Neurophysiological characterization of motor recovery in acute spinal cord injury

Passive activity enhances residual control ability in patients with complete spinal cord injury

JOURNAL/nrgr/04.03/01300535-202508000-00024/figure1/v/2024-09-30T120553Z/r/image-tiff Patients with complete spinal cord injury retain the potential for volitional muscle activity in muscles located below the spinal injury level. However, because of prolonged inactivity, initial attempts to activate these muscles may not effectively engage any of the remaining neurons in the descending pathway. A previous study unexpectedly found that a brief clinical round of passive activity significantly increased volitional muscle activation, as measured by surface electromyography. In this study, we further explored the effect of passive activity on surface electromyographic signals during volitional control tasks among individuals with complete spinal cord injury. Eleven patients with chronic complete thoracic spinal cord injury were recruited. Surface electromyography data from eight major leg muscles were acquired and compared before and after the passive activity protocol. The results indicated that the passive activity led to an increased number of activated volitional muscles and an increased frequency of activation. Although the cumulative root mean square of surface electromyography amplitude for volitional control of movement showed a slight increase after passive activity, the difference was not statistically significant. These findings suggest that brief passive activity may enhance the ability to initiate volitional muscle activity during surface electromyography tasks and underscore the potential of passive activity for improving residual motor control among patients with motor complete spinal cord injury.

Surface electromyography: A pilot study in canine spinal muscles

In veterinary practice, rehabilitation modalities are often used to help in the recovery of animals affected by InterVertebral Disc Disease (IVDD), a condition frequently observed in chondrodystrophic dog breeds and can lead to Spinal Cord Injury (SCI), resulting in pain, motor impairments and neurological deficits, but there is a lack of objective assessment tools for patient evolution. In this work, an innovative approach using surface ElectroMyoGraphy (sEMG) is proposed to be applied in the field of veterinary medicine rehabilitation. The observed results are thought to be a direct result of nerve compression, leading to unusual patterns of muscle activation; this phenomenon can be attributed to muscle denervation, where the loss of Motor Units (MU) is the primary cause. This is thought to be responsible for the decrease in recorded sEMG amplitude and the increase in frequency observed in the pathological group.•This study involved rigorous animal preparation and signal acquisition protocols, involving multiple exercises and sub-movements, which were subsequently analysed.•RMSA is most used metric to analyse amplitude in sEMG signals, as it results in a more representative measurement of the signal variability than the Mean amplitude or the Standard Deviation.

Enhanced inhibitory input to triceps brachii in humans with spinal cord injury

Most individuals with cervical spinal cord injury (SCI) show increased muscle weakness in the elbow extensor compared to elbow flexor muscles. Although this is a well-known functional deficit, the underlying neural mechanisms remain poorly understood. To address this question, we measured the suppression of voluntary electromyographic activity (svEMG; a measurement thought to reflect changes in intracortical inhibition) by applying low-intensity transcranial magnetic stimulation over the arm representation of the primary motor cortex during 10% of isometric maximal voluntary contraction (MVC) into elbow flexion or extension in individuals with and without chronic cervical SCI. We found that the svEMG latency and duration were not different between the biceps and triceps brachii in controls but prolonged in the triceps in individuals with SCI. The svEMG area was larger in the triceps compared to the biceps in both groups and further increased in SCI participants, suggesting a pronounced intracortical inhibitory input during elbow extension. A negative correlation was found between svEMG area and MVCs indicating that control and SCI participants with lower svEMG area had larger MVCs. The svEMG area was not different between 5% and 30% of MVC, making it less probable that differences in muscle strength between groups contributed to our results. These findings support the existence of strong inhibitory input to corticospinal projections controlling elbow extensor compared to flexor muscles, which is more pronounced after chronic cervical SCI. KEY POINTS: After cervical spinal cord injury (SCI), people often recover function in elbow flexor, but much less in elbow extensor muscles. The neural mechanisms contributing to this difference remain unknown. We measured the suppression of voluntary electromyographic activity (svEMG) elicited through low-intensity transcranial magnetic stimulation of the primary motor cortex (assumed to reflect changes in intracortical inhibition) in the biceps and triceps muscles in controls and individuals with cervical chronic incomplete SCI. We found increased svEMG area in the triceps compared to the biceps in controls and SCI participants, with this measurement being even more pronounced in the triceps after SCI. The svEMG area correlated with maximal voluntary contraction values in both groups, suggesting the people with lesser inhibition had larger motor output. Our results support the presence of strong cortical inhibitory input to corticospinal projections controlling elbow extensor compared to elbow flexors muscles after cervical SCI.

Clinical Assessment and Management of Acute Spinal Cord Injury

The information contained in this article is suitable for clinicians practicing in the United States desiring a general overview of the assessment and management of spinal cord injury (SCI), focusing on initial care, assessment, acute management, complications, prognostication, and future research directions. SCI presents significant challenges, affecting patients physically, emotionally, and financially, with variable recovery outcomes ranging from full functionality to lifelong dependence on caregivers. Initial care aims to minimize secondary injury through thorough neurological evaluations and imaging studies to assess the severity of the injury. Acute management prioritizes stabilizing respiratory and cardiovascular functions and maintaining proper spinal cord perfusion. Patients with unstable or progressive neurological decline benefit from timely surgical intervention to optimize neurological recovery. Subacute management focuses on addressing common complications affecting the respiratory, gastrointestinal, and genitourinary systems, emphasizing a holistic, multidisciplinary approach. Prognostication is currently based on neurological assessments and imaging findings, but emerging biomarkers offer the potential to refine outcome predictions further. Additionally, novel therapeutic interventions, such as hypothermia therapy and neuroprotective medications are being explored to mitigate secondary damage and enhance recovery. This paper serves as a high-yield refresher for clinicians for the assessment and management of acute spinal cord injury during index admission.

Evidence for reticulospinal plasticity underlying motor recovery in Brown-Séquard-plus Syndrome: a case report

Brown-Séquard Syndrome (BSS) is a rare neurological condition caused by a unilateral spinal cord injury (SCI). Upon initial ipsilesional hemiplegia, patients with BSS typically show substantial functional recovery over time. Preclinical studies on experimental BSS demonstrated that spontaneous neuroplasticity in descending motor systems is a key mechanism promoting functional recovery. The reticulospinal (RS) system is one of the main descending motor systems showing a remarkably high ability for neuroplastic adaptations after incomplete SCI. In humans, little is known about the contribution of RS plasticity to functional restoration after SCI. Here, we investigated RS motor drive to different muscles in a subject with Brown-Séquard-plus Syndrome (BSPS) five months post-injury using the StartReact paradigm. RS drive was compared between ipsi- and contralesional muscles, and associated with measures of functional recovery. Additionally, corticospinal (CS) drive was investigated using transcranial magnetic stimulation (TMS) in a subset of muscles. The biceps brachii showed a substantial enhancement of RS drive on the ipsi- vs. contralesional side, whereas no signs of CS plasticity were found ipsilesionally. This finding implies that motor recovery of ipsilesional elbow flexion is primarily driven by the RS system. Results were inversed for the ipsilesional tibialis anterior, where RS drive was not augmented, but motor-evoked potentials recovered over six months post-injury, suggesting that CS plasticity contributed to improvements in ankle dorsiflexion. Our findings indicate that the role of RS and CS plasticity in motor recovery differs between muscles, with CS plasticity being essential for the restoration of distal extremity motor function, and RS plasticity being important for the functional recovery of proximal flexor muscles after SCI in humans.

Upper limb electromyographic analysis of manual wheelchair transfer techniques in individuals with spinal cord injury: A systematic review

BACKGROUND AND PURPOSE

The objective of this study is to determine the upper limb muscle electromyographic (EMG) activity required during various manual wheelchair transfers in the population of spinal cord injury (SCI).

METHODS

This review included observational studies reporting the (EMG) activity of upper limb muscles during wheelchair transfers in people with SCI. We searched electronic databases and reference lists of relevant literature between 1995 and March 2022 with English language limits, yielding 3870 total articles. Two independent researchers performed data extraction and conducted quality assessment using two checklists, the Modified Downs and Blacks and National Heart, Lung, and Blood Institute for observational cohort and cross-sectional studies.

RESULTS

After eligibility screening, seven studies were included in this review. The sample size ranged from 10 to 32 participants aged 31-47 years. They assessed four types of transfers and mostly evaluated six upper limb muscles were biceps, triceps, anterior deltoid, pectoralis major, latissimus dorsi and ascending fibres of the trapezius. The peak EMG value indicated that muscle recruitment varied in both upper limbs according to the task demand, and the highest activity was seen during the lift-pivot transfer phase. Because of the data heterogeneity, a meta-analysis of study results was not feasible.

CONCLUSION

There were various ways of reporting the upper limb EMG muscle activity profile across all the included studies with a limited sample size. The crucial role of upper limb muscles during different types of manual wheelchair transfers was interpreted in this review. This is essential for predicting functional independence of individuals with SCI and warranting optimal rehabilitation strategies for wheelchair transfer skills.

Testing a Novel Wearable Device for Motor Recovery of the Elbow Extensor Triceps Brachii in Chronic Spinal Cord Injury

After corticospinal tract damage, reticulospinal connections to motoneurons strengthen preferentially to flexor muscles. This could contribute to the disproportionately poor recovery of extensors often seen after spinal cord injury (SCI) and stroke. In this study, we paired electrical stimulation over the triceps muscle with auditory clicks, using a wearable device to deliver stimuli over a prolonged period of time. Healthy human volunteers wore the stimulation device for ∼6 h and a variety of electrophysiological assessments were used to measure changes in triceps motor output. In contrast to previous results in the biceps muscle, paired stimulation: (1) did not increase the StartReact effect; (2) did not decrease the suppression of responses to transcranial magnetic brain stimulation (TMS) following a loud sound; (3) did not enhance muscle responses elicited by a TMS coil oriented to induce anterior-posterior current. In a second study, chronic cervical SCI survivors wore the stimulation device for ∼4 h every day for four weeks; this was compared with a four-week period without wearing the device. Functional and electrophysiological assessments were repeated at week 0, week 4, and week 8. No significant changes were observed in electrophysiological assessments after paired stimulation. Functional measurements such as maximal force and variability and speed of trajectories made during a planar reaching task also remained unchanged. Our results suggest that the triceps muscle shows less potential for plasticity than biceps; pairing clicks with muscle stimulation does not seem beneficial in enhancing triceps recovery after SCI.

Approach to Small Animal Neurorehabilitation by Locomotor Training: An Update

Neurorehabilitation has a wide range of therapies to achieve neural regeneration, reorganization, and repair (e.g., axon regeneration, remyelination, and restoration of spinal circuits and networks) to achieve ambulation for dogs and cats, especially for grade 1 (modified Frankel scale) with signs of spinal shock or grade 0 (deep pain negative), similar to humans classified with ASIA A lesions. This review aims to explain what locomotor training is, its importance, its feasibility within a clinical setting, and some possible protocols for motor recovery, achieving ambulation with coordinated and modulated movements. In addition, it cites some of the primary key points that must be present in the daily lives of veterinarians or rehabilitation nurses. These can be the guidelines to improve this exciting exercise necessary to achieve ambulation with quality of life. However, more research is essential in the future years.

Reduced Muscle Activity of the Upper Extremity in Individuals with Spinal Cord Injuries

Compromised physical ability due to musculoskeletal impairment among spinal cord injury (SCI) patients is known to negatively affect their quality of life. It is essential to comprehensively understand the muscle strength of the upper extremity among patients with SCI to enhance muscle function and capacity to engage in an active lifestyle. The objective of this study was to evaluate the muscle strength of 15 upper extremity muscles among patients with SCI and compare the relative weakness of individual muscles to the control group. Seven male patients with SCI with ASIA impairment scale D and E and 33 males in the control group participated in this study. Each participant performed maximal voluntary contraction of individual muscles, and the electromyography data were recorded. The results showed that the majority of the upper extremity muscles (12 out of 15) showed considerable weakness (24 to 53%) relative to the control group. Furthermore, the relative strength (ranking) of individual muscles among 15 upper extremity muscles was different between patients with SCI and the control group. This information would be useful to the selective strengthening of specific muscles as an intensive rehabilitation effort and prevent overuse and adverse injuries due to excessive muscle training.

Validity and Reliability of Surface Electromyography Features in Lower Extremity Muscle Contraction in Healthy and Spinal Cord-Injured Participants

Background: Spinal cord injury (SCI) has a significant impact on motor control and active force generation. Quantifying muscle activation following SCI may help indicate the degree of motor impairment and predict the efficacy of rehabilitative interventions. In healthy persons, muscle activation is typically quantified by electromyographic (EMG) signal amplitude measures. However, in SCI, these measures may not reflect voluntary effort, and therefore other nonamplitude-based features should be considered. Objectives: The purpose of this study was to assess the correlation of time-domain EMG features with the exerted joint torque (validity) and their test-retest repeatability (reliability), which may contribute to characterizing muscle activation following SCI. Methods: Surface EMG (SEMG) and torque were measured while nine uninjured participants and four participants with SCI performed isometric contractions of tibialis anterior (TA) and soleus (SOL). Data collection was repeated at a subsequent session for comparison across days. Validity and test-retest reliability of features were assessed by Spearman and intraclass correlation (ICC) of linear regression coefficients. Results: In healthy participants, SEMG features correlated well with torque (TA: ρ > 0.92; SOL: ρ > 0.94) and showed high reliability (ICC_mean = 0.90; range, 0.72-0.99). In an SCI case series, SEMG features also correlated well with torque (TA: ρ > 0.86; SOL: ρ > 0.86), and time-domain features appeared no less repeatable than amplitude-based measures. Conclusion: Time-domain SEMG features are valid and reliable measures of lower extremity muscle activity in healthy participants and may be valid measures of sublesional muscle activity following SCI. These features could be used to gauge motor impairment and progression of rehabilitative interventions or in controlling assistive technologies.

Quantitative evaluation of trunk function and the StartReact effect during reaching in patients with cervical and thoracic spinal cord injury

Objective.Impaired trunk stability is frequent in spinal cord injury (SCI), but there is a lack of quantitative measures for assessing trunk function. Our objectives were to: (a) evaluate trunk muscle activity and movement patterns during a reaching task in SCI patients, (b) compare the impact of cervical (cSCI) and thoracic (tSCI) injuries in trunk function, and (c) investigate the effects of a startling acoustic stimulus (SAS) in these patients.Approach.Electromyographic (EMG) and smartphone accelerometer data were recorded from 15 cSCI patients, nine tSCI patients, and 24 healthy controls, during a reaching task requiring trunk tilting. We calculated the response time (RespT) until pressing a target button, EMG onset latencies and amplitudes, and trunk tilt, lateral deviation, and other movement features from accelerometry. Statistical analysis was applied to analyze the effects of group (cSCI, tSCI, control) and condition (SAS, non-SAS) in each outcome measure.Main results.SCI patients, especially those with cSCI, presented significantly longer RespT and EMG onset latencies than controls. Moreover, in SCI patients, forward trunk tilt was accompanied by significant lateral deviation. RespT and EMG latencies were remarkably shortened by the SAS (the so-called StartReact effect) in tSCI patients and controls, but not in cSCI patients, who also showed higher variability.Significance. The combination of EMG and smartphone accelerometer data can provide quantitative measures for the assessment of trunk function in SCI. Our results show deficits in postural control and compensatory strategies employed by SCI patients, including delayed responses and higher lateral deviations, possibly to improve sitting balance. This is the first study investigating the StartReact responses in trunk muscles in SCI patients and shows that the SAS significantly accelerates RespT in tSCI, but not in cSCI, suggesting an increased cortical control exerted by these patients.

Properties of the surface electromyogram following traumatic spinal cord injury: a scoping review

Traumatic spinal cord injury (SCI) disrupts spinal and supraspinal pathways, and this process is reflected in changes in surface electromyography (sEMG). sEMG is an informative complement to current clinical testing and can capture the residual motor command in great detail-including in muscles below the level of injury with seemingly absent motor activities. In this comprehensive review, we sought to describe how the sEMG properties are changed after SCI. We conducted a systematic literature search followed by a narrative review focusing on sEMG analysis techniques and signal properties post-SCI. We found that early reports were mostly focused on the qualitative analysis of sEMG patterns and evolved to semi-quantitative scores and a more detailed amplitude-based quantification. Nonetheless, recent studies are still constrained to an amplitude-based analysis of the sEMG, and there are opportunities to more broadly characterize the time- and frequency-domain properties of the signal as well as to take fuller advantage of high-density EMG techniques. We recommend the incorporation of a broader range of signal properties into the neurophysiological assessment post-SCI and the development of a greater understanding of the relation between these sEMG properties and underlying physiology. Enhanced sEMG analysis could contribute to a more complete description of the effects of SCI on upper and lower motor neuron function and their interactions, and also assist in understanding the mechanisms of change following neuromodulation or exercise therapy.

Motor Control Changes after Innovative Aquatic Proprioceptive Training in Athletes with Anterior Cruciate Ligament Reconstruction: Voluntary Response Index Analysis

Objectives: The main aim of this study was to determine and compare the effects of innovative aquatic proprioceptive training plus conventional rehabilitation with conventional rehabilitation alone on voluntary response index (VRI) components in athletes with anterior cruciate ligament reconstruction (ACLR). Methods: Forty male athletes with ACLR (18 - 35 years of age) voluntarily participated in this study. They were randomly allocated into two groups. The conventional therapy group (n = 20) underwent conventional rehabilitation for ten weeks, three sessions a week. The aquatic proprioceptive training plus conventional rehabilitation (n = 20) group received the same conventional rehabilitation plus 30 sessions of innovative hydrotherapy exercises. Voluntary response index analysis was carried out to determine changes in motor control and muscle activation patterns based on electromyographic (EMG) outcome measures. Results: There was a significant difference in the magnitude (MAG) and similarity index (SI) between the two groups at all phases of the functional task (sit-stand-sit) (P < 0.05). Also, both groups showed a significant change in MAG and SI at all phases of the functional task (sit-stand-sit) after the intervention (P < 0.05). Effect size in both groups for MAG and SI at all phases of the functional task (sit-stand-sit) ranged from 2.5 to 4.61 and from 0.29 to 1.7, respectively. Conclusions: The incorporation of innovative aquatic proprioceptive training into conventional accelerated rehabilitation protocol leads to changes in motor control due to changes in the muscle activation pattern after the intervention.

Early delivery and prolonged treatment with nimodipine prevents the development of spasticity after spinal cord injury in mice

Spasticity, one of the most frequent comorbidities of spinal cord injury (SCI), disrupts motor recovery and quality of life. Despite major progress in neurorehabilitative and pharmacological approaches, therapeutic strategies for treating spasticity are lacking. Here, we show in a mouse model of chronic SCI that treatment with nimodipine-an L-type calcium channel blocker already approved from the European Medicine Agency and from the U.S. Food and Drug Administration-starting in the acute phase of SCI completely prevents the development of spasticity measured as increased muscle tone and spontaneous spasms. The aberrant muscle activities associated with spasticity remain inhibited even after termination of the treatment. Constitutive and conditional silencing of the L-type calcium channel Ca_V1.3 in neuronal subtypes demonstrated that this channel mediated the preventive effect of nimodipine on spasticity after SCI. This study identifies a treatment protocol and suggests that targeting Ca_V1.3 could prevent spasticity after SCI.

Neurophysiological Changes in the First Year After Cell Transplantation in Sub-acute Complete Paraplegia

Neurophysiological testing can provide quantitative information about motor, sensory, and autonomic system connectivity following spinal cord injury (SCI). The clinical examination may be insufficiently sensitive and specific to reveal evolving changes in neural circuits after severe injury. Neurophysiologic data may provide otherwise imperceptible circuit information that has rarely been acquired in biologics clinical trials in SCI. We reported a Phase 1 study of autologous purified Schwann cell suspension transplantation into the injury epicenter of participants with complete subacute thoracic SCI, observing no clinical improvements. Here, we report longitudinal electrophysiological assessments conducted during the trial. Six participants underwent neurophysiology screening pre-transplantation with three post-transplantation neurophysiological assessments, focused on the thoracoabdominal region and lower limbs, including MEPs, SSEPs, voluntarily triggered EMG, and changes in GSR. We found several notable signals not detectable by clinical exam. In all six participants, thoracoabdominal motor connectivity was detected below the clinically assigned neurological level defined by sensory preservation. Additionally, small voluntary activations of leg and foot muscles or positive lower extremity MEPs were detected in all participants. Voluntary EMG was most sensitive to detect leg motor function. The recorded MEP amplitudes and latencies indicated a more caudal thoracic level above which amplitude recovery over time was observed. In contrast, further below, amplitudes showed less improvement, and latencies were increased. Intercostal spasms observed with EMG may also indicate this thoracic “motor level.” Galvanic skin testing revealed autonomic dysfunction in the hands above the injury levels. As an open-label study, we can establish no clear link between these observations and cell transplantation. This neurophysiological characterization may be of value to detect therapeutic effects in future controlled studies.

Spinal Cord Imaging Markers and Recovery of Volitional Leg Movement With Spinal Cord Epidural Stimulation in Individuals With Clinically Motor Complete Spinal Cord Injury

Previous studies have shown that epidural stimulation of the lumbosacral spinal cord (scES) can re-enable lower limb volitional motor control in individuals with chronic, clinically motor complete spinal cord injury (SCI). This observation entails that residual supraspinal connectivity to the lumbosacral spinal circuitry still persisted after SCI, although it was non-detectable when scES was not provided. In the present study, we aimed at exploring further the mechanisms underlying scES-promoted recovery of volitional lower limb motor control by investigating neuroimaging markers at the spinal cord lesion site via magnetic resonance imaging (MRI). Spinal cord MRI was collected prior to epidural stimulator implantation in 13 individuals with chronic, clinically motor complete SCI, and the spared tissue of specific regions of the spinal cord (anterior, posterior, right, left, and total cord) was assessed. After epidural stimulator implantation, and prior to any training, volitional motor control was evaluated during left and right lower limb flexion and ankle dorsiflexion attempts. The ability to generate force exertion and movement was not correlated to any neuroimaging marker. On the other hand, spared tissue of specific cord regions significantly and importantly correlated with some aspects of motor control that include activation amplitude of antagonist (negative correlation) muscles during left ankle dorsiflexion, and electromyographic coordination patterns during right lower limb flexion. The fact that amount and location of spared spinal cord tissue at the lesion site were not related to the ability to generate volitional lower limb movements may suggest that supraspinal inputs through spared spinal cord regions that differ across individuals can result in the generation of lower limb volitional motor output prior to any training when epidural stimulation is provided.

A Survey on the Use and Barriers of Surface Electromyography in Neurorehabilitation

Historical, educational, and technical barriers have been reported to limit the use of surface electromyography (sEMG) in clinical neurorehabilitation settings. In an attempt to identify, review, rank, and interpret potential factors that may play a role in this scenario, we gathered information on (1) current use of sEMG and its clinical potential; (2) professional figures primarily dealing with sEMG; (3) educational aspects, and (4) possible barriers and reasons for its apparently limited use in neurorehabilitation. To this aim, an online 30-question survey was sent to 52 experts on sEMG from diverse standpoints, backgrounds, and countries. Participants were asked to respond to each question on a 5-point Likert scale or by ranking items. A cut-off of 75% agreement was chosen as the consensus threshold. Thirty-five invitees (67%) completed the electronic survey. Consensus was reached for 77% of the proposed questions encompassing current trends in sEMG use in neurorehabilitation, educational, technical, and methodological features as well as its translational utility for clinicians and patients. Data evidenced the clinical utility of sEMG for patient assessment, to define the intervention plan, and to complement/optimize other methods used to quantify muscle and physical function. The aggregate opinion of the interviewed experts confirmed that sEMG is more frequently employed in technical/methodological than clinical research. Moreover, the slow dissemination of research findings and the lack of education on sEMG seem to prevent prompt transfer into practice. The findings of the present survey may contribute to the ongoing debate on the appropriateness and value of sEMG for neurorehabilitation professionals and its potential translation into clinical settings.

Distinct Corticospinal and Reticulospinal Contributions to Voluntary Control of Elbow Flexor and Extensor Muscles in Humans with Tetraplegia

Humans with cervical spinal cord injury (SCI) often recover voluntary control of elbow flexors and, to a much lesser extent, elbow extensor muscles. The neural mechanisms underlying this asymmetrical recovery remain unknown. Anatomical and physiological evidence in animals and humans indicates that corticospinal and reticulospinal pathways differentially control elbow flexor and extensor motoneurons; therefore, it is possible that reorganization in these pathways contributes to the asymmetrical recovery of elbow muscles after SCI. To test this hypothesis, we examined motor-evoked potentials (MEPs) elicited by transcranial magnetic stimulation over the arm representation of the primary motor cortex, maximal voluntary contractions, the StartReact response (a shortening in reaction time evoked by a startling stimulus), and the effect of an acoustic startle cue on MEPs elicited by cervicomedullary stimulation (CMEPs) on biceps and triceps brachii in males and females with and without chronic cervical incomplete SCI. We found that SCI participants showed similar MEPs and maximal voluntary contractions in biceps but smaller responses in triceps compared with controls, suggesting reduced corticospinal inputs to elbow extensors. The StartReact and CMEP facilitation was larger in biceps but similar to controls in triceps, suggesting enhanced reticulospinal inputs to elbow flexors. These findings support the hypothesis that the recovery of biceps after cervical SCI results, at least in part, from increased reticulospinal inputs and that the lack of these extra inputs combined with the loss of corticospinal drive contribute to the pronounced weakness found in triceps.SIGNIFICANCE STATEMENT Although a number of individuals with cervical incomplete spinal cord injury show limited functional recovery of elbow extensors compared with elbow flexor muscles, to date, the neural mechanisms underlying this asymmetrical recovery remain unknown. Here, we provide for the first time evidence for increased reticulospinal inputs to biceps but not triceps brachii and loss of corticospinal drive to triceps brachii in humans with tetraplegia. We propose that this reorganization in descending control contributes to the asymmetrical recovery between elbow flexor and extensor muscles after cervical spinal cord injury.

The Effects of Adding Transcutaneous Spinal Cord Stimulation (tSCS) to Sit-To-Stand Training in People with Spinal Cord Injury: A Pilot Study

Spinal cord stimulation may enable recovery of volitional motor control in people with chronic Spinal Cord Injury (SCI). In this study we explored the effects of adding SCS, applied transcutaneously (tSCS) at vertebral levels T10/11, to a sit-to-stand training intervention in people with motor complete and incomplete SCI. Nine people with chronic SCI (six motor complete; three motor incomplete) participated in an 8-week intervention, incorporating three training sessions per week. Participants received either tSCS combined with sit-to-stand training (STIM) or sit-to-stand training alone (NON-STIM). Outcome measures were carried out before and after the intervention. Seven participants completed the intervention (STIM N = 5; NON-STIM N = 2). Post training, improvements in International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) motor scores were noted in three STIM participants (range 1.0–7.0), with no change in NON-STIM participants. Recovery of volitional lower limb muscle activity and/or movement (with tSCS off) was noted in three STIM participants. Unassisted standing was not achieved in any participant, although standing with minimal assistance was achieved in one STIM participant. This pilot study has shown that the recruitment of participants, intervention and outcome measures were all feasible in this study design. However, some modifications are recommended for a larger trial.

Interlimb conditioning of lumbosacral spinally evoked motor responses after spinal cord injury

OBJECTIVE

The importance of subcortical pathways to functional motor recovery after spinal cord injury (SCI) has been demonstrated in multiple animal models. The current study evaluated descending interlimb influence on lumbosacral motor excitability after chronic SCI in humans.

METHODS

Ulnar nerve stimulation and transcutaneous electrical spinal stimulation were used in a condition-test paradigm to evaluate the presence of interlimb connections linking the cervical and lumbosacral spinal segments in non-injured (n=15) and spinal cord injured (SCI) (n=18) participants.

RESULTS

Potentiation of spinally evoked motor responses (sEMRs) by ulnar nerve conditioning was observed in 7/7 SCI participants with volitional leg muscle activation, and in 6/11 SCI participants with no volitional activation. Of these six, conditioning of sEMRs was present only when the neurological level of injury was rostral to the ulnar innervation entry zones.

CONCLUSIONS

Descending modulation of lumbosacral motor pools via interlimb projections may exist in SCI participants despite the absence of volitional leg muscle activation.

SIGNIFICANCE

Evaluation of sub-clinical, spared pathways within the spinal cord after SCI may provide an improved understanding of both the contributions of different pathways to residual function, and the mechanisms of plasticity and functional motor recovery following rehabilitation..

Single session exercises and concurrent functional electrical stimulation are more effective on muscles' force generation than only exercises in spinal cord injured persons: a feasibility study

OBJECTIVES

To evaluate impact of first therapy session, containing functional electrical stimulation (FES) and therapeutic exercises (TE) on erector spinae (ES) and rectus abdominis (RA) force generation in persons with spinal cord injury (SCI).

METHODS

Five men with SCI were divided in two groups - FES+TE received concurrent FES on ES and RA and TE, TE only TE. Participants performed exercises for improving sitting balance and posture. Muscles' electrical activity was evaluated by electromyography; amplitude (AEMG) and median frequency (MF) were used for analysis.

RESULTS

AEMG of ES left (L) increased 292.9% (g=-0.92), right (R) 175% (g=-1.01), RA L 314.3% (g=-0,81, P<0.05), R 266.7% (g=-0.08) in FES+TE. AEMG of ES L increased 47.6% (g=-0.46), R 96.4% (g=-0.95); RA L 7.1% (g=-0.97), but R decreased 6.7% (g=0.12) in TE. MF of ES L increased 108.5% (g=-0.74), R 184% (g=-1.25); RA L 886.7% (g=3-05, P<0.05), R 817.6% (g=-2.55, P<0.05) in FES+TE. MF of ES L increased 95.2% (g=-1.02), R 161.4% (g=-1.64); RA L 3,2% (g=-0.06), R 30.8% (g=-0.46) in TE.

CONCLUSIONS

In SCI persons, single session exercises and concurrent functional electrical stimulation may be more effective on muscles` force generation than only exercises. However, replication of the results is needed before clinical implementation.

Muscle Activation Patterns During Movement Attempts in Children With Acquired Spinal Cord Injury: Neurophysiological Assessment of Residual Motor Function Below the Level of Lesion

Introduction: Characterization of residual neuromotor capacity after spinal cord injury (SCI) is challenging. The current gold standard for measurement of sensorimotor function after SCI, the International Society for Neurological Classification of Spinal Cord Injury (ISNCSCI) exam, seeks to determine isolated intentional muscle activation, however many individuals with SCI exhibit intentional movements and muscle activation patterns which are not confined to specific joint or muscle. Further, isolated muscle activation is a feature of the neuromuscular system that emerges during development, and thus may not be an appropriate measurement standard for children younger than 6.

Methods: We utilized neurophysiological assessment methodology, long studied in adult SCI populations, to evaluate residual neuromotor capacity in 24 children with SCI, as well as 19 typically developing (TD) children. Surface electromyography (EMG) signals were recorded from 11 muscles bilaterally, representing spinal motor output from all regions (i.e., cervical, thoracic, and lumbosacral), during standardized movement attempts. EMG records were subjectively analyzed based on spatiotemporal muscle activation characteristics, while the voluntary response index (VRI) was utilized for objective analysis of unilateral leg movement tasks.

Results: Evidence of intentional leg muscle activation below the level of lesion was found in 11/24 children with SCI, and was classified based on activation pattern. Trace activation, bilateral (generalized) activation, and unilateral or isolated activation occurred in 32, 49, and 8% of movement tasks, respectively. Similarly, VRI analyses objectively identified significant differences between TD and SCI children in both magnitude (p < 0.01) and similarity index (p < 0.05) for all unilateral leg movement tasks. Activation of the erector spinae muscles, recorded at the T10–T12 vertebral level, was observed in all children with SCI, regardless of injury level or severity.

Conclusions: Residual descending influence on spinal motor circuits may be present after SCI in children. Assessment of multi-muscle activation patterns during intentional movement attempts can provide objective evidence of the presence and extent of such residual muscle activation, and may provide an indicator of motor recovery potential following injury. The presence of residual intentional muscle activation has important implications for rehabilitation following pediatric-onset SCI.

Model of Traumatic Spinal Cord Injury for Evaluating Pharmacologic Treatments in Cynomolgus Macaques (Macaca fasicularis)

Here we present the results of experiments involving cynomolgus macaques, in which a model of traumatic spinal cord injury (TSCI) was created by using a balloon catheter inserted into the epidural space. Prior to the creation of the lesion, we inserted an EMG recording device to facilitate measurement of tail movement and muscle activity before and after TSCI. This model is unique in that the impairment is limited to the tail: the subjects do not experience limb weakness, bladder impairment, or bowel dysfunction. In addition, 4 of the 6 subjects received a combination treatment comprising thyrotropin releasing hormone, selenium, and vitamin E after induction of experimental TSCI. The subjects tolerated the implantation of the recording device and did not experience adverse effects due the medications administered. The EMG data were transformed into a metric of volitional tail moment, which appeared to be valid measure of initial impairment and subsequent natural or treatment-related recovery. The histopathologic assessment demonstrated widespread axon loss at the site of injury and areas cephalad and caudad. Histopathology revealed evidence of continuing inflammation, with macrophage activation. The EMG data did not demonstrate evidence of a statistically significant treatment effect.

EMG-triggered stimulation post spinal cord injury: A case report

BACKGROUND

Mechanical injury in patients with spinal cord injury (SCI) rarely transects the cord completely, even when the injury is classified as complete. These patients can show sub-clinical evidence of spared motor connections, which might be amenable to targeted rehabilitation. Neurophysiological evaluations can complement the clinical evaluation by providing objective data about conduction across the SCI site.

CASE DESCRIPTION

A twenty-four year old patient with SCI was admitted to a rehabilitation centre 49 days post traumatic SCI. His injury was categorized as motor and sensory complete (AIS A) with a neurological level of C4. The strength of his triceps bilaterally was recorded 0/5 repeatedly by his therapists during the five-month period post-injury. As a result, no training was provided for these muscles during the rehabilitation program. Neurophysiological Assessment: Motor evoked potentials (MEPs) were recorded from his left triceps with transcranial magnetic stimulation (TMS) which confirmed the existence of spared corticospinal connections to this muscle post-injury.

INTERVENTION

He completed a series of active-assisted exercises with an EMG-triggered neuromuscular stimulation (NMS) device for his left triceps comprising 20-minutes elbow extension (15 trials), three times per day for 4 weeks.

OUTCOME

The strength of his left triceps gradually improved to 2/5.

DISCUSSION

Neurophysiological evaluation can be useful in identifying residual function below the level of injury, which can, in turn, be enhanced through appropriate rehabilitation strategies.

Motor recovery after activity-based training with spinal cord epidural stimulation in a chronic motor complete paraplegic

The prognosis for recovery of motor function in motor complete spinal cord injured (SCI) individuals is poor. Our research team has demonstrated that lumbosacral spinal cord epidural stimulation (scES) and activity-based training can progressively promote the recovery of volitional leg movements and standing in individuals with chronic clinically complete SCI. However, scES was required to perform these motor tasks. Herein, we show the progressive recovery of voluntary leg movement and standing without scES in an individual with chronic, motor complete SCI throughout 3.7 years of activity-based interventions utilizing scES configurations customized for the different motor tasks that were specifically trained (standing, stepping, volitional leg movement). In particular, this report details the ongoing neural adaptations that allowed a functional progression from no volitional muscle activation to a refined, task-specific activation pattern and movement generation during volitional attempts without scES. Similarly, we observed the re-emergence of muscle activation patterns sufficient for standing with independent knee and hip extension. These findings highlight the recovery potential of the human nervous system after chronic clinically motor complete SCI.

Brain motor control assessment of upper limb function in patients with spinal cord injury

BACKGROUND

The brain motor control assessment (BMCA) for the upper limb has been developed to add resolution to the clinical evaluation in patients with spinal cord injury (SCI). BMCA is a surface electromyography (sEMG)-based measure of motor output from the central nervous system during a variety of reflex and voluntary motor tasks performed under strictly controlled conditions.

METHOD

Nine participants were recruited and assessed four times over a period of 1 year in a prospective cohort study design. The sEMG of 15 muscles (7 muscles from each upper limb and rectus abdominis) were recorded throughout the following stages of the BMCA protocol: (i) relaxation, (ii) reinforcement maneuvers, (iii) voluntary tasks, (iv) tendon-tap reflex responses, (v) vibration responses.

RESULTS

Similarity index (SI) values were significantly lower in the SCI group for unilateral shoulder abduction (P = 0.006) and adduction (P = 0.021), elbow extension (P = 0.038), wrist flexion/extension with palm up (P < 0.001; P < 0.001) and wrist flexion with palm down (P = 0.016). sEMG magnitudes were also significantly lower in the SCI group for wrist flexion/extension with palm up (P < 0.001; P = 0.042). SI changes over time were significant for tasks related to wrist joint (P = 0.002).

CONCLUSION

Clinicians who are involved in rehabilitation of patients with SCI can use the BMCA to assess their patients' motor control abilities and monitor their progression throughout their rehabilitation process. The results of this type of neurophysiological assessment might be useful to tailor therapeutic strategies for each patient.

Surface electromyography as a measure of trunk muscle activity in patients with spinal cord injury: a meta-analytic review

CONTEXT

Surface electromyography (SEMG) may be a sensitive marker for distinguishing the activity of trunk muscles, which are critical to functional mobility recovery in patients with spinal cord injury (SCI).

OBJECTIVES

This manuscript presents a systematic review and meta-analysis of the published literature on the effect of SEMG as a measure of trunk muscle activity in patients with SCI.

METHODS

A comprehensive search of the research literature included Pubmed, Medline, CNKI, WANFANG DATA, Web of Science, Elsevier, Wiley-Blackwell, Karger, OVID, and a review of reference lists within found articles. Case-control, cohort, and cross-sectional studies were included in the review.

RESULTS

Eleven studies were included in this meta-analysis. Trunk muscle activities for the sitting condition were greater in patients with SCI than normal subjects. SEMG activity of trunk muscles for the sitting condition and posterior transfer was greater in patients with high level (HL)-SCI compared to those with low level (LL)-SCI. In addition, across studies, the level of trunk muscle activity for various difficulty settings was different for a given SCI group.

CONCLUSION

This systematic review evaluated the value of trunk muscles for patients with SCI. We recommend use of SEMG as an assessment tool for improving the comparability and interpretability of trunk muscle activity of SCI therapeutic strategies.

Effects of Lumbosacral Spinal Cord Epidural Stimulation for Standing after Chronic Complete Paralysis in Humans

Sensory and motor complete spinal cord injury (SCI) has been considered functionally complete resulting in permanent paralysis with no recovery of voluntary movement, standing or walking. Previous findings demonstrated that lumbosacral spinal cord epidural stimulation can activate the spinal neural networks in one individual with motor complete, but sensory incomplete SCI, who achieved full body weight-bearing standing with independent knee extension, minimal self-assistance for balance and minimal external assistance for facilitating hip extension. In this study, we showed that two clinically sensory and motor complete participants were able to stand over-ground bearing full body-weight without any external assistance, using their hands to assist balance. The two clinically motor complete, but sensory incomplete participants also used minimal external assistance for hip extension. Standing with the least amount of assistance was achieved with individual-specific stimulation parameters, which promoted overall continuous EMG patterns in the lower limbs’ muscles. Stimulation parameters optimized for one individual resulted in poor standing and additional need of external assistance for hip and knee extension in the other participants. During sitting, little or negligible EMG activity of lower limb muscles was induced by epidural stimulation, showing that the weight-bearing related sensory information was needed to generate sufficient EMG patterns to effectively support full weight-bearing standing. In general, electrode configurations with cathodes selected in the caudal region of the array at relatively higher frequencies (25–60 Hz) resulted in the more effective EMG patterns for standing. These results show that human spinal circuitry can generate motor patterns effective for standing in the absence of functional supraspinal connections; however the appropriate selection of stimulation parameters is critical.

Reliability of surface EMG as an assessment tool for trunk activity and potential to determine neurorecovery in SCI

STUDY DESIGN

Reliability and validity study.

OBJECTIVE

This study investigates the responsiveness and reliability of the brain motor control assessment (BMCA) as a standardized neurophysiological assessment tool to: (i) characterize trunk neural activity in neurologically-intact controls; (ii) measure and quantify neurorecovery of trunk after spinal cord injury (SCI).

SETTING

Kessler Foundation Research Center, West Orange, NJ.

METHODS

A standardized BMCA protocol was performed to measure surface electromyography (sEMG) recordings for seven bilateral trunk muscles on 15 able-bodied controls during six maneuvers (inhalation, exhalation, neck flexion, jendrassik, unilateral grip). Additionally, sEMG recordings were analyzed for one chronic SCI individual before electrical stimulation (ES), after ES of the lower extremities while supine, and after active stand training using body-weight support with bilateral ES. sEMG recordings were collected on bilateral erector spinae, internal and external obliques, upper and middle trapezius, biceps and triceps. For each maneuver a voluntary response index was calculated: incorporating the magnitude of sEMG signal and a similarity index (SI), which quantifies the distribution of activity across all muscles.

RESULTS

Among all maneuvers, the SI presented reproducible assessment of trunk-motor function within (ICC: 0.860-0.997) and among (P⩾0.22) able-bodied individuals. In addition, potential changes were measured in a chronic SCI individual after undergoing two intensive ES protocols.

CONCLUSION

The BMCA provides reproducible characterization of trunk activity in able-bodied individuals, lending credence for its use in neurophysiological assessment of motor control. Additionally, the BMCA as an assessment tool to measure neurorecovery in an individual with chronic SCI after intense ES interventions was demonstrated.

Altering spinal cord excitability enables voluntary movements after chronic complete paralysis in humans

Previously, we reported that one individual who had a motor complete, but sensory incomplete spinal cord injury regained voluntary movement after 7 months of epidural stimulation and stand training. We presumed that the residual sensory pathways were critical in this recovery. However, we now report in three more individuals voluntary movement occurred with epidural stimulation immediately after implant even in two who were diagnosed with a motor and sensory complete lesion. We demonstrate that neuromodulating the spinal circuitry with epidural stimulation, enables completely paralysed individuals to process conceptual, auditory and visual input to regain relatively fine voluntary control of paralysed muscles. We show that neuromodulation of the sub-threshold motor state of excitability of the lumbosacral spinal networks was the key to recovery of intentional movement in four of four individuals diagnosed as having complete paralysis of the legs. We have uncovered a fundamentally new intervention strategy that can dramatically affect recovery of voluntary movement in individuals with complete paralysis even years after injury.

Respiratory motor control disrupted by spinal cord injury: mechanisms, evaluation, and restoration

Pulmonary complications associated with persistent respiratory muscle weakness, paralysis, and spasticity are among the most important problems faced by patients with spinal cord injury when lack of muscle strength and disorganization of reciprocal respiratory muscle control lead to breathing insufficiency. This review describes the mechanisms of the respiratory motor control and its change in individuals with spinal cord injury, methods by which respiratory function is measured, and rehabilitative treatment used to restore respiratory function in those who have experienced such injury.

A Brain Motor Control Assessment (BMCA) protocol for upper limb function

The Brain Motor Control Assessment (BMCA) protocol is a surface electromyography (sEMG)-based measure of motor output from central nervous system during a variety of reflex and voluntary motor tasks performed under strictly controlled conditions. The aim of this study was to evaluate the BMCA protocol for upper limb with the addition of shoulder voluntary tasks. The voluntary response index (VRI) was calculated from quantitative analysis of sEMG data during defined voluntary movement in neurologically intact people for comparison with that of patients after neurological injuries. The BMCA protocol included one bilateral and 4 unilateral voluntary tasks at different joints of both arms. The VRI, measured from 19 neurologically intact participants, comprises the total muscle activity recorded for the voluntary motor task (magnitude). The calculated similarity index (SI) for each phase of each task show the similarity of “the distribution of activity across the recorded muscles” for that task in this group off participants. Results: The VRI magnitude values from right and left sides for different tasks showed no significant difference (ANOVA: F_Side: 0.09, P = 0.77). Therefore these values were pooled before calculating SI. SI values were higher for tasks against gravity: elbow flexion (0.99±0.03), wrist flexion with palm up (0.98±0.03) and wrist extension with palm down (0.97±0.07). On the other hand, the SI values were the lowest for bilateral shoulder abduction (0.84±0.08) and shoulder adduction (0.84±0.08). Conclusion: To validate this index for clinical use, serial studies on patients with neurological impairments should be performed. Tasks involving movement against gravity may be more suitable in future BMCAs.

Accelerating locomotor recovery after incomplete spinal injury

A traumatic spinal injury can destroy cells, irreparably damage axons, and trigger a cascade of biochemical responses that increase the extent of injury. Although damaged central nervous system axons do not regrow well naturally, the distributed nature of the nervous system and its capacity to adapt provide opportunities for recovery of function. It is apparent that activity-dependent plasticity plays a role in this recovery and that the endogenous response to injury heightens the capacity for recovery for at least several weeks postinjury. To restore locomotor function, researchers have investigated the use of treadmill-based training, robots, and electrical stimulation to tap into adaptive activity-dependent processes. The current challenge is to maximize the degree of functional recovery. This manuscript reviews the endogenous neural system response to injury, and reviews data and presents novel analyses of these from a rat model of contusion injury that demonstrates how a targeted intervention can accelerate recovery, presumably by engaging processes that underlie activity-dependent plasticity.

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

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.

Profiling motor control in spinal cord injury: moving towards individualized therapy and evidence-based care progression

This article, based on the keynote address at the 5th National Spinal Cord Injury Conference in Toronto, addresses methods to neurophysiologically characterize patients after spinal cord injury and proposes how those methods could be used to individualize therapeutic interventions and monitor their efficacy over the course of neurorehabilitation.

Quantitative testing in spinal cord injury: overview of reliability and predictive validity

Object

The objective of this study was to identify commonly used physiological outcome measures and summarize evidence on the reliability and predictive validity of quantitative measures used in monitoring persons with spinal cord injury (SCI).

Methods

A systematic search of PubMed through January 5, 2012, was conducted to identify publications using common outcome measures in persons with SCI and for studies that were specifically designed to evaluate the reliability and predictive validity of selected quantitative measures. Quantitative measures were defined as tests that quantify sensory and motor function, such as amount of force or torque, as well as thresholds, amplitudes, and latencies of evoked potentials that might be useful in studies and monitoring of patients with SCI. Reliability studies reporting interclass correlation coefficients (ICCs) or weighted κ coefficients were considered for inclusion. Studies explicitly evaluating correlation between measures and specific functional outcomes were considered for predictive validity.

Results

From a total of 121 potentially relevant citations, 6 studies of reliability and 4 studies of predictive validity for quantitative tests met the inclusion criteria. In persons with incomplete SCI, ICCs for both interrater and intrarater reliability of electrical perceptual threshold (EPT) were ≥ 0.7 above the sensory level of SCI but were less reliable below the sensory level. Interclass correlation coefficients for interrater and intrarater reliability of the Graded Redefined Assessment of Strength, Sensibility, and Prehension (GRASSP) components ranged from 0.84 to 0.98. For electromyography, the ICC was consistently high for within-day tests. The overall quality of reliability of the majority of studies was poor, due to the potential for selection bias and small sample sizes. No classic validation studies were found for the selected measures, and evidence regarding the predictive validity of the measures was limited. Somatosensory evoked potentials (SSEPs) may be correlated with ambulatory capacity, as well as the Barthel Index and motor index scores, but this correlation was limited for evaluation of bladder function recovery in 3 studies that assessed the correlation between baseline or initial SSEPs and a specific clinical outcome at a later follow-up time. All studies used convenience samples and the overall sample quality was low.

Conclusions

Evidence on the reliability and validity of the quantitative measures selected for this review is limited, and the overall quality of existing studies is poor. There is some evidence for the reliability of the EPT, dermatomal SSEPs, and the GRASSP to suggest that they may be useful in longitudinal studies of patients with SCI. There is a need for high quality studies of reliability, responsiveness, and validity for quantitative measures to monitor the level and degree of SCI.

Spinal cord injury and physical activity: preservation of the body

SETTING

Spinal cord injury (SCI) causes devastating loss of function and can result in serious secondary complications. Although significant advances are being made to develop cellular and molecular therapies to promote regeneration, it is important to optimize physical interventions.

OBJECTIVES

The objective of this review was to examine the evidence for the effects of physical rehabilitation strategies on health and fitness, and maintenance of target systems below the level of injury (for example, muscle, bone, circulation).

RESULTS

Exercise appears to be a potent means of achieving these goals, using a variety of strategies.

CONCLUSION

Physical rehabilitation after SCI needs to move beyond the goal of maximizing independence to focus on maintenance of optimum health and fitness as well as maintenance of target system function below the level of injury. Issues requiring further investigation include identification of the optimum dosage of interventions to achieve specific goals, for example, prevention of muscle atrophy and osteoporosis, and development and validation of simple clinical measures to monitor the changes in body composition. Adoption of a classification system for physical interventions and standardized outcome measures would facilitate large-scale observational studies to identify the critical variables contributing to better outcomes.