Partial Spinal Cord Injury Research Articles

Improvement of Functional State of Patients after Spinal Cord Injury During Epidural Electrical Stimulation: Prospective Study

the lack of convincing evidence of a therapeutic effect.
 AIM. To evaluate the effect of complex rehabilitation using EPS and activation of the proprioceptive apparatus on the indicators of the functional state of patients with long-term consequences of spinal cord injury with partial spinal cord injury.
 MATERIALS AND METHODS. A prospective study was conducted with the participation of 29 patients with long-term consequences of spinal cord injury with partial spinal cord injury. The catamnesis of the disease was 3.7 ± 0.5 years. Comprehensive rehabilitation included epidural electrical stimulation by implantable electrode and activation of the proprioceptive apparatus. The neurological (ASIA scale) and functional (CSIM III scale) status of the patient was analyzed. Motor function was evaluated using 10-meter Walk test; M-responses of limb muscles — using electromyography, temperature and pain sensitivity — using esthesiometry.
 RESULTS. An increase in muscle strength and M-response of the muscles of the extremities, normalization of the motor deficit index, reduction of the walking test time, increase in movement speed and the patient’s independence index were revealed. There is an improvement in temperature and pain sensitivity at the level of damage and in the dermatomes located distally. The effect decreases in dermatomes far from the level of the electrode installation; but with increase in the number of courses the effect increases.
 DISCUSSION. The results obtained indicate that this rehabilitation complex, including UES, has a positive effect on the functioning of both the motor and sensitive spheres.
 CONCLUSION. Application of EES and activation of the proprioceptive apparatus improves the functional condition of sensorimotor sphere in the long-term consequences of spinal cord injury with partial spinal cord damage. Repeated rehabilitation courses have cumulative effect.

Reorganization of corticospinal projections after prominent recovery of finger dexterity from partial spinal cord injury in macaque monkeys.

We investigated morphological changes in the corticospinal tract (CST) to understand the mechanism underlying recovery of hand function after lesion of the CST at the C4/C5 border in 7 macaque monkeys. All monkeys exhibited prominent recovery of precision grip success ratio within a few months. The trajectories and terminals of CST from the contralesional (n = 4) and ipsilesional (n = 3) hand area of primary motor cortex (M1) were investigated at 5-29 months after the injury using an anterograde neural tracer, biotinylated dextran amine (BDA). Reorganization of the CST was assessed by counting the number of BDA-labeled axons and bouton-like swellings in the gray and white matters. Rostral to the lesion (at C3), the number of axon collaterals of the descending axons from both contralesional and ipsilesional M1 entering the ipsilesional and contralesional gray matter, respectively, were increased. Caudal to the lesion (at C8), axons originating from the contralesional M1, descending in the preserved gray matter around the lesion, and terminating in ipsilesional laminae VI/VII and IX were observed. In addition, axons and terminals from the ipsilesional M1 increased in the ipsilesional laminae IX after recrossing the midline, which were not observed in intact monkeys. Conversely, axons originating from the ipsilesional M1 and directed toward the contralesional laminae VII decreased. These results suggest that multiple reorganizations of the corticospinal projections to spinal segments both rostral and caudal to the lesion originating from bilateral M1 underlie a prominent recovery in long-term after spinal cord injury.SIGNIFICANCE STATEMENTPrevious studies have shown that dexterous finger movements recover prominently after lesion of the corticospinal tract (CST) at the mid-cervical segments through rehabilitative training in macaque monkeys. Here, we show reorganization of the CST including sprouting of axons originating from the contralesional and ipsilesional motor cortex in the gray matter both caudal and rostral to the lesion, including a re-direction of the CST to hand motoneurons in the monkeys 5-29 months after the lesion. Thus, multiple mechanisms of reorganization of CST axons underlie the recovery of impaired cortico-motoneuronal pathways for the long-term recovery of finger dexterity.

USEFULNESS OF THE SURFACE ELECTROMYOGRAPHICAL RECORDINGS FOR EVALUATION OF SYNERGISTIC MUSCLE FUNCTION IN THE LOWER EXTREMITIES OF PATIENTS AFTER INCOMPLETE SPINAL CORD INJURIES FOR THE PHYSIOTHERAPY PURPOSES

Introduction Electromyographic examinations with the use of surface leads (sEMG) in the standing and lying position are used in the diagnosis of musculoskeletal disorders and prognostically, assessing the patient’s therapeutic process, especially kinesiotherapy. There is little data on synergistic muscle function in patients with partial spinal cord injury (iSCI) from which an optimal isometric rehabilitation program can be determined. Aim The aim of the following pilot study is to demonstrate the pathological pattern of synergistic interaction of lower limb muscles in patients with (iSCI) preventing correct posture. This is to enable the future to create a detailed algorithm through selective and targeted activities aimed at restoring the correct pattern of muscle synergy. Material and methods The studies were carried out in 12 patients with (iSCI) (documented in the MRI at levels C3-C8 and Th7-S1). The electrodes recorded bipolar activity (sEMG) on both sides of the: gluteus maximus (GM), rectus femoris (RF), tibialis anterior (TIB), extensors of the back of the foot (EXT). Records were performed in the position that activated the proximal and distal muscles. Results The results show changes in the muscle synergy pattern for the lower extremities in patients with (iSCI), by the intensification of muscle interaction (GM) with (EXT). Conclusions The results demonstrate the behavior of the synergistic muscle pathways of the distal muscles of the lower extremities and the role of the interacting with (GM) activity in maintaining correct posture. Kinesiotherapy exercises should be aimed at returning balance between (RE) and (GM) to restore the patient’s correct posture.

PD24-04 DETECTION OF PELVIC FLOOR MUSCLE ACTIVITY AND QUANTIFICATION OF OXYGEN KINETICS IN WOMEN WITH SPINAL CORD INJURY AND NEUROGENIC LOWER URINARY TRACT DYSFUNCTION

You have accessJournal of UrologyCME1 May 2022PD24-04 DETECTION OF PELVIC FLOOR MUSCLE ACTIVITY AND QUANTIFICATION OF OXYGEN KINETICS IN WOMEN WITH SPINAL CORD INJURY AND NEUROGENIC LOWER URINARY TRACT DYSFUNCTION Lynn Stothers, and Andrew Macnab Lynn Stothers Lynn Stothers More articles by this author , and Andrew MacnabAndrew Macnab More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002566.04AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Paralysis and changes in sensation following spinal cord injury (SCI) are a significant barrier to the performance and quantification of pelvic floor muscle (PFM) exercise in women, although international guidelines recommend PFM therapy. Aims: (1) to translate for use in PFM evaluation, a validated optical measure of oxygen kinetics used in sports medicine which uses near infrared (NIR) spectroscopy to quantify the half recovery time of reoxygenation (HbDiff(½RT)) following sustained maximal voluntary muscle contraction (SMVC), and (2) design and test a vaginal interface incorporating NIRS technology specific to the needs of women with compromised PFM function due to SCI. METHODS: The vaginal interface (fig left) incorporates 4 NIRS emitter detector arrays; photons of NIR light (wavelengths 825, 950, 1000 nm) monitor changes in oxygenated and deoxygenated hemoglobin (O2Hb/HHb) at capture rates of 10 Hz during PFM muscle contractions. The study protocol included clinical assessment, bladder diary and Qualiveen symptom scores and perineometry, plus changes in O2Hb/HHb at rest and during PFM rehabilitation exercises. The absolute measure HbDiff(½RT) is derived from the slope of reoxygenation following release of each SMVC. RESULTS: N=15 women aged 25-59 yrs (5 controls, 10 SCI ASIA B, C, D) completed 4 weeks of PFMT; HbDiff(½RT) data sets were compared within individuals and between clinical groups. Repeatability of patterns of recovery were demonstrable within individuals (fig right). CONCLUSIONS: HbDiff(½RT) is a quantifiable absolute measure of skeletal muscle oxygen kinetics; use of the vaginal interface allows individual elements of the PFM to be evaluated; the ability to quantify right and left sided function independently is particularly relevant in women with PFM dysfunction due to partial SCI. Translation of measurement of HbDiff(½RT) to the PFM now allows a validated muscle reoxygenation parameter to be applied in evaluation of PFM dysfunction following SCI in women, and offers a means to quantify clinical training effects from rehabilitation exercise in NLUTD. Source of Funding: Craig Neilsen Foundation © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e416 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Lynn Stothers More articles by this author Andrew Macnab More articles by this author Expand All Advertisement PDF DownloadLoading ...

Preserved intersegmental coordination during locomotion after cervical spinal cord injury in common marmosets

It is known that primates including human regain some locomotor function after a partial spinal cord injury, but the locomotor pattern is different from before the injury. Although these observations have many implications for improving rehabilitative strategies, these mechanisms are not well understood. In this study, we used a common marmoset hemisection SCI model to examine temporal changes in locomotor pattern, in particular, intersegmental coordination of left hindlimb. Marmoset showed loss of detectable function in the left forelimb and hindlimb after left unilateral hemisection of cervical spinal cord. At two weeks after injury, weight-bearing of the left forelimb during locomotion was limited, but the left hindlimb was able to plantar step. Then marmosets showed gradual recovery in walking ability, but kinematics analysis showed differences in the endpoint trajectory and joint angle movement. Furthermore, intersegmental coordination in left hindlimb represented by planar covariation was preserved over time after the injury. Previous studies have reported that planar covariance is disrupted in patients with stroke or SCI, and that improvement in planarity correlates with recovery in walking ability after rehabilitation. In this study, quadrupedal marmosets were able to walk without loss of balance even after SCI; the different balance needs of bipedal and quadrupedal walkers may lead to differences in planar covariation. Our results show that planar covariation was preserved at all time points after the cervical unilateral hemisection.

Urodynamic Effect of Transcutaneous Electrical Posterior Tibial Nerve Stimulation in Overactive Bladder after Partial Spinal Cord Injury

Urodynamic Effect of Transcutaneous Electrical Posterior Tibial Nerve Stimulation in Overactive Bladder after Partial Spinal Cord Injury

Inhibition of central axon regeneration: perspective from chondroitin sulfate proteoglycans in lamprey spinal cord injury.

Inhibition of central axon regeneration: perspective from chondroitin sulfate proteoglycans in lamprey spinal cord injury.

Rehabilitative training improves skilled forelimb motor function after cervical unilateral contusion spinal cord injury in rats

Animal models of cervical spinal cord injury (SCI) have frequently utilized partial transection injuries to evaluate plasticity promoting treatments such as rehabilitation training of skilled reaching and grasping tasks. Though highly useful for studying the effects of cutting specific spinal tracts that are important for skilled forelimb motor function, cervical partial-transection SCI-models underappreciate the extensive spread of most human SCIs, thus offering poor predictability for the clinical setting. Conversely, moderate cervical contusion SCI models targeting the spinal tracts important for skilled reaching and grasping can better replicate the increased size of most human SCIs and are often considered more clinically relevant. However, it is unknown whether animals with moderate cervical contusion SCIs that damage key spinal motor tracts can train in skilled reaching and grasping tasks. In this study, we quantify the impact of injury size and distribution on recovery in a skilled motor task called the single pellet reaching, grasping and retrieval (SPRGR) task in rats with cervical unilateral contusion injuries (UCs), and compare to rats with a partial transection SCIs (i.e., dorsolateral quadrant transection; DLQ). We found that UCs damage key tracts important for performing skilled motor tasks, similar to DLQs, but UCs also produce more extensive grey matter damage and more ventral white matter damage than DLQs. We also compared forelimb functionality at 1, 3, and 5 weeks of rehabilitative motor training between trained and untrained rats and found a more severe drop in SPRGR performance than in DLQ SCIs. Nevertheless, despite more severe injuries and initially low SPRGR performance, rehabilitative training for contusion animals resulted in significant improvements in SPRGR performance and proportionally more recovery than DLQ rats. Our findings show that rehabilitative motor training can facilitate considerable amounts of motor recovery despite extensive spinal cord damage, especially grey matter damage, thus supporting the use of contusion or compression SCI models and showing that ventral grey and white matter damage are not necessarily detrimental to recovery after training.

Effects of Repetitive Transcranial Magnetic Stimulation (rTMS) and Treadmill Training on Recovery of Motor Function in a Rat Model of Partial Spinal Cord Injury.

BackgroundThis study aimed to investigate the effects of repetitive transcranial magnetic stimulation (rTMS) and treadmill training (TT) on motor function recovery in rats with partial spinal cord injury (SCI).Material/MethodsSixty rats with moderate partial SCI at the 9th thoracic vertebral level induced by a Louisville Injury System Apparatus impactor were randomly allocated to 5 groups: Sham surgery (Intact); Sham rTMS without TT (S-rTMS/Non-TT); Sham rTMS with TT (S-rTMS/TT); rTMS without TT (rTMS/Non-TT); and rTMS with TT (rTMS/TT). Interventions commenced 8 days after SCI and continued for 8 weeks. Outcomes studied were Basso, Beattie, and Bresnahan locomotor scale scores, grid walking test, and biochemical analysis of the brain-derived neurotrophic factor (BDNF), synapsin I (SYN), and postsynaptic density protein-95 (PSD-95) in the motor cortex and spinal cord.ResultsThe rTMS/TT contributed to greater Basso, Beattie, and Bresnahan scores compared with the S-rTMS/Non-TT (P<0.01), S-rTMS/TT (P<0.05), and rTMS/Non-TT (P<0.05), and showed obviously reduced numbers of foot drops compared with the S-rTMS/Non-TT (P<0.05). The rTMS/TT significantly increased the expressions of BDNF, SYN, and PSD-95 compared with the S-rTMS/Non-TT, both in the motor cortex (P<0.01, P<0.01, P<0.001, respectively) and spinal cord (P<0.001, P<0.01, P<0.05, respectively).ConclusionsIn a modified rat model of SCI, combined rTMS with TT improved motor function, indicating that this combined approach promoted adaptive neuroplasticity between the motor cortex and the spinal cord. A combined app roach to improving motor function following SCI requires further evaluation to determine the possible clinical applications.

Batch Bayesian optimization design for optimizing a neurostimulator.

Recently, spinal epidural neurostimulation is being considered for rehabilitation of persons suffering from partial spinal-cord injury. The neurostimulator must be programmed by a neurosurgeon, yet little work has been done to develop rigorous methods for optimally programming the device. We propose an adaptive design to efficiently optimize programming of the neurostimulator based on specified interim evaluations of patient reported preferences. Preferences for the eligible device configurations are estimated after each interim analysis through a conditionally autoregressive model that assumes preference for one configuration is related to preferences for neighboring configurations. Using the adaptively updated preferences, a group of configurations is programmed into the device for the patient to evaluate during the next follow-up period. This selection is based on a balance of device exploration and preference maximization. We repeat this process until a specified stopping rule or the calibration end is reached. We show simulation studies to evaluate the overall quality of the adaptive calibration for various configuration selection strategies and the effects of stopping itearly.

Image correction for diffusion tensor imaging of Rhesus monkey thoracic spinal cord.

The relatively tiny spinal cord of non-human primate (NHP) causes increased challenge in diffusion tensor imaging (DTI) post-processing. This study aimed to establish a reliable correction strategy applied to clinical DTI images of NHP. Six normal and partial spinal cord injury (SCI) rhesus monkeys underwent 3T MR scanning. A correction strategy combining multiple iterations and non-rigid deformation was used for DTI image post-processing. Quantitative evaluations were then conducted to investigate effects of distortion correction. After correction, longitudinal geometric distortion, global distortion, and residual distance errors were all significantly decreased (P<0.05). Fractional anisotropy at the injured site was remarkably lower than that at the contralateral site (P=0.0488) and was substantially lower than those at the adjacent superior (P=0.0157) and inferior (P=0.0128) areas at the same side. Our image correction strategy can improve the quality of the DTI images of NHP thoracic cords, contributing to the development of SCI preclinical research.

STOCHASTIC RESONANCE METHOD IN PHYSIOTHERAPY − A REVIEW OF THE LITERATURE

Non-linearity is an important feature of many human body structures that may result from deterministic properties of the body and noise. Noise is defined as accidental or irregular fluctuations or disturbances that are not part of the signal. Stochastic resonance (SR), the term originally used in a very specific context, is now widely used to describe any phenomenon in which the presence of noise in a nonlinear system is better for the quality of the output signal than its absence. The conducted research for the needs of physiotherapy consists in assessing the impact of the platform generating forced mechanical vibrations with specific parameters in selected disease entities, sports disciplines, as well as prevention. The aim of the work is to discuss the stochastic resonance method and to analyze the results of the most important works discussing the use and effectiveness of therapeutic impact on the human body. The use of the stochastic resonance method enforces mechanical vibrations, which are characterized by the variability of rhythm, amplitude and direction of vibrations, which enforces postural adjustment regulated by the CNS and response to stimuli that disturb the body's balance. The analysis of the effectiveness of therapeutic impact in the field of body balance disorders, reeducation of locomotion in people with partial spinal cord injury, motor motility and changes in hormonal concentrations was carried out. Stochastic resonance therapy can reduce or eliminate dysfunction in many disease entities, however, further studies are needed to assess the effectiveness of the therapy.

Dynamic Reorganization of Motor Networks During Recovery from Partial Spinal Cord Injury in Monkeys.

After spinal cord injury (SCI), the motor-related cortical areas can be a potential substrate for functional recovery in addition to the spinal cord. However, a dynamic description of how motor cortical circuits reorganize after SCI is lacking. Here, we captured the comprehensive dynamics of motor networks across SCI in a nonhuman primate model. Using electrocorticography over the sensorimotor areas in monkeys, we collected broadband neuronal signals during a reaching-and-grasping task at different stages of recovery of dexterous finger movements after a partial SCI at the cervical levels. We identified two distinct network dynamics: grasping-related intrahemispheric interactions from the contralesional premotor cortex (PM) to the contralesional primary motor cortex (M1) in the high-γ band (>70 Hz), and motor-preparation-related interhemispheric interactions from the contralesional to ipsilesional PM in the α and low-β bands (10-15 Hz). The strengths of these networks correlated to the time course of behavioral recovery. The grasping-related network showed enhanced activation immediately after the injury, but gradually returned to normal while the strength of the motor-preparation-related network gradually increased. Our findings suggest a cortical compensatory mechanism after SCI, where two interdependent motor networks redirect activity from the contralesional hemisphere to the other hemisphere to facilitate functional recovery.

Epistemic humility and empathic imagination.

Epistemic humility and empathic imagination Stowe Locke Teti In my professional role as a clinical ethicist, I see cases where treatment of chronic pain (CP) poses ethical issues, both as a risk of its [End Page 213] under-treatment, and as a potential source of iatrogenic harm. While I have heard arguments proffered by colleagues and in the literature, and know the science of the subject, my professional understanding is plaited by having lived with severe and intractable pain for 27 years—all my adult life. I was 19 when a catastrophic accident left me with a partial spinal cord injury, setting up a "cascading failure" of the spine, for which there was no cure. It began in college following an injury incurred while unloading boxes from a truck. Initially I thought I was ok; while my back hurt, a doctor determined I had strained muscles and would soon recover. A week later, the pain was no better; another doctor recommended bed rest. The pain continued, and as weeks passed, sciatic pain emerged and worsened. I began to lose sensation in my left leg. I found myself having to make a conscious effort to initiate movement from my hip: swinging my left leg forward, planting it on the ground, and then stepping forward on my right. This new gait was initially subtle, but as it worsened a foreboding sense grew in the back of my mind that the doctors were terribly wrong. I saw yet another doctor, who, on a hunch, ordered an MRI. I sat on an exam table in the hospital, the doctor studying my scans on the wall. He opened the door and called to a trio of doctors. Soon they were chatting amongst themselves, pointing at the films, folding and unfolding their arms, and rubbing their chins. "I've never seen anything like that," one of them said. When the others left, the doctor turned to me and explained the extent of my injuries were rare in someone my age, and were very serious. Immediate surgery was necessary to decompress the nerves before permanent damage was done. This was triage; they operated knowing it wouldn't resolve the problem permanently. I returned to school able to walk again, the sciatic pain and numbness in my leg having disappeared, but a locus of pain remained centered in my lower back. The surgeon prescribed Demerol and I was glad for it during the surgical recovery. I was still in school and doing my best to keep up with my academic work. Demerol was not ideal for ongoing pain because its short half-life meant I was constantly on a rollercoaster; pain relief came on strong, but the analgesia didn't last. As with most opioids, Demerol numbs one's cognitive abilities, so I took as little as I could. When I had recovered sufficiently, I began physical therapy and stopped the Demerol, intent on getting back to my life as it was before. The pain continued, but didn't seem to be worsening, so I focused on my studies. Unbeknownst to me, the nerves in and around my spine were slowly developing a chemical sensitivity to an enzyme that had been released when several spinal disks were crushed. The pain intensified as that sensitivity worsened. I began avoiding sitting upright and standing, both painful positions. I was slowly losing more abilities; I could no longer reach, bend over, or twist without stabbing, jarring back pain. I was worried, but optimistic and determined to overcome this malady. In the midst of doctoral studies in philosophy, my condition declined precipitously. Now both my legs were bathed in the electric shocks of sciatic pain, and my motor control was weakening. I returned to physical therapy, but I hurt too much to move. It felt as if I was on a planet with many times the gravity of earth; the sense of carrying far too heavy a weight, of being crushed. By this point, I couldn't walk unassisted or sit for more than a few minutes; attempting either was immediately met with a staggering agony that crumpled me into a ball. Wincing and gasping to catch my breath, I would try...

Identification of Intrinsic Axon Growth Modulators for Intact CNS Neurons after Injury

SUMMARYFunctional deficits persist after spinal cord injury (SCI) because axons in the adult mammalian central nervous system (CNS) fail to regenerate. However, modest levels of spontaneous functional recovery are typically observed after trauma and are thought to be mediated by the plasticity of intact circuitry. The mechanisms underlying intact circuit plasticity are not delineated. Here, we characterize the in vivo transcriptome of sprouting intact neurons from Ngr1 null mice after partial SCI. We identify the lysophosphatidic acid signaling modulators LPPR1 and LPAR1 as intrinsic axon growth modulators for intact corticospinal motor neurons after adjacent injury. Furthermore, in vivo LPAR1 inhibition or LPPR1 overexpression enhances sprouting of intact corticospinal tract axons and yields greater functional recovery after unilateral brainstem lesion in wild-type mice. Thus, the transcriptional profile of injury-induced sprouting of intact neurons reveals targets for therapeutic enhancement of axon growth initiation and new synapse formation.

Reorganization of Intact Descending Motor Circuits to Replace Lost Connections After Injury.

Neurons have a limited capacity to regenerate in the adult central nervous system (CNS). The inability of damaged axons to re-establish original circuits results in permanent functional impairment after spinal cord injury (SCI). Despite abortive regeneration of axotomized CNS neurons, limited spontaneous recovery of motor function emerges after partial SCI in humans and experimental rodent models of SCI. It is hypothesized that this spontaneous functional recovery is the result of the reorganization of descending motor pathways spared by the injury, suggesting that plasticity of intact circuits is a potent alternative conduit to enhance functional recovery after SCI. In support of this hypothesis, several studies have shown that after unilateral corticospinal tract (CST) lesion (unilateral pyramidotomy), the intact CST functionally sprouts into the denervated side of the spinal cord. Furthermore, pharmacologic and genetic methods that enhance the intrinsic growth capacity of adult neurons or block extracellular growth inhibitors are effective at significantly enhancing intact CST reorganization and recovery of motor function. Owing to its importance in controlling fine motor behavior in primates, the CST is the most widely studied descending motor pathway; however, additional studies in rodents have shown that plasticity within other spared descending motor pathways, including the rubrospinal tract, raphespinal tract, and reticulospinal tract, can also result in restoration of function after incomplete SCI. Identifying the molecular mechanisms that drive plasticity within intact circuits is crucial in developing novel, potent, and specific therapeutics to restore function after SCI. In this review we discuss the evidence supporting a focus on exploring the capacity of intact motor circuits to functionally repair the damaged CNS after SCI.Electronic supplementary materialThe online version of this article (doi:10.1007/s13311-016-0422-x) contains supplementary material, which is available to authorized users.

Accelerometer-based step initiation control for gait-assist neuroprostheses.

Electrical activation of paralyzed musculature can generate or augment joint movements required for walking after central nervous system trauma. Proper timing of stimulation relative to residual volitional control is critical to usefully affecting ambulation. This study evaluates three-dimensional accelerometers and customized algorithms to detect the intent to step from voluntary movements to trigger stimulation during walking in individuals with significantly different etiologies, mobility limitations, manual dexterities, and walking aids. Three individuals with poststroke hemiplegia or partial spinal cord injury exhibiting varying gait deficits were implanted with multichannel pulse generators to provide joint motions at the hip, knee, and ankle. An accelerometer integrated into the external control unit was used to detect heel strike or walker movement, and wireless accelerometers were used to detect crutch strike. Algorithms were developed for each sensor location to detect intent to step to progress through individualized stimulation patterns. Testing these algorithms produced detection accuracies of at least 90% on both level ground and uneven terrain. All participants use their accelerometer-triggered implanted gait systems in the community; the validation/system testing was completed in the hospital. The results demonstrated that safe, reliable, and convenient accelerometer-based step initiation can be achieved regardless of specific gait deficits, manual dexterities, and walking aids.

Potential associations between chronic whiplash and incomplete spinal cord injury.

This research utilized a cross-sectional design with control group inclusion. Preliminary evidence suggests that a portion of the patient population with chronic whiplash may have sustained spinal cord damage. Our hypothesis is that in some cases of chronic whiplash-associated disorders (WAD), observed muscle weakness in the legs will be associated with local signs of a partial spinal cord injury of the cervical spine. University based laboratory in Chicago, IL, USA. Five participants with chronic WAD were compared with five gender/age/height/weight/body mass index (BMI) control participants. For a secondary investigation, the chronic WAD group was compared with five unmatched participants with motor incomplete spinal cord injury (iSCI). Spinal cord motor tract integrity was assessed using magnetization transfer imaging. Muscle fat infiltration (MFI) was quantified using fat/water separation magnetic resonance imaging. Central volitional muscle activation of the plantarflexors was assessed using a burst superimposition technique. We found reduced spinal cord motor tract integrity, increased MFI of the neck and lower extremity muscles and significantly impaired voluntary plantarflexor muscle activation in five participants with chronic WAD. The lower extremity structural changes and volitional weakness in chronic WAD were comparable to participants with iSCI. The results support the position that a subset of the chronic whiplash population may have sustained partial damage to the spinal cord. NIH R01HD079076-01A1, NIH T32 HD057845 and the Foundation for Physical Therapy Promotion of Doctoral Studies program.

Inducing hindlimb locomotor recovery in adult rat after complete thoracic spinal cord section using repeated treadmill training with perineal stimulation only.

Although a complete thoracic spinal cord section in various mammals induces paralysis of voluntary movements, the spinal lumbosacral circuitry below the lesion retains its ability to generate hindlimb locomotion. This important capacity may contribute to the overall locomotor recovery after partial spinal cord injury (SCI). In rats, it is usually triggered by pharmacological and/or electrical stimulation of the cord while a robot sustains the animals in an upright posture. In the present study we daily trained a group of adult spinal (T7) rats to walk with the hindlimbs for 10 wk (10 min/day for 5 days/wk), using only perineal stimulation. Kinematic analysis and terminal electromyographic recordings revealed a strong effect of training on the reexpression of hindlimb locomotion. Indeed, trained animals gradually improved their locomotion while untrained animals worsened throughout the post-SCI period. Kinematic parameters such as averaged and instant swing phase velocity, step cycle variability, foot drag duration, off period duration, and relationship between the swing features returned to normal values only in trained animals. The present results clearly demonstrate that treadmill training alone, in a normal horizontal posture, elicited by noninvasive perineal stimulation is sufficient to induce a persistent hindlimb locomotor recovery without the need for more complex strategies. This provides a baseline level that should be clearly surpassed if additional locomotor-enabling procedures are added. Moreover, it has a clinical value since intrinsic spinal reorganization induced by training should contribute to improve locomotor recovery together with afferent feedback and supraspinal modifications in patients with incomplete SCI.

Plastic Changes in Lumbar Locomotor Networks after a Partial Spinal Cord Injury in Cats.

After an incomplete spinal cord injury (SCI), we know that plastic reorganization occurs in supraspinal structures with residual descending tracts. However, our knowledge about spinal plasticity is rather limited. Our recent studies point to changes within the spinal cord below the lesion. After a lateral left hemisection (T10), cats recovered stepping with both hindlimbs within 3 weeks. After a complete section (T13) in these cats, bilateral stepping was seen on the next day, a skill usually acquired after several weeks of treadmill training. This indicates that durable plastic changes occurred below the lesion. However, because sensory feedback entrains the stepping rhythm, it is difficult to reveal central pattern generator (CPG) adaptation. Here, we investigated whether lumbar segments of cats with a chronic hemisection were able to generate fictive locomotion-that is, without phasic sensory feedback as monitored by five muscle nerves in each hindlimb. With a chronic left hemisection, the number of muscle nerves displaying locomotor bursts was larger on the left than on the right. In addition, transmission of cutaneous reflexes was relatively facilitated on the left. Later during the acute experiment, a complete spinalization (T13) was performed and clonidine was injected to induce rhythmic activities. There were still more muscle nerves displaying locomotor bursts on the left. The results demonstrate that spinal networks were indeed modified after a hemisection with a clear asymmetry between left and right in the capacity to generate locomotion. Plastic changes in CPG and reflex transmission below the lesion are thus involved in the stepping recovery after an incomplete SCI.