Training-induced modifications of corticospinal reactivity in severely affected stroke survivors

Using mechanistic knowledge to appraise contemporary approaches to the rehabilitation of upper limb function following stroke

It is a paradox of neurological rehabilitation that, in an era in which preclinical models have produced significant advances in our mechanistic understanding of neural plasticity, there is inadequate support for many therapies recommended for use in clinical practice. When the goal is to estimate the probability that a specific form of therapy will have a positive clinical effect, the integration of mechanistic knowledge (concerning 'the structure or way of working of the parts in a natural system') may improve the quality of inference. This is illustrated by analysis of three contemporary approaches to the rehabilitation of lateralized dysfunction affecting people living with stroke: constraint-induced movement therapy; mental practice; and mirror therapy. Damage to 'cross-road' regions of the structural (white matter) brain connectome generates deficits that span multiple domains (motor, language, attention and verbal/spatial memory). The structural integrity of these regions determines not only the initial functional status, but also the response to therapy. As structural disconnection constrains the recovery of functional capability, 'disconnectome' modelling provides a basis for personalized prognosis and precision rehabilitation. It is now feasible to refer a lesion delineated using a standard clinical scan to a (dis)connectivity atlas derived from the brains of other stroke survivors. As the individual disconnection pattern thus obtained suggests the functional domains most likely be compromised, a therapeutic regimen can be tailored accordingly. Stroke is a complex disorder that burdens individuals with distinct constellations of brain damage. Mechanistic knowledge is indispensable when seeking to ameliorate the behavioural impairments to which such damage gives rise.

Correlations in abnormal synergies between the upper and lower extremities across various phases of stroke

The flexion synergy and extension synergy are a representative consequence of a stroke and appear in the upper extremity and the lower extremity. Since the ipsilesional corticospinal tract (CST) is the most influential neural pathway for both extremities in motor execution, damage by a stroke to this tract could lead to similar motor pathological features (e.g., abnormal synergies) in both extremities. However, less attention has been paid to the interlimb correlations in the flexion synergy and extension synergy across different recovery phases of a stroke. We used results of the Fugl-Meyer assessment (FMA) to characterize those correlations in a total of 512 participants with hemiparesis after stroke from the acute phase to 1 year. The FMA provides indirect indicators of the degrees of the flexion synergy and extension synergy after stroke. We found that, generally, strong interlimb correlations (r > 0.65 with all P values < 0.0001) between the flexion synergy and extension synergy appeared in the acute-to-subacute phase (<90 days). However, the correlations of the lower-extremity extension synergy with the upper-extremity flexion synergy and extension synergy decreased (down to r = 0.38) 360 days after stroke (P < 0.05). These results suggest that the preferential use of alternative neural pathways after damage by a stroke to the CST enhances the interlimb correlations between the flexion synergy and extension synergy. At the same time, the results imply that the recovery of CST integrity or/and the fragmentation (remodeling) of the alternative neural substrates in the chronic phase may contribute to diversity in neural pathways in motor execution, eventually leading to reduced interlimb correlations.NEW & NOTEWORTHY For the first time, this article addresses the asynchronous relationships in the strengths of flexion and extension synergy expressions between the paretic upper extremity and lower extremity across various phases of stroke.

Evidence of the existence of multiple modules for the stroke-caused flexion synergy from Fugl-Meyer assessment scores

Stroke-caused synergies may result from the preferential use of the reticulospinal tract (RST) due to damage to the corticospinal tract. The RST branches multiple motoneuron pools across the arm together resulting in gross motor control or abnormal synergies, and accordingly, the controllability of individual muscles decreases. However, it is not clear whether muscles involuntarily activated by abnormal synergy vary depending on the muscles voluntarily activated when motor commands descend through the RST. Studies showed that abnormal synergies may originate from the merging and reweighting of synergies in individuals without neurological deficits. This leads to a hypothesis that those abnormal synergies are still selectively excited depending on the context. In this study, we test this hypothesis, leveraging the Fugl-Meyer assessment that could characterize the neuroanatomical architecture in individuals with a wide range of impairments. We examine the ability to perform an out-of-synergy movement with the flexion synergy caused by either shoulder or elbow loading. The results reveal that about 14% [8/57, 95% confidence interval (5.0%, 23.1%)] of the participants with severe impairment (total Fugl-Meyer score <29) in the chronic phase (6 months after stroke) are able to keep the elbow extended during shoulder loading and keep the shoulder at neutral during elbow loading. Those participants underwent a different course of neural reorganization, which enhanced abnormal synergies in comparison with individuals with mild impairment (P < 0.05). These results provide evidence that separate routes and synergy modules to motoneuron pools across the arm might exist even if the motor command is mediated possibly via the RST.NEW & NOTEWORTHY We demonstrate that abnormal synergies are still selectively excited depending on the context.

Adaptation in the spinal cord after stroke: Implications for restoring cortical control over the final common pathway

Control of voluntary movement is predicated on integration between circuits in the brain and spinal cord. Although damage is often restricted to supraspinal or spinal circuits in cases of neurological injury, both spinal motor neurons and axons linking these cells to the cortical origins of descending motor commands begin showing changes soon after the brain is injured by stroke. The concept of 'transneuronal degeneration' is not new and has been documented in histological, imaging and electrophysiological studies dating back over a century. Taken together, evidence from these studies agrees more with a system attempting to survive rather than one passively surrendering to degeneration. There tends to be at least some preservation of fibres at the brainstem origin and along the spinal course of the descending white matter tracts, even in severe cases. Myelin-associated proteins are observed in the spinal cord years after stroke onset. Spinal motor neurons remain morphometrically unaltered. Skeletal muscle fibres once innervated by neurons that lose their source of trophic input receive collaterals from adjacent neurons, causing spinal motor units to consolidate and increase in size. Although some level of excitability within the distributed brain network mediating voluntary movement is needed to facilitate recovery, minimal structural connectivity between cortical and spinal motor neurons can support meaningful distal limb function. Restoring access to the final common pathway via the descending input that remains in the spinal cord therefore represents a viable target for directed plasticity, particularly in light of recent advances in rehabilitation medicine.

Influence of Sports Participation on the Behaviors of Customers of Sports Services: Linear and Qualitative Comparative Analysis Models

Sports services have become an important enclave for our society. Due to its complete sports offer, customers can perform physical activity that helps them to improve their health and well-being. In fitness centers, managers try to know what their customers are looking for in order to create more personalized experiences, as well as to improve their health. This study seeks to understand the influence that sports frequency has on the future behavior of users of a sports center, using two complementary methodologies. A sample of 383 users of a private sports center was used. The two complementary methodologies used were linear models and comparative qualitative analysis, based on the combination of sets. The results show how sports frequency influences the process of creating users' future behaviors. Considering that none of the variables are necessary, it is observed that perceived value has a significant influence on users' future behaviors. The use of two complementary methodologies provides a more complete understanding, which helps sports managers to plan and manage effectively to ensure user satisfaction and loyalty. In addition, facilities can incentivize customers through loyalty programs and promotions to maintain their engagement, as well as healthy styles to encourage service recommendations.

Administration of intramuscular AAV-BDNF and intranasal AAV-TrkB promotes neurological recovery via enhancing corticospinal synaptic connections in stroke rats

Stroke causes long-term disability in survivors. BDNF/TrkB plays an important role in synaptic plasticity and synaptic transmission in the central nervous system (CNS), promoting neurological recovery. In this study, we performed non-invasive treatment methods focused on intramuscular injection into stroke-injured forelimb muscles, or intranasal administration using adeno-associated virus (AAV) vectors carrying genes encoding BDNF or TrkB. In a permanent rat middle cerebral artery occlusion (MCAO) model, we assessed the effects of combination therapy with AAV-BDNF and AAV-TrkB on motor functional recovery and synaptic plasticity of the corticospinal connections. Our results showed that BDNF or TrkB gene transduced in the spinal anterior horn neurons and cerebral cortical neurons. Compared to AAV vector treatment alone, behavioral and electrophysiological results showed that the combination therapy significantly improved upper limb motor functional recovery and neurotransmission efficiency after stroke. BDA tracing, immunofluorescence staining, qRT-PCR, and transmission electron microscopy of synaptic ultrastructure results revealed that the combination therapy not only potently increased the expression of Synapsin I, PSD-95, and GAP-43, but also promoted the axonal remodeling and restoration of abnormal synaptic structures. These findings provide a new strategy for enhancing neural plasticity and a potential means to treat stroke clinically.

Effects of Cross-Education on Neural Adaptations Following Non-Paretic Limb Training in Stroke: A Scoping Review with Implications for Neurorehabilitation

Current stroke rehabilitation interventions focus on intensive task specific training of the paretic limb, which may not be feasible for individuals with higher levels of impairment or in the early phase of stroke. Cross-education, a mechanism that improves strength or skill of the untrained limb following unilateral motor training, has high clinical relevance for stroke rehabilitation. Despite its potential benefits, our knowledge on the application and efficacy of cross-education in stroke is limited. We performed a scoping review to synthesize the current evidence regarding neurophysiological and motor effects of cross-education training in stroke. Low to strong evidence from five studies demonstrated strength gains ranging from 31-200% in the untrained paretic limb following non-paretic muscle training. Neurophysiological mechanisms underlying cross-education were unclear as the three studies that used transcranial magnetic stimulation to probe functional connectivity demonstrated mixed results in low sample size. Our review suggests that cross-education is a promising clinical approach in stroke, however high quality studies focusing on neurophysiological mechanisms are required to establish the efficacy and underlying mechanisms of cross-education in stroke. Recommendations regarding future directions and clinical utility are provided.

Upper Limbs Muscle Co-contraction Changes Correlated With the Impairment of the Corticospinal Tract in Stroke Survivors: Preliminary Evidence From Electromyography and Motor-Evoked Potential

Objective

Increased muscle co-contraction of the agonist and antagonist muscles during voluntary movement is commonly observed in the upper limbs of stroke survivors. Much remain to be understood about the underlying mechanism. The aim of the study is to investigate the correlation between increased muscle co-contraction and the function of the corticospinal tract (CST).

Methods

Nine stroke survivors and nine age-matched healthy individuals were recruited. All the participants were instructed to perform isometric maximal voluntary contraction (MVC) and horizontal task which consist of sponge grasp, horizontal transportation, and sponge release. We recorded electromyography (EMG) activities from four muscle groups during the MVC test and horizontal task in the upper limbs of stroke survivors. The muscle groups consist of extensor digitorum (ED), flexor digitorum (FD), triceps brachii (TRI), and biceps brachii (BIC). The root mean square (RMS) of EMG was applied to assess the muscle activation during horizontal task. We adopted a co-contraction index (CI) to evaluate the degree of muscle co-contraction. CST function was evaluated by the motor-evoked potential (MEP) parameters, including resting motor threshold, amplitude, latency, and central motor conduction time. We employed correlation analysis to probe the association between CI and MEP parameters.

Results

The RMS, CI, and MEP parameters on the affected side showed significant difference compared with the unaffected side of stroke survivors and the healthy group. The result of correlation analysis showed that CI was significantly correlated with MEP parameters in stroke survivors.

Conclusion

There existed increased muscle co-contraction and impairment in CST functionality on the affected side of stroke survivors. The increased muscle co-contraction was correlated with the impairment of the CST. Intervention that could improve the excitability of the CST may contribute to the recovery of muscle discoordination in the upper limbs of stroke survivors.

The Strength of the Corticospinal Tract Not the Reticulospinal Tract Determines Upper-Limb Impairment Level and Capacity for Skill-Acquisition in the Sub-Acute Post-Stroke Period

Background. Upper-limb impairment in patients with chronic stroke appears to be partly attributable to an upregulated reticulospinal tract (RST). Here, we assessed whether the impact of corticospinal (CST) and RST connectivity on motor impairment and skill-acquisition differs in sub-acute stroke, using transcranial magnetic stimulation (TMS)–based proxy measures. Methods. Thirty-eight stroke survivors were randomized to either reach training 3-6 weeks post-stroke (plus usual care) or usual care only. At 3, 6 and 12 weeks post-stroke, we measured ipsilesional and contralesional cortical connectivity (surrogates for CST and RST connectivity, respectively) to weak pre-activated triceps and deltoid muscles with single pulse TMS, accuracy of planar reaching movements, muscle strength (Motricity Index) and synergies (Fugl-Meyer upper-limb score). Results. Strength and presence of synergies were associated with ipsilesional (CST) connectivity to the paretic upper-limb at 3 and 12 weeks. Training led to planar reaching skill beyond that expected from spontaneous recovery and occurred for both weak and strong ipsilesional tract integrity. Reaching ability, presence of synergies, skill-acquisition and strength were not affected by either the presence or absence of contralesional (RST) connectivity. Conclusion. The degree of ipsilesional CST connectivity is the main determinant of proximal dexterity, upper-limb strength and synergy expression in sub-acute stroke. In contrast, there is no evidence for enhanced contralesional RST connectivity contributing to any of these components of impairment. In the sub-acute post-stroke period, the balance of activity between CST and RST may matter more for the paretic phenotype than RST upregulation per se.

TMS-Induced Central Motor Conduction Time at the Non-Infarcted Hemisphere Is Associated with Spontaneous Motor Recovery of the Paretic Upper Limb after Severe Stroke

Background: Stroke affects the neuronal networks of the non-infarcted hemisphere. The central motor conduction time (CMCT) induced by transcranial magnetic stimulation (TMS) could be used to determine the conduction time of the corticospinal tract of the non-infarcted hemisphere after a stroke. Objectives: Our primary aim was to demonstrate the existence of prolonged CMCT in the non-infarcted hemisphere, measured within the first 48 h when compared to normative data, and secondly, if the severity of motor impairment of the affected upper limb was significantly associated with prolonged CMCTs in the non-infarcted hemisphere when measured within the first 2 weeks post stroke. Methods: CMCT in the non-infarcted hemisphere was measured in 50 patients within 48 h and at 11 days after a first-ever ischemic stroke. Patients lacking significant spontaneous motor recovery, so-called non-recoverers, were defined as those who started below 18 points on the FM-UE and showed less than 6 points (10%) improvement within 6 months. Results: CMCT in the non-infarcted hemisphere was prolonged in 30/50 (60%) patients within 48 h and still in 24/49 (49%) patients at 11 days. Sustained prolonged CMCT in the non-infarcted hemisphere was significantly more frequent in non-recoverers following FM-UE. Conclusions: The current study suggests that CMCT in the non-infarcted hemisphere is significantly prolonged in 60% of severely affected, ischemic stroke patients when measured within the first 48 h post stroke. The likelihood of CMCT is significantly higher in non-recoverers when compared to those that show spontaneous motor recovery early post stroke.

Neuromuscular electrical stimulation-promoted plasticity of the human brain

The application of neuromuscular electrical stimulation (NMES) to paretic limbs has demonstrated utility for motor rehabilitation following brain injury. When NMES is delivered to a mixed peripheral nerve, typically both efferent and afferent fibres are recruited. Muscle contractions brought about by the excitation of motor neurons are often used to compensate for disability by assisting actions such as the formation of hand aperture, or by preventing others including foot drop. In this context, exogenous stimulation provides a direct substitute for endogenous neural drive. The goal of the present narrative review is to describe the means through which NMES may also promote sustained adaptations within central motor pathways, leading ultimately to increases in (intrinsic) functional capacity. There is an obvious practical motivation, in that detailed knowledge concerning the mechanisms of adaptation has the potential to inform neurorehabilitation practice. In addition, responses to NMES provide a means of studying CNS plasticity at a systems level in humans. We summarize the fundamental aspects of NMES, focusing on the forms that are employed most commonly in clinical and experimental practice. Specific attention is devoted to adjuvant techniques that further promote adaptive responses to NMES thereby offering the prospect of increased therapeutic potential. The emergent theme is that an association with centrally initiated neural activity, whether this is generated in the context of NMES triggered by efferent drive or via indirect methods such as mental imagery, may in some circumstances promote the physiological changes that can be induced through peripheral electrical stimulation.

The unsolved role of heightened connectivity from the unaffected hemisphere to paretic arm muscles in chronic stroke

OBJECTIVE

Ipsilateral connectivity from the non-stroke hemisphere to paretic arm muscles appears to play little role in functional recovery, which instead depends on contralateral connectivity from the stroke hemisphere. Yet the incidence of ipsilateral projections in stroke survivors is often reported to be higher than normal. We tested this directly using a sensitive measure of connectivity to proximal arm muscles.

METHOD

TMS of the stroke and non-stroke motor cortex evoked responses in pre-activated triceps and deltoid muscles of 17 stroke survivors attending reaching training. Connectivity was defined as a clear MEP or a short-latency silent period in ongoing EMG in ≥ 50% of stimulations. We measured reaching accuracy at baseline, improvement after training and upper limb Fugl-Meyer (F-M) score.

RESULTS

Incidence of ipsilateral connections to triceps (47%) and deltoid (58%) was high, but unrelated to baseline reaching accuracy and F-M scores. Instead, these were related to contralateral connectivity from the stroke hemisphere. Absolute but not proportional improvement after training was greater in patients with ipsilateral responses.

CONCLUSIONS

Despite enhanced ipsilateral connectivity, arm function and learning was related most strongly to contralateral pathway integrity from the stroke hemisphere.

SIGNIFICANCE

Further work is needed to decipher the role of ipsilateral connections.

A Bout of High Intensity Interval Training Lengthened Nerve Conduction Latency to the Non-exercised Affected Limb in Chronic Stroke

Objective: Evaluate intensity-dependent effects of a single bout of high intensity interval training (HIIT) compared to moderate intensity constant-load exercise (MICE) on corticospinal excitability (CSE) and effects on upper limb performance in chronic stroke.

Design: Randomized cross-over trial.

Setting: Research laboratory in a tertiary rehabilitation hospital.

Participants: Convenience sample of 12 chronic stroke survivors.

Outcome measures: Bilateral CSE measures of intracortical inhibition and facilitation, motor thresholds, and motor evoked potential (MEP) latency using transcranial magnetic stimulation. Upper limb functional measures of dexterity (Box and Blocks Test) and strength (pinch and grip strength).

Results: Twelve (10 males; 62.50 ± 9.0 years old) chronic stroke (26.70 ± 23.0 months) survivors with moderate level of residual impairment participated. MEP latency from the ipsilesional hemisphere was lengthened after HIIT (pre: 24.27 ± 1.8 ms, and post: 25.04 ± 1.8 ms, p = 0.01) but not MICE (pre: 25.49 ± 1.10 ms, and post: 25.28 ± 1.0 ms, p = 0.44). There were no significant changes in motor thresholds, intracortical inhibition or facilitation. Pinch strength of the affected hand decreased after MICE (pre: 8.96 ± 1.9 kg vs. post: 8.40 ± 2.0 kg, p = 0.02) but not after HIIT (pre: 8.83 ± 2.0 kg vs. post: 8.65 ± 2.2 kg, p = 0.29). Regardless of type of aerobic exercise, higher total energy expenditure was associated with greater increases in pinch strength in the affected hand after exercise (R² = 0.31, p = 0.04) and decreases in pinch strength of the less affected hand (R² = 0.26 p = 0.02).

Conclusion: A single bout of HIIT resulted in lengthened nerve conduction latency in the affected hand that was not engaged in the exercise. Longer latency could be related to the cross-over effects of fatiguing exercise or to reduced hand spasticity. Somewhat counterintuitively, pinch strength of the affected hand decreased after MICE but not HIIT. Regardless of the structure of exercise, higher energy expended was associated with pinch strength gains in the affected hand and strength losses in the less affected hand. Since aerobic exercise has acute effects on MEP latency and hand strength, it could be paired with upper limb training to potentiate beneficial effects.

SMART Arm Training With Outcome-Triggered Electrical Stimulation in Subacute Stroke Survivors With Severe Arm Disability: A Randomized Controlled Trial

Background. Stroke survivors with severe upper limb disability need opportunities to engage in task-oriented practice to achieve meaningful recovery. Objective. To compare the effect of SMART Arm training, with or without outcome-triggered electrical stimulation to usual therapy, on arm function for stroke survivors with severe upper limb disability undergoing inpatient rehabilitation. Methods. A prospective, multicenter, randomized controlled trial was conducted with 3 parallel groups, concealed allocation, assessor blinding and intention-to-treat analysis. Fifty inpatients within 4 months of stroke with severe upper limb disability were randomly allocated to 60 min/d, 5 days a week for 4 weeks of (1) SMART Arm with outcome-triggered electrical stimulation and usual therapy, (2) SMART Arm alone and usual therapy, or (3) usual therapy. Assessment occurred at baseline (0 weeks), posttraining (4 weeks), and follow-up (26 and 52 weeks). The primary outcome measure was Motor Assessment Scale item 6 (MAS6) at posttraining. Results. All groups demonstrated a statistically ( P < .001) and clinically significant improvement in arm function at posttraining (MAS6 change ≥1 point) and at 52 weeks (MAS6 change ≥2 points). There were no differences in improvement in arm function between groups (P = .367). There were greater odds of a higher MAS6 score in SMART Arm groups as compared with usual therapy alone posttraining (SMART Arm stimulation generalized odds ratio [GenOR] = 1.47, 95%CI = 1.23-1.71) and at 26 weeks (SMART Arm alone GenOR = 1.31, 95% CI = 1.05-1.57). Conclusion. SMART Arm training supported a clinically significant improvement in arm function, which was similar to usual therapy. All groups maintained gains at 12 months.

Interhemispheric Pathways Are Important for Motor Outcome in Individuals with Chronic and Severe Upper Limb Impairment Post Stroke

Background

Severity of arm impairment alone does not explain motor outcomes in people with severe impairment post stroke.

Objective

Define the contribution of brain biomarkers to upper limb motor outcomes in people with severe arm impairment post stroke.

Methods

Paretic arm impairment (Fugl-Meyer upper limb, FM-UL) and function (Wolf Motor Function Test rate, WMFT-rate) were measured in 15 individuals with severe (FM-UL ≤ 30/66) and 14 with mild–moderate (FM-UL > 40/66) impairment. Transcranial magnetic stimulation and diffusion weight imaging indexed structure and function of the corticospinal tract and corpus callosum. Separate models of the relationship between possible biomarkers and motor outcomes at a single chronic (≥6 months) time point post stroke were performed.

Results

Age (ΔR²0.365, p = 0.017) and ipsilesional-transcallosal inhibition (ΔR²0.182, p = 0.048) explained a 54.7% (p = 0.009) variance in paretic WMFT-rate. Prefrontal corpus callous fractional anisotropy (PF-CC FA) alone explained 49.3% (p = 0.007) variance in FM-UL outcome. The same models did not explain significant variance in mild–moderate stroke. In the severe group, k-means cluster analysis of PF-CC FA distinguished two subgroups, separated by a clinically meaningful and significant difference in motor impairment (p = 0.049) and function (p = 0.006) outcomes.

Conclusion

Corpus callosum function and structure were identified as possible biomarkers of motor outcome in people with chronic and severe arm impairment.

Changes in transcranial magnetic stimulation outcome measures in response to upper-limb physical training in stroke: A systematic review of randomized controlled trials

BACKGROUND

Physical training is known to be an effective intervention to improve sensorimotor impairments after stroke. However, the link between brain plastic changes, assessed by transcranial magnetic stimulation (TMS), and sensorimotor recovery in response to physical training is still misunderstood. We systematically reviewed reports of randomized controlled trials (RCTs) involving the use of TMS over the primary motor cortex (M1) to probe brain plasticity after upper-limb physical training interventions in people with stroke.

METHODS

We searched 5 databases for articles published up to October 2016, with additional studies identified by hand-searching. RCTs had to investigate pre/post-intervention changes in at least one TMS outcome measure. Two independent raters assessed the eligibility of potential studies and reviewed the selected articles' quality by using 2 critical appraisal scales.

RESULTS

In total, 14 reports of RCTs (pooled participants=358; mean 26±12 per study) met the selection criteria. Overall, 11 studies detected plastic changes with TMS in the presence of clinical improvements after training, and these changes were more often detected in the affected hemisphere by using map area and motor evoked potential (MEP) latency outcome measures. Plastic changes mostly pointed to increased M1/corticospinal excitability and potential interhemispheric rebalancing of M1 excitability, despite sometimes controversial results among studies. Also, the strength of the review observations was affected by heterogeneous TMS methods and upper-limb interventions across studies as well as several sources of bias within the selected studies.

CONCLUSIONS

The current evidence encourages the use of TMS outcome measures, especially MEP latency and map area to investigate plastic changes in the brain after upper-limb physical training post-stroke. However, more studies involving rigorous and standardized TMS procedures are needed to validate these observations.

Repetitive reaching training combined with transcranial Random Noise Stimulation in stroke survivors with chronic and severe arm paresis is feasible: a pilot, triple-blind, randomised case series

Background

Therapy that combines repetitive training with non-invasive brain stimulation is a potential avenue to enhance upper limb recovery after stroke. This study aimed to investigate the feasibility of transcranial Random Noise Stimulation (tRNS), timed to coincide with the generation of voluntary motor commands, during reaching training.

Methods

A triple-blind pilot RCT was completed. Four stroke survivors with chronic (6-months to 5-years) and severe arm paresis, not taking any medications that had the potential to alter cortical excitability, and no contraindications to tRNS or MRI were recruited. Participants were randomly allocated to 12 sessions of reaching training over 4-weeks with active or sham tRNS delivered over the lesioned hemisphere motor representation. tRNS was triggered to coincide with a voluntary movement attempt, ceasing after 5-s. At this point, peripheral nerve stimulation enabled full range reaching. To determine feasibility, we considered adverse events, training outcomes, clinical outcomes, corticospinal tract (CST) structural integrity, and reflections on training through in-depth interviews from each individual case.

Results

Two participants received active and two sham tRNS. There were no adverse events. All training sessions were completed, repetitive practice performed and clinically relevant improvements across motor outcomes demonstrated. The amount of improvement varied across individuals and appeared to be independent of group allocation and CST integrity.

Conclusion

Reaching training that includes tRNS timed to coincide with generation of voluntary motor commands is feasible. Clinical improvements were possible even in the most severely affected individuals as evidenced by CST integrity.

Trial registration

This study was registered on the Australian and New Zealand Clinical Trials Registry (ANZCTR) http://www.ANZCTR.org.au/ACTRN12614000952640.aspx. Registration date 4 September 2014, first participant date 9 September 2014.

Tele-Supervised FES-Assisted Exercise for Hemiplegic Upper Limb

Stroke survivors often have upper limb (UL) hemiparesis, limiting their ability to perform activities of daily life (ADLs). Intensive, task-oriented exercise therapy (ET) can improve UL function, but motivation to perform sufficient ET is difficult to maintain. Here, we report on a trial in which a workstation was deployed in the homes of chronic stroke survivors to enable tele-coaching of ET in the guise of computer games. Participants performed six weeks of 1 h/day, five days/week ET. Hand opening and grasp were assisted with functional electrical stimulation (FES). The primary outcome measure was the Action Research Arm Test (ARAT). Secondary outcome measures included a quantitative test of UL function performed on the workstation, grasp force measurements and transcranial magnetic stimulation (TMS). Improvements were seen in the functional tests, but surprisingly, not in the TMS responses. An important finding was that participants commencing with intermediate functional scores improved the most.

CONCLUSIONS

(1) Daily, tele-supervised FES-ET in chronic stroke survivors is feasible with commercially-available technology. (2) The intervention can significantly improve UL function, particularly in people who start with an intermediate level of function. (3) Significant improvements in UL function can occur in the absence of changes in TMS responses.

The efficacy of SMART Arm training early after stroke for stroke survivors with severe upper limb disability: a protocol for a randomised controlled trial

Background

Recovery of upper limb function after stroke is poor. The acute to subacute phase after stroke is the optimal time window to promote the recovery of upper limb function. The dose and content of training provided conventionally during this phase is however, unlikely to be adequate to drive functional recovery, especially in the presence of severe motor disability. The current study concerns an approach to address this shortcoming, through evaluation of the SMART Arm, a non-robotic device that enables intensive and repetitive practice of reaching by stroke survivors with severe upper limb disability, with the aim of improving upper limb function. The outcomes of SMART Arm training with or without outcome-triggered electrical stimulation (OT-stim) to augment movement and usual therapy will be compared to usual therapy alone.

Methods/Design

A prospective, assessor-blinded parallel, three-group randomised controlled trial is being conducted. Seventy-five participants with a first-ever unilateral stroke less than 4 months previously, who present with severe arm disability (three or fewer out of a possible six points on the Motor Assessment Scale [MAS] Item 6), will be recruited from inpatient rehabilitation facilities. Participants will be randomly allocated to one of three dose-matched groups: SMART Arm training with OT-stim and usual therapy; SMART Arm training without OT-stim and usual therapy; or usual therapy alone. All participants will receive 20 hours of upper limb training over four weeks. Blinded assessors will conduct four assessments: pre intervention (0-weeks), post intervention (4-weeks), 26 weeks and 52 weeks follow-up. The primary outcome measure is MAS item 6. All analyses will be based on an intention-to-treat principle.

Discussion

By enabling intensive and repetitive practice of a functional upper limb task during inpatient rehabilitation, SMART Arm training with or without OT-stim in combination with usual therapy, has the potential to improve recovery of upper limb function in those with severe motor disability. The immediate and long-term effects of SMART Arm training on upper limb impairment, activity and participation will be explored, in addition to the benefit of training with or without OT-stim to augment movement when compared to usual therapy alone.

Trial registration

ACTRN12608000457347

Rasch-based scoring offered more precision in differentiating patient groups in measuring upper limb function

OBJECTIVE

To compare the discriminatory ability of Rasch-based and summative scoring in the context of assessing upper limb function of patients with stroke.

STUDY DESIGN AND SETTING

Data were from a cohort study of 497 adults with stroke undergoing physiotherapy. Upper limb function was assessed at admission and discharge using the upper limb subscale of the Motor Assessment Scale (UL-MAS). Rasch analysis was used to transform raw UL-MAS scores into interval measures. A relative precision (RP) index was used to differentiate patients by discharge destination.

RESULTS

The analysis confirmed the unidimensional structure of UL-MAS at both admission and discharge and demonstrated the adequate fit of the items. The RP index favored the Rasch-based scoring over the summative scoring in differentiating between the two patient groups, with significant gains in precision at admission (15%) and discharge (11%). When examining patients in the upper or lower quartile of UL-MAS, the gains in precision were statistically significant in favor of the Rasch-based scoring, with 20% precision at admission and 19% precision at discharge.

CONCLUSION

Rasch-based scoring was more precise in differentiating patient groups by discharge destination than the summative scoring used to measure upper limb function, especially at the extreme range of the scale.