scholarly journals Characterization of Volitional Electromyographic Signals in the Lower Extremity After Motor Complete Spinal Cord Injury

2017 ◽  
Vol 31 (6) ◽  
pp. 583-591 ◽  
Author(s):  
Elizabeth Heald ◽  
Ronald Hart ◽  
Kevin Kilgore ◽  
P. Hunter Peckham
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Lower Extremity ◽  
Visual Inspection ◽  
Surface Emg ◽  
Emg Activity ◽  
Automatic Identification ◽  
Emg Signal ◽  
Cord Injury ◽  
Complete Spinal Cord Injury

Background. Previous studies have demonstrated the presence of intact axons across a spinal cord lesion, even in those clinically diagnosed with complete spinal cord injury (SCI). These axons may allow volitional motor signals to be transmitted through the injury, even in the absence of visible muscle contraction. Objective. To demonstrate the presence of volitional electromyographic (EMG) activity below the lesion in motor complete SCI and to characterize this activity to determine its value for potential use as a neuroprosthetic command source. Methods. Twenty-four subjects with complete (AIS A or B), chronic, cervical SCI were tested for the presence of volitional below-injury EMG activity. Surface electrodes recorded from 8 to 12 locations of each lower limb, while participants were asked to attempt specific movements of the lower extremity in response to visual and audio cues. EMG trials were ranked through visual inspection, and were scored using an amplitude threshold algorithm to identify channels of interest with volitional motor unit activity. Results. Significant below-injury muscle activity was identified through visual inspection in 16 of 24 participants, and visual inspection rankings were well correlated to the algorithm scoring. Conclusions. The surface EMG protocol utilized here is relatively simple and noninvasive, ideal for a clinical screening tool. The majority of subjects tested were able to produce a volitional EMG signal below their injury level, and the algorithm developed allows automatic identification of signals of interest. The presence of this volitional activity in the lower extremity could provide an innovative new command signal source for implanted neuroprostheses or other assistive technology.

Quantitative and sensitive assessment of neurophysiological status after human spinal cord injury

2012 ◽  
Vol 17 (Suppl1) ◽  
pp. 77-86 ◽  
Author(s):  
Kun Li ◽  
Darryn Atkinson ◽  
Maxwell Boakye ◽  
Carie Z. Tolfo ◽  
Sevda Aslan ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Motor Function ◽  
Surface Emg ◽  
Emg Activity ◽  
Motor Score ◽  
Emg Signal ◽  
Cord Injury ◽  
Kendall Correlation ◽  
Lesion Severity

Object This study was designed to develop an objective and sensitive spinal cord injury (SCI) characterization protocol based on surface electromyography (EMG) activity. Methods Twenty-four patients at both acute and chronic time points post-SCI, as well as 4 noninjured volunteers, were assessed using neurophysiological and clinical measures of volitional motor function. The EMG amplitude was recorded from 15 representative muscles bilaterally during standardized maneuvers as a neurophysiological assessment of voluntary motor function. International Standards for the Neurological Classification of Spinal Cord Injury (ISNCSCI) examinations were performed as a clinical assessment of lesion severity. Results Sixty-six functional neurophysiological assessments were performed in 24 patients with SCI and in 4 neurologically intact individuals. The collected EMG data were organized by quantitative parameters and statistically analyzed. The correlation between root mean square (RMS) of the EMG signals and ISNCSCI motor score was confirmed by Kendall correlation analysis. The Kendall correlation value between overall muscles/levels, motor scores, and the RMS of the EMG data is 0.85, with the 95% CI falling into the range of 0.76–0.95. Significant correlations were also observed for the soleus (0.51 [0.28–0.74]), tibialis anterior (TA) (0.53 [0.33–0.73]), tricep (0.52, [0.34–0.70]), and extensor carpi radialis (ECR) (0.80 [0.42–1.00]) muscles. Comparisons of RMS EMG values in groups defined by ISNCSCI motor score further confirmed these results. At the bicep and ECR, patients with motor scores of 5 had nearly significantly higher RMS EMG values than patients with motor scores of 0 (p = 0.059 and 0.052, respectively). At the soleus and TA, the RMS of the EMG value was significantly higher (p < 0.01) for patients with American Spinal Injury Association Impairment Scale motor scores of 5 than for those with ISNCSCI motor scores of 0. Those with C-7 ISNCSCI motor scores of 5 had significantly higher RMS EMG values at the tricep than those with motor scores of 4 (p = 0.008) and 0 (p = 0.02). Results also show that surface EMG signals recorded from trunk muscles allowed the examiner to pick up subclinical changes, even though no ISNCSCI scores were given. Conclusions Surface EMG signal is suitable for objective neurological SCI characterization protocol design. The quantifiable features of surface EMG may increase SCI characterization resolution by adding subclinical details to the clinical picture of lesion severity and distribution.

EFFECT OF LOWER EXTREMITY EXOSKELETON ROBOT IMPROVING WALKING FUNCTION AND ACTIVITY IN PATIENTS WITH COMPLETE SPINAL CORD INJURY

2019 ◽  
Vol 19 (08) ◽  
pp. 1940060
Author(s):  
XINGANG BAI ◽  
XIANG GOU ◽  
WENCHUN WANG ◽  
CHAO DONG ◽  
FANGXU QUE ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Adverse Events ◽  
Lower Extremity ◽  
Controlled Trial ◽  
Walking Ability ◽  
Walk Test ◽  
Exoskeleton Robot ◽  
Cord Injury ◽  
Complete Spinal Cord Injury

The objective of this research was to evaluate the effectiveness and safety of Lower Extremity Exoskeleton Robot improving walking function and activity in patients with complete spinal cord injury. A prospective, open and self-controlled trial was conducted which include eight patients with complete spinal cord injury accepted Lower Extremity Exoskeleton Robot training with Aider 1.0 and Aider 1.1 for 2 weeks. The 6[Formula: see text]min Walk Test (6MWT), 10[Formula: see text]m Walk Test (10 MWT), Hoffer walking ability rating, Lower Extremity Motor Score (LEMS), Spinal Cord Independence Motor (SCIM), Walking Index for Spinal Cord Injury Version II (WISCI II) were recorded before, 1 week and 2 weeks after training. During the training, the incidence of adverse events (AE), the incidence of serious adverse events (SAE), the incidence of device defects and other safety indicators were observed. Compared with the pre-training, indicators (6MWT, 10MWT, Hoffer walking ability rating, WISCI II) were significantly different after 1 week of training and after 2 weeks of training. Four adverse events occurred during the training period and the incidence of adverse events was 50%. And there was no SAE or device defects. Therefore, it is safe and effective to use the lower extremity exoskeleton robot to complete the walking ability of patients with complete spinal cord injury.

Lower extremity robotic exoskeleton training: Case studies for complete spinal cord injury walking

2017 ◽  
Vol 41 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Edward D. Lemaire ◽  
Andrew J. Smith ◽  
Andrew Herbert-Copley ◽  
Vidya Sreenivasan
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Lower Extremity ◽  
Case Studies ◽  
Robotic Exoskeleton ◽  
Cord Injury ◽  
Complete Spinal Cord Injury ◽  
Training Case

scholarly journals Intraspinal microstimulation and diaphragm activation after cervical spinal cord injury

2017 ◽  
Vol 117 (2) ◽  
pp. 767-776 ◽  
Author(s):  
L. M. Mercier ◽  
E. J. Gonzalez-Rothi ◽  
K. A. Streeter ◽  
S. S. Posgai ◽  
A. S. Poirier ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Cervical Spinal Cord ◽  
Emg Activity ◽  
Motor Nucleus ◽  
Adult Rats ◽  
Intraspinal Microstimulation ◽  
Emg Signal ◽  
Cord Injury ◽  
Diaphragm Activity

Intraspinal microstimulation (ISMS) using implanted electrodes can evoke locomotor movements after spinal cord injury (SCI) but has not been explored in the context of respiratory motor output. An advantage over epidural and direct muscle stimulation is the potential of ISMS to selectively stimulate components of the spinal respiratory network. The present study tested the hypothesis that medullary respiratory activity could be used to trigger midcervical ISMS and diaphragm motor unit activation in rats with cervical SCI. Studies were conducted after acute (hours) and subacute (5–21 days) C2 hemisection (C2Hx) injury in adult rats. Inspiratory bursting in the genioglossus (tongue) muscle was used to trigger a 250-ms train stimulus (100 Hz, 100–200 μA) to the ventral C4 spinal cord, targeting the phrenic motor nucleus. After both acute and subacute injury, genioglossus EMG activity effectively triggered ISMS and activated diaphragm motor units during the inspiratory phase. The ISMS paradigm also evoked short-term potentiation of spontaneous inspiratory activity in the previously paralyzed hemidiaphragm (i.e., bursting persisting beyond the stimulus period) in ∼70% of the C2Hx animals. We conclude that medullary inspiratory output can be used to trigger cervical ISMS and diaphragm activity after SCI. Further refinement of this method may enable “closed-loop-like” ISMS approaches to sustain ventilation after severe SCI. NEW & NOTEWORTHY We examined the feasibility of using intraspinal microstimulation (ISMS) of the cervical spinal cord to evoke diaphragm activity ipsilateral to acute and subacute hemisection of the upper cervical spinal cord of the rat. This proof-of-concept study demonstrated the efficacy of diaphragm activation, using an upper airway respiratory EMG signal to trigger ISMS at the level of the ipsilesional phrenic nucleus during acute and advanced postinjury intervals.

scholarly journals Predictors of volitional motor recovery with epidural stimulation in individuals with chronic spinal cord injury

Brain ◽  
2020 ◽  
Author(s):  
Samineh Mesbah ◽  
Tyler Ball ◽  
Claudia Angeli ◽  
Enrico Rejc ◽  
Nicholas Dietz ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Lower Extremity ◽  
Lower Limb ◽  
Motor Recovery ◽  
Cervical Cord ◽  
Voluntary Movements ◽  
Epidural Stimulation ◽  
Cord Injury ◽  
Complete Spinal Cord Injury

Abstract Spinal cord epidural stimulation (scES) has enabled volitional lower extremity movements in individuals with chronic and clinically motor complete spinal cord injury and no clinically detectable brain influence. The aim of this study was to understand whether the individuals’ neuroanatomical characteristics or positioning of the scES electrode were important factors influencing the extent of initial recovery of lower limb voluntary movements in those with clinically motor complete paralysis. We hypothesized that there would be significant correlations between the number of joints moved during attempts with scES prior to any training interventions and the amount of cervical cord atrophy above the injury, length of post-traumatic myelomalacia and the amount of volume coverage of lumbosacral enlargement by the stimulation electrode array. The clinical and imaging records of 20 individuals with chronic and clinically motor complete spinal cord injury who underwent scES implantation were reviewed and analysed using MRI and X-ray integration, image segmentation and spinal cord volumetric reconstruction techniques. All individuals that participated in the scES study (n = 20) achieved, to some extent, lower extremity voluntary movements post scES implant and prior to any locomotor, voluntary movement or cardiovascular training. The correlation results showed that neither the cross-section area of spinal cord at C3 (n = 19, r = 0.33, P = 0.16) nor the length of severe myelomalacia (n = 18, r = −0.02, P = 0.93) correlated significantly with volitional lower limb movement ability. However, there was a significant, moderate correlation (n = 20, r = 0.59, P = 0.006) between the estimated percentage of the lumbosacral enlargement coverage by the paddle electrode as well as the position of the paddle relative to the maximal lumbosacral enlargement and the conus tip (n = 20, r = 0.50, P = 0.026) with the number of joints moved volitionally. These results suggest that greater coverage of the lumbosacral enlargement by scES may improve motor recovery prior to any training, possibly because of direct modulatory effects on the spinal networks that control lower extremity movements indicating the significant role of motor control at the level of the spinal cord.

scholarly journals Neurophysiological markers predicting recovery of standing in humans with chronic motor complete spinal cord injury

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Samineh Mesbah ◽  
Federica Gonnelli ◽  
Claudia A. Angeli ◽  
Ayman El-baz ◽  
Susan J. Harkema ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Total Power ◽  
Emg Activity ◽  
Median Frequency ◽  
Epidural Stimulation ◽  
Cord Injury ◽  
Lower Variability ◽  
Complete Spinal Cord Injury ◽  
Selection Of

Abstract The appropriate selection of individual-specific spinal cord epidural stimulation (scES) parameters is crucial to re-enable independent standing with self-assistance for balance in individuals with chronic, motor complete spinal cord injury, which is a key achievement toward the recovery of functional mobility. To date, there are no available algorithms that contribute to the selection of scES parameters for facilitating standing in this population. Here, we introduce a novel framework for EMG data processing that implements spectral analysis by continuous wavelet transform and machine learning methods for characterizing epidural stimulation-promoted EMG activity resulting in independent standing. Analysis of standing data collected from eleven motor complete research participants revealed that independent standing was promoted by EMG activity characterized by lower median frequency, lower variability of median frequency, lower variability of activation pattern, lower variability of instantaneous maximum power, and higher total power. Additionally, the high classification accuracy of assisted and independent standing allowed the development of a prediction algorithm that can provide feedback on the effectiveness of muscle-specific activation for standing promoted by the tested scES parameters. This framework can support researchers and clinicians during the process of selection of epidural stimulation parameters for standing motor rehabilitation.

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