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Objective: To corroborate findings suggesting that spinally targeted paired associative stimulation improves upper extremity motor function in chronic incomplete spinal cord injury., Design: Prospective interventional study., Subjects: Five adults with chronic tetraplegia., Methods: Participants received paired associative stimulation, combining peripheral nerve stimulation and navigated transcranial magnetic stimulation towards 1 arm (16 1-h sessions during 4 consecutive weeks, targeting the 3 large nerves). Manual muscle testing (MMT) was performed in 23 muscles in each arm, at 3 time points (pre-stimulation, t0; the week following the stimulation period, t1; and 4-5 weeks post-stimulation, t2). Additionally, grip strength and changes in the Canadian Occupational Performance Measure were assessed., Results: The mean improvement in manual muscle testing scores in the targeted extremity was +0.49 at t1 (p = 0.078) and +0.55 at t2 (p = 0.062). Grip strength in the stimulated extremity increased by 3.2 kg at t1 and 3.4 kg at t2, and in the non-targeted extremity by 2.2 and 3.6 kg, respectively. Performance and satisfaction increased by 2.1/2.4 points at t1, and by 2.0/1.9 points at t2., Conclusion: Paired associative stimulation improved motor function: at the group level, MMT of the stimulated hand (p = 0.06) and non-stimulated hand (p = 0.04). Most participants achieved clinically relevant improvement. Thus, the results corroborate prior studies. The method may complement conventional rehabilitation for improving upper extremity function in incomplete tetraplegia.

Introduction/aims: Accurately diagnosing Guillain-Barré syndrome (GBS) in its early stages and distinguishing it from mimics poses challenges. This study aimed to evaluate the utility of an existing electrodiagnostic criterion in very early GBS (VEGBS) for discerning mimics. Additionally, we explored specific electrophysiological abnormalities in VEGBS to design a new diagnostic criterion for more accurate VEGBS diagnosis., Methods: We retrospectively identified all patients with flaccid quadriparesis initially suspected of GBS who underwent nerve conduction studies (NCS) ≤4 days from symptom onset. We then retrieved their NCS data and applied an existing electrodiagnostic criterion for sensitivity and specificity analyses based on the final discharge diagnosis. Furthermore, we designed a new criterion based on the observed electrophysiological abnormalities that have maximum specificity and at least 50% sensitivity., Results: Among 70 patients suspected of VEGBS, 44 (63%) received a final diagnosis of GBS, while in 26 (37%), the GBS diagnosis was later refuted. Umapathi's definite criterion exhibited a sensitivity of 61.36% and a specificity of 92.31%. The probable and possible groups showed very high sensitivity (90.91% and 100%, respectively); however, specificity was low (57.69% and 30.77%, respectively) in the very early stage. Our proposed criterion demonstrated a sensitivity of 88.64% (CI: 75.44%-96.21%) and a specificity of 96.15% (CI: 80.36%-99.90%)., Discussion: The criterion based on presumed electrophysiological correlates of specific early GBS pathophysiology proved more effective than the existing electrodiagnostic criterion in differentiating VEGBS from mimics., (© 2024 Wiley Periodicals LLC.)

Introduction: Tetraplegia causes extensive sensorimotor deficits affecting activity, participation and quality of life. People with C6-C7 tetraplegia can learn to grasp objects by performing wrist extension movement (ie, tenodesis grasp), and motor imagery (MI) added to rehabilitation significantly improved tenodesis grasp. We hypothesise that this improvement can be further boosted by adding neurofeedback during MI. Thus, we design a randomised controlled trial investigating the effect of MI training on grasping ability in people with C6-C7 tetraplegia., Methods and Analysis: We will perform a bicentric, assessor-blinded, randomised controlled study. During rehabilitation, 21 inpatients with C6-C7 tetraplegia will be allocated to MI with neurofeedback (MI training with graphical display on a computer screen based on mu (8-13 Hz) and beta (18-25 Hz) frequency rhythms measured with 32-channel electroencephalography), MI alone (only MI training) and control (watching movies and visualisation of geometric shapes). All participants will receive three 45-min training sessions per week for 5 weeks.The primary outcome measure will be wrist extension angle immediately after the intervention during tenodesis grasp measured with a 3D motion analysis system (VICON). Secondary outcomes will include a range of measures: kinematic, grip strength, upper limb range of motion, upper limb strength (manual muscle test and hand-held dynamometer measure), dexterity (box and block test, 9-hole peg test, Jebsen test, capabilities of upper extremity questionnaire), quality of life (WHOQOL-Bref), daily life autonomy (Quadriplegic Index of Function), MI capacity and brain reorganisation (magnetoencephalography only available in Lyon, n=15). We will measure all outcomes five times: during weeks 1, 3 and 5 (baseline), week 11 (immediately after the intervention end) and week 18 (8 weeks after the intervention end)., Ethics and Dissemination: Ethical approval was granted on 29 September 2017 (CPP Nord-Ouest-IV 17/25, N°2017-A00990-53). Dissemination will occur via presentation of results in scientific meetings and publication in peer-reviewed academic journals., Trial Registration Number: NCT03190863 (ClinicalTrials.gov)., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Intracortical brain-computer interfaces (iBCIs) enable people with tetraplegia to gain intuitive cursor control from movement intentions. To translate to practical use, iBCIs should provide reliable performance for extended periods of time. However, performance begins to degrade as the relationship between kinematic intention and recorded neural activity shifts compared to when the decoder was initially trained. In addition to developing decoders to better handle long-term instability, identifying when to recalibrate will also optimize performance. We propose a method, "MINDFUL", to measure instabilities in neural data for useful long-term iBCI, without needing labels of user intentions. Longitudinal data were analyzed from two BrainGate2 participants with tetraplegia as they used fixed decoders to control a computer cursor spanning 142 days and 28 days, respectively. We demonstrate a measure of instability that correlates with changes in closed-loop cursor performance solely based on the recorded neural activity (Pearson r = 0.93 and 0.72, respectively). This result suggests a strategy to infer online iBCI performance from neural data alone and to determine when recalibration should take place for practical long-term use., (© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Disabled people with a high cervical cord injury or quadriplegia face difficulties when controlling a computer. This study presents a digital mouth-controlled mouse-control aid called the bite-press mouth-controlled mouse (BPMCM) to replace the traditional computer mouse. The BPMCM is equipped with a joystick and micro switch, and the disabled person uses neck and head movements to push the joystick and control the cursor position while the three mouse functions (i.e., left-click, right-click, and drag) are activated by bite-pressing for different time intervals. The proposed design eliminates the sip-and-puff technique and the need to recite orders for reduced adaptation time and increased convenience. Furthermore, this design supports plug-and-play and hot plugging in modern mainstream operating systems that can often be directly operated via mouse functions. Experimental results demonstrated that disabled people using a BPMCM were as capable as healthy participants in operating a computer, with both experiments completed within 5 min, and voluntary disabled people immediately adapted to the BPMCM. The proposed design is expected to allow disabled people to operate computers at the same level as healthy participants. The BPMCM also required only half the physical exertion of other mouth-controlled mouse-control aids that require orders to be recited., (© 2024 Author(s). Published under an exclusive license by AIP Publishing.)

Thermoregulation is impaired in individuals with a spinal cord lesion (SCI), affecting sweat capacity, heat loss, and core temperature. This can be particularly problematic for athletes with SCI who exercise in hot and humid conditions, like those during the Tokyo 2020 Paralympic Games. Heat acclimation can support optimal preparation for exercise in such challenging environments, but evidence is limited in endurance athletes with SCI. We evaluated whether seven consecutive days of exercise in the heat would result in heat acclimation. Five elite para-cycling athletes with SCI participated (two females, three males, median (Q1-Q3) 35 (31-51) years, four with paraplegia and one with tetraplegia). All tests and training sessions were performed in a heat chamber (30°C and 75% relative humidity). A time-to-exhaustion test was performed on day 1 (pretest) and day 7 (posttest). On days 2-6, athletes trained daily for one hour at 50-60% of individual peak power (P Peak ). Comparing pretest and posttest, all athletes increased their body mass loss (p=0.04), sweat rate (p=0.04), and time to exhaustion (p=0.04). Effects varied between athletes for core temperature and heart rate. All athletes appeared to benefit from our heat acclimation protocol, helping to optimize their preparation for the Tokyo 2020 Paralympic Games., Competing Interests: The authors declare that there are no conflicts of interest, intellectual, financial, or proprietary conflicts., (Thieme. All rights reserved.)

Central cord syndrome (CCS) is the most prevalent and debated incomplete spinal cord injury (SCI) syndrome, with its hallmark feature being more pronounced weakness of the upper extremities than of the lower extremities. Varying definitions encapsulate multiple clinical features under the single umbrella term of CCS, complicating evaluation of its frequency, prognosis discussions, and outcomes research. Often, people with CCS are excluded from research protocols, as it is thought to have a favorable prognosis, but the vague nature of CCS raises doubts about the validity of this practice. The objective of this study was to categorize CCS into specific subsets with clear quantifiable differences, to assess whether this would enhance the ability to determine if individuals with CCS or its subsets exhibit distinct neurological and functional outcomes relative to others with incomplete tetraplegia. This study retrospectively reviewed individuals with new motor incomplete tetraplegia from traumatic SCI who enrolled in the Spinal Cord Injury Model Systems (SCIMS) database from 2010 to 2020. Through an assessment of the prevailing criteria for CCS, coupled with data analysis, we used two key criteria, including the severity of distal upper extremity weakness (i.e., hands and fingers) and extent of symmetry, to delineate three CCS subsets: full CCS, unilateral CCS, and borderline CCS. Of the 1490 participants in our sample, 17.5% had full, 25.6% had unilateral, and 9% had borderline CCS, together encompassing >50% of motor incomplete tetraplegia cases. Despite the increased sensitivity and specificity of these subsets compared with existing quantifiable criteria, substantial variability in clinical presentation was still observed. Overall, individuals meeting CCS subset criteria showed a higher likelihood of American Spinal Injury Association (ASIA) Impairment Scale (AIS) D grade than those with motor incomplete tetraplegia without CCS. Upper Extremity Motor Score (UEMS) for those with CCS was lower on admission, a difference that diminished by discharge, whereas their Lower Extremity Motor Score (LEMS) consistently remained higher than for those without CCS. However, these neurological distinctions did not result in significant functional differences, as lower and upper extremity functional outcomes at discharge were mostly similar, with some differences observed within those with AIS D grade. The AIS grade, rather than the diagnosis of CCS, remains the foremost determinant influencing neurological and functional outcomes. We recommend that future studies consider incorporating motor incomplete tetraplegia into their inclusion/exclusion criteria, instead of relying on criteria specific to CCS. Although there remains clinical value in characterizing an injury pattern as CCS and perhaps using the different subsets to better characterize the impairments, it does not appear to be a useful research criterion.

Central and peripheral nervous system lesions may disrupt the intricate balance of the prime movers of the wrist. In spasticity, hyperactive wrist flexors create a flexion moment and, if untreated, can lead to flexion contractures. In patients with C6 spinal cord injury and tetraplegia, the posterior interosseus nerve is typically affected by a complex pattern of upper and/or lower motoneuron lesions causing radial deviation of the wrist due to loss of ulnar deviation actuators. In this report, we illustrate severe pathomechanics that may occur even with relatively modest changes in wrist balance. These results illustrate how thorough understanding of muscle-tendon-joint interaction aids in designing tendon and nerve reconstructive surgeries to normalize wrist positions and balance in neuromuscular conditions., Competing Interests: Declaration of conflicting interestsThe author(s) declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Introduction: Locked-in syndrome (LIS) is characterized by tetraplegia, anarthria, paralysis of cranial nerves, and facial musculature, with the preservation of consciousness and cognitive abilities, as well as vertical eye movements and eyelid movements, hearing, and breathing. Three types of LIS are distinguished: classic, incomplete, and total. The aim of the present study was to describe the life history of a person with LIS, as well as the wife's experience and perspective of this life history., Methods: A qualitative life history study was conducted with two participants: a 54-year-old man diagnosed with LIS and his 50-year-old wife. Data were collected through interviews and autobiographical documents submitted by the participants and analyzed following Braun and Clarke's method of inductive thematic analysis., Results: Five main themes were identified: (1) how to understand and overcome the new situation; (2) the process of care and rehabilitation; (3) communication; (4) writing as a way of helping oneself and others; and (5) personal autonomy and social participation., Conclusion: The participants valued the support of their friends and family in the acceptance stage of the new situation, giving special importance to the communication skills and medical attention received after diagnosis., (© 2024 The Authors. Brain and Behavior published by Wiley Periodicals LLC.)

Distal nerve transfers can restore precise motor control in tetraplegic patients. When nerve transfers are not successful, tendon transfers may be used for subsequent reconstruction. In this case, an extensor carpi radialis brevis (ECRB) tendon transfer was used to restore thumb and finger flexion following an unsuccessful ECRB to anterior interosseous nerve transfer in a young tetraplegic patient. Twelve months following tendon transfer, the patient demonstrated functional grip and pinch strength and was using both hands for daily activities. Level of Evidence: Level V (Therapeutic).

Background: The Seated Reach Test (SRT) is an assessment tool for evaluating the sitting balance of individuals with a spinal cord injury (SCI). We developed the Shoulder Shifting Test (SST), which is a tool for measuring the reaching distance of individuals with difficulty in raising their arms, such as individuals with tetraplegia., Objective: To investigate the agreement between the SST and the SRT and the usefulness of the SST., Subjects and Methods: Sixteen subjects with SCI (age 52.9 ± 13.0 yrs; four with tetraplegia) performed the SST and the SRT. We determined the correlation coefficient to determine the relationship between the two tests. A Bland-Altman analysis was performed to confirm the systematic error, and the relative error (RE) was used to determine the compatibility of the two tests in three directions (front, right, left). We assessed the SST's usefulness by determining how many of 47 subjects (age 59.6 ± 13.6 yrs; 23 with tetraplegia) could not perform the SRT and how many could perform the SST., Results: The tests were strongly correlated. No systematic errors between the tests were observed. In all three directions, >75% of the subjects had an RE <20%. Eleven of the 47 subjects with SCI were unable to perform either test. Four to ten of the 36 subjects performed the SST due to the difficulty in raising their arms., Conclusion: The SST was compatible with the SRT, and the sitting balance of more individuals with SCI could be assessed by the combination of these tests.

Nerve transfer after spinal cord injury has become increasingly popular. Accurate preoperative identification of lower motor neuron involvement in potential recipient nerves is critical. Electrodiagnostic testing has been shown to correlate with intraoperative findings; however, it is time-consuming, costly and may not be readily available. Stimulated manual muscle testing is an alternative diagnostic approach. It is inexpensive and easily done by the surgeon or therapist in the office; however, correlation with intraoperative stimulation has not been reported. A retrospective review was conducted for patients who underwent nerve transfer for tetraplegia with recorded preoperative stimulated manual muscle testing and intraoperative stimulation results. Nine patients including 37 nerve transfers were included. Of the 37 nerve transfers, 36 were accurately graded preoperatively by stimulated manual muscle testing. Stimulated manual muscle testing had a sensitivity of 89%, specificity of 100%, positive predictive value of 100% and a negative predictive value of 97%. This study supports stimulated manual muscle testing for preoperative distinction between upper versus lower motor neuron injuries. Level of evidence: IV.

Athletes with tetraplegia may experience marked hyperthermia while exercising under environmental heat stress due to their limited ability to dissipate heat through evaporative means. This study investigated the effectiveness of two external cooling strategies (i.e., spraying water onto the body surface or using a cooling vest) on physiological and perceptual variables in tetraplegic athletes during and after an aerobic exercise session in a hot environment. Nine male wheelchair rugby players performed an incremental test to determine their maximum aerobic power output. After that, they were subjected to three experimental trials in a counter-balanced order: control (CON, no body cooling), cooling vest (CV), and water spraying (WS). During these trials, they performed 30 min of a submaximal exercise (at 65% of their maximum aerobic power) inside an environmental chamber set to maintain the dry-bulb temperature at 32 °C. The following variables were recorded at regular intervals during the exercise and for an additional 30 min following the exertion (i.e., post-exercise recovery) with the participants also exposed to 32 °C: body core temperature (T CORE ), skin temperature (T SKIN ), heart rate (HR), rating of perceived exertion (RPE), thermal comfort (TC), and thermal sensation (TS). While exercising in CON conditions, the tetraplegic athletes had the expected increases in T CORE , T SKIN , HR, RPE, and TC and TS scores. HR, TC, and TS decreased gradually toward pre-exercise values after the exercise, whereas T CORE and T SKIN remained stable at higher values. Using a cooling vest decreased the temperature measured only on the chest and reduced the scores of RPE, TC, and TS during and after exercise but did not influence the other physiological responses of the tetraplegic athletes. In contrast, spraying water onto the athletes' body surface attenuated the exercise-induced increase in T SKIN , led to lower HR values during recovery, and was also associated with better perception during and after exercise. We conclude that water spraying is more effective than the cooling vest in attenuating physiological strain induced by exercise-heat stress. However, although both external cooling strategies do not influence exercise hyperthermia, they improve the athletes' thermal perception and reduce perceived exertion., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to declare., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Study Design: Non-randomized clinical trial., Objectives: Examine the feasibility, physical and psychosocial effects of a high intensity functional training (HIFT) exercise program for people with spinal cord injury (pSCI) and their care partners (CPs)., Setting: Community fitness center in a Medically Underserved Area (Fort Smith, USA.) METHODS: A single-group design with three assessment points (before the program, at midpoint (13 weeks), and post-program (25 weeks) was used to examine the effects of up to 49 HIFT sessions over 25-weeks. Sessions were 60 to 75 min in duration and adapted to the abilities of participants. Feasibility measures included recruitment, retention, attendance, safety and fidelity (exercise intensity rated via session-Rating of Perceived Exertion (RPE). Physical measures included cardiovascular endurance, anaerobic power, and muscular strength. Psychosocial measures included perceived social support for exercise, exercise self-efficacy and health-related quality of life., Results: Fourteen pSCI (7 with paraplegia and 7 with tetraplegia, 2 females) and 6 CPs (4 females) were included (median age = 60) (IQR = 15.8). Recruitment rates were 40% for pSCI and 32% for CPs. On average, participants attended 73% (22%) of exercise sessions with a median session-RPE of 5 (IQR = 1). Retention rates were 83% and 67% for pSCI and CPs, respectively. For pSCI and their CPs, large effect sizes were observed for cardiovascular endurance, anaerobic power, muscular strength, and social support for exercise., Conclusions: For pSCI and their CPs, HIFT appears feasible and potentially leads to improvements in physical and psychosocial health for both groups., (© 2024. The Author(s).)

Speech brain-machine interfaces (BMIs) translate brain signals into words or audio outputs, enabling communication for people having lost their speech abilities due to diseases or injury. While important advances in vocalized, attempted and mimed speech decoding have been achieved, results for internal speech decoding are sparse and have yet to achieve high functionality. Notably, it is still unclear from which brain areas internal speech can be decoded. Here two participants with tetraplegia with implanted microelectrode arrays located in the supramarginal gyrus (SMG) and primary somatosensory cortex (S1) performed internal and vocalized speech of six words and two pseudowords. In both participants, we found significant neural representation of internal and vocalized speech, at the single neuron and population level in the SMG. From recorded population activity in the SMG, the internally spoken and vocalized words were significantly decodable. In an offline analysis, we achieved average decoding accuracies of 55% and 24% for each participant, respectively (chance level 12.5%), and during an online internal speech BMI task, we averaged 79% and 23% accuracy, respectively. Evidence of shared neural representations between internal speech, word reading and vocalized speech processes was found in participant 1. SMG represented words as well as pseudowords, providing evidence for phonetic encoding. Furthermore, our decoder achieved high classification with multiple internal speech strategies (auditory imagination/visual imagination). Activity in S1 was modulated by vocalized but not internal speech in both participants, suggesting no articulator movements of the vocal tract occurred during internal speech production. This work represents a proof-of-concept for a high-performance internal speech BMI., (© 2024. The Author(s).)

Cervical spinal cord injury (SCI) causes devastating loss of upper limb function and independence. Restoration of upper limb function can have a profound impact on independence and quality of life. In low-cervical SCI (level C5-C8), upper limb function can be restored via reinnervation strategies such as nerve transfer surgery. The translation of recovered upper limb motor function into functional independence in activities of daily living (ADLs), however, remains unknown in low cervical SCI (i.e., tetraplegia). The objective of this study was to evaluate the association of patterns in upper limb motor recovery with functional independence in ADLs. This will then inform prioritization of reinnervation strategies focused to maximize function in patients with tetraplegia. This retrospective study performed a secondary analysis of patients with low cervical (C5-C8) enrolled in the SCI Model Systems (SCIMS) database. Baseline neurological examinations and their association with functional independence in major ADLs-i.e., eating, bladder management, and transfers (bed/wheelchair/chair)-were evaluated. Motor functional recovery was defined as achieving motor strength, in modified research council (MRC) grade, of ≥ 3 /5 at one year from ≤ 2/5 at baseline. The association of motor function recovery with functional independence at one-year follow-up was compared in patients with recovered elbow flexion (C5), wrist extension (C6), elbow extension (C7), and finger flexion (C8). A multi-variable logistic regression analysis, adjusting for known factors influencing recovery after SCI, was performed to evaluate the impact of motor function at one year on a composite outcome of functional independence in major ADLs. Composite outcome was defined as functional independence measure score of 6 or higher (complete independence) in at least two domains among eating, bladder management, and transfers. Between 1992 and 2016, 1090 patients with low cervical SCI and complete neurological/functional measures were included. At baseline, 67% of patients had complete SCI and 33% had incomplete SCI. The majority of patients were dependent in eating, bladder management, and transfers. At one-year follow-up, the largest proportion of patients who recovered motor function in finger flexion (C8) and elbow extension (C7) gained independence in eating, bladder management, and transfers. In multi-variable analysis, patients who had recovered finger flexion (C8) or elbow extension (C7) had higher odds of gaining independence in a composite of major ADLs (odds ratio [OR] = 3.13 and OR = 2.87, respectively, p  < 0.001). Age 60 years (OR = 0.44, p  = 0.01), and complete SCI (OR = 0.43, p  = 0.002) were associated with reduced odds of gaining independence in ADLs. After cervical SCI, finger flexion (C8) and elbow extension (C7) recovery translate into greater independence in eating, bladder management, and transfers. These results can be used to design individualized reinnervation plans to reanimate upper limb function and maximize independence in patients with low cervical SCI.

Objective: Spinal cord injury (SCI) interrupts motor, sensory, and autonomic pathways, impairing mobility and increasing heat storage during warm seasonal temperatures due to compromised autonomic control of vasodilation and sweating and recognition of body temperature. Thus, persons with SCI are more vulnerable to hyperthermia and its adverse effects. However, information regarding how persons with SCI perceive warmer seasons and whether thermal discomfort during warmer seasons restricts routine activities remains anecdotal., Design: Cross-sectional, self-report surveys., Setting: VA Medical Center and Kessler Institute for Rehabilitation., Participants: Three groups of 50 participants each: tetraplegia, paraplegia, and matched non-SCI controls., Outcome Measures: Tetraplegia, paraplegia, and control groups responded "yes" or "no" when asked whether warm seasonal temperatures adversely affected comfort or participation in routine activities., Results: The percentage of responses differed among tetraplegia, paraplegia, and control groups when asked if they required ≥20 min to cool down once overheated (44 vs. 20 vs. 12%; X 2  = 14.7, P < 0.001), whether heat-related discomfort limited their ability to go outside (62 vs. 34 vs. 32%; X 2  = 11.5, P = 0.003), if they needed to use a water-mister because of the heat (70 vs. 44 vs. 42%; X 2  = 9.8, P = 0.008), and if heat-related discomfort limited participation in social activities (40 vs. 20 vs. 16%; X 2  = 8.7, P = 0.01)., Conclusion: Warmer seasonal temperatures had a greater negative impact on reported comfort and daily activities of persons with SCI than non-SCI controls. Those with tetraplegia were most adversely affected. Our findings warrant increasing awareness and identifying interventions to address the vulnerability of persons with SCI to hyperthermia.

Cervical spinal cord injury (SCI) leads to permanent impairment of arm and hand functions. Here we conducted a prospective, single-arm, multicenter, open-label, non-significant risk trial that evaluated the safety and efficacy of ARC EX Therapy to improve arm and hand functions in people with chronic SCI. ARC EX Therapy involves the delivery of externally applied electrical stimulation over the cervical spinal cord during structured rehabilitation. The primary endpoints were safety and efficacy as measured by whether the majority of participants exhibited significant improvement in both strength and functional performance in response to ARC EX Therapy compared to the end of an equivalent period of rehabilitation alone. Sixty participants completed the protocol. No serious adverse events related to ARC EX Therapy were reported, and the primary effectiveness endpoint was met. Seventy-two percent of participants demonstrated improvements greater than the minimally important difference criteria for both strength and functional domains. Secondary endpoint analysis revealed significant improvements in fingertip pinch force, hand prehension and strength, upper extremity motor and sensory abilities and self-reported increases in quality of life. These results demonstrate the safety and efficacy of ARC EX Therapy to improve hand and arm functions in people living with cervical SCI. ClinicalTrials.gov identifier: NCT04697472 ., (© 2024. The Author(s).)

Objectives: To determine whether spinal cord injury (SCI) is associated with adverse changes in coagulation and fibrinolytic factors that underlie thrombogenesis and contribute to atherothrombotic events such as myocardial infarctions (MIs) and strokes., Design: Cross-sectional study., Setting: Neurorehabilitation hospital and general community., Participants: Thirty young and middle-aged (20-58 years) adults (N=30) were studied: 14 non-injured community dwelling adults. (11M/4F) and 16 with subacute tetraplegic motor complete SCI during initial inpatient rehabilitation (13M/3F; time since injury: 11.8±5.3 wk)., Interventions: Not applicable., Main Outcome Measures: Circulating markers of coagulation [von Willebrand factor (vWf) and factors VII, VIII, and X], the fibrinolytic system [tissue-type plasminogen activator (t-PA), and plasminogen activator inhibitor-1 (PAI-1) antigen and activity], and fibrin formation (D-dimer) were determined by enzyme immunoassay., Results: Thirty young and middle-aged (20-58 years) adults were studied: 14 non-injured (11M/4F) and 16 with subacute tetraplegic motor complete SCI (13M/3F; time since injury: range 4-25 wk). Circulating levels of coagulation factors VII, VIII, and X were significantly higher (∼20%-45%; P<.05) in the adults with SCI than non-injured adults, whereas vWf was similar between groups. Fibrinolytic markers were adversely disrupted with SCI with t-PA antigen, PAI-1 antigen and PAI-1 activity were markedly higher (∼50%-800%; P<.05) in adults with SCI compared with non-injured adults. The molar concentration ratio of active t-PA to PAI-1 was significantly higher (∼350%) in adults with SCI. Concordant with coagulation cascade activation and fibrinolytic system inhibition, D-dimer concentrations were markedly ∼70% higher (P<.05) in adults with SCI compared with non-injured adults., Conclusions: Subacute tetraplegic motor complete SCI is associated with a prothrombotic hemostatic profile. Adverse changes in the coagulation cascade and fibrinolytic system appear to occur early after injury and may contribute to the increased atherothrombotic risk in adults living with SCI., (Copyright © 2023 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)

The loss of bilateral hand function is a debilitating challenge for millions of individuals that suffered a motor-complete spinal cord injury (SCI). We have recently demonstrated in eight tetraplegic individuals the presence of highly functional spared spinal motor neurons in the extrinsic muscles of the hand that are still capable of generating proportional flexion and extension signals. In this work, we hypothesized that an artificial intelligence (AI) system could automatically learn the spared electromyographic (EMG) patterns that encode the attempted movements of the paralyzed digits. We constrained the AI to continuously output the attempted movements in the form of a digital hand so that this signal could be used to control any assistive system (e.g. exoskeletons, electrical stimulation). We trained a convolutional neural network using data from 13 uninjured (control) participants and 8 tetraplegic participants (7 motor-complete, 1 incomplete) to study the latent space learned by the AI. Our model can automatically differentiate between eight different hand movements, including individual finger flexions, grasps, and pinches, achieving a mean accuracy of 98.3% within the SCI group. Analysis of the latent space of the model revealed that proportionally controllable movements exhibited an elliptical path, while movements lacking proportional control followed a chaotic trajectory. We found that proportional control of a movement can only be correctly estimated if the latent space embedding of the movement follows an elliptical path (correlation =0.73; p <0.001). These findings emphasize the reliability of the proposed system for closed-loop applications that require an accurate estimate of spinal cord motor output.

Following tetraplegia, independence for completing essential daily tasks, such as opening doors and eating, significantly declines. Assistive robotic manipulators (ARMs) could restore independence, but typically input devices for these manipulators require functional use of the hands. We created and validated a hands-free multimodal input system for controlling an ARM in virtual reality using combinations of a gyroscope, eye-tracking, and heterologous surface electromyography (sEMG). These input modalities are mapped to ARM functions based on the user's preferences and to maximize the utility of their residual volitional capabilities following tetraplegia. The two participants in this study with tetraplegia preferred to use the control mapping with sEMG button functions and disliked winking commands. Non-disabled participants were more varied in their preferences and performance, further suggesting that customizability is an advantageous component of the control system. Replacing buttons from a traditional handheld controller with sEMG did not substantively reduce performance. The system provided adequate control to all participants to complete functional tasks in virtual reality such as opening door handles, turning stove dials, eating, and drinking, all of which enable independence and improved quality of life for these individuals.

Consolidation of memory is believed to involve offline replay of neural activity. While amply demonstrated in rodents, evidence for replay in humans, particularly regarding motor memory, is less compelling. To determine whether replay occurs after motor learning, we sought to record from motor cortex during a novel motor task and subsequent overnight sleep. A 36-year-old man with tetraplegia secondary to cervical spinal cord injury enrolled in the ongoing BrainGate brain-computer interface pilot clinical trial had two 96-channel intracortical microelectrode arrays placed chronically into left precentral gyrus. Single- and multi-unit activity was recorded while he played a color/sound sequence matching memory game. Intended movements were decoded from motor cortical neuronal activity by a real-time steady-state Kalman filter that allowed the participant to control a neurally driven cursor on the screen. Intracortical neural activity from precentral gyrus and 2-lead scalp EEG were recorded overnight as he slept. When decoded using the same steady-state Kalman filter parameters, intracortical neural signals recorded overnight replayed the target sequence from the memory game at intervals throughout at a frequency significantly greater than expected by chance. Replay events occurred at speeds ranging from 1 to 4 times as fast as initial task execution and were most frequently observed during slow-wave sleep. These results demonstrate that recent visuomotor skill acquisition in humans may be accompanied by replay of the corresponding motor cortex neural activity during sleep. SIGNIFICANCE STATEMENT Within cortex, the acquisition of information is often followed by the offline recapitulation of specific sequences of neural firing. Replay of recent activity is enriched during sleep and may support the consolidation of learning and memory. Using an intracortical brain-computer interface, we recorded and decoded activity from motor cortex as a human research participant performed a novel motor task. By decoding neural activity throughout subsequent sleep, we find that neural sequences underlying the recently practiced motor task are repeated throughout the night, providing direct evidence of replay in human motor cortex during sleep. This approach, using an optimized brain-computer interface decoder to characterize neural activity during sleep, provides a framework for future studies exploring replay, learning, and memory., (Copyright © 2022 Rubin et al.)

Restoring arm and hand function has been indicated by individuals with tetraplegia as one of the most important factors for regaining independence. The overall goal of our research is to develop assistive technologies that allow individuals with tetraplegia to control functional reaching movements. This study served as an initial step toward our overall goal by assessing the feasibility of using eye movements to control the motion of an effector in an experimental environment. We aimed to understand how additional motor requirements placed on the eyes affected eye-hand coordination during functional reaching. We were particularly interested in how eye fixation error was affected when the sensory and motor functions of the eyes were entangled due to the additional motor responsibility. We recorded participants' eye and hand movements while they reached for targets on a monitor. We presented a cursor at the participant's point of gaze position which can be thought of as being similar to the control of an assistive robot arm. To measure eye fixation error, we used an offline filter to extract eye fixations from the raw eye movement data. We compared the fixations to the locations of the targets presented on the monitor. The results show that not only are humans able to use eye movements to direct the cursor to a desired location (1.04 ± 0.15 cm), but they can do so with error similar to that of the hand (0.84 ± 0.05 cm). In other words, despite the additional motor responsibility placed on the eyes during direct eye-movement control of an effector, the ability to coordinate functional reaching movements was unaffected. The outcomes of this study support the efficacy of using the eyes as a direct command input for controlling movement., Competing Interests: The authors have declared that no competing interests exist.

Motor neurons convey information about motor intent that can be extracted and interpreted to control assistive devices. However, most methods for measuring the firing activity of single neurons rely on implanted microelectrodes. Although intracortical brain-computer interfaces (BCIs) have been shown to be safe and effective, the requirement for surgery poses a barrier to widespread use that can be mitigated by instead using noninvasive interfaces. The objective of this study was to evaluate the feasibility of deriving motor control signals from a wearable sensor that can detect residual motor unit activity in paralyzed muscles after chronic cervical spinal cord injury (SCI). Despite generating no observable hand movement, volitional recruitment of motor units below the level of injury was observed across attempted movements of individual fingers and overt wrist and elbow movements. Subgroups of motor units were coactive during flexion or extension phases of the task. Single digit movement intentions were classified offline from the electromyogram (EMG) power [root-mean-square (RMS)] or motor unit firing rates with median classification accuracies >75% in both cases. Simulated online control of a virtual hand was performed with a binary classifier to test feasibility of real-time extraction and decoding of motor units. The online decomposition algorithm extracted motor units in 1.2 ms, and the firing rates predicted the correct digit motion 88 ± 24% of the time. This study provides the first demonstration of a wearable interface for recording and decoding firing rates of motor units below the level of injury in a person with motor complete SCI. NEW & NOTEWORTHY A wearable electrode array and machine learning methods were used to record and decode myoelectric signals and motor unit firing in paralyzed muscles of a person with motor complete tetraplegia. The myoelectric activity and motor unit firing rates were task specific, even in the absence of visible motion, enabling accurate classification of attempted single-digit movements. This wearable system has the potential to enable people with tetraplegia to control assistive devices through movement intent.

Objectives: To reach agreement on standardized protocols for assessing upper limb strength and grip and pinch force for upper limb reconstructive surgery for tetraplegia., Methods: Selected members of an expert panel composed of international therapists formed at the 2018 International Congress for Upper Limb Surgery for Tetraplegia conducted a literature review of current practice that identified gaps and inconsistencies in measurement protocols and presented to workshop attendees. To resolve discrepancies, a set of questions was presented to workshop attendees who voted electronically. Consensus was set at 75% agreement., Results: For manual muscle testing, consensus was reached for using the Medical Research Council scale, without plus or minus, and the use of resistance through range when testing grade 4 and grade 5 strength. Pectoralis major and serratus anterior should be routinely tested, however there was no consensus on other shoulder muscles. Grip and pinch strength should be tested according to the American Society of Hand Therapists positioning. For grip strength, either the Jamar or Biometrics dynamometer expressed in kilograms should be used. For grip and pinch strength, three measurements should be performed at each testing. No consensus was reached on a device for pinch strength., Conclusion: This work is an important step to enable comparable data in the future. Further consensus methods will work toward developing more comprehensive guidelines in this population. Building international consensus for pre- and postoperative measures of function supports objective evaluation of novel therapies and interpretation of multicenter studies., Competing Interests: Conflicts of Interest The authors declare no conflicts of interest., (© 2021 American Spinal Injury Association.)

Objectives: Determine the extent and underlying causes of post-exercise hyperthermia in athletes with a spinal cord injury following exercise., Design: Observational., Methods: Thirty-one males (8 with tetraplegia [TP; C5-C8], 7 with high paraplegia [HP; T1-T5], 8 with low paraplegia [LP; T6-L1] and 8 able-bodied [AB]), recovered in 35°C/50%RH for 45min after 30-min of exercise at a metabolic heat production (H prod ) of 4.0W/kg (AB vs TP) or 6.0W/kg (AB vs HP vs LP). Esophageal (T es ), gastrointestinal (T gi ) and skin temperatures, H prod , local sweat rate (LSR) and mean arterial pressure were measured., Results: TP maintained a higher T es (38.05°C [95% CI: 37.83°C, 38.28°C], AB: 36.77°C [36.56°C, 36.98°C], p<0.001) and T gi (TP: 38.36°C [38.15°C, 38.58°C], AB: 37.26°C [37.04°C, 37.47°C], p<0.001), with peak values observed 45min post-exercise. Core temperatures all declined in HP, LP and AB, but HP maintained a higher T es than AB (p=0.030), and higher T gi than LP and AB (p=0.019). No differences in post-exercise H prod were observed between TP and AB (p=0.264), or HP, LP and AB (p=0.124). Evaporative heat loss was estimated to be zero in TP, while back LSR was greater in HP than LP (p=0.009). Minimal dry heat loss occurred in SCI groups (TP: 9W/m 2 [6, 12], HP: 4W/m 2 [1, 6], LP: 2W/m 2 [0, 5])., Conclusions: Substantial post-exercise hyperthermia is evident in TP (∼1.4°C hotter than AB after 45min of post-exercise recovery) due to minimal evaporation. HP have delayed post-exercise thermoregulatory recovery whereas LP respond similarly to AB., (Copyright © 2021. Published by Elsevier Ltd.)

Aim : To identify abnormalities in muscle tone and motor function associated with congenital Zika syndrome (CZS). Method : A cross-sectional observational study involving 96 children (55 males) with CZS at a mean (SD) age 35.2 ± 2.9 months. Children's muscle tone was investigated using the pull to sit, scarf sign, shoulder suspension and ventral suspension tests and the modified Ashworth scale (MAS). Motor impairment was determined using the Gross Motor Function Classification System (GMFCS) and body segments most affected with motor impairment. Results : 58 (60,5%) children tested positive for ≥1 maneuver used to evaluate muscle tone, while 38 (39.5%) tested negative in all the tests. MAS score was >0 for at least one of the appendicular muscles in 91 children (94.8%). In 88 children (91.7%), all four limbs were affected. Conclusion : Findings suggestive of axial hypotonia and appendicular hypertonia associated with severe motor impairment were prevalent in children with CZS.

Objective: Vertebral artery compression of the medulla is a rare vascular finding that causes a variety of clinical presentations, from asymptomatic to neurological disability. This article presents the largest literature review to date on medullary compression of the vertebral arteries., Methods: An English literature search was performed using the PubMed database and the keywords vertebral artery tortuosity, vertebral artery compression, and medullary compression., Results: A comprehensive literature search yielded 68 patients (57% male) with medullary compression by an intracranial vertebral artery (ICVA). The left side of the medulla was compressed in 44, the right side in 19, and bilateral in 7. The most common clinical symptom was weakness - 26 patients (36%) - 6 had quadriparesis and 6 had hemiparesis. 21 patients reported imbalance; 12 various sensory symptoms; 4 patients were asymptomatic., Conclusions: Understanding the anatomy of the vasculature can help mitigate future debilitating stroke symptoms. Concrete guidelines for revascularization surgery in symptomatic patients may also be effective. Future studies are needed to further clarify the prevalence, natural history, vascular etiology, and treatment of this condition, including asymptomatic patients and the likelihood that they will develop further neurological signs and disability., Competing Interests: Declaration of Competing Interest Cameron J. Sabet has nothing to disclose., (Published by Elsevier Inc.)

Introduction: Potentially life-threatening disorders may present in the emergency department with acute tetraparesis, and their recognition is crucial for an appropriate management and timely treatment. Our review aims to systematize the differential diagnosis of acute non-traumatic tetraparesis., Results: Causes of tetraparesis can be classified based on the site of defect: upper motor neuron (UMN), peripheral nerve, neuromuscular junction or muscle. History of present illness should include the distribution of weakness (symmetric/asymmetric or distal/proximal/diffuse) and associated clinical features (pain, sensory findings, dysautonomia, and cranial nerve abnormalities such as diplopia and dysphagia). Neurological examination, particularly tendon reflexes, helps further in the localization of nerve lesions and distinction between UMN and lower motor neuron. Ancillary studies include blood and cerebral spinal fluid analysis, neuroaxis imaging, electromyography, muscle magnetic resonance and muscle biopsy., Conclusions: Acute tetraparesis is still a debilitating and potentially serious neurological condition. Despite all the supplementary ancillary tests, the neurological examination is the key to achieve a correct diagnosis. The identification of life-threatening neurologic disorders is pivotal, since failing to identify patients at risk of complications, such as acute respiratory failure, may have catastrophic results., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: SARS-CoV2 virus could be potentially myopathic. Serum creatinine phosphokinase (CPK) is frequently found elevated in severe SARS-CoV2 infection, which indicates skeletal muscle damage precipitating limb weakness or even ventilatory failure., Case Presentation: We addressed such a patient in his forties presented with features of severe SARS-CoV2 pneumonia and high serum CPK. He developed severe sepsis and acute respiratory distress syndrome (ARDS) and received intravenous high dose corticosteroid and tocilizumab to counter SARS-CoV2 associated cytokine surge. After 10 days of mechanical ventilation (MV), weaning was unsuccessful albeit apparently clear lung fields, having additionally severe and symmetric limb muscle weakness. Ancillary investigations in addition with serum CPK, including electromyogram, muscle biopsy, and muscle magnetic resonance imaging (MRI) suggested acute myopathy possibly due to skeletal myositis., Conclusion: We wish to stress that myopathogenic medication in SARS-CoV2 pneumonia should be used with caution. Additionally, serum CPK could be a potential marker to predict respiratory failure in SARS-CoV2 pneumonia as skeletal myopathy affecting chest muscles may contribute ventilatory failure on top of oxygenation failure due to SARS-CoV2 pneumonia.

Objective: To investigate the validity and reliability of a Chinese version of Spinal Cord Independence Measure III (SCIM III) in individuals with spinal cord injury., Design: Study on psychometric properties., Setting: An inpatient rehabilitation facility in China., Subjects: 102 participants with spinal cord injury. Mean (SD) age was 48.8 (15.6) years; tetraplegia/paraplegia ratio was 50/52; median time post injury was 2 months., Intervention: SCIM III was translated into Chinese. Chinese versions of Barthel Index and SCIM III were filled out for each participant by Rater 1. SCIM III was then administered by Rater 2 after 24 hours ( n  = 67) and 7 days ( n  = 65)., Main Measures: Validity, inter-rater/test-retest reliability, and internal consistency of the Chinese version of SCIM III., Results: The total scores between the two raters were similar (mean ± SD: 33.8 ± 25.8 vs 33.8 ± 25.5, P  = 0.95). Total agreement between the raters in each item was >80%, with both Pearson and intraclass correlation coefficients >0.97 ( P  < 0.01) for each subscale and total score. The Pearson correlation coefficients of the two independent assessments performed by Rater 2 were also >0.97 ( P  < 0.01) for each subscale and the total score. Cronbach α was >0.7 for each subscale and the total score for both raters. High consistency was found between Barthel Index and SCIM III total scores (Pearson correlation coefficient = 0.88, P  < 0.01)., Conclusion: The Chinese version of SCIM III is valid and reliable for the functional assessment of patients with SCI.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the infectious agent responsible for coronavirus disease 2019 (COVID-19). Respiratory and gastrointestinal manifestations of SARS-CoV-2 are well described, less defined is the clinical neurological spectrum of COVID-19. We reported a case of COVID-19 patient with acute monophasic Guillain-Barré syndrome (GBS), and a literature review on the SARS-CoV-2 and GBS etiological correlation., Case Description: A 68 years-old man presented to the emergency department with symptoms of acute progressive symmetric ascending flaccid tetraparesis. Oropharyngeal swab for SARS-CoV-2 tested positive. Neurological examination showed bifacial nerve palsy and distal muscular weakness of lower limbs. The cerebrospinal fluid assessment showed an albuminocytologic dissociation. Electrophysiological studies showed delayed distal latencies and absent F waves in early course. A diagnosis of Acute Inflammatory Demyelinating Polyradiculoneuropathy (AIDP) subtype of GBS was then made., Conclusions: Neurological manifestations of COVID-19 are still under study. The case we described of GBS in COVID-19 patient adds to those already reported in the literature, in support of SARS-CoV-2 triggers GBS. COVID-19 associated neurological clinic should probably be seen not as a corollary of classic respiratory and gastrointestinal symptoms, but as SARS-CoV-2-related standalone clinical entities. To date, it is essential for all Specialists, clinicians and surgeons, to direct attention towards the study of this virus, to better clarify the spectrum of its neurological manifestations.

We describe the case of a 21-year-old man with a background of sickle cell disease (SCD) who was on acute presentation in a sickle cell crisis required immediate intensive care admission with red blood cell exchange and ventilatory support. He had right frontal lobe infarcts and extensive bilateral deep white matter lesions most likely secondary to fat embolism. Inpatient investigations demonstrated a patent foramen ovale, explaining the route of spread of the fat embolus. He then had a transcatheter closure of the atrial defect. The patient needed prolonged inpatient rehabilitation. He was discharged from hospital in a wheelchair secondary to severe lower limb neurology and bilateral knee heterotopic ossification. He lives with the possibility of early onset dementia and cognitive decline, requiring constant care. The case highlights the multiple manifestations of SCD and their diverse and debilitating consequences., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

A 42-year-old man from rural India presented with asymmetric progressive paraparesis mimicking compressive dorsal myelopathy, followed by distal upper limb, truncal and neck-flexor weakness, further complicated by acute urinary retention. His sensory deficits were marked by loss of joint position sense (JPS) and graded loss of vibration sense, along with a definite sensory level. Deep tendon jerks were hypo-to-areflexic, plantar was bilaterally extensor. He had become less attentive and occasionally failed to keep track with conversations. A syndromic diagnosis of myeloradiculoneuropathy with cognitive impairments was made. Further tailored investigations revealed vitamin B 12 deficiency with positive anti-parietal cell antibody. Diagnosis of subacute combined cord degeneration (SACD) was confirmed. Neuro-imaging revealed intramedullary intensity changes only along lateral aspect of spinal cord instead of characteristic posterior involvement. Following parenteral vitamin B 12 supplementation, patient started showing improvement in motor power and subjective sensory symptoms. His bladder symptoms persisted initially, however recovered finally after 6 months., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Reconstruction of arm and hand function in patients with a cervical spinal cord injury can improve their quality of life. Elbow extension, wrist extension, grip function and opening of the hand can be reconstructed. Traditionally, this has been done through tendon transpositions. Nerve transfer is a new technique. A functioning motor nerve branch is moved and connected to a muscle or muscle group damaged by the spinal cord injury. This technique has several advantages. Multiple functions can be restored by one nerve transfer, no long-term hand-rehabilitation is required and there is no risk of adhesions of the transposition. The most important disadvantage is the recovery time, as a results of the slow ingrowth of the nerve transfer, which takes at least 12 to 18 months. For each spinal cord injury patient, an individual action plan must be made, because not every patient has the same options and these are sometimes very limited.

Epidural electrical stimulation (EES) of lumbosacral sensorimotor circuits improves leg motor control in animals and humans with spinal cord injury (SCI). Upper-limb motor control involves similar circuits, located in the cervical spinal cord, suggesting that EES could also improve arm and hand movements after quadriplegia. However, the ability of cervical EES to selectively modulate specific upper-limb motor nuclei remains unclear. Here, we combined a computational model of the cervical spinal cord with experiments in macaque monkeys to explore the mechanisms of upper-limb motoneuron recruitment with EES and characterize the selectivity of cervical interfaces. We show that lateral electrodes produce a segmental recruitment of arm motoneurons mediated by the direct activation of sensory afferents, and that muscle responses to EES are modulated during movement. Intraoperative recordings suggested similar properties in humans at rest. These modelling and experimental results can be applied for the development of neurotechnologies designed for the improvement of arm and hand control in humans with quadriplegia.

Intracortical brain-computer interfaces (iBCIs) allow people with paralysis to directly control assistive devices using neural activity associated with the intent to move. Realizing the full potential of iBCIs critically depends on continued progress in understanding how different cortical areas contribute to movement control. Here we present the first comparison between neuronal ensemble recordings from the left middle frontal gyrus (MFG) and precentral gyrus (PCG) of a person with tetraplegia using an iBCI. As expected, PCG was more engaged in selecting and generating intended movements than in earlier perceptual stages of action planning. By contrast, MFG displayed movement-related information during the sensorimotor processing steps preceding the appearance of the action plan in PCG, but only when the actions were instructed using auditory cues. These results describe a previously unreported function for neurons in the human left MFG in auditory processing contributing to motor control.

Paired corticospinal-motoneuronal stimulation (PCMS) elicits spinal synaptic plasticity in humans with chronic incomplete cervical spinal cord injury (SCI). Here, we examined whether PCMS-induced plasticity could be potentiated by acute intermittent hypoxia (AIH), a treatment also known to induce spinal synaptic plasticity in humans with chronic incomplete cervical SCI. During PCMS, we used 180 pairs of stimuli where corticospinal volleys evoked by transcranial magnetic stimulation over the hand representation of the primary motor cortex were timed to arrive at corticospinal-motoneuronal synapses of the first dorsal interosseous (FDI) muscle ~1-2 ms before the arrival of antidromic potentials elicited in motoneurons by electrical stimulation of the ulnar nerve. During AIH, participants were exposed to brief alternating episodes of hypoxic inspired gas (1 min episodes of 9% O 2 ) and room air (1 min episodes of 20.9% O 2 ). We examined corticospinal function by measuring motor evoked potentials (MEPs) elicited by cortical and subcortical stimulation of corticospinal axons and voluntary motor output in the FDI muscle before and after 30 min of PCMS combined with AIH (PCMS+AIH) or sham AIH (PCMS+sham-AIH). The amplitude of MEPs evoked by magnetic and electrical stimulation increased after both protocols, but most after PCMS+AIH, consistent with the hypothesis that their combined effects arise from spinal plasticity. Both protocols increased electromyographic activity in the FDI muscle to a similar extent. Thus, PCMS effects on spinal synapses of hand motoneurons can be potentiated by AIH. The possibility of different thresholds for physiological vs behavioral gains needs to be considered during combinatorial treatments., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: To evaluate changes in duration of physical activity (PA) and sedentary behavior (SB) from discharge to 1 year after inpatient rehabilitation in ambulatory people with spinal cord injury (SCI)., Design: Longitudinal cohort study with objective measurements of physical behavior at discharge and at 6 and 12 months post discharge., Setting: Three rehabilitation centers and the participant's home environment., Participants: Participants (N=47) with ambulatory function were consecutively recruited from the self-management and self-efficacy in patients with SCI cohort (age 18 years or older, recent SCI, expected inpatient stay ≥4wk). Mean age was 54.5±12.9 years, all had incomplete lesions, 53% were men, 49% had tetraplegia, and 51% were community ambulators at discharge., Interventions: Not applicable., Main Outcome Measures: Duration (min) of PA (summed duration of walking, cycling, running, and wheeling) and SB (sitting/lying)., Results: Mean duration of PA increased by 21 min/d (95% confidence interval, 7-35) and SB decreased by 64 min/d (95% confidence interval, -94 to -35) from discharge to 6 months after inpatient rehabilitation. No changes were found in the second half-year. One year after discharge mean PA was 116±59 min/d and mean SB was 665±121 min/d. The increase in PA was the result of an almost doubling of time spent walking. Variability in physical behavior and its change was large. Older age and lower ambulation level were associated with lower PA, lower ambulation level with higher SB, and tetraplegia was associated with a reduced increase in PA., Conclusions: At group level, duration of PA and SB improved following inpatient rehabilitation in ambulatory people with SCI. However, there were large differences between individuals. Levels 1 year after discharge were still unfavorable, particularly regarding SB., (Copyright © 2020 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2020 the authors.)

Introduction: Respiratory complications (RC) are a leading cause of death after spinal cord injury (SCI) due to compromised immune function and respiratory muscle weakness. Thus, individuals with SCI are at high risk of developing COVID-19 related RC. Results of a SCI clinical trial showed a supervised respiratory muscle training (RMT) program decreased risk of developing RC. The feasibility of conducting unsupervised RMT is not well documented. Four publications (n = 117) were identified in which unsupervised RMT was performed. Significant improvements in respiratory outcomes were reported in two studies: Maximal Inspiratory and Expiratory Pressure (MIP40% and MEP25%, respectively), Peak Expiratory Flow (PEF9%), seated and supine Forced Vital Capacity (FVC23% and 26%, respectively), and Peak Cough Flow (28%). This review and case report will attempt to show that an inspiratory muscle training (IMT) home exercise program (HEP) is feasible and may prepare the respiratory system for RC associated with COVID-19 in patients with SCI., Case Presentation: A 23-year-old with tetraplegia (P1), history of mechanical ventilation, and hospitalization for RC, completed 27 IMT HEP sessions in one month. MIP and sustained MIP (SMIP) increased from baseline by 28% and 26.5%, respectively. Expiratory volumes and rates also improved (FVC, FEV1, and PEF: 11.7%, 8.3%, and 14.2%, respectively)., Discussion: The effects of COVID-19 on patients with SCI remains inconclusive, but recent literature and the results of this case suggest that unsupervised IMT is feasible and may limit the severity of RC in patients with SCI who contract COVID-19.

Respiratory dysfunction is one of the most debilitating effects of spinal cord injury (SCI) impacting the quality of life of patients and caregivers. In addition, breathing difficulties impact the rehabilitation routine a patient may potentially undergo. Transcutaneous electrical spinal cord neuromodulation (TESCoN) is a novel approach to reactivate and retrain spinal circuits after paralysis. We demonstrate that acute and chronic TESCoN therapy over the cervical spinal cord positively impacts the breathing and coughing ability in a patient with chronic tetraplegia. ln addition, we show that the improved breathing and coughing ability are not only observed in the presence of TESCoN but persisted for a few days after TESCoN was stopped. NEW & NOTEWORTHY Noninvasive spinal neuromodulation improves breathing and coughing in a patient with severe and complete tetraplegia.

Purpose: Spinal epidural hematoma is a rare but important disease as it can be a stroke mimic. Our aim was to investigate the clinical characteristics of patients with an activated stroke code and spinal epidural hematoma., Methods: Patients with an activated stroke code were examined retrospectively. Patients with spinal epidural hematoma were evaluated with further neurological examinations and neuroimaging., Results: Of 2866 patients with an activated stroke code, spinal epidural hematoma was detected in 5 (0.2%, 63-79 years, 2 men). In all 5 cases, hematoma was located in the unilateral dorsal region of the spinal canal and spread to 5-9 vertebral segments at the C1-T3 level. None of the patients had a medical history of head or neck injury, coagulopathy, or use of anti-thrombotic agents. All of the patients had occipital, neck, and/or back pain, and their hemiparesis occurred simultaneously or within 1 h after the onset of pain. Hyperalgesia ipsilateral to the hematoma was observed in 1 patient, hypoalgesia contralateral to the hematoma was observed in 1, and quadriparesis and bilateral hypoalgesia were observed in 1. The hematomas spontaneously decreased in size in 4 patients, and cervical laminectomy was performed in the other patient. In the 1860 patients with an activated stroke code and spontaneous eye opening, the sensitivity of pain as a predictor of spinal epidural hematoma was 100%, with a specificity of 88.7%, and positive predictive value of 2.3%., Conclusion: Patients with spinal epidural hematoma could present with clinical characteristics mimicking ischemic stroke. Spinal epidural hematoma should be differentiated in patients treated under stroke code activation., Competing Interests: Declaration of Competing Interest The authors declare that they have no competing interests., (Copyright © 2020 Elsevier Inc. All rights reserved.)

With improvements in medical care, pediatric patients with spinal cord injuries with tetraplegia are living into adulthood. The goal of rehabilitation following loss of upper extremity function caused by tetraplegia is to maximize function and independence. Physiatrists must be aware of appropriate timing of referral for upper extremity surgery because it can have significant ramifications on the outcome. This article discusses the 2 most commonly used surgical strategies to restore upper extremity function: upper extremity tendon transfer and nerve grafting/transfer. Patient selection, physical examination, electrodiagnostic evaluation, and optimization of postoperative rehabilitation are important., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: This study describes the first use of a robotic walker in youth and young adults with cerebral palsy (CP) Gross Motor Function Classification (GMFCS) IV. Methods: Semi-structured interviews were conducted before and after each robotic walker trial. Interviews were recorded, then transcribed and subjected to thematic analysis. Results: Five participants (4 male, 13-22 years of age) with quadriplegia secondary to CP were recruited. Four individuals with mixed tone quadriplegia GMFCS IV were able to independently walk with the device. One individual with significant dyskinesia was unable to utilize the device. The assessment team included two physiotherapists, an occupational therapist, a physiatrist and three engineers. Major themes related to physical and social impacts were identified. Some physical advantages include the ability to walk hands-free and promotion of physical fitness. Examples of physical barriers include limited harness design and large device size. Social advantages include increased independence and peer engagement. Finally, a social disadvantage identified was limited use on uneven terrains. Discussion: Suggestions for modifications for identified challenges and disadvantages include decreasing the size of the robotic walker, more harness designs, decreasing the force required to take an initial step, adding a joy stick for user control and creating a more versatile base that can be used on different terrains such as ice or baseball fields. Conclusion: Robotics holds great hope for individuals with CP where mobility options are limited. Physical and social advantages are evident. Recommendations for future improvement and studies of use in exercise and participation are provided.IMPLICATIONS FOR REHABILITATIONAs youth and young adults with cerebral palsy age, options for mobilization can become limited with challenges in placing them in a walking device due to size and numerous other physical limitations.A robotic walker with a built-in mechanical lift is available for individuals with cerebral palsy.This study was able to gather important information and recommendations to tailor a new robotic walker prototype specifically for individuals with cerebral palsy.

We investigated how early injuries to developing brain affect the interaction of locomotor patterns with the voluntary action required by obstacle clearance. This task requires higher cognitive load and specific anticipatory sensorimotor integration than more automated steady-state gait. To this end, we compared the adaptive gait patterns during obstacle clearance in 40 children with cerebral palsy (CP) (24 diplegic, 16 hemiplegic, 2-12 yr) and 22 typically developing (TD) children (2-12 yr) by analyzing gait kinematics, joint moments during foot elevation, electromyographic (EMG) activity of 11 pairs of bilateral muscles, and muscle modules evaluated by factorization of the EMG signals. The results confirmed generally slower task performance, plus difficulty in motor planning and control in CP. Thus ~30% of diplegic children failed to perform the task. Children with CP demonstrated higher foot lift, smaller range of motion of distal segments, difficulties in properly activating the hamstring muscles at liftoff, and a modified hip strategy when elevating the trailing limb. Basic muscle modules were generally roughly similar to TD patterns, though they showed a limited adaptation. Thus a distinct activation burst in the adaptable muscle module timed to the voluntary task (liftoff) was less evident in CP. Children with CP also showed prolonged EMG burst durations. Impaired obstacle task performance may reflect impaired or less adaptable supraspinal and spinal control of gait when a locomotor task is superimposed with the voluntary movement. Neurorehabilitation of gait in CP may thus be beneficial by adding voluntary tasks such as obstacle clearance during gait performance. NEW & NOTEWORTHY Previous studies mainly evaluated the neuromuscular pattern generation in cerebral palsy (CP) during unobstructed gait. Here we characterized impairments in the obstacle task performance associated with a limited adaptation of the task-relevant muscle module timed to the foot lift during obstacle crossing. Impaired task performance in children with CP may reflect basic developmental deficits in the adaptable control of gait when the locomotor task is superimposed with the voluntary movement.