Outcome Measures for Acute/Subacute Cervical Sensorimotor Complete (AIS-A) Spinal Cord Injury During a Phase 2 Clinical Trial

A quality improvement initiative to develop an interprofessional peripheral nerve transfer clinic for individuals with traumatic cervical spinal cord injury

PURPOSE

Loss of upper extremity (UE) function impacts almost every aspect of daily life and upper limb recovery is reported to be a major priority of individuals living with tetraplegia. Surgical peripheral nerve transfer (PNT) offers the potential to restore volitional control of elbow, wrist and hand function of individuals with C5-C8 tetraplegia AIS A-C. Unfortunately, while there is growing evidence supporting the role of PNT in spinal cord injury (SCI) rehabilitation, there are currently no internationally-recognized consensus-derived best practices for provision of PNT following spinal cord injury (SCI) and few programs have focused on interdisciplinary collaboration during patient selection, surgical decision making, management of medical comorbidities and postoperative rehabilitation. This quality improvement initiative aimed to establish a novel, interdisciplinary PNT program with the goal of optimizing UE recovery and function in individuals with tetraplegia in Canada.

MATERIALS AND METHODS

An interprofessional team assembled to complete a detailed exploration of care segments, organizing and sequencing care delivery.

RESULTS AND CONCLUSIONS

As a result of this initiative, a care map of planned interprofessional services, their optimal timing across the continuum of care, and clinical functional and community integration outcomes were developed. Data collection and program evaluation are ongoing, and further work to mitigate barriers and develop educational materials around PNT surgery are intended to improve medical decision making and best practice implementation.

Upper Extremity Functional Status in Patients with Chronic Tetraplegia in Universiti Malaya Medical Centre

Background

Persons with tetraplegia rank improved upper extremity (UE) function as the most important rehabilitation outcome because it allows them greater independence in activities of daily living (ADL). The aim of this study was to describe UE status in patients with tetraplegia using the International Spinal Cord Injury Upper Extremity Basic Data Set version 1.1 (ISCI-UE 1.1) and to determine differences in UE status between tetraplegic individuals with traumatic and non-traumatic SCIs.

Methods

This cross-sectional study was conducted among patients with tetraplegia who attended the SCI rehabilitation clinic of a tertiary hospital from September 2021 to August 2022. Both upper limbs were assessed using ISCI-UE 1.1.

Results

One hundred patients were included in this study, of whom 80 were men. The mean (SD) age of the patients was 54.30 (16.95) years old. In these patients, most SCIs (62%) were of traumatic origin. Two hundred UEs were evaluated, of which 109 showed good hand function (level 5) and 10 had the poorest hand function (level 1). Meanwhile, 130 UEs showed good shoulder function (level D) and 10 had the poorest shoulder function (level A). A statistically significant association with UE status (reach-and-grasp ability and shoulder function) was found in both the non-traumatic and traumatic SCI groups, with better hand and shoulder functions in the non-traumatic SCI group (right-hand, P = 0.004 and left hand, P = 0.001; right shoulder, P < 0.001 and left shoulder, P = 0.002).

Conclusion

ISCI-UE 1.1 is a feasible tool for documenting UE function in patients with tetraplegia. Compared with the individuals with traumatic SCI in this study, those with non-traumatic SCI demonstrated better upper extremity functionality.

Importance of Prospective Registries and Clinical Research Networks in the Evolution of Spinal Cord Injury Care

Only 100 years ago, traumatic spinal cord injury (SCI) was commonly lethal. Today, most people who sustain SCI survive with continual efforts to improve their quality of life and neurological outcomes. SCI epidemiology is changing as preventative interventions reduce injuries in younger individuals, and there is an increased incidence of incomplete injuries in aging populations. Early treatment has become more intensive with decompressive surgery and proactive interventions to improve spinal cord perfusion. Accurate data, including specialized outcome measures, are crucial to understanding the impact of epidemiological and treatment trends. Dedicated SCI clinical research and data networks and registries have been established in the United States, Canada, Europe, and several other countries. We review four registry networks: the North American Clinical Trials Network (NACTN) SCI Registry, the National Spinal Cord Injury Model Systems (SCIMS) Database, the Rick Hansen SCI Registry (RHSCIR), and the European Multi-Center Study about Spinal Cord Injury (EMSCI). We compare the registries' focuses, data platforms, advanced analytics use, and impacts. We also describe how registries' data can be combined with electronic health records (EHRs) or shared using federated analysis to protect registrants' identities. These registries have identified changes in epidemiology, recovery patterns, complication incidence, and the impact of practice changes such as early decompression. They've also revealed latent disease-modifying factors, helped develop clinical trial stratification models, and served as matched control groups in clinical trials. Advancing SCI clinical science for personalized medicine requires advanced analytical techniques, including machine learning, counterfactual analysis, and the creation of digital twins. Registries and other data sources help drive innovation in SCI clinical science.

Early and intensive motor training to enhance neurological recovery in people with spinal cord injury: trial protocol

STUDY DESIGN

Protocol for a multi-centre randomised controlled trial (the SCI-MT trial).

OBJECTIVES

To determine whether 10 weeks of intensive motor training enhances neurological recovery in people with recent spinal cord injury (SCI).

SETTING

Fifteen spinal injury units in Australia, Scotland, England, Italy, Netherlands, Norway, and Belgium.

METHODS

A pragmatic randomised controlled trial will be undertaken. Two hundred and twenty people with recent SCI (onset in the preceding 10 weeks, American Spinal Injuries Association Impairment Scale (AIS) A lesion with motor function more than three levels below the motor level on one or both sides, or an AIS C or D lesion) will be randomised to receive either usual care plus intensive motor training (12 h of motor training per week for 10 weeks) or usual care alone. The primary outcome is neurological recovery at 10 weeks, measured with the Total Motor Score from the International Standards for Neurological Classification of SCI. Secondary outcomes include global measures of motor function, ability to walk, quality of life, participants' perceptions about ability to perform self-selected goals, length of hospital stay and participants' impressions of therapeutic benefit at 10 weeks and 6 months. A cost-effectiveness study and process evaluation will be run alongside the trial. The first participant was randomised in June 2021 and the trial is due for completion in 2025.

CONCLUSIONS

The findings of the SCI-MT Trial will guide recommendations about the type and dose of inpatient therapy that optimises neurological recovery in people with SCI.

TRIAL REGISTRATION

ACTRN12621000091808 (1.2.2021).

A phase 1/2a dose-escalation study of oligodendrocyte progenitor cells in individuals with subacute cervical spinal cord injury

OBJECTIVE

The primary objective of this study was to evaluate the safety of 3 escalating doses of oligodendrocyte progenitor cells (LCTOPC1; previously known as GRNOPC1 and AST-OPC1) administered at a single time point between 21 and 42 days postinjury to participants with subacute cervical spinal cord injuries (SCIs). The secondary objective was to evaluate changes in neurological function following administration of LCTOPC1.

METHODS

This study was designed as an open-label, dose-escalation, multicenter clinical trial. Twenty-five participants with C4-7 American Spinal Injury Association Impairment Scale grade A or B injuries received a single dose of either 2 × 106, 1 × 107, or 2 × 107 LCTOPC1 delivered via intraparenchymal injection into the spinal cord at the site of injury using a custom-designed syringe positioning device. Low-dose tacrolimus was administered until day 60. Outcome measures included adverse event (AE) monitoring and neurological function as measured by the International Standards for Neurological Classification of Spinal Cord Injury.

RESULTS

All 25 participants experienced at least one AE, with a total of 534 AEs (32 study-related vs 502 study-unrelated anticipated complications of SCI) reported at the completion of 1-year follow-up. There were 29 serious AEs reported. Two grade 3 serious AEs (CSF leak in one participant and a bacterial infection in another) were considered related to the injection procedure and to immunosuppression with tacrolimus, respectively. The CSF leakage resolved with sequelae, including self-limited altered mental status, and the infection resolved with antibiotic therapy. For all participants, MRI scans demonstrated no evidence of an enlarging mass, spinal cord damage related to the injection procedure, inflammatory lesions in the spinal cord, or masses in the ventricular system. At 1-year follow-up, 21/22 (96%) of the intention-to-treat group recovered one or more levels of neurological function on at least one side of their body, and 7/22 (32%) recovered two or more levels of neurological function on at least one side of their body.

CONCLUSIONS

LCTOPC1 can be safely administered to participants in the subacute period after cervical SCI. The injection procedure, low-dose temporary immunosuppression regimen, and LCTOPC1 were well tolerated. The safety and neurological function data support further investigation to determine the efficacy of LCTOPC1 in the treatment of SCI. Clinical trial registration no.: NCT02302157 (ClinicalTrials.gov).

Minimal Clinically Important Difference of Graded Redefined Assessment of Strength, Sensibility, and Prehension Version 1 in Acute Cervical Traumatic Spinal Cord Injury

The Graded Redefined Assessment of Strength, Sensibility, and Prehension Version 1 (GRASSP v1) is a validated measure of upper extremity impairment shown to be sensitive and responsive for traumatic cervical spinal cord injury (SCI) in both North American (NA) and European (EU) cohorts. The minimal clinically important difference (MCID) is the quantitative change in an assessment scale that patients perceive as being beneficial. Our aim was to establish the MCID of all subtests of the GRASSP v1 for cervical SCI. We prospectively analyzed 127 patients from NA and EU for up to six months after motor complete and incomplete cervical SCI using the GRASSP v1, Spinal Cord Independence Measure, and International Standards of Neurological Classification of Spinal Cord Injury. We used a patient global rating of change and the anchor-based method to calculate MCID of GRASSP v1 at six months post-injury. The MCID was established for the whole group, dividing the sample by "better" and "much better." Improvement in GRASSP v1 Strength and Prehension Performance scores of 13 and 3 are the MCID for the better category, and 19 and 7 are the MCID for the much better category, respectively. The MCID was also established for the motor complete and incomplete groups. Improvement in GRASSP v1 Strength and Prehension Performance scores of 12 and 6 are the MCID for the motor complete group, and 17 and 12 are the MCID for the motor incomplete group, respectively. The GRASSP v1 Strength subscore is the most sensitive for detecting meaningful clinical change in patients and is most closely related to measures of independence. Thus, use of GRASSP v1 Strength and Prehension Performance as measures of change is substantiated by this study.

Phase 1 Safety Trial of Autologous Human Schwann Cell Transplantation in Chronic Spinal Cord Injury

A phase 1 open-label, non-randomized clinical trial was conducted to determine feasibility and safety of autologous human Schwann cell (ahSC) transplantation accompanied by rehabilitation in participants with chronic spinal cord injury (SCI). Magnetic resonance imaging (MRI) was used to screen eligible participants to estimate an individualized volume of cell suspension to be implanted. The trial incorporated standardized multi-modal rehabilitation before and after cell delivery. Participants underwent sural nerve harvest, and ahSCs were isolated and propagated in culture. The dose of culture-expanded ahSCs injected into the chronic spinal cord lesion of each individual followed a cavity-filling volume approach. Primary outcome measures for safety and trend-toward efficacy were assessed. Two participants with American Spinal Injury Association Impairment Scale (AIS) A and two participants with incomplete chronic SCI (AIS B, C) were each enrolled in cervical and thoracic SCI cohorts (n = 8 total). All participants completed the study per protocol, and no serious adverse events related to sural nerve harvest or ahSC transplantation were reported. Urinary tract infections and skin abrasions were the most common adverse events reported. One participant experienced a 4-point improvement in motor function, a 6-point improvement in sensory function, and a 1-level improvement in neurological level of injury. Follow-up MRI in the cervical (6 months) and thoracic (24 months) cohorts revealed a reduction in cyst volume after transplantation with reduced effect over time. This phase 1 trial demonstrated the feasibility and safety of ahSC transplantation combined with a multi-modal rehabilitation protocol for participants with chronic SCI.

Quantifying an Upper Extremity Everyday Task With 3D Kinematic Analysis in People With Spinal Cord Injury and Non-disabled Controls

Objectives: Upper extremity function after spinal cord injury (SCI) is an important factor for performance of activities of daily living. An objective assessment of upper extremity function preferably in purposeful daily tasks is essential in understanding its impact on real-life activities. This study aimed to identify which movement parameters of upper extremity, measured by kinematic analysis during a purposeful daily task, are impaired in people with cervical or thoracic SCI.

Materials and Methods: The study included 29 adults (mean 59.5 years, 9 women and 20 men) with cervical (n = 19) or thoracic (n = 10) established complete (n = 15) or incomplete (n = 14) SCI, and 54 non-disabled controls with commensurable age and sex (mean 59 years, 15 women, 39 men). The 3D kinematic data were captured with a five-camera system during a standardized unilateral daily task (drinking from a glass). In SCI, the upper extremity functioning of each arm was assessed with Action Research Arm Test (ARAT). Having a full score in ARAT indicated full functioning; a score of <57 points indicated limited functioning. Kinematic data from full functioning arms (n = 27) and limited functioning arms (n = 30) in SCI were compared with the non-dominant arms (n = 54) in controls.

Results: In the limited upper extremity functioning group, movement time, smoothness, arm abduction, wrist angle, trunk displacement, and inter-joint coordination, but not peak velocity of the hand, angular velocity of elbow, and relative time to peak velocity, all differed from controls. In the full upper extremity functioning group, arm abduction alone was significantly different from controls.

Conclusions: The findings demonstrate that apart from measures of peak velocity, kinematic measures of movement quality including movement time, smoothness, trunk displacement, and joint angles are impaired in people with limited upper extremity functioning after SCI. The study provides robust results applicable to a representative population of individuals with established cervical or thoracic SCI. The results suggest that kinematic analysis might be useful for those with limited functioning in order to get a better understanding of the specific movement impairments in daily tasks after SCI.

Evaluation of Functional Independence in Cervical Spinal Cord Injury: Implications for Surgery to Restore Upper Limb Function

PURPOSE

To help individuals make informed choices regarding the optimal type and timing of restorative surgical treatment for cervical spinal cord injury (SCI), more precise information is needed on their ability to perform activities of daily living. The goal of this work was to describe functional independence achieved by individuals with differing levels of cervical SCI.

METHODS

Using the comprehensive European Multicenter Study of Spinal Cord Injury dataset, analysis was undertaken of individuals with traumatic SCI, motor-level C5-C8. Data on feeding, bladder management, and transfers (bed to wheelchair) were compared between individuals with different levels of injury. Subgroup analyses of symmetrical and asymmetrical SCI and between complete and incomplete SCI were performed. The impact of age, sex, and time postinjury on functional independence was ascertained.

RESULTS

Data were available for individuals with symmetrical (n = 204) and asymmetrical (n = 95) patterns of SCI. Independence with feeding, urinary function, and transfer ability was increased in individuals with strong finger flexion. Unexpectedly, the presence of strong elbow extension did not uniformly result in the ability to transfer independently. There was no change in any of the analyzed activities between 6 and 12 months postinjury.

CONCLUSIONS

People with cervical SCI who gain finger flexion have greater independence with feeding, urinary, and transfer activities. Restoration of finger flexion should be a reconstructive priority for individuals with midcervical-level SCI.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic IV.

An Analysis of Variability in "CatWalk" Locomotor Measurements to Aid Experimental Design and Interpretation

Preclinical studies in models of neurologic injury and disease rely on behavioral outcomes to measure intervention efficacy. For spinal cord injury, the CatWalk system provides unbiased quantitative assessment of subtle aspects of locomotor function in rodents and so can powerfully detect significant differences between experimental and control groups. Although clearly of key importance, summary group-level data can obscure the variability within and between individual subjects and therefore make it difficult to understand the magnitude of effect in individual animals and the proportion of a group that may show benefit. Here, we calculate reference change intervals (RCIs) that define boundaries of normal variability for measures of rat locomotion on the CatWalk. Our results indicate that many commonly-used outcome measures are highly variable, such that differences of up to 70% from baseline value must be considered normal variation. Many CatWalk outcome variables are also highly correlated and dependent on run speed. Application of calculated RCIs to open access data (https://scicrunch.org/odc-sci) on hindlimb stride length in spinal cord-injured rats illustrates the complementarity between group-level (16 mm change; p = 0.0009) and individual-level (5/32 animals show change outside RCI boundaries) analysis between week 3 and week 6 after injury. We also conclude that interdependence among CatWalk variables implies that test “batteries” require careful composition to ensure that different aspects of defective gait are analyzed. Calculation of RCIs aids in experimental design by quantifying variability and enriches overall data analysis by providing details of change at an individual level that complement group-level analysis.

A Distance-Based Neurorehabilitation Evaluation Method Using Linear SVM and Resting-State fMRI

During neurorehabilitation, clinical measurements are widely adopted to evaluate behavioral improvements after treatment. However, it is not able to identify or monitor the change of central nervous system (CNS) of each individual patient. Resting-state functional magnetic resonance imaging (rs-fMRI) has been widely used to investigate brain functions in healthy controls (HCs) and patients with neurological diseases, which could find functional changes following neurorehabilitation. In this paper, a distance-based rehabilitation evaluation method based on rs-fMRI was proposed. Specifically, we posit that in the functional connectivity (FC) space, patients and HCs distribute separately. Linear support vector machines (SVM) were trained on the brain networks to firstly separate patients from HCs. Second, the FC similarity between patients and HCs was measured by the L2 distance of each subject's feature vector to the separating hyperplane. Finally, statistical analysis of the distance revealed rehabilitation program induced improvements in patients and predicted rehabilitation outcomes. An rs-fMRI dataset with 22 HCs and 18 spinal cord injury (SCI) patients was utilized to validate our method. We built whole-brain networks using five atlases to test the robustness of the method and search for features under different node resolutions. The classifier successfully separated patients and HCs. Significant improvements in FC after treatment were found for the patients for all five atlases using the proposed method, which was consistent with clinical measurements. Furthermore, distance obtained from individual patient's longitudinal data showed a similar trend with each one's clinical scores, implying the possibility of individual rehabilitation outcome tracking and prediction. Our method not only provides a novel perspective of applying rs-fMRI to neurorehabilitation monitoring but also proves the potential in individualized rehabilitation prediction.

The graded redefined assessment of strength sensibility and prehension version 2 (GV2): Psychometric properties

Context: GRASSP Version 1 (GV1) was developed in 2010, is an upper extremity measure specifically designed to assess recovery after traumatic tetraplegia. A second version was developed to reduce length of the test and refine instructions/standardization. The purpose of this post hoc analysis was to calculate psychometric properties of GRASSP Version 2 (GV2). Design/Setting: A post-hoc analysis of datasets for the GRASSP cross-sectional (n = 72 chronic,) and longitudinal (n = 127 acute) studies was conducted. Reliability, validity and MDD were calculated from the chronic sample and responsiveness was re-calculated from the longitudinal sample. Both studies were observational. Participants: A chronic sample (n = 72) and acute longitudinal sample (n = 127) of individuals with traumatic tetraplegia (AIS A to D, NLI C2 to C8) were studied. Outcome Measures: GV1, the Spinal Cord Independence Measure III (SCIM), International Standards of Neurological Classification of Spinal Cord Injury (ISNCSCI) were administered in both studies at all centers and the Capabilities of the Upper Extremity Questionnaire (CUE-Q) was administered in North American sites only. GRASSP-Palmar Sensation, GRASSP-Prehension Performance subtest items included in GV2 were re-analyzed for reliability; validity, MDD and responsiveness. Results: Inter-rater and test-retest reliability for all subtests ranged between 0.849-0.971 and 0.950-0.971 respectively. Concurrent validity between domains of GV2 were positively and moderately (0.530-0.830, P < 0.0001) correlated to SCIM, SCIM self-care subscore (SS) and CUE-Q. MDD values were 4 and 3 points for sensation and prehension performance (single side). Responsiveness values were .84-.88 for GR-Sens and .93-1.22 for GR-PP respectively. Conclusions: GV2 retains excellent psychometric properties as does GV1.

Effects of Combined Upper Limb Robotic Therapy in Patients With Tetraplegic Spinal Cord Injury

OBJECTIVE

To confirm the effects of combined upper limb robotic therapy (RT) as compared to conventional occupational therapy (OT) in tetraplegic spinal cord injury (SCI) patients and to suggest the optimized treatment guidelines of combined upper limb RT.

METHODS

After subject recruitment and screening for eligibility, the baseline evaluation for outcome measures were performed. We evaluated the Graded and Redefined Assessment of Strength, Sensibility, and Prehension (GRASSP), the American Spinal Injury Association upper extremity motor score, grip and pinch strength, and the Spinal Cord Independence Measurement III (SCIM-III). In this study, the pre-tested participants were divided randomly into the RT and OT group. The utilized interventions included combined upper limb RT using ArmeoPower and Amadeo (RT group), or conventional OT (OT group) in addition to daily inpatient rehabilitation program. The participants underwent 40 minutes×3 sessions×5 weeks of interventions.

RESULTS

A total of 30 tetraplegic SCI patients completed entire study program. After 5 weeks of intervention, both groups demonstrated increases in GRASSP-strength and SCIM-III. The manual muscle test scores of elbow flexion, elbow extension, 2-5th metacarpophalangeal extension, and SCIM-III subscores of bathing-upper, dressing-upper, and grooming as well as the GRASSP-qualitative prehension score were noted to have been significantly increased in the RT group as evaluated. The OT group showed improvements in the GRASSP-quantitative prehension score and some items in grip and pinch strength. There was no significant difference between the two groups in almost all measurements except for the SCIM-III bathing-upper subscore.

CONCLUSION

Combined upper limb RT demonstrated beneficial effects on the upper limb motor function in patients with tetraplegic SCI, which were comparable with conventional OT.

Spinal cord injury pharmacotherapy: Current research & development and competitive commercial landscape as of 2015

CONTEXT

Current treatment of spinal cord injury (SCI) focuses on cord stabilization to prevent further injury, rehabilitation, management of non-motor symptoms, and prevention of complications. Currently, no approved treatments are available, and limited treatment options exist for symptoms and complications associated with chronic SCI. This review describes the pharmacotherapy landscape in SCI from both commercial and research and development (R&D) standpoints through March 2015.

METHODS

Information about specific compounds has been obtained through drug pipeline monographs in the Pharmaprojects® (Citeline, Inc., New York, New York, USA) drug database (current as of a search on May 30, 2014), websites of individual companies with compounds in development for SCI (current as of March 24, 2015), and a literature search of published R&D studies to validate the Pharmaprojects® source for selected compounds (current as of March 24, 2015).

RESULTS

Types of studies conducted and outcomes measured in earlier phases of development are described for compounds in clinical development Currently four primary mechanisms are under investigation and may yield promising therapeutic targets: 1) neuronal regeneration; 2) neuroprotection (including anti-inflammation); 3) axonal reconnection; and 4) neuromodulation and signal enhancement. Many other compounds are no longer under investigation for SCI are mentioned; however, in most cases, the reason for terminating their development is not clear.

CONCLUSION

There is urgent need to develop disease-modifying therapy for SCI, yet the commercial landscape remains small and highly fragmented with a paucity of novel late-stage compounds in R&D.

Lower extremity outcome measures: considerations for clinical trials in spinal cord injury

STUDY DESIGN

This is a focused review article.

OBJECTIVES

To identify important concepts in lower extremity (LE) assessment with a focus on locomotor outcomes and provide guidance on how existing outcome measurement tools may be best used to assess experimental therapies in spinal cord injury (SCI). The emphasis lies on LE outcomes in individuals with complete and incomplete SCI in Phase II-III trials.

METHODS

This review includes a summary of topics discussed during a workshop focusing on LE function in SCI, conceptual discussion of corresponding outcome measures and additional focused literature review.

RESULTS

There are a number of sensitive, accurate, and responsive outcome tools measuring both quantitative and qualitative aspects of LE function. However, in trials with individuals with very acute injuries, a baseline assessment of the primary (or secondary) LE outcome measure is often not feasible.

CONCLUSION

There is no single outcome measure to assess all individuals with SCI that can be used to monitor changes in LE function regardless of severity and level of injury. Surrogate markers have to be used to assess LE function in individuals with severe SCI. However, it is generally agreed that a direct measurement of the performance for an appropriate functional activity supersedes any surrogate marker. LE assessments have to be refined so they can be used across all time points after SCI, regardless of the level or severity of spinal injury.

SPONSORS

Craig H. Neilsen Foundation, Spinal Cord Outcomes Partnership Endeavor.

First-in-Man Intrathecal Application of Neurite Growth-Promoting Anti-Nogo-A Antibodies in Acute Spinal Cord Injury

Background. Neutralization of central nervous system neurite growth inhibitory factors, for example, Nogo-A, is a promising approach to improving recovery following spinal cord injury (SCI). In animal SCI models, intrathecal delivery of anti-Nogo-A antibodies promoted regenerative neurite growth and functional recovery. Objective. This first-in-man study assessed the feasibility, safety, tolerability, pharmacokinetics, and preliminary efficacy of the human anti-Nogo-A antibody ATI355 following intrathecal administration in patients with acute, complete traumatic paraplegia and tetraplegia. Methods. Patients (N = 52) started treatment 4 to 60 days postinjury. Four consecutive dose-escalation cohorts received 5 to 30 mg/2.5 mL/day continuous intrathecal ATI355 infusion over 24 hours to 28 days. Following pharmacokinetic evaluation, 2 further cohorts received a bolus regimen (6 intrathecal injections of 22.5 and 45 mg/3 mL, respectively, over 4 weeks). Results. ATI355 was well tolerated up to 1-year follow-up. All patients experienced ≥1 adverse events (AEs). The 581 reported AEs were mostly mild and to be expected following acute SCI. Fifteen patients reported 16 serious AEs, none related to ATI355; one bacterial meningitis case was considered related to intrathecal administration. ATI355 serum levels showed dose-dependency, and intersubject cerebrospinal fluid levels were highly variable after infusion and bolus injection. In 1 paraplegic patient, motor scores improved by 8 points. In tetraplegic patients, mean total motor scores increased, with 3/19 gaining >10 points, and 1/19 27 points at Week 48. Conversion from complete to incomplete SCI occurred in 7/19 patients with tetraplegia. Conclusions. ATI335 was well tolerated in humans; efficacy trials using intrathecal antibody administration may be considered in acute SCI.

The Graded and Redefined Assessment of Strength, Sensibility, and Prehension Version 2 Provides Interval Measure Properties

The Graded and Redefined Assessment of Strength, Sensibility and Prehension (GRASSP) is a valid, reliable, and responsive outcome measure to evaluate upper limb function in individuals with tetraplegia. GRASSP generates ordinal total scores; therefore, applicability as an interval level measurement requires testing of its measurement properties. This study examined the metric characteristics with Rasch Analysis to derive interval level scales of the respective GRASSP subtests. The GRASSP was recorded within 10 days, and at 1, 3, 6, and 12 months after cervical spinal cord injury (SCI). Rasch analysis was performed for each GRASSP subscale to assess the following metric assumptions: absence of local item dependency (LID), unidimensionality, monotonicity, item and model fit, reliability, and absence of differential item functioning (DIF) for side (left and right) and examination stage. If these assumptions could not be met, adjustments were undertaken to achieve a good fit to the Rasch model. Seventy-seven individuals with cervical SCI were included (n = 154 arms). Stacking the data for the side (left and right) resulted in a total of 614 observations, which were based on the repeated measurements. With minor adjustments, the GRASSP subscales showed good reliability, item fit, and ordered response options. Local item dependencies were found in the strength and sensibility subscales. Redundancies among some measurement items allowed shortening of the subscales without reasonable loss of reliability. Absence of DIF for the examination stage supported robustness of the subscales over time. The modified GRASSP, now Version 2, subtest scores can be applied as interval level measurements, and the reduction of items within subscales allows for shorter assessment times in clinical studies without degrading metric properties.

Rho Inhibitor VX-210 in Acute Traumatic Subaxial Cervical Spinal Cord Injury: Design of the SPinal Cord Injury Rho INhibition InvestiGation (SPRING) Clinical Trial

Traumatic spinal cord injury (SCI) is associated with a lifetime of disability stemming from loss of motor, sensory, and autonomic functions; these losses, along with increased comorbid sequelae, negatively impact health outcomes and quality of life. Early decompression surgery post-SCI can enhance patient outcomes, but does not directly facilitate neural repair and regeneration. Currently, there are no U.S. Food and Drug Administration-approved pharmacological therapies to augment motor function and functional recovery in individuals with traumatic SCI. After an SCI, the enzyme, Rho, is activated by growth-inhibitory factors and regulates events that culminate in collapse of the neuronal growth cone, failure of axonal regeneration, and, ultimately, failure of motor and functional recovery. Inhibition of Rho activation is a potential treatment for injuries such as traumatic SCI. VX-210, an investigational agent, inhibits Rho. When administered extradurally after decompression (corpectomy or laminectomy) and stabilization surgery in a phase 1/2a study, VX-210 was well tolerated. Here, we describe the design of the SPRING trial, a multicenter, phase 2b/3, randomized, double-blind, placebo-controlled clinical trial to evaluate the efficacy and safety of VX-210 (NCT02669849). A subset of patients with acute traumatic cervical SCI is currently being enrolled in the United States and Canada. Medical, neurological, and functional changes are evaluated at 6 weeks and at 3, 6, and 12 months after VX-210 administration. Efficacy will be assessed by the primary outcome measure, change in upper extremity motor score at 6 months post-treatment, and by secondary outcomes that include question-based and task-based evaluations of functional recovery.

Generating level-dependent models of cervical and thoracic spinal cord injury: Exploring the interplay of neuroanatomy, physiology, and function

The majority of spinal cord injuries (SCI) occur at the cervical level, which results in significant impairment. Neurologic level and severity of injury are primary endpoints in clinical trials; however, how level-specific damages relate to behavioural performance in cervical injury is incompletely understood. We hypothesized that ascending level of injury leads to worsening forelimb performance, and correlates with loss of neural tissue and muscle-specific neuron pools. A direct comparison of multiple models was made with injury realized at the C5, C6, C7 and T7 vertebral levels using clip compression with sham-operated controls. Animals were assessed for 10weeks post-injury with numerous (40) outcome measures, including: classic behavioural tests, CatWalk, non-invasive MRI, electrophysiology, histologic lesion morphometry, neuron counts, and motor compartment quantification, and multivariate statistics on the total dataset. Histologic staining and T1-weighted MR imaging revealed similar structural changes and distinct tissue loss with cystic cavitation across all injuries. Forelimb tests, including grip strength, F-WARP motor scale, Inclined Plane, and forelimb ladder walk, exhibited stratification between all groups and marked impairment with C5 and C6 injuries. Classic hindlimb tests including BBB, hindlimb ladder walk, bladder recovery, and mortality were not different between cervical and thoracic injuries. CatWalk multivariate gait analysis showed reciprocal and progressive changes forelimb and hindlimb function with ascending level of injury. Electrophysiology revealed poor forelimb axonal conduction in cervical C5 and C6 groups alone. The cervical enlargement (C5-T2) showed progressive ventral horn atrophy and loss of specific motor neuron populations with ascending injury. Multivariate statistics revealed a robust dataset, rank-order contribution of outcomes, and allowed prediction of injury level with single-level discrimination using forelimb performance and neuron counts. Level-dependent models were generated using clip-compression SCI, with marked and reliable differences in forelimb performance and specific neuron pool loss.

Non-concomitant cortical structural and functional alterations in sensorimotor areas following incomplete spinal cord injury

Brain plasticity, including anatomical changes and functional reorganization, is the physiological basis of functional recovery after spinal cord injury (SCI). The correlation between brain anatomical changes and functional reorganization after SCI is unclear. This study aimed to explore whether alterations of cortical structure and network function are concomitant in sensorimotor areas after incomplete SCI. Eighteen patients with incomplete SCI (mean age 40.94 ± 14.10 years old; male:female, 7:11) and 18 healthy subjects (37.33 ± 11.79 years old; male:female, 7:11) were studied by resting state functional magnetic resonance imaging. Gray matter volume (GMV) and functional connectivity were used to evaluate cortical structure and network function, respectively. There was no significant alteration of GMV in sensorimotor areas in patients with incomplete SCI compared with healthy subjects. Intra-hemispheric functional connectivity between left primary somatosensory cortex (BA1) and left primary motor cortex (BA4), and left BA1 and left somatosensory association cortex (BA5) was decreased, as well as inter-hemispheric functional connectivity between left BA1 and right BA4, left BA1 and right BA5, and left BA4 and right BA5 in patients with SCI. Functional connectivity between both BA4 areas was also decreased. The decreased functional connectivity between the left BA1 and the right BA4 positively correlated with American Spinal Injury Association sensory score in SCI patients. The results indicate that alterations of cortical anatomical structure and network functional connectivity in sensorimotor areas were non-concomitant in patients with incomplete SCI, indicating the network functional changes in sensorimotor areas may not be dependent on anatomic structure. The strength of functional connectivity within sensorimotor areas could serve as a potential imaging biomarker for assessment and prediction of sensory function in patients with incomplete SCI. This trial was registered with the Chinese Clinical Trial Registry (registration number: ChiCTR-ROC-17013566).

Intrathecal transplantation of autologous adipose-derived mesenchymal stem cells for treating spinal cord injury: A human trial

CONTEXT

Spinal cord injury (SCI) can cause irreversible damage to neural tissues. However, there is currently no effective treatment for SCI. The therapeutic potential of adipose-derived mesenchymal stem cells (ADMSCs) has been emerged.

OBJECTIVE

We evaluated the effects and safety of the intrathecal transplantation of autologous ADMSCs in patients with SCI. Participants/Interventions: Fourteen patients with SCI were enrolled (12 for ASIA A, 1 for B, and 1 for D; duration of impairments 3-28 months). Six patients were injured at cervical, 1 at cervico-thoracic, 6 at thoracic, and 1 at lumbar level. Autologous ADMSCs were isolated from lipoaspirates of patients' subcutaneous fat tissue and 9 × 10⁷ ADMSCs per patient were administered intrathecally through lumbar tapping. MRI, hematological parameters, electrophysiology studies, and ASIA motor/sensory scores were assessed before and after transplantation.

RESULTS

ASIA motor scores were improved in 5 patients at 8 months follow-up (1-2 grades at some myotomes). Voluntary anal contraction improvement was seen in 2 patients. ASIA sensory score recovery was seen in 10, although degeneration was seen in 1. In somatosensory evoked potential test, one patient showed median nerve improvement. There was no interval change of MRI between baseline and 8 months post-transplantation. Four adverse events were observed in three patients: urinary tract infection, headache, nausea, and vomiting.

CONCLUSIONS

Over the 8 months of follow-up, intrathecal transplantation of autologous ADMSCs for SCI was free of serious adverse events, and several patients showed mild improvements in neurological function. Patient selection, dosage, and delivery method of ADMSCs should be investigated further.

Multi-Day Recordings of Wearable Sensors Are Valid and Sensitive Measures of Function and Independence in Human Spinal Cord Injury

Wearable sensor assessment tools have proven to be reliable in measuring function in normal and impaired movement disorders during well-defined assessment protocols. While such assessments can provide valid and sensitive measures of upper limb activity in spinal cord injury (SCI), no assessment tool has yet been introduced into unsupervised daily recordings to complement clinical assessments during rehabilitation. The objective of this study was to measure the overall amount of upper-limb activity in subjects with acute SCI using wearable sensors and relate this to lesion characteristics, independence, and function. The overall amount of upper extremity activity counts, measures of wheeling (speed and distance), and limb-use laterality were measured in 30 in-patients with an acute cervical or thoracic SCI three months after injury. The findings were related to the international standards for neurological classification of SCI, the spinal cord independence measure, and the upper extremity motor scores of the Graded and Redefined Assessment of Strength, Sensibility, and Prehension. Overall upper extremity activity counts were successfully recorded in all patients and correlated with the neurological level of injury and independence. Clinical measures of proximal muscle strength were related to overall activity count and peak velocity of wheeling. Compared with paraplegics, tetraplegics showed significantly lower activity counts and increased limb-use laterality. This is the first cross-sectional study showing the feasibility and clinical value of sensor recordings during unsupervised daily activities in rehabilitation. The strong relationship between sensor-based measures and clinical outcomes supports the application of such technology to assess and track changes in function during rehabilitation and in clinical trials.

Predictive Value of Upper Limb Muscles and Grasp Patterns on Functional Outcome in Cervical Spinal Cord Injury

Objective. To determine which single or combined upper limb muscles as defined by the International Standards for the Neurological Classification of Spinal Cord Injury (ISNCSCI); upper extremity motor score (UEMS) and the Graded Redefined Assessment of Strength, Sensibility, and Prehension (GRASSP), best predict upper limb function and independence in activities of daily living (ADLs) and to assess the predictive value of qualitative grasp movements (QlG) on upper limb function in individuals with acute tetraplegia. Method. As part of a Europe-wide, prospective, longitudinal, multicenter study ISNCSCI, GRASSP, and Spinal Cord Independence Measure (SCIM III) scores were recorded at 1 and 6 months after SCI. For prediction of upper limb function and ADLs, a logistic regression model and unbiased recursive partitioning conditional inference tree (URP-CTREE) were used. Results. Logistic regression and URP-CTREE revealed that a combination of ISNCSCI and GRASSP muscles (to a maximum of 4) demonstrated the best prediction (specificity and sensitivity ranged from 81.8% to 96.0%) of upper limb function and identified homogenous outcome cohorts at 6 months. The URP-CTREE model with the QlG predictors for upper limb function showed similar results. Conclusion. Prediction of upper limb function can be achieved through a combination of defined, specific upper limb muscles assessed in the ISNCSCI and GRASSP. A combination of a limited number of proximal and distal muscles along with an assessment of grasping movements can be applied for clinical decision making for rehabilitation interventions and clinical trials.

Reliability and validity of the capabilities of upper extremity test (CUE-T) in subjects with chronic spinal cord injury

OBJECTIVE

To determine the reliability and validity of the capabilities of upper extremity test (CUE-T), a measure of functional limitations, in patients with chronic tetraplegia.

DESIGN

Repeated measures.

SETTING

Outpatient rehabilitation center.

PARTICIPANTS

Fifty subjects (36 male/14 female) with spinal cord injury (SCI) of ≥1-year duration participated. Subjects were 17-81 years old (mean 48.1 ± 18.2); neurological levels ranged from C2 through T6, American Spinal Injury Association Impairment Scale grades A-D.

INTERVENTIONS

Not applicable.

OUTCOME MEASURES

Intraclass correlation coefficients (ICC), weighted kappa and repeatability values for CUE-T; Spearman correlations of CUE-T with upper extremity motor scores (UEMS), and self-care and mobility portions of the Spinal Cord Independence Measure, vIII (SCIM III).

RESULTS

Score ranges for UEMS were 8-50, CUE-T 7-135, self-care SCIM 0-20, and mobility SCIM 0-40. The ICC values for total, right, and left side scores were excellent (0.97-0.98; 95% confidence interval 0.96-0.99). Item weighted kappa values were ≥0.60 for all but five items, four of which were right and left pronation and supination. Repeatability of total score was 10.8 points, right and left sides 6.3 and 6.1 points. Spearman correlations of the total CUE-T with the UEMS and SCIM self-care and mobility scores were 0.83, 0.70, and 0.55 respectively.

CONCLUSIONS

The CUE-T displays excellent test-retest reliability, and good-excellent correlation with impairment and capacity measures in persons with chronic SCI. After revising pronation and supination test procedures, the sensitivity to change should be determined.

Common data elements for spinal cord injury clinical research: a National Institute for Neurological Disorders and Stroke project

OBJECTIVES

To develop a comprehensive set of common data elements (CDEs), data definitions, case report forms and guidelines for use in spinal cord injury (SCI) clinical research, as part of the CDE project at the National Institute of Neurological Disorders and Stroke (NINDS) of the US National Institutes of Health.

SETTING

International Working Groups.

METHODS

Nine working groups composed of international experts reviewed existing CDEs and instruments, created new elements when needed and provided recommendations for SCI clinical research. The project was carried out in collaboration with and cross-referenced to development of the International Spinal Cord Society (ISCoS) International SCI Data Sets. The recommendations were compiled, subjected to internal review and posted online for external public comment. The final version was reviewed by all working groups and the NINDS CDE team before release.

RESULTS

The NINDS SCI CDEs and supporting documents are publically available on the NINDS CDE website and the ISCoS website. The CDEs span the continuum of SCI care and the full range of domains of the International Classification of Functioning, Disability and Health.

CONCLUSION

Widespread use of CDEs can facilitate SCI clinical research and trial design, data sharing and retrospective analyses. Continued international collaboration will enable consistent data collection and reporting, and will help ensure that the data elements are updated, reviewed and broadcast as additional evidence is obtained.

Toward Inclusive Trial Protocols in Heterogeneous Neurological Disorders

Background. Several novel drug- and cell-based potential therapies for spinal cord injury (SCI) have either been applied or will be considered for future clinical trials. Limitations on the number of eligible patients require trials be undertaken in a highly efficient and effective manner. However, this is particularly challenging when people living with incomplete SCI (iSCI) represent a very heterogeneous population in terms of recovery patterns and can improve spontaneously over the first year after injury. Objective. The current study addresses 2 requirements for designing SCI trials: first, enrollment of as many eligible participants as possible; second, refined stratification of participants into homogeneous cohorts from a heterogeneous iSCI population. Methods. This is a retrospective, longitudinal analysis of prospectively collected SCI data from the European Multicenter study about Spinal Cord Injury (EMSCI). We applied conditional inference trees to provide a prediction-based stratification algorithm that could be used to generate decision rules for the appropriate inclusion of iSCI participants to a trial. Results. Based on baseline clinical assessments and a defined subsequent clinical endpoint, conditional inference trees partitioned iSCI participants into more homogeneous groups with regard to the illustrative endpoint, upper extremity motor score. Assuming a continuous endpoint, the conditional inference tree was validated both internally as well as externally, providing stable and generalizable results. Conclusion. The application of conditional inference trees is feasible for iSCI participants and provides easily implementable, prediction-based decision rules for inclusion and stratification. This algorithm could be utilized to model various trial endpoints and outcome thresholds.

Changes in Strength, Sensation, and Prehension in Acute Cervical Spinal Cord Injury

Objective. To investigate the internal and external responsiveness and recovery profiles of the Graded Redefined Assessment of Strength, Sensibility, and Prehension (GRASSP) instrument in revealing changes in upper limb function within the first year following cervical spinal cord injury (SCI). Method. A European prospective, longitudinal, multicenter study assessing the GRASSP at 1, 3, 6, and 12 months after cervical SCI. Subtests of GRASSP were compared to the upper extremity motor (UEMS) and light touch scores (LT) according to the International Standards of Neurological Classification of Spinal Cord Injury (ISNCSCI), the Spinal Cord Independence Measure self-care subscore (SCIM-SS), as well as a clinician-rated outcome measure (CROM) of clinical relevance. Data were analyzed for GRASSP responsiveness and recovery rate over time. Results. Seventy-four participants entered the study. GRASSP subtests proved responsive (standardized response mean [SRM] ranged from 0.79 to 1.48 for strength, 0.50 to 1.03 for prehension, and 0.14 to 0.64 for sensation) between all examination time points. In comparison, UEMS and LT showed lower responsiveness (SRM UEMS ranged from 0.69 to 1.29 and SRM LT ranged from 0.30 to −0.13). All GRASSP subtests revealed significant, moderate-to-excellent correlations with UEMS, LT, and SCIM-SS at each time point, and changes in GRASSP subtests were in accordance with the CROM. GRASSP prehension and motor recovery was largest between 1 and 3 months. Conclusion. The GRASSP showed excellent responsiveness, detecting distinct changes in strength and prehension relating to the severity of cervical SCI. It detected clinically significant changes complimentary to the ISNCSCI and SCIM-SS assessments.

The influence of time from injury to surgery on motor recovery and length of hospital stay in acute traumatic spinal cord injury: an observational Canadian cohort study

To determine the influence of time from injury to surgery on neurological recovery and length of stay (LOS) in an observational cohort of individuals with traumatic spinal cord injury (tSCI), we analyzed the baseline and follow-up motor scores of participants in the Rick Hansen Spinal Cord Injury Registry to specifically assess the effect of an early (less than 24 h from injury) surgical procedure on motor recovery and on LOS. One thousand four hundred and ten patients who sustained acute tSCIs with baseline American Spinal Injury Association Impairment Scale (AIS) grades A, B, C, or D and were treated surgically were analyzed to determine the effect of the timing of surgery (24, 48, or 72 h from injury) on motor recovery and LOS. Depending on the distribution of data, we used different types of generalized linear models, including multiple linear regression, gamma regression, and negative binomial regression. Persons with incomplete AIS B, C, and D injuries from C2 to L2 demonstrated motor recovery improvement of an additional 6.3 motor points (SE=2.8 p<0.03) when they underwent surgical treatment within 24 h from the time of injury, compared with those who had surgery later than 24 h post-injury. This beneficial effect of early surgery on motor recovery was not seen in the patients with AIS A complete SCI. AIS A and B patients who received early surgery experienced shorter hospital LOS. While the issues of when to perform surgery and what specific operation to perform remain controversial, this work provides evidence that for an incomplete acute tSCI in the cervical, thoracic, or thoracolumbar spine, surgery performed within 24 h from injury improves motor neurological recovery. Early surgery also reduces LOS.

Cervical spinal cord injury: tailoring clinical trial endpoints to reflect meaningful functional improvements

Cervical spinal cord injury (SCI) results in partial to full paralysis of the upper and lower extremities. Traditional primary endpoints for acute SCI clinical trials are too broad to assess functional recovery in cervical subjects, raising the possibility of false positive outcomes in trials for cervical SCI. Endpoints focused on the recovery of hand and arm control (e.g., upper extremity motor score, motor level change) show the most potential for use as primary outcomes in upcoming trials of cervical SCI. As the field moves forward, the most reliable way to ensure meaningful clinical testing in cervical subjects may be the development of a composite primary endpoint that measures both neurological recovery and functional improvement.

Comparison of neurological and functional outcomes after administration of granulocyte-colony-stimulating factor in motor-complete versus motor-incomplete postrehabilitated, chronic spinal cord injuries: a phase I/II study

Granulocyte-colony-stimulating factor (G-CSF) is a major growth factor in the activation and differentiation of granulocytes. This cytokine has been widely and safely employed in different disease conditions over many years. The administration of the growth factors in spinal cord injury (SCI) has been reported elsewhere; here we have tried to see the effect of SCI severity on the neurological outcomes after neuroprotective treatment for SCI with G-CSF. Seventy-four consecutive patients with SCI of at least 6 months' duration, with stable neurological status in the last 3 months, having informed consent for the treatment were included in the study. All the patients had undergone at least 3 months of standard rehabilitation. Patients were assessed by the American Spinal Injury Association (ASIA) scale, Spinal Cord Independence Measure (SCIM) III, and International Association of Neurorestoratology-Spinal Cord Injury Functional Rating Scale (IANR-SCIFRS) just before intervention and periodically until 6 months after subcutaneous administration of 5 µg/kg per day of G-CSF for 7 consecutive days. Multiple linear regression models were performed for statistical evaluation of lesion completeness and level of injury on changes in ASIA motor, light touch, pinprick, IANR-SCIFRS, and SCIM III scores, as a phase I/II comparative study. The study consisted of 52 motor-complete and 22 motor-incomplete SCI patients. There was no significant difference regarding age and sex, chronicity, and level of SCI between the two groups. Motor-incomplete patients had significantly more improvement in ASIA motor score compared to the motor-complete patients (7.68 scores, p < 0.001); also they had significant improvement in light touch (6.42 scores, p = 0.003) and pinprick sensory scores (4.89 scores, p = 0.011). Therefore, G-CSF administration in motor-incomplete SCIs is associated with significantly higher motor improvement, and also the higher the initial ASIA Impairment Scale (AIS) grade, the less would be the final AIS change, and incomplete cases are more welcome into the future studies. This manuscript is published as part of the International Association of Neurorestoratology (IANR) special issue of Cell Transplantation.

Prediction and Stratification of Upper Limb Function and Self-Care in Acute Cervical Spinal Cord Injury With the Graded Redefined Assessment of Strength, Sensibility, and Prehension (GRASSP)

Background. There is inherent heterogeneity within individuals suffering from cervical spinal cord injury (SCI), and early prediction of upper limb function and self-care is challenging. As a result, considerable uncertainty exists regarding the prediction of functional outcome following cervical SCI within 1 year of injury. Objective. To evaluate the value of Graded Redefined Assessment of Strength, Sensibility, and Prehension (GRASSP) in predicting upper limb function and self-care outcomes in individuals with cervical SCI. Method. A prospective longitudinal multicenter study was performed. Data from the GRASSP, the Spinal Cord Independence Measure (SCIM III), and the American Spinal Injury Association (ASIA) Impairment Scale were recorded at 1, 6, and 12 months after cervical SCI. For prediction of functional outcome at 6 and 12 months, a logistic regression model, receiver operating characteristics (ROC), and unbiased recursive partitioning conditional inference tree (URP-CTREE) were used with 8 different predictor variables. Results. Logistic regression analysis, ROC analysis, and URP-CTREE all revealed that the strength subtest within GRASSP is the strongest predictor for upper limb function and self-care outcomes. URP-CTREE provides useful information on the distribution of different outcomes in acute cervical SCI and can be used to predict cohorts with homogeneous outcomes. Conclusion. The GRASSP at 1 month can accurately predict upper limb function and self-care outcomes even in a heterogeneous group of individuals across a wide spectrum of neurological recovery. The application of URP-CTREE can reveal the distribution of outcome categories and, based on this, inform trial protocols with respect to outcomes analysis and patient stratification.

Identifying Homogeneous Subgroups in Neurological Disorders

Background. The reliable stratification of homogeneous subgroups and the prediction of future clinical outcomes within heterogeneous neurological disorders is a particularly challenging task. Nonetheless, it is essential for the implementation of targeted care and effective therapeutic interventions. Objective. This study was designed to assess the value of a recently developed regression tool from the family of unbiased recursive partitioning methods in comparison to established statistical approaches (eg, linear and logistic regression) for predicting clinical endpoints and for prospective patients’ stratification for clinical trials. Methods. A retrospective, longitudinal analysis of prospectively collected neurological data from the European Multicenter study about Spinal Cord Injury (EMSCI) network was undertaken on C4-C6 cervical sensorimotor complete subjects. Predictors were based on a broad set of early (<2 weeks) clinical assessments. Endpoints were based on later clinical examinations of upper extremity motor scores and recovery of motor levels, at 6 and 12 months, respectively. Prediction accuracy for each statistical analysis was quantified by resampling techniques. Results. For all settings, overlapping confidence intervals indicated similar prediction accuracy of unbiased recursive partitioning to established statistical approaches. In addition, unbiased recursive partitioning provided a direct way of identification of more homogeneous subgroups. The partitioning is carried out in a data-driven manner, independently from a priori decisions or predefined thresholds. Conclusion. Unbiased recursive partitioning techniques may improve prediction of future clinical endpoints and the planning of future SCI clinical trials by providing easily implementable, data-driven rationales for early patient stratification based on simple decision rules and clinical read-outs.

Human spinal cord injury: motor unit properties and behaviour

Spinal cord injury (SCI) results in widespread variation in muscle function. Review of motor unit data shows that changes in the amount and balance of excitatory and inhibitory inputs after SCI alter management of motoneurons. Not only are units recruited up to higher than usual relative forces when SCI leaves few units under voluntary control, the force contribution from recruitment increases due to elevation of twitch/tetanic force ratios. Force gradation and precision are also coarser with reduced unit numbers. Maximal unit firing rates are low in hand muscles, limiting voluntary strength, but are low, normal or high in limb muscles. Unit firing rates during spasms can exceed voluntary rates, emphasizing that deficits in descending drive limit force production. SCI also changes muscle properties. Motor unit weakness and fatigability seem universal across muscles and species, increasing the muscle weakness that arises from paralysis of units, motoneuron death and sensory impairment. Motor axon conduction velocity decreases after human SCI. Muscle contractile speed is also reduced, which lowers the stimulation frequencies needed to grade force when paralysed muscles are activated with patterned electrical stimulation. This slowing does not necessarily occur in hind limb muscles after cord transection in cats and rats. The nature, duration and level of SCI underlie some of these species differences, as do variations in muscle function, daily usage, tract control and fibre-type composition. Exploring this diversity is important to promote recovery of the hand, bowel, bladder and locomotor function most wanted by people with SCI.

Traversing the translational trail for trials

The principles of spinal cord injury clinical trial programs are briefly reviewed as one example of the challenge faced by most human studies of neurologically directed therapeutic interventions, including rehabilitation strategies. Different trial protocols are reviewed, as are inclusion/exclusion criteria for study subjects, the choice of clinical endpoints, and the statistical approaches that might be used in a trial program. Potential factors that might confound the accurate interpretation of trial data are also identified. Regardless of the specific therapeutic target or the rehabilitation strategy to be evaluated, there are many unresolved issues that will have to be answered before specific and effective prescriptions can be delivered.