Motor compensation and its effects on neural reorganization after stroke

Context-dependent reduction in corticomuscular coupling for balance control in chronic stroke survivors

Balance control is an important indicator of mobility and independence in activities of daily living. How the functional coupling between the cortex and the muscle for balance control is affected following stroke remains to be known. We investigated the changes in coupling between the cortex and leg muscles during a challenging balance task over multiple frequency bands in chronic stroke survivors. Fourteen participants with stroke and ten healthy controls performed a challenging balance task. They stood on a computerized support surface that was either fixed (low difficulty condition) or sway-referenced with varying gain (medium and high difficulty conditions). We computed corticomuscular coherence between electrodes placed over the sensorimotor area (electroencephalography) and leg muscles (electromyography) and assessed balance performance using clinical and laboratory-based tests. We found significantly lower delta frequency band coherence in stroke participants when compared with healthy controls under medium difficulty condition, but not during low and high difficulty conditions. These differences were found for most of the distal but not for proximal leg muscle groups. No differences were found at other frequency bands. Participants with stroke showed poor balance clinical scores when compared with healthy controls, but no differences were found for laboratory-based tests. The observation of effects at distal but not at proximal muscle groups suggests differences in the (re)organization of the descending connections across two muscle groups for balance control. We argue that the observed group difference in delta band coherence indicates balance context-dependent alteration in mechanisms for the detection of somatosensory modulation resulting from sway-referencing of the support surface for balance maintenance following stroke.

Task-Oriented Training by a Personalized Electromyography-Driven Soft Robotic Hand in Chronic Stroke: A Randomized Controlled Trial

BACKGROUND

Intensive task-oriented training has shown promise in enhancing distal motor function among patients with chronic stroke. A personalized electromyography (EMG)-driven soft robotic hand was developed to assist task-oriented object-manipulation training effectively. Objective. To compare the effectiveness of task-oriented training using the EMG-driven soft robotic hand.

METHODS

A single-blinded, randomized controlled trial was conducted with 34 chronic stroke survivors. The subjects were randomly assigned to the Hand Task (HT) group (n = 17) or the control (CON) group (n = 17). The HT group received 45 minutes of task-oriented training by manipulating small objects with the robotic hand for 20 sessions, while the CON group received 45 minutes of hand-functional exercises without objects using the same robot. Fugl-Meyer assessment (FMA-UE), Action Research Arm Test (ARAT), Modified Ashworth Score (MAS), Box and Block test (BBT), Maximum Grip Strength, and active range of motion (AROM) of fingers were assessed at baseline, after intervention, and 3 months follow-up. The muscle co-contraction index (CI) was analyzed to evaluate the session-by-session variation of upper limb EMG patterns.

RESULTS

The HT group showed more significant improvement in FMA-UE (wrist/hand, shoulder/elbow) compared to the CON group (P < .05). At 3-month follow-up, the HT group demonstrated significant improvements in FMA-UE, ARAT, BBT, MAS (finger), and AROMs (P < .05). The HT group exhibited a more significant decrease in muscle co-contractions compared to the CON group (P < .05).

CONCLUSIONS

EMG-driven task-oriented training with the personalized soft robotic hand was a practical approach to improving motor function and muscle coordination.

CLINICAL TRIAL REGISTRY NAME

Soft Robotic Hand System for Stroke Rehabilitation.

CLINICAL TRIAL REGISTRATION-URL

https://clinicaltrials.gov/.

UNIQUE IDENTIFIER

NCT03286309.

Kinematic synergies show good consistency when extracted with a low-cost markerless device and a marker-based motion tracking system

Recently, markerless tracking systems, such as RGB-Depth cameras, have spread to overcome some of the limitations of the gold standard marker-based tracking systems. Although these systems are valuable substitutes for human motion analysis, as they guarantee higher flexibility, faster setup time and lower costs, their tracking accuracy is lower with respect to marker-based systems. Many studies quantified the error made by markerless systems in terms of body segment length estimation, articular angles, and biomechanics, concluding that they are appropriate for many clinical applications related to motion analysis. We propose an innovative approach to compare a markerless tracking system (Kinect V2) with a gold standard marker-based system (Vicon), based on motor control assessment. We quantified kinematic synergies from the tracking data of fifteen participants performing multi-directional upper limb movements. Kinematic synergy analysis decomposes the kinematic data into a reduced set of motor primitives that describe how the central nervous system coordinates motion at spatial and temporal level. Synergies were extracted with the recently released mixed-matrix factorization algorithm. Four synergies were extracted from both marker-based and markerless datasets and synergies were grouped in 6 clusters for each dataset. Cosine similarity in each cluster was ⩾0.60 in both systems, showing good consistency of synergies. Good matching was found between synergies extracted from markerless and from marker-based data, with a cosine similarity between matched synergies ⩾0.60 in 5 out 6 synergies. These results showed that the markerless sensor can be feasible for kinematic synergy analysis for gross movements, as it correctly estimates the number of synergies and in most cases also their spatial and temporal organization.

Utilising redundancy in musculoskeletal systems for adaptive stiffness and muscle failure compensation: a model-free inverse statics approach

Vertebrates possess a biomechanical structure with redundant muscles, enabling adaptability in uncertain and complex environments. Harnessing this inspiration, musculoskeletal systems offer advantages like variable stiffness and resilience to actuator failure and fatigue. Despite their potential, the complex structure presents modelling challenges that are difficult to explicitly formulate and control. This difficulty arises from the need for comprehensive knowledge of the musculoskeletal system, including details such as muscle arrangement, and fully accessible muscle and joint states. Whilst existing model-free methods do not need explicit formulations, they also underutilise the benefits of muscle redundancy. Consequently, they necessitate retraining in the event of muscle failure and require manual tuning of parameters to control joint stiffness limiting their applications under unknown payloads. Presented here is a model-free local inverse statics controller for musculoskeletal systems, employing a feedforward neural network trained on motor babbling data. Experiments with a musculoskeletal leg model showcase the controller's adaptability to complex structures, including mono and bi-articulate muscles. The controller can compensate for changes such as weight variations, muscle failures, and environmental interactions, retaining reasonable accuracy without the need for any additional retraining.

An analysis of the effect of motor experience on muscle synergy in the badminton jump smash

The jump smash is badminton's most aggressive technical manoeuvre, which is often the key to winning a match. This paper aims to explore the neuromuscular control strategies of advanced and beginner players when jumping smash in different ways. Collecting sEMG and kinematic data from 18 subjects with different motor experiences when jumping smash. Nonnegative Matrix Factorization and K-Means clustering were used to extract muscle synergies and exclude irrelevant combined synergies. Uncontrolled manifold analysis was then used to explore the association between synergies and shoulder stability. In addition, motor output at the spinal cord level was assessed by mapping sEMG to each spinal cord segment. The study found that advanced subjects could respond to different jump smash styles by adjusting the coordinated activation strategies of the upper-limb and postural muscles. Long-term training can induce a rapid decrease in the degree of co-variation of the synergies before contact with a shuttlecock to better cope with an upcoming collision. It is recommended that beginners should focus more on training the coordination of upper-limb muscles and postural muscles.

Neither Amphetamine nor Sub-Anesthetic Ketamine Treatment during Adolescence Impairs Devaluation in Rats Tested during Adulthood

BACKGROUND

Much of the existing animal literature on the devaluation task suggests that prior repeated exposure to drugs of abuse during adulthood can impair goal-directed action, but the literature on human drug users is mixed. Also, the initiation of drug use often occurs during adolescence, but examinations of the effects of drug exposure during adolescence on behavior in the devaluation task are lacking.

METHODS

We examined whether repeated exposure during adolescence to amphetamine (3 mg/kg injections every-other day from post-natal day 27-45) or ketamine (twice daily 30 mg/kg injections from post-natal day 35-44) would impair behavior in a devaluation test when tested drug-free in adulthood. Rats were trained to press a left lever with a steady cue-light above it for one reinforcer and a right lever with a flashing cue-light above it for a different reinforcer. We tested whether any impairments in goal-directed action could be overcome by compensation between strategies by giving rats information based on lever-location and cue-lights during the test that was either congruent (allowing compensation) or incongruent (preventing compensation between strategies) with the configurations during training.

RESULTS

Our results provided no evidence for impairment of goal-directed action during adulthood after adolescent amphetamine or ketamine exposure.

CONCLUSIONS

We discuss possible reasons for this discrepancy with the prior literature, including (1) the age of exposure and (2) the pattern in the previous literature that most previous demonstrations of drug exposure impairing devaluation in laboratory animals may be attributed to either drug-associated cues present in the testing environment and/or accelerated habit learning in tasks that predispose laboratory animals towards habit formation with extended training (with training procedures that should resist the formation of habits in the current experiment). However, additional research is needed to examine the effects of these factors, as well a potential role for the particular doses and washout periods to determine the cause of our finding of no devaluation impairment after drug exposure.

Comprehensive Assessment of Ischemic Stroke in Nonhuman Primates: Neuroimaging, Behavioral, and Serum Proteomic Analysis

Ischemic strokes, prevalence and impactful, underscore the necessity of advanced research models closely resembling human physiology. Our study utilizes nonhuman primates (NHPs) to provide a detailed exploration of ischemic stroke, integrating neuroimaging data, behavioral outcomes, and serum proteomics to elucidate the complex interplay of factors involved in stroke pathophysiology. We observed a consistent pattern in infarct volume, peaking at 1-month postmiddle cerebral artery occlusion (MCAO) and then stabilized. This pattern was strongly correlated to notable changes in motor function and working memory performance. Using diffusion tensor imaging (DTI), we detected significant alterations in fractional anisotropy (FA) and mean diffusivity (MD) values, signaling microstructural changes in the brain. These alterations closely correlated with the neurological and cognitive deficits that we observed, highlighting the sensitivity of DTI metrics in stroke assessment. Behaviorally, the monkeys exhibited a reliance on their unaffected limb for compensatory movements, a common response to stroke impairment. This adaptation, along with consistent DTI findings, suggests a significant impact of stroke on motor function and spatial perception. Proteomic analysis through MS/MS functional enrichment identified two distinct groups of proteins with significant changes post-MCAO. Notably, MMP9, THBS1, MB, PFN1, and YWHAZ were identified as potential biomarkers and therapeutic targets for ischemic stroke. Our results underscore the complex nature of stroke and advocate for an integrated approach, combining neuroimaging, behavioral studies, and proteomics, for advancing our understanding and treatment of this condition.

A general theory of rehabilitation: Rehabilitation catalyses and assists adaptation to illness

BACKGROUND

There is no general theory of rehabilitation, only definitions and descriptions, with the biopsychosocial model of illness as a structure.

OBJECTIVE

To develop a general theory of rehabilitation that explains how healthcare rehabilitation changes outcomes and to evaluate its validity.

NEED

A general rehabilitation theory would help research, improve services, increase understanding, modify resource allocation and explain some anomalies, such as how rehabilitation helps when no natural recovery occurs.

BUILDING BLOCKS

People adapt to change throughout their lives. Illness is a change, and people adapt to their illness. Adaptation's purpose is to maintain an equilibrium in a person's life. The balanced components are related to Maslow's five needs: basic, safety, affiliation, status and self-fulfilment. The general theory of behaviour suggests that a person's behaviours change to maintain balance, regulated by a central homeostatic mechanism.

THE THEORY

Rehabilitation aids adaptation to changes associated with illness through accurate diagnosis and formulation, catalysing adaptation, optimising the environment and assisting the person in making necessary changes by safely practising activities and teaching self-management.

IMPLICATIONS

The theory makes the person the central active agent, emphasises the importance of the environment in facilitating adaptation, explains why all conditions may benefit, including progressive and static conditions, suggests that health can be equated to someone maintaining their equilibrium and explains why a small dose may be very effective.

CONCLUSION

The general theory of rehabilitation emphasises the catalytic effects of rehabilitation in facilitating and guiding adaptation and suggests areas for research and improvement.

Functional Training for Lower Extremities in Stroke Survivors: A Scoping Review

Engaging in meaningful and repetitive goal-oriented functional tasks can effectively enhance neuroplasticity and facilitate recovery following a stroke. This particular approach has primarily been studied in relation to functional outcomes and has predominantly focused on late subacute and chronic stroke patients. However, there is a lack of information regarding the standardized protocol of lower extremity functional training, its constituent elements, and its impact on motor recovery during the early subacute phase of stroke. The aim of this study was to examine the available evidence related to the intervention protocol of lower extremity functional training in order to identify common training elements and assess their impact on motor and functional outcomes in stroke survivors. A systematic search was conducted on PubMed and Scopus, covering the period from 2000 to 2022. A total of 1786 articles were retrieved and screened based on predefined inclusion criteria. A total of 36 articles were included in this review. The primary findings were classified into categories such as intervention protocols for functional training and their constituent elements, outcome measures utilized, minimal clinically important differences (MCID) reported, and the conclusions drawn by the respective studies. Only a limited quantity of studies reported on the intervention protocol of lower extremity functional training. The majority of these studies focused on the efficacy of functional training for enhancing gait and balance, as evaluated through functional outcome assessments, particularly in the context of chronic stroke patients. In most studies, the evaluation of outcomes was typically based on statistical significance rather than clinical significance. In light of these findings, it is recommended that future studies be conducted during the early subacute phase of stroke to further investigate the impact of functional training on motor outcomes. This will contribute to a broader understanding of the benefits of functional training in facilitating motor recovery in the lower extremities and its clinical significance in stroke survivors.

Effects of non-invasive cervical spinal cord neuromodulation by trans-spinal electrical stimulation on cortico-muscular descending patterns in upper extremity of chronic stroke

Background: Trans-spinal electrical stimulation (tsES) to the intact spinal cord poststroke may modulate the cortico-muscular control in stroke survivors with diverse lesions in the brain. This work aimed to investigate the immediate effects of tsES on the cortico-muscular descending patterns during voluntary upper extremity (UE) muscle contractions by analyzing cortico-muscular coherence (CMCoh) and electromyography (EMG) in people with chronic stroke. Methods: Twelve chronic stroke participants were recruited to perform wrist-hand extension and flexion tasks at submaximal levels of voluntary contraction for the corresponding agonist flexors and extensors. During the tasks, the tsES was delivered to the cervical spinal cord with rectangular biphasic pulses. Electroencephalography (EEG) data were collected from the sensorimotor cortex, and the EMG data were recorded from both distal and proximal UE muscles. The CMCoh, laterality index (LI) of the peak CMCoh, and EMG activation level parameters under both non-tsES and tsES conditions were compared to evaluate the immediate effects of tsES on the cortico-muscular descending pathway. Results: The CMCoh and LI of peak CMCoh in the agonist distal muscles showed significant increases (p < 0.05) during the wrist-hand extension and flexion tasks with the application of tsES. The EMG activation levels of the antagonist distal muscle during wrist-hand extension were significantly decreased (p < 0.05) with tsES. Additionally, the proximal UE muscles exhibited significant decreases (p < 0.05) in peak CMCoh and EMG activation levels by applying tsES. There was a significant increase (p < 0.05) in LI of peak CMCoh of proximal UE muscles during tsES. Conclusion: The cervical spinal cord neuromodulation via tsES enhanced the residual descending excitatory control, activated the local inhibitory circuits within the spinal cord, and reduced the cortical and proximal muscular compensatory effects. These results suggested the potential of tsES as a supplementary input for improving UE motor functions in stroke rehabilitation.

Factors Influencing Real-World Use of the More-Affected Upper Limb After Stroke: A Scoping Review

IMPORTANCE

Current interventions are limited in improving use of the more-affected upper limb in real-world daily occupations and functional independence poststroke. A comprehensive understanding of the factors influencing real-world upper limb use is required to develop interventions to improve functional independence poststroke.

OBJECTIVE

To systematically review the factors that influence real-world use of the more-affected upper limb poststroke.

DATA SOURCES

We searched MEDLINE, Embase, PsycINFO, and the Physiotherapy Evidence Database for English-language articles from 2012 to 2023.

STUDY SELECTION AND DATA COLLECTION

Of 774 studies, we included 33 studies that had participants at least age 18 yr who exhibited upper limb impairments poststroke, objectively measured real-world upper limb use using a movement sensor, and measured factors affecting upper limb use. Two reviewers independently screened the abstracts.

FINDINGS

The results were categorized by International Classification of Functioning, Disability and Health domains. Prominent factors were upper limb impairment; motor ability; functional independence; task type; hand dominance; stroke-related factors, including time since stroke; and perception of use of the more-affected upper limb.

CONCLUSIONS AND RELEVANCE

Existing interventions primarily focus on upper limb impairments and motor ability. Our findings suggest that interventions should also incorporate other factors: task type (unilateral vs. bilateral), hand dominance, self-efficacy, and perception of more-affected limb use as active ingredients in improving real-world use of the more-affected upper limb poststroke. We also provide recommendations to use behavioral activation theory in designing an occupation-focused intervention to augment self-efficacy and confidence in use of the more-affected upper limb in daily occupations. Plain-Language Summary: In order to develop interventions to improve functional independence poststroke, occupational therapy practitioners must have a comprehensive understanding of the factors that influence real-world more-affected upper limb use. The study findings provide a set of distinct factors that practitioners can target separately or in combination to improve real-world use of the more-affected upper limb poststroke.

Diffusion MRI Fiber Tractography and Benzodiazepine SPECT Imaging for Assessing Neural Damage to the Language Centers in an Elderly Patient after Successful Reperfusion Therapy

BACKGROUND

Intravenous thrombolysis and mechanical thrombectomy are the first-line reperfusion therapies for acute ischemic stroke. Here, we describe the utility of diffusion magnetic resonance imaging (MRI) fiber tractography and 123I-iomazenil benzodiazepine receptor single-photon emission computed tomography to estimate the prognosis of post-stroke aphasia after successful reperfusion therapy.

CASE REPORT

An 81-year-old man was admitted to the hospital approximately 3.5 h after the onset of symptoms, including decreased consciousness, right hemiparesis, and aphasia. An MRI revealed acute cerebral infarction due to M1 segment occlusion. Intravenous alteplase thrombolysis followed by endovascular thrombectomy resulted in recanalization of the left middle cerebral artery territory. A subsequent MRI showed no new ischemic or hemorrhagic lesions. Although the patient's motor hemiparesis gradually recovered, motor aphasia persisted. Diffusion MRI fiber tractography performed 2 weeks after admission revealed partial injury to the left arcuate fasciculus, indicated by lower fractional anisotropy values than on the contralateral side. A decreased benzodiazepine receptor density was also detected in the left perisylvian and temporoparietal cortices. The patient showed no clear signs of further improvement in the chronic stage post-stroke and was discharged to a nursing home after 3 months.

CONCLUSIONS

The application of functional neuroimaging techniques to assess neuronal damage to the primary brain regions 2 weeks after reperfusion therapy for large-vessel occlusion may allow for an accurate prognosis of post-stroke aphasia. This may have a direct clinical implication for navigating subacute-to-chronic phases of rehabilitative care.

Motor mapping of the hand muscles using peripheral innervation-based navigated transcranial magnetic stimulation to identify functional reorganization of primary motor regions in malignant tumors

Tumor-related motor reorganization remains unclear. Navigated transcranial magnetic stimulation (nTMS) can investigate plasticity non-invasively. nTMS-induced motor-evoked potentials (MEPs) of different muscles are commonly used to measure the center of gravity (CoG), the location with the highest density of corticospinal neurons in the precentral gyrus. We hypothesized that a peripheral innervation-based MEP analysis could outline the tumor-induced motor reorganization with a higher clinical and oncological relevance. Then, 21 patients harboring tumors inside the left corticospinal tract (CST) or precentral gyrus were enrolled in group one (G1), and 24 patients with tumors outside the left CST or precentral gyrus were enrolled in Group 2 (G2). Median- and ulnar-nerve-based MEP analysis combined with diffusion tensor imaging fiber tracking was used to explore motor function distribution. There was no significant difference in CoGs or size of motor regions and underlying tracts between G1 and G2. However, G1 involved a sparser distribution of motor regions and more motor-positive sites in the supramarginal gyrus-tumors inside motor areas induced motor reorganization. We propose an "anchor-and-ship theory" hypothesis for this process of motor reorganization: motor CoGs are stably located in the cortical projection area of the CST, like a seated anchor, as the core area for motor output. Primary motor regions can relocate to nearby gyri via synaptic plasticity and association fibers, like a ship moving around its anchor. This principle can anticipate functional reorganization and be used as a neuro-oncological tool for local therapy, such as radiotherapy or surgery.

Scalp acupuncture for post-stroke spastic hemiparesis: A systematic review and meta-analysis

BACKGROUND

Spastic paralysis is one of the most common sequelae of stroke, severely affecting patients' limb function and reducing their quality of life. Scalp acupuncture (SA) has been shown to significantly improve cerebral blood supply and reduce the severity of limb spasticity. This meta-analysis aims to systematically evaluate the clinical efficacy of SA in the treatment of post-stroke spastic paralysis, providing evidence-based medicine for clinical management of this condition.

METHODS

We comprehensively searched databases including China National Knowledge Infrastructure, Wanfang Data, VIP Chinese Science and Technology Periodical Database, China Biomedical Literature Database, PubMed, Embase, and Cochrane Library. Randomized controlled trials investigating the efficacy of SA in post-stroke spastic paralysis were identified until July 28, 2023. Meta-analysis was conducted using RevMan 5.4 and Stata17.0.

RESULTS

A total of 16 studies were included. Meta-analysis showed that the modified Ashworth spasticity assessment scale in the SA group was significantly higher than that in the rehabilitation group (mean difference [MD] = -0.56, 95% confidence interval [CI] [-0.75, -0.37], Z = 5.67, P < .00001). The simplified Fugl-Meyer motor function assessment scale in the SA group was significantly higher than that in the rehabilitation group (MD = 5.86, 95% CI [3.26, 8.46], Z = 4.41, P < .0001). The modified Barthel index assessment scale in the SA group was significantly higher than that in the rehabilitation group (MD = 5.79, 95% CI [4.73, 6.84], Z = 10.77, P < .00001). Additionally, the clinical effective rate in the SA group was significantly higher than that in the rehabilitation group (relative risk = 1.25, 95% CI [1.16, 1.36], Z = 5.42, P < .00001).

CONCLUSION

SA combined with rehabilitation therapy has certain advantages in reducing limb spasticity, improving limb function, and enhancing activities of daily living in patients with post-stroke spastic paralysis. This study provides reference and theoretical support for the promotion of SA in the treatment of this condition.

[Research on mode adjustment control strategy of upper limb rehabilitation robot based on fuzzy recognition of interaction force]

In the process of robot-assisted training for upper limb rehabilitation, a passive training strategy is usually used for stroke patients with flaccid paralysis. In order to stimulate the patient's active rehabilitation willingness, the rehabilitation therapist will use the robot-assisted training strategy for patients who gradually have the ability to generate active force. This study proposed a motor function assessment technology for human upper-limb based on fuzzy recognition on interaction force and human-robot interaction control strategy based on assistance-as-needed. A passive training mode based on the calculated torque controller and an assisted training mode combined with the potential energy field were designed, and then the interactive force information collected by the three-dimensional force sensor during the training process was imported into the fuzzy inference system, the degree of active participation σ was proposed, and the corresponding assisted strategy algorithms were designed to realize the adaptive adjustment of the two modes. The significant correlation between the degree of active participation σ and the surface electromyography signals (sEMG) was found through the experiments, and the method had a shorter response time compared to a control strategy that only adjusted the mode through the magnitude of interaction force, making the robot safer during the training process.

Motor patterns of patients with spinal muscular atrophy suggestive of sensory and corticospinal contributions to the development of locomotor muscle synergies

Complex locomotor patterns are generated by combination of muscle synergies. How genetic processes, early sensorimotor experiences, and the developmental dynamics of neuronal circuits contribute to the expression of muscle synergies remains elusive. We shed light on the factors that influence development of muscle synergies by studying subjects with spinal muscular atrophy (SMA, types II/IIIa), a disorder associated with degeneration and deafferentation of motoneurons and possibly motor cortical and cerebellar abnormalities, from which the afflicted would have atypical sensorimotor histories around typical walking onset. Muscle synergies of children with SMA were identified from electromyographic signals recorded during active-assisted leg motions or walking, and compared with those of age-matched controls. We found that the earlier the SMA onset age, the more different the SMA synergies were from the normative. These alterations could not just be explained by the different degrees of uneven motoneuronal losses across muscles. The SMA-specific synergies had activations in muscles from multiple limb compartments, a finding reminiscent of the neonatal synergies of typically developing infants. Overall, while the synergies shared between SMA and control subjects may reflect components of a core modular infrastructure determined early in life, the SMA-specific synergies may be developmentally immature synergies that arise from inadequate activity-dependent interneuronal sculpting due to abnormal sensorimotor experience and other factors. Other mechanisms including SMA-induced intraspinal changes and altered cortical-spinal interactions may also contribute to synergy changes. Our interpretation highlights the roles of the sensory and descending systems to the typical and abnormal development of locomotor modules.NEW & NOTEWORTHY This is likely the first report of locomotor muscle synergies of children with spinal muscular atrophy (SMA), a subject group with atypical developmental sensorimotor experience. We found that the earlier the SMA onset age, the more the subjects' synergies deviated from those of age-matched controls. This result suggests contributions of the sensory/corticospinal activities to the typical expression of locomotor modules, and how their disruptions during a critical period of development may lead to abnormal motor modules.

Corticospinal tract: a new hope for the treatment of post-stroke spasticity

Stroke is the third leading cause of death and disability worldwide. Post-stroke spasticity (PSS) is the most common complication of stroke but represents only one of the many manifestations of upper motor neuron syndrome. As an upper motor neuron, the corticospinal tract (CST) is the only direct descending motor pathway that innervates the spinal motor neurons and is closely related to the recovery of limb function in patients with PSS. Therefore, promoting axonal remodeling in the CST may help identify new therapeutic strategies for PSS. In this review, we outline the pathological mechanisms of PSS, specifically their relationship with CST, and therapeutic strategies for axonal regeneration of the CST after stroke. We found it to be closely associated with astroglial scarring produced by astrocyte activation and its secretion of neurotrophic factors, mainly after the onset of cerebral ischemia. We hope that this review offers insight into the relationship between CST and PSS and provides a basis for further studies.

A Study of Racket Weight Adaptation in Advanced and Beginner Badminton Players

The jump smash is the most aggressive manoeuvre in badminton. Racket parameters may be the key factor affecting the performance of jump smash. Previous studies have focused only on the biomechanical characteristics of athletes or on racket parameters in isolation, with less observation of the overall performance of the human-racket system. This study aims to explore the effects of different racket weights on neuromuscular control strategies in advanced and beginner players. Nonnegative matrix factorisation (NMF) was used to extract the muscle synergies of players when jumping smash using different rackets (3U, 5U), and K-means clustering was used to obtain the fundamental synergies. Uncontrolled manifold (UCM) analyses were used to establish links between synergy and motor performance, and surface electromyography (sEMG) was mapped to each spinal cord segment. The study found significant differences (P  < 0.05) in the postural muscles of skilled players and significant differences (P  < 0.001) in the upper-limb muscles of beginners when the racket weight was increased. Advanced players adapt to the increase in racket weight primarily by adjusting the timing of the activation of the third synergy. Combined synergy in advanced players is mainly focused on the backswing, while that in beginners is mainly focused on the frontswing. This suggests that advanced players may be more adept at utilising the postural muscles and their coordination with the upper-limb muscles to adapt to different rackets. In addition, the motor experience can help athletes adapt more quickly to heavier rackets, and this adaptation occurs primarily by adjusting the temporal phase and covariation characteristics of the synergies rather than by increasing the number of synergies.

Wearable Sensor to Monitor Quality of Upper Limb Task Practice for Stroke Survivors at Home

Many stroke survivors experience persistent upper extremity impairment that limits performance in activities of daily living. Upper limb recovery requires high repetitions of task-specific practice. Stroke survivors are often prescribed task practices at home to supplement rehabilitation therapy. A poor quality of task practices, such as the use of compensatory movement patterns, results in maladaptive neuroplasticity and suboptimal motor recovery. There currently lacks a tool for the remote monitoring of movement quality of stroke survivors' task practices at home. The objective of this study was to evaluate the feasibility of classifying movement quality at home using a wearable IMU. Nineteen stroke survivors wore an IMU sensor on the paretic wrist and performed four functional upper limb tasks in the lab and later at home while videorecording themselves. The lab data served as reference data to classify home movement quality using dynamic time warping. Incorrect and correct movement quality was labeled by a therapist. The home task practice movement quality was classified with an accuracy of 92% and F1 score of 0.95 for all tasks combined. Movement types contributing to misclassification were further investigated. The results support the feasibility of a home movement quality monitoring system to assist with upper limb rehabilitation post stroke.

Uncovering the Neural Mechanisms of Inter-Hemispheric Balance Restoration in Chronic Stroke Through EMG-Driven Robot Hand Training: Insights From Dynamic Causal Modeling

EMG-driven robot hand training can facilitate motor recovery in chronic stroke patients by restoring the interhemispheric balance between motor networks. However, the underlying mechanisms of reorganization between interhemispheric regions remain unclear. This study investigated the effective connectivity (EC) between the ventral premotor cortex (PMv), supplementary motor area (SMA), and primary motor cortex (M1) using Dynamic Causal Modeling (DCM) during motor tasks with the paretic hand. Nineteen chronic stroke subjects underwent 20 sessions of EMG-driven robot hand training, and their Action Reach Arm Test (ARAT) showed significant improvement ( β =3.56, [Formula: see text]). The improvement was correlated with the reduction of inhibitory coupling from the contralesional M1 to the ipsilesional M1 (r=0.58, p=0.014). An increase in the laterality index was only observed in homotopic M1, but not in the premotor area. Additionally, we identified an increase in resting-state functional connectivity (FC) between bilateral M1 ( β =0.11, p=0.01). Inter-M1 FC demonstrated marginal positive relationships with ARAT scores (r=0.402, p=0.110), but its changes did not correlate with ARAT improvements. These findings suggest that the improvement of hand functions brought about by EMG-driven robot hand training was driven explicitly by task-specific reorganization of motor networks. Particularly, the restoration of interhemispheric balance was induced by a reduction in interhemispheric inhibition from the contralesional M1 during motor tasks of the paretic hand. This finding sheds light on the mechanistic understanding of interhemispheric balance and functional recovery induced by EMG-driven robot training.

Personalized robots for long-term telerehabilitation after stroke: a perspective on technological readiness and clinical translation

Stroke rehabilitation, which demands consistent, intensive, and adaptable intervention in the long term, faced significant challenges due to the COVID-19 pandemic. During this time, telerehabilitation emerged as a noteworthy complement to traditional rehabilitation services, offering the convenience of at-home care delivery and overcoming geographical and resource limitations. Self-help rehabilitation robots deliver repetitive and intensive physical assistance, thereby alleviating the labor burden. However, robots have rarely demonstrated long-term readiness for poststroke telerehabilitation services. The transition from research trials to general clinical services presents several challenges that may undermine the rehabilitative gains observed in these studies. This perspective discusses the technological readiness of personal use robots in the context of telerehabilitation and identifies the potential challenges for their clinical translation. The goal is to leverage technology to seamlessly integrate it into standard clinical workflows, ultimately enhancing the outcomes of stroke rehabilitation.

Methods for evaluating gait associated dynamic balance and coordination in rodents

Balance is the dynamic and unconscious control of the body's centre of mass to maintain postural equilibrium. Regulated by the vestibular system, head movement and acceleration are processed by the brain to adjust joints. Several conditions result in a loss of balance, including Alzheimer's Disease, Parkinson's Disease, Menière's Disease and cervical spondylosis, all of which are caused by damage to certain parts of the vestibular pathways. Studies about the impairment of the vestibular system are challenging to carry out in human trials due to smaller study sizes limiting applications of the results and a lacking understanding of the human balance control mechanism. In contrast, more controlled research can be performed in animal studies which have fewer confounding factors than human models and allow specific conditions that affect balance to be replicated. Balance control can be studied using rodent balance-related behavioural tests after spinal or brain lesions, such as the Basso, Beattie and Bresnahan (BBB) Locomotor Scale, Foot Fault Scoring System, Ledged Beam Test, Beam Walking Test, and Ladder Beam Test, which are discussed in this review article along with their advantages and disadvantages. These tests can be performed in preclinical rodent models of femoral nerve injury, stroke, spinal cord injury and neurodegenerative diseases.

ENHANCE proof-of-concept three-arm randomized trial: effects of reaching training of the hemiparetic upper limb restricted to the spasticity-free elbow range

Post-stroke motor recovery processes remain unknown. Timescales and patterns of upper-limb (UL) recovery suggest a major impact of biological factors, with modest contributions from rehabilitation. We assessed a novel impairment-based training motivated by motor control theory where reaching occurs within the spasticity-free elbow range. Patients with subacute stroke (≤ 6 month; n = 46) and elbow flexor spasticity were randomly allocated to a 10-day UL training protocol, either personalized by restricting reaching to the spasticity-free elbow range defined by the tonic stretch reflex threshold (TSRT) or non-personalized (non-restricted) and with/without anodal transcranial direct current stimulation. Outcomes assessed before, after, and 1 month post-intervention were elbow flexor TSRT angle and reach-to-grasp arm kinematics (primary) and stretch reflex velocity sensitivity, clinical impairment, and activity (secondary). Results were analyzed for 3 groups as well as those of the effects of impairment-based training. Clinical measures improved in both groups. Spasticity-free range training resulted in faster and smoother reaches, smaller (i.e., better) arm-plane path length, and closer-to-normal shoulder/elbow movement patterns. Non-personalized training improved clinical scores without improving arm kinematics, suggesting that clinical measures do not account for movement quality. Impairment-based training within a spasticity-free elbow range is promising since it may improve clinical scores together with arm movement quality.Clinical Trial Registration: URL: http://www.clinicaltrials.gov . Unique Identifier: NCT02725853; Initial registration date: 01/04/2016.

Motor rehabilitation after stroke: European Stroke Organisation (ESO) consensus-based definition and guiding framework

PURPOSE

To propose a consensus-based definition and framework for motor rehabilitation after stroke.

METHODS

An expert European working group reviewed the literature, attaining internal consensus after external feedback.

FINDINGS

Motor rehabilitation is defined as a process that engages people with stroke to benefit their motor function, activity capacity and performance in daily life. It is necessary for people with residual motor disability whose goal is to enhance their functioning, independence and participation. Motor rehabilitation operates through learning- and use-dependent mechanisms. The trajectory of motor recovery varies across patients and stages of recovery. Early behavioral restitution of motor function depends on spontaneous biological mechanisms. Further improvements in activities of daily living are achieved by compensations. Motor rehabilitation is guided by regular assessment of motor function and activity using consensus-based measures, including patient-reported outcomes. Results are discussed with the patient and their carers to set personal goals. During motor rehabilitation patients learn to optimize and adapt their motor, sensory and cognitive functioning through appropriately dosed repetitive, goal-oriented, progressive, task- and context-specific training. Motor rehabilitation supports people with stroke to maximize health, well-being and quality of life. The framework describes the International Classification of Functioning, Disability and Health in the context of stroke, describes neurobiological mechanisms of behavioral restitution and compensation, and summarizes recommendations for clinical assessment, prediction tools, and motor interventions with strong recommendations from clinical practice guidelines (2016-2022).

CONCLUSIONS

This definition and framework may guide clinical educators, inform clinicians on current recommendations and guidelines, and identify gaps in the evidence base.

Spatial mapping of posture-dependent resistance to passive displacement of the hypertonic arm post-stroke

BACKGROUND

Muscles in the post-stroke arm commonly demonstrate abnormal reflexes that result in increased position- and velocity-dependent resistance to movement. We sought to develop a reliable way to quantify mechanical consequences of abnormal neuromuscular mechanisms throughout the reachable workspace in the hemiparetic arm post-stroke.

METHODS

Survivors of hemiparetic stroke (HS) and neurologically intact (NI) control subjects were instructed to relax as a robotic device repositioned the hand of their hemiparetic arm between several testing locations that sampled the arm's passive range of motion. During transitions, the robot induced motions at either the shoulder or elbow joint at three speeds: very slow (6°/s), medium (30°/s), and fast (90°/s). The robot held the hand at the testing location for at least 20 s after each transition. We recorded and analyzed hand force and electromyographic activations from selected muscles spanning the shoulder and elbow joints during and after transitions.

RESULTS

Hand forces and electromyographic activations were invariantly small at all speeds and all sample times in NI control subjects but varied systematically by transport speed during and shortly after movement in the HS subjects. Velocity-dependent resistance to stretch diminished within 2 s after movement ceased in the hemiparetic arms. Hand forces and EMGs changed very little from 2 s after the movement ended onward, exhibiting dependence on limb posture but no systematic dependence on movement speed or direction. Although each HS subject displayed a unique field of hand forces and EMG responses across the workspace after movement ceased, the magnitude of steady-state hand forces was generally greater near the outer boundaries of the workspace than in the center of the workspace for the HS group but not the NI group.

CONCLUSIONS

In the HS group, electromyographic activations exhibited abnormalities consistent with stroke-related decreases in the stretch reflex thresholds. These observations were consistent across repeated testing days. We expect that the approach described here will enable future studies to elucidate stroke's impact on the interaction between the neural mechanisms mediating control of upper extremity posture and movement during goal-directed actions such as reaching and pointing with the arm and hand.

Can mixed circuit training elicit the recommended exercise intensity and energy expenditure in people after stroke?

PURPOSE

To investigate whether mixed circuit training (MCT) elicits the recommended exercise intensity and energy expenditure in people after stroke, and to establish the between-day reproducibility for the percentages of heart rate reserve (%HRR), oxygen uptake reserve (%VO2R), and energy expenditure elicited during two bouts of MCT.

METHODS

Seven people aged 58 (12) yr, who previously had a stroke, performed a cardiopulmonary exercise test, a non-exercise control session, and two bouts of MCT. The MCT included 3 circuits of 10 resistance exercises at 15-repetition maximum intensity, with each set of resistance exercise interspersed with 45-s of walking. Expired gases were collected during the MCT and control session and for 40 min afterward. Control session was necessary to calculate the net energy expenditure associated with each bout of MCT.

RESULTS

Mean %VO2R (1st MCT: 51.1%, P = .037; 2nd MCT: 54.0%, P = .009) and %HRR (1st MCT: 66.4%, P = .007; 2nd MCT: 67.9%, P = .010) exceeded the recommended minimum intensity of 40%. Both %VO2R (P = .586 and 0.987, respectively) and %HRR (P = .681 and 0.237, respectively) during the 1st and 2nd bouts of MCT were not significantly different to their corresponding gas exchange threshold values derived from cardiopulmonary exercise testing. Mean net total energy expenditure significantly exceeded the minimum recommend energy expenditure in the 1st (P = .048) and 2nd (P = .023) bouts of MCT. Between-day reproducibility for %HRR, %VO2R, and energy expenditure was excellent (ICC: 0.92-0.97).

CONCLUSIONS

MCT elicited physiological strain recommended for improving health-related fitness in people after stroke and these responses demonstrated excellent between-day reproducibility.

Adaptive olfactory circuitry restores function despite severe olfactory bulb degeneration

The olfactory bulb (OB) is a critical component of mammalian olfactory neuroanatomy. Beyond being the first and sole relay station for olfactory information to the rest of the brain, it also contains elaborate stereotypical circuitry that is considered essential for olfaction. Indeed, substantial lesions of the OB in rodents lead to anosmia. Here, we examined the circuitry that underlies olfaction in a mouse model with severe developmental degeneration of the OB. These mice could perform odor-guided tasks and even responded normally to innate olfactory cues. Despite the near total loss of the OB, piriform cortices in these mice responded to odors, and its neural activity sufficed to decode odor identity. We found that sensory neurons express the full repertoire of olfactory receptors, and their axons project primarily to the rudiments of the OB but also, ectopically, to olfactory cortical regions. Within the OB, the number of principal neurons was greatly reduced, and the morphology of their dendrites was abnormal, extending over large regions within the OB. Glomerular organization was totally lost in the severe cases of OB degeneration and altered in the more conserved OBs. This study shows that olfactory functionality can be preserved despite reduced and aberrant circuitry that is missing many of the elements believed to be essential for olfaction, and it may explain reported retention of olfaction in humans with degenerated OBs.

Rethinking Remapping: Circuit Mechanisms of Recovery after Stroke

Stroke is one of the most common causes of disability, and there are few treatments that can improve recovery after stroke. Therapeutic development has been hindered because of a lack of understanding of precisely how neural circuits are affected by stroke, and how these circuits change to mediate recovery. Indeed, some of the hypotheses for how the CNS changes to mediate recovery, including remapping, redundancy, and diaschisis, date to more than a century ago. Recent technological advances have enabled the interrogation of neural circuits with ever greater temporal and spatial resolution. These techniques are increasingly being applied across animal models of stroke and to human stroke survivors, and are shedding light on the molecular, structural, and functional changes that neural circuits undergo after stroke. Here we review these studies and highlight important mechanisms that underlie impairment and recovery after stroke. We begin by summarizing knowledge about changes in neural activity that occur in the peri-infarct cortex, specifically considering evidence for the functional remapping hypothesis of recovery. Next, we describe the importance of neural population dynamics, disruptions in these dynamics after stroke, and how allocation of neurons into spared circuits can restore functionality. On a more global scale, we then discuss how effects on long-range pathways, including interhemispheric interactions and corticospinal tract transmission, contribute to post-stroke impairments. Finally, we look forward and consider how a deeper understanding of neural circuit mechanisms of recovery may lead to novel treatments to reduce disability and improve recovery after stroke.

Longitudinal optogenetic mapping reveals enhanced motor control by the contralesional cortex after traumatic brain injury in mice

Traumatic brain injury (TBI) is a significant cause of human disability, and understanding its spontaneous recovery pattern after injury is critical for potential treatments. However, studies on the function of the contralesional cortex after TBI have mostly focused on acute-phase changes, and long-term dynamic changes in the control of the affected limb by the contralesional cortex are less understood. To unravel long-term adaptations in the contralesional cortex, we developed a mouse model of TBI and used longitudinal optogenetic motor mapping to observe the function of contralesional corticospinal neurons (CSNs) projecting to the unilateral seventh cervical (C7) segment of the spinal cord. We injected a retrograde adeno-associated virus (AAV) expressing channelrhodopsin-2 to optogenetically stimulate and map the functional connections of the motor-sensory cortex. We validated the effectiveness of transcranial optogenetic stimulation for functional mapping and observed a general increase in the control of the affected limb by the contralesional cortex over time. Using retrograde labeling techniques, we showed that TBI does not affect the distribution of C7-CSNs but alters their function, and the labeled CSNs are concentrated in the caudal and rostral forelimb areas. Our findings provide new insights into harnessing contralesional cortical plasticity to improve treatment for affected limbs. This study sheds light on the long-term adaptations in the contralesional cortex after TBI, paving the way for potential clinical applications of optogenetic stimulation to improve motor control and rehabilitation outcomes.

Aiming Movement After Stroke: Do Time-Since-Injury and Impairment Severity Influence Ipsilateral Performance?

In this cross-sectional study, we evaluated post-stroke ipsilesional (less affected) upper limb aiming movement in individuals whose strokes were either 2-5 months (n = 16) or >6 months (n = 17) prior to our testing; we also compared both stroke groups to a control group of healthy individuals (n = 14). We evaluated the participants' level of movement impairment in the contralateral upper limb from the site of the cerebrovascular lesion as an indicator of the severity of the participants' impairment. Participants were asked to move a stylus on a tablet with their ipsilesional upper limb according to a visual stimulus seen on a monitor. Those who had experienced more recent strokes showed poorer movement planning and execution, regardless of their impairment level. Since the stroke occurred, the amount of time was significantly associated with the ipsilesional aiming movement, and improvement over time brought performance levels closer to that of healthy controls.

Neural oscillations after acute large artery atherosclerotic cerebral infarction during resting state and sleep spindles

Electroencephalogram-microstate analysis was conducted using low-resolution electromagnetic tomography (LORETA)-KEY to evaluate dynamic brain network changes in patients with acute large artery atherosclerotic cerebral infarction (LAACI) during the rest and sleep stages. This study included 35 age- and sex-matched healthy controls and 34 patients with acute LAACI. Each participant performed a 3-h, 19-channel video electroencephalogram test. Subsequently, 20 epochs of 2-s sleep spindles during stage N2 sleep and five epochs of 10-s electroencephalogram data in the resting state for each participant were obtained. In both the resting state and sleep spindles, patients with LAACI displayed altered neural oscillations. The parameters of microstate A (coverage, occurrence, and duration) increased during the resting state in the patients with LAACI compared with healthy controls. The coverage and occurrence of microstate B and D were reduced in the LAACI group compared with the healthy controls (p < 0.05). Moreover, during sleep spindles, the duration of microstate A and the transition probability from microstate A and B to C decreased, but the coverage of microstate B and the transition rate from microstate B to D increased (p < 0.05) in the LAACI group compared with the healthy controls. These results enable better understanding of how neural oscillations are modified in patients with LAACI during the resting state and sleep spindles. Following LAACI, the dynamic brain network undergoes changes during sleep spindles and the resting state. Continued long-term investigations are required to determine how well these changes in brain dynamics reflect the clinical characteristics of patients with LAACI.

Responsiveness of the Reaching Performance Scale for Stroke

OBJECTIVE

The objective of the study was to estimate the internal and external responsiveness of the Reaching Performance Scale for Stroke (RPSS) in individuals with stroke.

DESIGN

Retrospective analysis of data from 4 randomized controlled trials.

SETTING

Recruitment locations spanning rehabilitation centers and hospitals in Canada, Italy, Argentina, Peru, and Thailand.

PARTICIPANTS

Data from 567 participants (acute to chronic stroke; N=567) were available.

INTERVENTIONS

All 4 studies involved training using virtual reality for upper limb rehabilitation.

MAIN OUTCOME MEASURES

RPSS and upper extremity Fugl-Meyer Assessment (FMA-UE) scores. Responsiveness was quantified for all data and across different stages of stroke. Internal responsiveness of the RPSS was quantified as effect-sizes calculated using post and preintervention change data. External responsiveness was quantified using orthogonal regressions between FMA-UE and RPSS scores. The area under the Receiver Operating Characteristic curve (AUC) was quantified based on the ability of RPSS scores to detect change above FMA-UE minimal clinically important different values across different stages of stroke.

RESULTS

The RPSS had high internal responsiveness overall and across the acute or subacute and chronic stages of stroke. For external responsiveness, orthogonal regression analyses indicated that change in FMA-UE scores had positive moderate correlations with both RPSS Close and Far Target scores for all data and across the acute or subacute and chronic stages of stroke (0.6

CONCLUSIONS

In addition to being reliable and valid, the RPSS is also responsive. Along with the FMA-UE, using RPSS scores can help present a more comprehensive picture of motor compensations to characterize poststroke upper limb motor improvement.

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Key Words

• Movement quality
• cerebrovascular accident
• compensation
• outcomes
• reaching
• restitution or true recovery
• upper limb

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MESH Headings

• Humans
• Disability Evaluation
• Recovery of Function
• Retrospective Studies
• Stroke
• Stroke Rehabilitation
• Upper Extremity
• Randomized Controlled Trials as Topic

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Grants Collapse

Affiliation(s)

Sandeep K Subramanian Departments of Physical Therapy, Physician Assistant Studies and Rehabilitation Medicine, University of Texas Health San Antonio, San Antonio, TX
Gita Margolese School of Physical and Occupational Therapy, McGill University, Montreal, Canada; Centre for Interdisciplinary Research in Rehabilitation, Montreal, Canada
Andrea Turolla Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy; Laboratory of Rehabilitation Technologies, Hospital San Camillo IRCCS, Venice, Italy
Gustavo Saposnik Stroke Outcomes and Decision Neuroscience Unit, Unity Health Toronto, University of Toronto, Toronto, Canada
Mindy F Levin School of Physical and Occupational Therapy, McGill University, Montreal, Canada; Centre for Interdisciplinary Research in Rehabilitation, Montreal, Canada.

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Exploring the Feasibility of Computer Vision for Detecting Post-Stroke Compensatory Movements

Compensatory movements are commonly observed post-stroke and can negatively affect long-term motor recovery. In this context, a system that monitors movement quality and provides feedback would be beneficial. In this study, we aimed to detect compensatory movements during seated reaching using a conventional tablet camera and an open-source markerless body pose tracking algorithm called MediaPipe [1]. We annotated compensatory movements of stroke patients per frame based on the comparison between the paretic and non-paretic arms. We trained a binary classification model using the XGBoost algorithm to detect compensatory movements, which showed an average accuracy of 0.92 (SD 0.07) in leave-one-trial-out cross-validation across four participants. Although we observed good model performance, we also encountered challenges such as missing landmarks and misalignment, when using MediaPipe Pose. This study highlights the feasibility of using near real-time compensatory movement detection with a simple camera system in stroke rehabilitation. More work is necessary to assess the generalizability of our approach across diverse groups of stroke survivors and fully implement near real-time compensatory movement detection on a mobile device.

The Translation of Mobile-Exoneuromusculoskeleton-Assisted Wrist-Hand Poststroke Telerehabilitation from Laboratory to Clinical Service

Rehabilitation robots are helpful in poststroke telerehabilitation; however, their feasibility and rehabilitation effectiveness in clinical settings have not been sufficiently investigated. A non-randomized controlled trial was conducted to investigate the feasibility of translating a telerehabilitation program assisted by a mobile wrist/hand exoneuromusculoskeleton (WH-ENMS) into routine clinical services and to compare the rehabilitative effects achieved in the hospital-service-based group (n = 12, clinic group) with the laboratory-research-based group (n = 12, lab group). Both groups showed significant improvements (p ≤ 0.05) in clinical assessments of behavioral motor functions and in muscular coordination and kinematic evaluations after the training and at the 3-month follow-up, with the lab group demonstrating better motor gains than the clinic group (p ≤ 0.05). The results indicated that the WH-ENMS-assisted tele-program was feasible and effective for upper limb rehabilitation when integrated into routine practice, and the quality of patient-operator interactions physically and remotely affected the rehabilitative outcomes.

Application of Deep Learning Algorithm to Monitor Upper Extremity Task Practice

Upper extremity hemiplegia is a serious problem affecting the lives of many people post-stroke. Motor recovery requires high repetitions and quality of task-specific practice. Sufficient practice cannot be completed during therapy sessions, requiring patients to perform additional task practices at home on their own. Adherence to and quality of these home task practices are often limited, which is likely a factor reducing rehabilitation effectiveness post-stroke. However, home adherence is typically measured by self-reports that are known to be inconsistent with objective measurement. The objective of this study was to develop algorithms to enable the objective identification of task type and quality. Twenty neurotypical participants wore an IMU sensor on the wrist and performed four representative tasks in prescribed fashions that mimicked correct, compensatory, and incomplete movement qualities typically seen in stroke survivors. LSTM classifiers were trained to identify the task being performed and its movement quality. Our models achieved an accuracy of 90.8% for task identification and 84.9%, 81.1%, 58.4%, and 73.2% for movement quality classification for the four tasks for unseen participants. The results warrant further investigation to determine the classification performance for stroke survivors and if quantity and quality feedback from objective monitoring facilitates effective task practice at home, thereby improving motor recovery.

The Influence of Experience on Neuromuscular Control of the Body When Cutting at Different Angles

Cutting is an offensive technique commonly used in football and basketball to pass the opponent's defence by changing direction quickly in running. This paper aims to investigate the effect of experience and angle on the neuromuscular control strategies of the trunk and lower limbs during cutting. Non-negative matrix factorisation and K-means were used to extract muscle synergies (muscles that are activated in parallel) of 12 subjects with cut experience and 9 subjects without experience based on the sEMG signal collected from cutting at three cut angles (45°, 90°, and 135°), which was also mapped into the spinal motor output. Uncontrolled manifold analysis was used to establish the relationship between muscle synergies and COP. This study found that experienced subjects tended to use the lower limb muscles rather than the postural muscles as stabiliser muscles compared to novices. Experienced subjects can recruit an additional set of muscle synergy to cope with large-angle cuts. In addition, experienced subjects can activate the second muscle synergy, involving the hip and ankle stabilisation muscles, in advance to improve postural stability when cutting in large-angle. Synergy index of experienced subjects dropped rapidly before the quick stop and was relatively high during the change of direction. These results suggest that experience can modify the postural stabilisation mechanisms during cutting, and prompt the lower limb muscle synergy to produce anticipatory adjustment to improve postural stability in the anterior-posterior and internal-external directions.

Impairments and Compensation in String-pulling After Middle Cerebral Artery Occlusion in the Rat

Stroke is a leading cause of long-term disability in humans, and it is frequently associated with impairments in the skilled use of the arms and hands. Many human upper limb impairments and compensatory changes have been successfully modeled in rodent studies of neocortical stroke, especially those that evaluate single limb use in tasks, such as reaching for food. Humans also use their hands for bilaterally coordinated movements, dependent upon interhemispheric cortical projections, which are also compromised by unilateral stroke. This study describes middle cerebral artery occlusion (MCAO) dependent changes in the bilaterally dependent hand use behavior of string-pulling in the rat. The task involves making hand-over-hand movements to pull down a string that contains a food reward attached to its end. MCAO rats missed the string more often with both hands than Sham rats. When the string was missed on the contralateral to MCAO body side, rats continued to cycle through subcomponents of string-pulling behavior as if the string were grasped in the hand. Rats also failed to make a grasping motion with the contralateral to MCAO hand when the string was missed and instead, demonstrated an open-handed raking-like motions. Nevertheless, with repeated attempts, rats performed components of string-pulling well enough to obtain a reward on the end of the string. Thus, string-pulling behavior is sensitive to bilateral impairments but is achieved with compensatory adjustments following MCAO. These aspects of MCAO string-pulling provide a foundation for studies that investigate the efficacy of therapeutic intervention which might enhance neuroplasticity and recovery. DATA AVAILABILITY: The datasets generated during the current study are available upon request.

The Role of Technological Rehabilitation in Patients with Intensive Care Unit Weakness: A Randomized Controlled Pilot Study

Intensive-Care-Unit-Acquired Weakness (ICU-AW) is the most common neuromuscular impairment in critically ill patients and can have a significant impact on long-term disability. Early rehabilitation has been suggested to facilitate the natural recovery process. This is a pilot, randomized, single-blind study that aimed to evaluate the effectiveness of intensive combined technological rehabilitation treatment including focal muscle vibration and non-immersive virtual reality for patients with severe acquired brain injury (sABI) and ICU-AW. Twenty-four patients were randomized into the conventional group, which performed only conventional rehabilitation, and the experimental group, which also performed technological treatment. At baseline and after 3 weeks of treatment, assessments of motor function, autonomy, disability and quality of life were conducted. At the end of the intervention, both groups showed significant improvements. However, patients in the experimental group achieved greater improvements in disability (p = 0.001) and quality of life (p = 0.001). The results show that intensive structured rehabilitation is effective in improving the motor function, disability and quality of life of patients with severe acquired brain injury and acquired weakness. The combination of non-immersive virtual reality training and focal muscle vibration can result in a significant improvement in overall disability and quality of life compared with conventional treatment alone.

The reliability and validity of the Korean version of the reaching performance scale for stroke after translation and cross-cultural adaptation

The reaching performance scale for stroke evaluates reach-to grasp movement of the upper extremity and compensatory movements. The objective of the study was to translate and cross-culturally adapt the reaching performance scale for stroke into Korean and assess its reliability and validity. An expert committee supervised the forward and backward translation and the final translated Korean version of reaching performance scale for stroke (K-RPSS). Ninety-eight individuals (mean age 63.63 ± 13.13 years), with hemiplegia after stroke (97.82 ± 191.50 weeks) were evaluated independently by physiatrist and occupational therapist using K-RPSS. Degree of the motor impairment and functional status of patients were evaluated with the Fugl-Meyer assessment for upper limb and manual function test. The K-RPSS demonstrated excellent intra-rater (intraclass correlation coefficient = 0.9865), inter-rater (intraclass correlation coefficient 0.9866) reliability, and internal consistency (Cronbach α = 0.977 for total score). The validity of K-RPSS was confirmed with strong correlation with Fugl-Meyer assessment and manual function test. The K-RPSS had ceiling effect and the 3 points is the score change needed to indicate a change in a patient. K-RPSS has been shown to be a reliable and valid tool for assessing the compensation and movement quality of the upper limb and trunk when performing a reach-to grasp task. The K-RPSS is expected to be used widely by Korean speaking clinicians and researchers.

Spared Premotor Areas Undergo Rapid Nonlinear Changes in Functional Organization Following a Focal Ischemic Infarct in Primary Motor Cortex of Squirrel Monkeys

Recovery of motor function after stroke is accompanied by reorganization of movement representations in spared cortical motor regions. It is widely assumed that map reorganization parallels recovery, suggesting a causal relationship. We examined this assumption by measuring changes in motor representations in eight male and six female squirrel monkeys in the first few weeks after injury, a time when motor recovery is most rapid. Maps of movement representations were derived using intracortical microstimulation techniques in primary motor cortex (M1), ventral premotor cortex (PMv), and dorsal premotor cortex (PMd) in 14 adult squirrel monkeys before and after a focal infarct in the M1 distal forelimb area. Maps were derived at baseline and at either 2 (n = 7) or 3 weeks (n = 7) postinfarct. In PMv the forelimb maps remained unchanged at 2 weeks but contracted significantly (-42.4%) at 3 weeks. In PMd the forelimb maps expanded significantly (+110.6%) at 2 weeks but contracted significantly (-57.4%) at 3 weeks. Motor deficits were equivalent at both time points. These results highlight two features of plasticity after M1 lesions. First, significant contraction of distal forelimb motor maps in both PMv and PMd is evident by 3 weeks. Second, an unpredictable nonlinear pattern of reorganization occurs in the distal forelimb representation in PMd, first expanding at 2 weeks, and then contracting at 3 weeks postinjury. Together with previous results demonstrating reliable map expansions in PMv several weeks to months after M1 injury, the subacute time period may represent a critical window for the timing of therapeutic interventions.SIGNIFICANCE STATEMENT The relationship between motor recovery and motor map reorganization after cortical injury has rarely been examined in acute/subacute periods. In nonhuman primates, premotor maps were examined at 2 and 3 weeks after injury to primary motor cortex. Although maps are known to expand late after injury, the present study demonstrates early map expansion at 2 weeks (dorsal premotor cortex) followed by contraction at 3 weeks (dorsal and ventral premotor cortex). This nonlinear map reorganization during a time of gradual behavioral recovery suggests that the relationship between map plasticity and motor recovery is much more complex than previously thought. It also suggests that rehabilitative motor training may have its most potent effects during this early dynamic phase of map reorganization.

Neurovascular coupling is preserved in chronic stroke recovery after targeted photothrombosis

Functional neuroimaging, which measures hemodynamic responses to brain activity, has great potential for monitoring recovery in stroke patients and guiding rehabilitation during recovery. However, hemodynamic responses after stroke are almost always altered relative to responses in healthy subjects and it is still unclear if these alterations reflect the underlying brain physiology or if the alterations are purely due to vascular injury. In other words, we do not know the effect of stroke on neurovascular coupling and are therefore limited in our ability to use functional neuroimaging to accurately interpret stroke pathophysiology. To address this challenge, we simultaneously captured neural activity, through fluorescence calcium imaging, and hemodynamics, through intrinsic optical signal imaging, during longitudinal stroke recovery. Our data suggest that neurovascular coupling was preserved in the chronic phase of recovery (2 weeks and 4 weeks post-stoke) and resembled pre-stroke neurovascular coupling. This indicates that functional neuroimaging faithfully represents the underlying neural activity in chronic stroke. Further, neurovascular coupling in the sub-acute phase of stroke recovery was predictive of long-term behavioral outcomes. Stroke also resulted in increases in global brain oscillations, which showed distinct patterns between neural activity and hemodynamics. Increased neural excitability in the contralesional hemisphere was associated with increased contralesional intrahemispheric connectivity. Additionally, sub-acute increases in hemodynamic oscillations were associated with improved sensorimotor outcomes. Collectively, these results support the use of hemodynamic measures of brain activity post-stroke for predicting functional and behavioral outcomes.

The immediate effects of iTBS on the muscle activation pattern under challenging balance conditions in the patients with chronic low back pain: A preliminary study

Background

The patients with chronic low back pain (CLBP) showed impaired postural control, especially in challenging postural task. The dorsolateral prefrontal cortex (DLPFC) is reported to involve in the complex balance task, which required considerable attentional control. The effect of intermittent theta burst stimulation (iTBS) over the DLPFC to the capacity of postural control of CLBP patients is still unknown.

Methods

Participants diagnosed with CLBP received a single-session iTBS over the left DLPFC. All the participants completed the postural control tasks of single-leg (left/right) standing before and after iTBS. The activation changes of the DLPFC and M1 before and after iTBS were recorded by functional near-infrared spectroscopy (fNIRS). The activation pattern of the trunk [transversus abdominis (TrA), superficial lumbar multifidus (SLM)] and leg [tibialis anterior (TA), gastrocnemius medialis (GM)] muscles including root mean square (RMS) and co-contraction index (CCI) during single-leg standing were measured by surface electromyography (sEMG) before and after the intervention. The paired t-test was used to test the difference before and after iTBS. Pearson correlation analyses were performed to test the relationship between the oxyhemoglobin concentration and sEMG outcome variables (RMS and CCI).

Results

Overall, 20 participants were recruited. In the right-leg standing condition, compared with before iTBS, the CCI of the right TrA/SLM was significantly decreased (t = −2.172, p = 0.043), and the RMS of the right GM was significantly increased (t = 4.024, p = 0.001) after iTBS. The activation of the left DLPFC (t = 2.783, p = 0.012) and left M1 (t = 2.752, p = 0.013) were significantly decreased and the relationship between the left DLPFC and M1 was significant after iTBS (r = 0.575, p = 0.014). Correlation analysis showed the hemoglobin concentration of M1 was negatively correlated with the RMS of the right GM (r = −0.659, p = 0.03) and positively correlated between CCI of the right TrA/SLM (r = 0.503, p = 0.047) after iTBS. There was no significant difference in the brain or muscle activation change in the left leg-standing condition between before and after iTBS.

Conclusion

Intermittent theta burst stimulation over the left DLPFC seems to be able to improve the muscle activation pattern during postural control ability in challenging postural task, which would provide a new approach to the treatment of CLBP.

Repeatability and Temporal Consistency of Lower Limb Biomechanical Variables Expressing Interlimb Coordination during the Double-Support Phase in People with and without Stroke Sequelae

Reliable biomechanical methods to assess interlimb coordination during the double-support phase in post-stroke subjects are needed for assessing movement dysfunction and related variability. The data obtained could provide a significant contribution for designing rehabilitation programs and for their monitorisation. The present study aimed to determine the minimum number of gait cycles needed to obtain adequate values of repeatability and temporal consistency of lower limb kinematic, kinetic, and electromyographic parameters during the double support of walking in people with and without stroke sequelae. Eleven post-stroke and thirteen healthy participants performed 20 gait trials at self-selected speed in two separate moments with an interval between 72 h and 7 days. The joint position, the external mechanical work on the centre of mass, and the surface electromyographic activity of the tibialis anterior, soleus, gastrocnemius medialis, rectus femoris, vastus medialis, biceps femoris, and gluteus maximus muscles were extracted for analysis. Both the contralesional and ipsilesional and dominant and non-dominant limbs of participants with and without stroke sequelae, respectively, were evaluated either in trailing or leading positions. The intraclass correlation coefficient was used for assessing intra-session and inter-session consistency analysis. For most of the kinematic and the kinetic variables studied in each session, two to three trials were required for both groups, limbs, and positions. The electromyographic variables presented higher variability, requiring, therefore, a number of trials ranging from 2 to >10. Globally, the number of trials required inter-session ranged from 1 to >10 for kinematic, from 1 to 9 for kinetic, and 1 to >10 for electromyographic variables. Thus, for the double support analysis, three gait trials were required in order to assess the kinematic and kinetic variables in cross-sectional studies, while for longitudinal studies, a higher number of trials (>10) were required for kinematic, kinetic, and electromyographic variables.

Effects of Tai Chi Yunshou on upper-limb function and balance in stroke survivors: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

Physical rehabilitation plays an important role in the recovery of motor function after a stroke. This study aimed to evaluate the effects of Tai Chi Yunshou (TCY), a form of physical therapy, on upper-limb function and balance in stroke survivors.

METHODS

MEDLINE, Embase, CENTRAL and five Chinese databases were retrieved from inception to July 1, 2020 (updated on March 31, 2022). Randomized controlled trials of TCY versus no-treatment for stroke were included. The RoB-2 was used to evaluate the quality of included studies. Upper-limb motor impairment, balance, and activities of daily living (ADLs) were measured by Fugl-Meyer Assessment Upper Extremity Scale (FMA-UE), Berg Balance Scale (BBS), and Barthel Index (BI), respectively. Data synthesis was performed using RevMan (v5.3), and expressed as mean difference (MD) with 95% confidence intervals (CI).

RESULTS

Seven studies with 529 participants were included. Compared with no-treatment, TCY improved FMA-UE (MD = 7.31, 95% CI: 5.86-8.77, minimal clinically important difference [MCID]: 9-10), BBS (MD = 4.68, 95% CI: 0.28-9.07, MCID: 4), and BI (MD = 4.12, 95% CI: 3.28-4.96, MCID: 1.85) in stroke survivors.

CONCLUSION

TCY may benefit balance and ADLs in rehabilitation after a stroke, but it may not improve upper-limb function clinically.

Adaptive control is reversed between hands after left hemisphere stroke and lost following right hemisphere stroke

Human motor adaptability is of utmost utility after neurologic injury such as unilateral stroke. For successful adaptive control of movements, the nervous system must learn to correctly identify the source of a movement error and predictively compensate for this error. The current understanding is that in bimanual tasks, this process is flexible such that errors are assigned to, and compensated for, by the limb that is more likely to produce those errors. Here, we tested the flexibility of the error assignment process in right-handed chronic stroke survivors using a bimanual reaching task in which the hands jointly controlled a single cursor. We predicted that the nondominant left hand in neurotypical adults and the paretic hand in chronic stroke survivors will be more responsible for cursor errors and will compensate more within a trial and learn more from trial to trial. We found that in neurotypical adults, the nondominant left hand does compensate more than the right hand within a trial but learns less trial-to-trial. After a left hemisphere stroke, the paretic right hand compensates more than the nonparetic left hand within-trial but learns less trial-to-trial. After a right hemisphere stroke, the paretic left hand neither corrects more within-trial nor learns more trial-to-trial. Thus, adaptive control of visually guided bimanual reaching movements is reversed between hands after the left hemisphere stroke and lost following the right hemisphere stroke. These results indicate that responsibility assignment is not fully flexible but depends on a central mechanism that is lateralized to the right hemisphere.

Clinically Applicable Experimental Design and Considerations for Stroke Recovery Preclinical Studies

Development of stroke recovery therapies is an active field of research and represents an opportunity to reduce the global impact of stroke as the leading cause of acquired, long-term disability in adults. The negative outcomes of recent large-scale clinical trials have highlighted deficiencies in the translational process and endanger the trajectory of post-stroke recovery research. Because of this, a number of strategies have been recommended by experts to better navigate the translational pipeline. To assist the field in advancing to the next stage for successful clinical translation, the goal of this chapter is to discuss concepts relevant to the experimental design of in vivo preclinical pharmacological studies to make them clinically relevant and informative for future trials.

Feasibility of an Enhanced Therapy Model of Care for Hospitalized Stroke Patients

INTRODUCTION

The aim of this study was to determine the safety and feasibility of an enhanced therapy model for hospitalized stroke patients.

METHODS

This was a quasi-experimental cohort study of acute stroke patients from a single hospital. In the intervention group, all hospitalized patients on the acute stroke service were seen by at least two therapy disciplines daily in addition to routine stroke care. The comparison group consisted of all patients admitted to the same stroke service 1 year before who received the standard of care. The primary endpoint was the number of completed therapy sessions. Exploratory endpoints compared the length of hospital stay, hospital readmission rates, and degree of disability measured by the 90-day modified Rankin Scale score.

RESULTS

A total of 1110 records were analyzed with 553 subjects in the intervention group and 557 in the control group. The intervention group received a significantly higher number of therapy sessions. There was no significant difference in length of hospital stay. However, 30-day readmission rates were lower, and the percentage of patients who achieved a good functional outcome on the modified Rankin Scale was higher during the intervention period.

CONCLUSION

Increasing exposure to intensive multidisciplinary therapy comparable with that of acute inpatient rehabilitation in the hospital setting is feasible and may reduce both readmission rates and disability.

Modified constraint-induced movement therapy enhances cortical plasticity in a rat model of traumatic brain injury: a resting-state functional MRI study

Modified constraint-induced movement therapy (mCIMT) has shown beneficial effects on motor function improvement after brain injury, but the exact mechanism remains unclear. In this study, amplitude of low frequency fluctuation (ALFF) metrics measured by resting-state functional magnetic resonance imaging was obtained to investigate the efficacy and mechanism of mCIMT in a control cortical impact (CCI) rat model simulating traumatic brain injury. At 3 days after control cortical impact model establishment, we found that the mean ALFF (mALFF) signals were decreased in the left motor cortex, somatosensory cortex, insula cortex and the right motor cortex, and were increased in the right corpus callosum. After 3 weeks of an 8-hour daily mCIMT treatment, the mALFF values were significantly increased in the bilateral hemispheres compared with those at 3 days postoperatively. The mALFF signal values of left corpus callosum, left somatosensory cortex, right medial prefrontal cortex, right motor cortex, left postero dorsal hippocampus, left motor cortex, right corpus callosum, and right somatosensory cortex were increased in the mCIMT group compared with the control cortical impact group. Finally, we identified brain regions with significantly decreased mALFF values at 3 days postoperatively. Pearson correlation coefficients with the right forelimb sliding score indicated that the improvement in motor function of the affected upper limb was associated with an increase in mALFF values in these brain regions. Our findings suggest that functional cortical plasticity changes after brain injury, and that mCIMT is an effective method to improve affected upper limb motor function by promoting bilateral hemispheric cortical remodeling. mALFF values correlate with behavioral changes and can potentially be used as biomarkers to assess dynamic cortical plasticity after traumatic brain injury.

Transcranial Direct Current Stimulation Electrode Montages May Differentially Impact Variables of Walking Performance in Individuals Poststroke: A Preliminary Study

PURPOSE

Transcranial direct current stimulation (tDCS) has mixed effects on walking performance in individuals poststroke. This is likely the result of variations in tDCS electrode montages and individualized responses. The purpose of this study was to quantify the effects of a single session of tDCS using various electrode montages on poststroke walking performance.

METHODS

Individuals with chronic stroke ( n = 16) participated in a double-blind, randomized cross-over study with sham stimulation and three tDCS electrode montages. Gait speed, paretic step ratio, and paretic propulsion were assessed prestimulation and poststimulation at self-selected and fastest comfortable speeds. Changes in muscle activation patterns with self-selected walking were quantified by the number of modules derived from nonnegative matrix factorization of EMG signals for hypothesis generation.

RESULTS

There was no significant effect of active stimulation montages compared with sham. Comparisons between each participant's best response to tDCS and sham show personalized tDCS may have a positive effect on fastest comfortable overground gait speed ( P = 0.084), paretic step ratio ( P = 0.095) and paretic propulsion ( P = 0.090), and self-selected paretic step ratio ( P = 0.012). Participants with two or three modules at baseline increased module number in response to the all experimental montages and sham, but responses were highly variable.

CONCLUSIONS

A single session of tDCS may affect clinical and biomechanical walking performance, but effects seem to be dependent on individual response variability to different electrode montages. Findings of this study are consistent with responses to various tDCS electrode montages being the result of underlying neuropathology, and the authors recommend examining how individual factors affect responses to tDCS.

Neurological scoring and gait kinematics to assess functional outcome in an ovine model of ischaemic stroke

Background

Assessment of functional impairment following ischaemic stroke is essential to determine outcome and efficacy of intervention in both clinical patients and pre-clinical models. Although paradigms are well described for rodents, comparable methods for large animals, such as sheep, remain limited. This study aimed to develop methods to assess function in an ovine model of ischaemic stroke using composite neurological scoring and gait kinematics from motion capture.

Methods

Merino sheep (n = 26) were anaesthetised and subjected to 2 hours middle cerebral artery occlusion. Animals underwent functional assessment at baseline (8-, 5-, and 1-day pre-stroke), and 3 days post-stroke. Neurological scoring was carried out to determine changes in neurological status. Ten infrared cameras measured the trajectories of 42 retro-reflective markers for calculation of gait kinematics. Magnetic resonance imaging (MRI) was performed at 3 days post-stroke to determine infarct volume. Intraclass Correlation Coefficients (ICC's) were used to assess the repeatability of neurological scoring and gait kinematics across baseline trials. The average of all baselines was used to compare changes in neurological scoring and kinematics at 3 days post-stroke. A principal component analysis (PCA) was performed to determine the relationship between neurological score, gait kinematics, and infarct volume post-stroke.

Results

Neurological scoring was moderately repeatable across baseline trials (ICC > 0.50) and detected marked impairment post-stroke (p < 0.05). Baseline gait measures showed moderate to good repeatability for the majority of assessed variables (ICC > 0.50). Following stroke, kinematic measures indicative of stroke deficit were detected including an increase in stance and stride duration (p < 0.05). MRI demonstrated infarction involving the cortex and/or thalamus (median 2.7 cm³, IQR 1.4 to 11.9). PCA produced two components, although association between variables was inconclusive.

Conclusion

This study developed repeatable methods to assess function in sheep using composite scoring and gait kinematics, allowing for the evaluation of deficit 3 days post-stroke. Despite utility of each method independently, there was poor association observed between gait kinematics, composite scoring, and infarct volume on PCA. This suggests that each of these measures has discreet utility for the assessment of stroke deficit, and that multimodal approaches are necessary to comprehensively characterise functional impairment.