, William Z. Rymer, Ping Zhou, Sheng Li (2013) Reevaluation of EMG-torque relations in chronic stroke using high-density EMG
recordings (in preparation)
Acknowledgement
 Zev Rymer, MD, PhD (RIC)
 R24 HD050821-08 under subcontract with Rehabilitation
Institute of Chicago
Collaborators
 Minal Bhadane PhD (UTHealth)
 Ping Zhou, PhD (RIC)
 Jie Liu, PhD (RIC)