Spinal Cord Injury Subjects Research Articles

A Randomized Case-Control Study on High-Frequency Chest Wall Oscillator Versus Conventional Chest Physical Therapy in Spinal Cord Injury Subjects

Study Design: This study is a randomized case-control trial. Setting: Indian Spinal Injuries Centre, Vasant Kunj, New Delhi, India. Background: Spinal cord injury (SCI) often results in severe respiratory dysfunction, leading to increased morbidity and mortality. Respiratory complications, including atelectasis and pneumonia, are prevalent and exacerbated by compromised lung function and ineffective cough. CCPT poses risks like hypoxemia and arrhythmias. HFCWO has emerged as a promising alternative, facilitating airway clearance and improving lung function without manual intervention. Despite its efficacy in other conditions, its specific benefits in SCI require further study. Objective: To study the effect of High-Frequency Chest Wall Oscillator versus Conventional Chest Physical Therapy in candidates with Spinal Cord Injury. Methodology: A sample of 78 SCI patients was selected, with 71 completing the study. Patients were divided into Group A (HFCWO) and Group B (CCPT). Baseline vital, clinical, and radiological parameters were recorded. Group A received HFCWO twice daily for 15 minutes over 5 days, while Group B received CCPT that included positioning, percussions on the affected lobe, and mechanical vibration for 5 days as indicated. Suctioning was performed post-intervention in both groups. Parameters were re-evaluated post-treatment and after 5 days by an intensivist. Results: The median (IQR) age of participants was 32 (18 to 60). Wilcoxon signed- rank test was used for intragroup analysis. The intervention group (HFCWO) had a median age of 49, and the control group (CCPT) had a median age of 22.In the HFCWO group, RR significantly decreased and SpO2 significantly increased (p<0.05) from Day 1 to Day 5. No significant changes were observed in HR and MAP. PEEP, FiO2, and ROASSCI significantly decreased (p<0.05). In the CCPT group, RR, HR, and MAP significantly increased (p<0.05), with no significant change in SpO2. PEEP and FiO2 significantly decreased, but ROASSCI did not change. Both groups showed significant improvement in Chest X-ray scores (p<0.05). Conclusion: This study compares High-Frequency Chest Wall Oscillator (HFCWO) with conventional chest physical therapy (CCPT) in spinal cord injury patients. HFCWO showed superior improvements in clinical and radiological parameters, facilitating earlier ventilator weaning. These findings suggest that HFCWO is a more effective alternative to CCPT for airway clearance in intubated SCI patients.

Harmonization of Longitudinal Diffusion Tensor Imaging Data of the Pediatric Cervical and Thoracic Spinal Cord at 3T Using Longitudinal ComBat.

Diffusion tensor imaging (DTI) of the spinal cord has been extensively used to identify biomarkers for spinal cord pathology. Previously, the longitudinal ComBat (longComBat) technique was examined to reduce scanner effects in multi-site, multi-scanner spinal cord DTI data. This study aimed to assess its effectiveness on longitudinal scans using a single-scanner pediatric dataset, including healthy and spinal cord injury (SCI) subjects. Two identical datasets were collected from 42 healthy and 27 SCI subjects with a 2-hour interval between scans on a 3T Siemens MRI scanner. Axial DTI images of the entire cervical and thoracic spinal cord were obtained, and various average diffusion tensor metrics (FA, MD, RD, & AD) were measured at each vertebral level. Pearson correlation and intraclass correlation coefficients were used to evaluate inter- and intra-subject agreement pre- and post-harmonization. Minimal improvement in agreement was observed with the mean square residual (MSR) model, while the restricted maximum likelihood estimator (REML) model showed reduced intra-subject agreement in all the tensor metrics. The significant variability between longitudinal DTI scans within a single scanner was likely due to physiological motion rather than scanner effects. Post-harmonization using the longComBat MSR model showed limited improvement in agreement.

Time-dependent reduction in oxidative capacity among cultured myotubes from spinal cord injured individuals.

Skeletal muscle adapts in reaction to contractile activity to efficiently utilize energy substrates, primarily glucose and free fatty acids (FA). Inactivity leads to atrophy and a change in energy utilization in individuals with spinal cord injury (SCI). The present study aimed to characterize possible inactivity-related differences in the energy metabolism between skeletal muscle cells cultured from satellite cells isolated 1- and 12-months post-SCI. To characterize inactivity-related disturbances in spinal cord injury, we studied skeletal muscle cells isolated from SCI subjects. Cell cultures were established from biopsy samples from musculus vastus lateralis from subjects with SCI 1 and 12 months after the injury. The myoblasts were proliferated and differentiated into myotubes before fatty acid and glucose metabolism were assessed and gene and protein expressions were measured. The results showed that glucose uptake was increased, while oleic acid oxidation was reduced at 12 months compared to 1 month. mRNA expressions of PPARGC1α, the master regulator of mitochondrial biogenesis, and MYH2, a determinant of muscle fiber type, were significantly reduced at 12 months. Proteomic analysis showed reduced expression of several mitochondrial proteins. In conclusion, skeletal muscle cells isolated from immobilized subjects 12 months compared to 1 month after SCI showed reduced fatty acid metabolism and reduced expression of mitochondrial proteins, indicating an increased loss of oxidative capacity with time after injury.

Postural effects on blood pressure, intraocular pressure, and ocular perfusion pressure in patients with spinal cord injury

Background Reduced ocular perfusion pressure (OPP) from hypotension and consistent OPP variability due to blood pressure (BP) fluctuations are predisposing factors for glaucoma. Low resting BP and orthostatic hypotension (OH) in spinal cord injury (SCI) patients may increase the risk of glaucoma post-injury. This study investigated BP, intraocular pressure (IOP), and OPP changes between supine and sitting positions in SCI and normal individuals. Methods Twenty SCI cases (high paraplegia, T1–T6 n = 6; low paraplegia, T7–L3 n = 14) and matched controls (1:1) were included. Systolic and diastolic BP (SBP and DBP) were measured digitally, and IOP with rebound tonometry. Measurements were taken one minute apart in both positions. Mean arterial pressure (MAP) was calculated, and OPP was determined using position-specific formulas. Results No SCI subjects exhibited OH. Both groups experienced significant BP increment (P < 0.05) from supine to sitting. SBP increased by 4.4 ± 8.4 mmHg (SCI) and 3.6 ± 6.2 mmHg (normal), while DBP increased by 4.2 ± 5.1 mmHg (SCI) and 6.7 ± 5.5 mmHg (normal). IOP and OPP decreased significantly (P < 0.05) after postural change in both groups, yet differences between them were not significant. Analysis by injury level revealed lower parameter values in high paraplegia than in low paraplegia, with the latter group showing a more significant reduction in OPP after postural change. Conclusion Postural changes differently affect BP, IOP, and OPP in SCI compared to normal individuals, with variations based on the level of SCI. While not directly assessing glaucoma, the study offers insights into ocular hemodynamics in SCI compared to normals.

126 Association of PAG Connectivity in SCI Subjects With Neuropathic Pain in a Resting-State FMRI Study

INTRODUCTION: Neuropathic pain (NP) is estimated to be present in 61% of subjects with chronic spinal cord injury (SCI). Periaqueductal Grey (PAG) plays a crucial role in descending pain modulation system. Few studies assessed PAG’s functional connectivity (FC) in pain syndromes, however, it has not been studied in SCI. METHODS: 10 SCI subjects with NP were divided into two groups (moderate-severe n = 7, mild-no pain n = 3), and 10 healthy controls (HC) were enrolled. Resting-state fMRI was performed for subjects using a 3T Philips Ingenia scanner with a dedicated 32 channels head coil. Seed-to-voxel analysis was performed using CONN toolbox with the PAG as the seed region. Group-based analysis was performed between three groups with age and gender as confounding variables. A voxel threshold p-value of &lt;0.05 was used, with the results corrected for multiple comparisons using fdr with a significance level of 0.05. RESULTS: Compared to HCs, SCI with NP demonstrated decreased FC between PAG and one cluster. SCI with pain compared to SCI without pain demonstrated Increased FC in one and decreased FC in two clusters. For each common anatomical region between pairwise analyses, FC alterations were compared to assess whether they are the result of SCI or NP. CONCLUSIONS: Altered FC was observed between PAG and regions involved in the pain modulation in SCI with NP compared with SCI without pain and HCs. We hypothesized that alterations between PAG and the Frontal cortex, Thalamus, Brain stem, and Cerebellum could be the result of NP sequela rather than the SCI itself. Further studies with more subjects will be needed to assess this hypothesis.

Tissue Oxygenation in Individuals with Spinal Cord Injury: A Pilot Study.

Pressure injuries (PI) are debilitating tissue lesions characterised by slow healing and a high risk of severe infection. These injuries result from continued tissue hypoxia, or low tissue oxygen saturation (StO2), which is a consequence of impaired blood circulation caused by continued pressure against tissue. PI result in significant suffering and a substantial financial burden. Therefore, we aim to develop an effective preventive measure. Persons with spinal cord injury (SCI) are at a high risk for PI due to their impaired mobility and lack of sensation to alert them to danger. The aim was to test the feasibility of an alert system based on StO2 monitoring in persons with SCI using a novel textile-based near-infrared spectroscopy (NIRS) sensor.Sensors consisted of two emission and two detection points, each point comprising eight fibres each with three light-coupling bends. Textile integration of fibres was achieved by stitching on a mass-production stitching machine. Emission fibres were connected to LEDs of 740 nm and 810 nm. Detection fibres were connected to avalanche photodiodes. Sensors were attached to the skin in the high-PI-risk buttocks area covering the bony prominences of the ischial tuberosity. StO2 was measured in three healthy subjects and two subjects with SCI during repeated sitting and pressure recovery phases.Our experiments showed decreases in StO2 in both groups during sitting phases: during low-pressure sitting phases, StO2 decreased on average -0.32%/min in the healthy subjects and at -1.24%/min in the SCI subjects. During high-pressure sitting, these rates increased to -1.16%/min for the healthy subjects and -2.16%/min for the SCI subjects. During recovery phases, StO2 returned towards normal values, but did not always reach the initial baseline. No discomfort or skin irritation was observed.These first measurements show physiologically reasonable StO2 values and demonstrate sufficient comfort while sitting on a sensor with no skin irritation or other adverse effects of sitting on the sensor for over 30 min. The nurses involved were satisfied with the easy-of-use, materials used, and patient safety demonstrated during the study. These results show that it is feasible to develop an alert system for PI prevention using a safe, wearable, textile-based NIRS sensor.

Contribution of mechanoreceptors to spinal cord injury-induced mechanical allodynia.

Evidence from previous studies supports the concept that spinal cord injury (SCI)-induced neuropathic pain (NP) has its neural roots in the peripheral nervous system. There is uncertainty about how and to which degree mechanoreceptors contribute. Sensorimotor activation-based interventions (eg, treadmill training) have been shown to reduce NP after experimental SCI, suggesting transmission of pain-alleviating signals through mechanoreceptors. The aim of the present study was to understand the contribution of mechanoreceptors with respect to mechanical allodynia in a moderate mouse contusion SCI model. After genetic ablation of tropomyosin receptor kinase B expressing mechanoreceptors before SCI, mechanical allodynia was reduced. The identical genetic ablation after SCI did not yield any change in pain behavior. Peptidergic nociceptor sprouting into lamina III/IV below injury level as a consequence of SCI was not altered by either mechanoreceptor ablation. However, skin-nerve preparations of contusion SCI mice 7 days after injury yielded hyperexcitability in nociceptors, not in mechanoreceptors, which makes a substantial direct contribution of mechanoreceptors to NP maintenance unlikely. Complementing animal data, quantitative sensory testing in human SCI subjects indicated reduced mechanical pain thresholds, whereas the mechanical detection threshold was not altered. Taken together, early mechanoreceptor ablation modulates pain behavior, most likely through indirect mechanisms. Hyperexcitable nociceptors seem to be the main drivers of SCI-induced NP. Future studies need to focus on injury-derived factors triggering early-onset nociceptor hyperexcitability, which could serve as targets for more effective therapeutic interventions.

HGF secreted by hUC-MSCs mitigates neuronal apoptosis to repair the injured spinal cord via phosphorylation of Akt/FoxO3a pathway

Spinal cord injury (SCI) can cause severe and permanent neurological damage, and neuronal apoptosis could inhibit functional recovery of damaged spinal cord greatly. Human umbilical cord mesenchymal stem cells (hUC-MSCs) have great potential to repair SCI because of a series of advantages, including inhibition of neuronal apoptosis and multiple differentiation. The former may play an important role. However, the detailed regulatory mechanism associated with the inhibition of neuronal apoptosis after hUC-MSCs administration has not been elucidated. In this study, proteomics analysis of precious human cerebrospinal fluid (CSF) samples collected from SCI subjects receiving hUC-MSCs delivery indicated that hepatocyte growth factor (HGF) is largely involved in SCI repair. Furthermore, overexpression of HGF derived from hUC-MSCs could decrease reactive oxygen species to prevent neuron apoptosis to the maximum, and thus lead to significant recovery of spinal cord dysfunction. Moreover, HGF could promote phosphorylation of Akt/FoxO3a pathway to decrease reactive oxygen species to reduce neuron apoptosis. For the first time, our research revealed that HGF secreted by hUC-MSCs inhibits neuron apoptosis by phosphorylation of Akt/FoxO3a to repair SCI. This study provides important clues associated with drug selection for the effective treatment of SCI in humans.

Sensitivity Analysis of CMAP Scan Step Index to Different Stimulation Parameters and Examination of Muscles Affected by Spinal Cord Injury.

Step index (STEPIX) is a recently developed compound muscle action potential (CMAP) scan method for evaluating motor unit loss and remodeling changes. This study investigates the influence of different stimulation parameters during CMAP scan on STEPIX and its examination of muscles affected by spinal cord injury (SCI). CMAP scan of the first dorsal interosseous (FDI) muscle was performed using different stimulus pulse widths (0.1 ms, 0.2 ms) and different numbers of stimuli (500, 1000) in 12 neurologically intact subjects. STEPIX was derived from each CMAP scan of all subjects. A significantly higher STEPIX was obtained using 1000 stimuli than 500 stimuli, while no significant difference in STEPIX was observed using 0.1 and 0.2 ms stimulus pulse widths. STEPIX was further applied to process CMAP scans of the FDI muscle from 13 tetraplegia and 13 healthy control subjects using the same stimulation parameter setting (0.1 ms, 500 stimuli), along with other methods including MScanFit motor unit number estimation (MUNE) and D50. STEPIX was significantly lower for the SCI subjects compared with the healthy control subjects. STEPIX was significantly correlated with MscanFit MUNE and D50, but had a smaller relative width of the overlapping zone (WOZ%) between tetraplegic and healthy control groups compared with MScanFit MUNE and D50. The findings of the study highlight the importance of maintaining a consistent stimulation parameter setting in CMAP scan studies and confirm the usefulness of STEPIX as a convenient CMAP scan parameter for examination of motor unit number changes.

An Introduction to the North American Clinical Trials Network for Spinal Cord Injury Special Edition: Reflections on Accomplishments and a Look to the Future.

The North American Clinical Trials Network (NACTN) has been established as a network of translational clinical research centers focused on traumatic spinal cord injury (SCI) with the goals of facilitating clinical translational research, promotion of enhanced clinical care protocols including the principle of early surgery for SCI, and improving outcomes for individuals with acute SCI. Since its foundation in 2004 by Dr. Robert Grossman, NACTN has evolved into a powerful multi-stakeholder consortium of eight neurosurgical department faculties at university-affiliated institutions in the United States and Canada, a data management center, and a pharmacological center. To date, high-quality data from more than 1000 patients have been prospectively collected, providing us with a strong body of evidence surrounding SCI epidemiology, the natural history, and complications of acute and subacute SCI management. Key accomplishments of NACTN are summarized in this Focus issue. They include the launch, in collaboration with AO Spine, of the international, multi-center, placebo-controlled, Phase III Riluzole in Acute Spinal Cord Injury Study (RISCIS) that recruited 192 patients. While the primary analyses did not achieve the predetermined endpoint of efficacy for Riluzole, likely related to insufficient power, pre-planned secondary analyses demonstrated that all subgroups of cervical SCI subjects (AIS grades A, B and C) treated with Riluzole showed significant gains in functional recovery. The Focus Issue also includes a detailed analysis of the pharmacokinetics and pharmacodynamics of riluzole in the setting of acute SCI (RISCIS-PK study). Additional achievements include key contributions to the evidence supporting the role of early surgery in acute SCI, and a better understanding of the impact of complications on the outcomes of SCI. Future directions of NACTN will build on past accomplishments and focus on enhanced collaborations with other SCI networks, advanced analytics to examine large datasets, and a greater focus on chronic SCI.

Elevated high-sensitivity cardiac troponin T serum concentration in subjects with spinal cord injury

BackgroundThe biochemical analysis of high-sensitivity cardiac troponins (hs-cTn) from peripheral blood specimens has been established as biomarker for myocardial injury. Independently of myocardial injury, increased serum hs-cTn concentrations have been described in patients with myopathies. The relevance and frequency of noncardiac hs-cTn elevations in spinal cord injury (SCI) is unknown. Our study aimed to 1) determine the frequency of increased hs-cTn concentrations of supposedly noncardiac origin above the 99th percentile (upper reference limit, URL) in an unselected SCI population and 2) compare the two protagonist analytes cTnT and cTnI with respect to these noncardiac elevations. MethodsIn this monocentric, cross-sectional study, we sampled blood from n = 30 SCI subjects without cardiac symptoms to test for hs-cTnT and hs-cTnI serum concentrations. Results18/30 (60%) of SCI subjects showed increased hs-cTnT concentrations above the URL of 14 ng/l (p < 0.001). In 4 subjects (22.2%) concentrations were >50 ng/l. Moreover, 3 of these four subjects fulfilled the 6-h troponin dynamics criterion for acute myocardial injury in serial hs-cTnT testing. In contrast, no subject demonstrated increased hs-cTnI concentrations according to the URL of 40 ng/l. 6-h troponin dynamics were also unremarkable for hs-cTnI testing. ConclusionsSCI subjects frequently have increased hs-cTnT concentrations without clinical and hs-cTnI evidence of myocardial injury. Clinicians must be aware of cTnT “skeletal muscle false-positives” in SCI, which applies to elevated baseline cTnT concentrations and troponin dynamics in serial measurements. In case of diagnostic uncertainty, simultaneous analysis of cTnI might be helpful.

157. Periodic proton nuclear magnetic resonance-based serum metabolite profiling predicts neurological recovery in acute spinal cord injury subjects

157. Periodic proton nuclear magnetic resonance-based serum metabolite profiling predicts neurological recovery in acute spinal cord injury subjects

Spinal Cord Injury Patients Exhibit Changes in Motor-Related Activity and Topographic Distribution.

Spinal Cord Injury (SCI) is a common disease that usually limits the patient's independence by affecting their motor function. SCI patients usually present neuroplasticity, which allows brain signals transmission through spread pathways. Some innovative rehabilitation therapies, such as functional electrical stimulation (FES) or Brain-computer interfaces (BCIs) jointly with motor neuroprostheses, provide hope for functional restoration. BCIs require the analysis of event-related EEG potentials (ERPs). Movement-related cortical potentials (MRCPs) and event-related desynchroni-zation and synchronization (ERD/ERS) are the most commonly studied ERPs during motor activity. ERPs of healthy subjects may vary from SCI patients. Thus, this study aimed to compare ERPs between healthy subjects and SCI patients during upper-limb movements (forearm supination and pronation, and hand open). Differences between controls and SCI patients were shown in terms of ERPs' amplitude as well as in topographic maps. Changes in amplitude were more substantial in ERD potentials than in MRCPs, while topographic maps showed better localization of all features in healthy patients. The level of SCI injury determines the patients' mobility. A comparison between complete, partial and no motor function subjects showed lower values of feature's amplitudes in the latter group.Clinical Relevance- This demonstrates the existence of significant statistical differences between healthy and SCI subjects, and might be helpful when performing SCI rehabilitation techniques such as designing BCI and neuroprostheses, or analyzing and understanding the brain plasticity process.

A Novel Analysis of CMAP Scans From Perspective of Information Theory: CMAP Distribution Index (CDIX).

The compound muscle action potential (CMAP) scan is a useful technique for examination of neuromuscular disorders. The objective of this study is to develop a novel analysis of CMAP scans from the perspective of information theory. A novel index parameter called CMAP distribution index (CDIX) was developed to characterize CMAP scan based on calculation of the information entropy. The performance of CDIX was evaluated using CMAP scan data from healthy control and spinal cord injury (SCI) subjects, and compared with D50 and MScanFit motor unit number estimation (MUNE). CDIX was significantly lower for the SCI subjects compared with the healthy control subjects (p < 0.001). A significant correlation ( R2 = 0.58, p < 0.001) was found between CDIX and MScanFit MUNE. Among all tested parameters (maximum CMAP, D50, MScanFit MUNE and CDIX), CDIX achieved the smallest relative width of the overlapping zone (WOZ%) between SCI and healthy control subjects. CDIX can be inferred as a useful index reflecting motor unit loss and muscle fiber reinnervation changes.

ICEP: An Instrumented Cycling Ergometer Platform for the Assessment of Advanced FES Strategies.

Functional electrical stimulation (FES) cycling has seen an upsurge in interest over the last decade. The present study describes the novel instrumented cycling ergometer platform designed to assess the efficiency of electrical stimulation strategies. The capabilities of the platform are showcased in an example determining the adequate stimulation patterns for reproducing a cycling movement of the paralyzed legs of a spinal cord injury (SCI) subject. Two procedures have been followed to determine the stimulation patterns: (1) using the EMG recordings of the able-bodied subject; (2) using the recordings of the forces produced by the SCI subject's stimulated muscles. the stimulation pattern derived from the SCI subject's force output was found to produce 14% more power than the EMG-derived stimulation pattern. the cycling platform proved useful for determining and assessing stimulation patterns, and it can be used to further investigate advanced stimulation strategies.

Mobile Robotic Balance Assistant (MRBA): a gait assistive and fall intervention robot for daily living

BackgroundAging degrades the balance and locomotion ability due to frailty and pathological conditions. This demands balance rehabilitation and assistive technologies that help the affected population to regain mobility, independence, and improve their quality of life. While many overground gait rehabilitation and assistive robots exist in the market, none are designed to be used at home or in community settings.MethodsA device named Mobile Robotic Balance Assistant (MRBA) is developed to address this problem. MRBA is a hybrid of a gait assistive robot and a powered wheelchair. When the user is walking around performing activities of daily living, the robot follows the person and provides support at the pelvic area in case of loss of balance. It can also be transformed into a wheelchair if the user wants to sit down or commute. To achieve instability detection, sensory data from the robot are compared with a predefined threshold; a fall is identified if the value exceeds the threshold. The experiments involve both healthy young subjects and an individual with spinal cord injury (SCI). Spatial Parametric Mapping is used to assess the effect of the robot on lower limb joint kinematics during walking. The instability detection algorithm is evaluated by calculating the sensitivity and specificity in identifying normal walking and simulated falls.ResultsWhen walking with MRBA, the healthy subjects have a lower speed, smaller step length and longer step time. The SCI subject experiences similar changes as well as a decrease in step width that indicates better stability. Both groups of subjects have reduced joint range of motion. By comparing the force sensor measurement with a calibrated threshold, the instability detection algorithm can identify more than 93% of self-induced falls with a false alarm rate of 0%.ConclusionsWhile there is still room for improvement in the robot compliance and the instability identification, the study demonstrates the first step in bringing gait assistive technologies into homes. We hope that the robot can encourage the balance-impaired population to engage in more activities of daily living to improve their quality of life. Future research includes recruiting more subjects with balance difficulty to further refine the device functionalities.

A Novel Analysis of Compound Muscle Action Potential Scan: Staircase Function Fitting and StairFit Motor Unit Number Estimation.

Compound muscle action potential (CMAP) scan provides a detailed stimulus-response curve for examination of neuromuscular disease. The objective of the study is to develop a novel CMAP scan analysis to extract motor unit number estimation (MUNE) and other physiological or diagnostic information. A staircase function was used as the basic mathematical model of the CMAP scan. An optimal staircase function fitting model was estimated for each given number of motor units, and the fitting model with the minimum number of motor units that meets a predefined error requirement was accepted. This yields MUNE as well as the spike amplitude and activation threshold of each motor unit that contributes to the CMAP scan. The significance of the staircase function fit was confirmed using simulated CMAP scans with different motor unit number (20, 50, 100 and 150) and baseline noise (1 µV, 5 µV and 10 µV) inputs, in terms of MUNE performance, repeatability, and the test-retest reliability. For experimental data, the average MUNE of the first dorsal interosseous muscle derived from the staircase function fitting was 57.5 ± 26.9 for the tested spinal cord injury subjects, which was significantly lower than 101.2 ± 16.9, derived from the control group (p < 0.001). The staircase function fitting provides an appropriate approach to CMAP scan processing, yielding MUNE and other useful parameters for examination of motor unit loss and muscle fiber reinnervation.

Electromyography-Force Relation and Muscle Fiber Conduction Velocity Affected by Spinal Cord Injury.

A surface electromyography (EMG) analysis was performed in this study to examine central neural and peripheral muscle changes after a spinal cord injury (SCI). A linear electrode array was used to record surface EMG signals from the biceps brachii (BB) in 15 SCI subjects and 14 matched healthy control subjects as they performed elbow flexor isometric contractions from 10% to 80% maximum voluntary contraction. Muscle fiber conduction velocity (MFCV) and BB EMG-force relation were examined. MFCV was found to be significantly slower in the SCI group than the control group, evident at all force levels. The BB EMG-force relation was well fit by quadratic functions in both groups. All healthy control EMG-force relations were best fit with positive quadratic coefficients. In contrast, the EMG-force relation in eight SCI subjects was best fit with negative quadratic coefficients, suggesting impaired EMG modulation at high forces. The alterations in MFCV and EMG-force relation after SCI suggest complex neuromuscular changes after SCI, including alterations in central neural drive and muscle properties.

Sample Entropy-Based Surface Electromyographic Examination With a Linear Electrode Array in Survivors With Spinal Cord Injury.

This study aimed to evaluate the utility of sample entropy (SampEn) of surface electromyographic signals (sEMG) in quantifying neuromuscular changes after spinal cord injury (SCI). Using a linear electrode array, sEMG signals were obtained from the biceps brachii muscles of 13 healthy control subjects and 13 SCI subjects during isometric elbow flexion muscle contraction at various constant force levels. The SampEn analysis was performed on both the representative channel (emerging the largest signal amplitude) and the channel over muscle innervation zone (IZ) determined by the linear array. The SampEn values were further averaged across muscle force levels to examine difference between SCI survivors and control subjects. Results showed that SampEn values after SCI had a significantly greater range than those of the control subjects at the group level. Abnormal increases or decreases in SampEn were also found after SCI at the individual subject level. In addition, a significant difference was found between the representative channel and the IZ channel. SampEn is a valuable indicator for identifying neuromuscular changes after SCI, and the effect of the IZ on the sEMG examination is particularly noteworthy. The approach presented in this study may facilitate the development of appropriate rehabilitation methods to enhance motor recovery.

Monkeys playing video games lead to a paralysed man walking

Spinal cord injury (SCI) frequently results in complete, permanent paralysis. Although it is possible to reverse the effects of incomplete paralysis, complete paralysis effects are permanent. At present, there is no cure for SCI, but engineers can bypass the spinal cord and restore the connection from the brain to the muscles through brain-machine or brain-computer interfaces (BMIs or BCIs). These experiments initially began with rodents and non-human primates (NHPs), which were trained to move cursors, joysticks or robots with their minds beginning in the 20th century. Research progressed to human clinical trials in the late 20th century. In this paper, I present the work done to train a new NHP model for behavioural experiments, how these NHPs were trained, and the neurophysiology involved in training BMI algorithms. With this knowledge, we then moved to non-invasive human clinical trials, in which 8 SCI and 6 control subjects were able to control the opening and closing of their hands with a BCI system using electroencephalographic (EEG) signals from the motor cortex. Finally, we used these algorithms with a SCI subject in an invasive human clinical trial. The subject successfully completed activities of daily living (ADLs) and was able to control an ambulatory device that enabled him to walk upright. The overall accuracy for the BMI was approximately 90% for the upper extremity task and 85% for the lower extremity task. In addition, the subject improved in performance and speed on the Jebsen Hand Function Test (JHFT) during the 20 weeks of the study. Our subject was then sent home with a mechanical glove to continue performing upper-extremity ADLs in the home environment.