Unilateral Strength Training of the Less Affected Hand Improves Cortical Excitability and Clinical Outcomes in Patients With Subacute Stroke: A Randomized Controlled Trial

Differences in brain activation and connectivity during unaffected hand exercise in subacute and convalescent stroke patients

Patients experiencing severe hemiplegia following a stroke struggle to rehabilitate their affected limbs. Cross-education (CE) training emerges as a promising rehabilitation method due to its safety, simplicity, low risk, and ability to effectively improve muscle strength in the affected limb. However, controversy surrounds the neural mechanisms and clinical applications of CE. To address this, we employed functional near-infrared spectroscopy to monitor the response of regions of interest (ROI) and functional connectivity in patients with stroke experiencing severe hemiplegia during one session of 50% maximal voluntary contraction (MVC) strength training with less-affected hand in both subacute and convalescent phases. Our objective was to compare the two stroke groups to gain insight into the potential utility for unilateral training of the less-affected limb as an effective rehabilitation approach during different phases post of stroke. The findings revealed varying degrees of activation in the ROIs within the affected hemisphere across both groups during the task. Additionally, we found that the subacute stroke patients with severe hemiplegia (SPS) had higher blood oxygen levels in the ipsilesional primary motor (iM1), ipsilesional pre-motor and supplementary motor area (iP-SMA) and contralesional P-SMA (cP-SMA). Functional connectivity strength between the iM1 and contralesional brain regions, as well as between the iP-SMA and ipsilesional ROIs, showed statistically significant differences in SPS compared to convalescent stroke patients with severe hemiplegia (CPS) during a 50% MVC strength training session using the less-affected hand. SIGNIFICANCE STATEMENT: Exploring the neural mechanisms underlying one session of 50% MVC strength training with less-affected hand sheds light on a safe therapy. The study enhances our understanding of less-affected hand training and investigates the feasibility as a future rehabilitation approach. Analyzing how one session of 50% MVC strength training with less-affected hand affects brain activation and connectivity could lead to more tailored and effective rehabilitation strategies.

Prescribing strength training for stroke recovery: a systematic review and meta-analysis of randomised controlled trials

Objective

To examine the effects of strength training on patient-important outcomes of stroke recovery and to quantify the influence of the exercise prescription on treatment effects.

Design

Systematic review and meta-analysis.

Data sources

Eight electronic databases (MEDLINE, EMBASE, EMCARE, AMED, PsycINFO, CINAHL, SPORTDiscus, and Web of Science) and two clinical trial registries (ClinicalTrials.gov and WHO International Clinical Trials Registry Platform) were searched from inception to 19 June 2024.

Eligibility criteria

Randomised controlled trials were eligible if they examined the effects of strength training compared with no exercise or usual care and reported at least one exercise prescription parameter. An advisory group of community members with lived experience of stroke helped inform outcomes most relevant to stroke recovery.

Results

Forty-two randomised trials (N=2204) were included. Overall risk of bias was high across most outcomes. Strength training improved outcomes rated as ‘critical for decision-making’ by the advisory group, including walking capacity (standardised mean difference (SMD)=0.95 (95% CI 0.34–1.56)), balance (SMD=1.13 (0.51–1.75)), functional ability and mobility (SMD=0.61 (0.09–1.14)), and habitual (mean difference (MD)=0.05 m/s (0.02–0.09)) and fast-paced walking speed (MD=0.09 m/s (0.01–0.17)), with very low to moderate certainty of evidence, mainly due to risk of bias and inconsistency. More frequent strength training, traditional strength training programmes and power-focused intensities (ie, emphasis on movement velocity) were positively associated with walking capacity, health-related quality of life and fast-paced walking speed.

Conclusion

Strength training alone or combined with usual care improves stroke recovery outcomes that are important for decision-making. More frequent strength training, power-focused intensities and traditional programme designs may best support stroke recovery.

PROSPERO registration number

CRD42023414077.

Mirror therapy combined with contralaterally controlled functional electrical stimulation for the upper limb motor function after stroke: a randomized controlled trial

PURPOSE

In this study, we investigated the effects of mirror therapy (MT) combined with contralaterally controlled functional electrical stimulation (CCFES) on upper limb motor function, activities of daily life, and corticospinal excitability in post-stroke patients.

METHODS

Sixty post-stroke patients were randomly divided into four groups: CCFES, MT, MT combined with CCFES, and control. All the patients underwent routine rehabilitation. Those in the MT, CCFES, MT combined with CCFES, and control groups received MT, CCFES, MT combined with CCFES, and routine rehabilitation alone, respectively. Upper limb motor function, activities of daily living, and corticospinal excitability were evaluated before and after a 3-week intervention period.

RESULTS

MT combined with CCFES demonstrated a significantly greater therapeutic effect on motor function of the paretic wrist than CCFES, MT, or routine rehabilitation alone. However, there was no significant difference in the overall motor function of the affected upper limb, activities of daily life, or corticospinal excitability between the MT combined with CCFES group and the other three groups.

CONCLUSION

MT combined with CCFES may be a potential adjuvant therapy to promote motor function in paretic wrist after stroke.

Effects of Resistance Training on Spasticity in People with Stroke: A Systematic Review

Resistance training induces neuromuscular adaptations and its impact on spasticity remains inadequately researched. This systematic review (PROSPERO: CRD42022322164) aimed to analyze the effects of resistance training, compared with no treatment, conventional therapy, or other therapies, in people with stroke-related spasticity. A comprehensive search was conducted up to October 2023 in PubMed, PEDro, Cochrane, Web of Science, and Scopus databases. Selection criteria were randomized controlled trials involving participants with stroke-related spasticity intervened with resistance training. The PEDro scale was used to evaluate the methodological quality. From a total of 274 articles, 23 full-text articles were assessed for eligibility and nine articles were included in the systematic review, involving 225 participants (155 males, 70 females; mean age: 59.4 years). Benefits were found to spasticity after resistance training. Furthermore, studies measuring spasticity also reported benefits to function, strength, gait, and balance. In conclusion, resistance training was superior to, or at least equal to, conventional therapy, other therapies, or no intervention for improving spasticity, as well as function, strength, gait, and balance. However, the results should be taken with caution because of the heterogeneity of the protocols used. Further research is needed to explore the effects of resistance training programs on people with stroke.

Overactivity of the Less Affected Side as a Possible Pattern of Asymmetry in Sitting in Patients Suffering from First-Time Ischemic Stroke-An Observational Study

It has been observed that in some people in the acute phase of ischemic stroke (IS) there is a tendency to shift the body weight towards the side more affected by the disease and a tendency to spontaneous movements of the upper and/or lower limbs (not covered by the neurological syndrome). The purposes of this study were: to define the kind of behavior observed, and to select symptoms which can predict its occurrence. Participants (n = 222) hospitalized due to first-time IS were assigned to three groups. A: 78 patients with no lateralization of the neurological syndrome (lateralization of the neurological syndrome-LoNS); B: 109 patients with LoNS; O+ group: 35 patients, who at the beginning of hospitalization presented, apart from LoNS, characteristic motor symptoms performed by the less affected side. Patients underwent therapy depending on the neurological symptoms. If the patient showed potential symptoms of a new phenomenon, overactivity of the less affected side (OLAS), a trial therapy (focused on this behavior) was used to confirm it. The predictive symptoms, selected among these from the index day, for the occurrence of OLAS in sitting were distinguished: asymmetry in supine posture and simple, repetitive movements of the nonparetic upper extremity.

To assess the effects of cross-education on strength and motor function in post stroke rehabilitation: a systematic literature review and meta-analysis

BACKGROUND

Cross-education refers to the increase in motor output of the untrained limb following unilateral training of the opposite limb. Cross education has been shown to be beneficial in clinical settings.

OBJECTIVES

This systematic literature and meta-analysis aims to assess the effects of cross-education on strength and motor function in post stroke rehabilitation.

DATA SOURCES

MEDLINE, CINAHL, Cochrane Library, PubMed, PEDro, Web of Science, ClinicalTrails.gov and Cochrane Central registers were searched up to 1st October 2022.

STUDY SELECTION

Controlled trials using unilateral training of the less affected limb in individuals diagnosed with stroke and English language.

DATA SYNTHESIS

Methodological quality was assessed using Cochrane Risk-of-Bias tools. Quality of evidence was evaluated using Grading of Recommendations Assessment, Development and Evaluation. Meta-analyses were performed using RevMan 5.4.1.

RESULTS

Five studies capturing 131 participants were included in the review and three studies capturing 95 participants were included in the meta-analysis. Cross education was shown to have a statistically and clinically significant effect on upper limb strength (p < 0.003; SMD 0.58; 95% CI 0.20-0.97; n = 117) and upper limb function (p = 0.04; SMD 0.40; 95% CI 0.02-0.77; n = 119).

LIMITATIONS

Small number of studies, with all studies identified as having some risk of bias. Quality of evidence graded 'low' due to limitations and imprecision.

CONCLUSION

Cross education may be beneficial in improving strength and motor function in the more affected upper limb post stroke. Further studies are needed as the research into the benefits of cross education in stroke rehabilitation is still limited. Systematic Review Registration Number: PROSPERO (CRD42020219058).

EFFECTS OF STRENGTH TRAINING ON PHYSICAL STABILITY IN DANCERS

ABSTRACT Introduction: Ballroom dance has evolved from a simple self-taught part of folklore to a technical, performative, and artistic competitive dance called the International Standard Dance. Objective: Study the effects of special lower limb strength training on the physical stability of dancers. Methods: 20 volunteers, students of a university specialized in dance, were divided into experimental and control groups, undergoing training of 30 minutes daily, 3 times a week, for 3 months. The control group followed the daily training, while the experimental group received special lower limb strength training. The relevant physical data measured before and after the intervention were statistically analyzed. Results: Compared to the control group, there was a significant difference in the athletes of the experimental group (P<0.05). The experimental group's lower limb strength and special skills were significantly improved. Conclusion: The lower extremity strength training protocol significantly improved the dancers’ muscle strength, proportionally increasing the stability of the sports skills. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

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.

Ipsilesional Motor Cortex Activation with High-force Unimanual Handgrip Contractions of the Less-affected Limb in Participants with Stroke

Stroke is a leading cause of severe disability that often presents with unilateral motor impairment. Conventional rehabilitation approaches focus on motor practice of the affected limb and aim to suppress brain activity in the contralesional hemisphere. Conversely, exercise of the less-affected limb promotes contralesional brain activity which is typically viewed as contraindicated in stroke recovery due to the interhemispheric inhibitory influence onto the ipsilesional hemisphere. Yet, high-force unimanual handgrip contractions are known to increase ipsilateral brain activation in control participants, and it remains to be determined if high-force contractions with the less-affected limb would promote ipsilateral brain activation in participants with stroke (i.e., the ipsilesional hemisphere). Therefore, this study aimed to determine how parametric increases in handgrip force during repeated contractions with the less-affected limb impacts brain activity bilaterally in participants with stroke and in a cohort of neurologically intact controls. Participants performed repeated submaximal contractions at 25%, 50%, and 75% of their maximum voluntary contraction during separate functional magnetic resonance imaging brain scans. Brain activation during the tasks was quantified as the present change from resting levels. In this study, higher force contractions were found to increase brain activation in the ipsilesional (stroke)/ipsilateral (controls) hemisphere in both groups (p = .002), but no between group differences were observed. These data suggest that high-force exercise with the less-affected limb may promote ipsilesional cortical plasticity to promote motor recovery of the affected-limb in participants with stroke.

Neural mechanisms mediating cross education: With additional considerations for the ageing brain

CALVERT, G.H.M., and CARSON, R.G. Neural mechanisms mediating cross education: With additional considerations for the ageing brain. NEUROSCI BIOBEHAV REV 21(1) XXX-XXX, 2021. - Cross education (CE) is the process whereby a regimen of unilateral limb training engenders bilateral improvements in motor function. The contralateral gains thus derived may impart therapeutic benefits for patients with unilateral deficits arising from orthopaedic injury or stroke. Despite this prospective therapeutic utility, there is little consensus concerning its mechanistic basis. The precise means through which the neuroanatomical structures and cellular processes that mediate CE may be influenced by age-related neurodegeneration are also almost entirely unknown. Notwithstanding the increased incidence of unilateral impairment in later life, age-related variations in the expression of CE have been examined only infrequently. In this narrative review, we consider several mechanisms which may mediate the expression of CE with specific reference to the ageing CNS. We focus on the adaptive potential of cellular processes that are subserved by a specific set of neuroanatomical pathways including: the corticospinal tract, corticoreticulospinal projections, transcallosal fibres, and thalamocortical radiations. This analysis may inform the development of interventions that exploit the therapeutic utility of CE training in older persons.