Skeletal muscle changes after hemiparetic stroke and potential beneficial effects of exercise intervention strategies

Are age-predicted equations valid in predicting maximum heart rate in individuals after stroke?

PURPOSE

To investigate the validity of six age-predicted maximum heart rate (HRmax) equations after stroke.

MATERIAL AND METHODS

Sixty individuals (54 (12) years; 64 (69) months after stroke) were included. A Cardiopulmonary Exercise Test (CPET) performed on a treadmill obtained the HRmax. The most used age-predicted equations were investigated: (1) 220-age, proposed by Fox; (2) 206.9- (0.67 × age), proposed by Gellish; (3) 208- (0.7 × age), proposed by Tanaka; (4) 216.6- (0.84 × age), proposed by Astrand; (5) 164- (0.72 × age) and (6) 200- (0.92 × age) proposed by Brawner.

RESULTS

No statistically significant agreement was found between the HRmax obtained by the CPET and the one predicted by the equations 1-5 (-0.18 ≤ 95% confidence interval ≤0.79). A significant and moderate agreement was found between the HRmax obtained by the CPET and the one predicted by equation (6) (95% CI= 0.05-0.75; Intraclass Correlation Coefficient= 0.51). Bland-Altman plots showed that equations (1-4) and (6) overestimated the HRmax. Equation (6) presented the lower mean difference.

CONCLUSIONS

The equations developed for non-disabled individuals (1-4) are not adequate to be used in individuals after a stroke. Equation (6) (Brawner) showed the best results to be used in individuals after stroke; however, it should be used cautiously.

Peripheral vascular function in stroke: systematic review and meta-analysis

Peripheral vascular dysfunction, measured as flow-mediated dilation (FMD), is present across all phases of stroke recovery and elevates the risk for recurrent cardiovascular events. The objective of this systematic review and meta-analysis was to characterize baseline FMD in individuals' poststroke, with consideration for each phase of stroke recovery. Three databases (PubMed, CINAHL, and Embase) were searched between January 1, 2000 and October 12, 2023 for studies that examined baseline FMD in stroke. Three reviewers conducted abstract and full-text screening, data extraction, and quality assessment. A random effects model was used to estimate FMD across studies. Meta-regression was used to examine the impact of age and time since stroke (acute, subacute, chronic) on FMD. Twenty-eight studies with ischemic and hemorrhagic stroke were included. Descriptive statistics for the demographics and FMD values of each study are presented. For the meta-analysis, average estimate FMD was 3.9% (95% CI: 2.5-5.3%). We report a large amount of heterogeneity (Cochrane's Q P value <0.001, and I2 = 99.6%). Differences in average age and the time poststroke between studies were not significantly associated with differences in FMD values. Despite the large heterogeneity for FMD values across studies, our primary finding suggests that FMD remains impaired across all phases of stroke.NEW & NOTEWORTHY This systematic review and meta-analysis offers invaluable insight into poststroke vascular function. Despite the inherent heterogeneity among the 28 studies analyzed, we report that peripheral vascular dysfunction, as quantified by flow-mediated dilation, exists across all stages of stroke recovery. This finding underscores the importance for interventions that focus on improving vascular health and secondary stroke prevention.

A modified rehabilitation paradigm bilaterally increased rat extensor digitorum communis muscle size but did not improve forelimb function after stroke

Malnutrition after stroke may lessen the beneficial effects of rehabilitation on motor recovery through influences on both brain and skeletal muscle. Enriched rehabilitation (ER), a combination of environmental enrichment and forelimb reaching practice, is used preclinically to study recovery of skilled reaching after stroke. However, the chronic food restriction typically used to motivate engagement in reaching practice is a barrier to using ER to investigate interactions between nutritional status and rehabilitation. Thus, our objectives were to determine if a modified ER program comprised of environmental enrichment and skilled reaching practice motivated by a short fast would enhance post-stroke forelimb motor recovery and preserve forelimb muscle size and metabolic fiber type, relative to a group exposed to stroke without ER. At one week after photothrombotic cortical stroke, male, Sprague-Dawley rats were assigned to modified ER or standard care for 2 weeks. Forelimb recovery was assessed in the Montoya staircase and cylinder task before stroke and on days 5-6, 22-23, and 33-34 after stroke. ER failed to improve forelimb function in either task (p > 0.05). Atrophy of extensor digitorum communis (EDC) and triceps brachii long head (TBL) muscles was not evident in the stroke-targeted forelimb on day 35, but the area occupied by hybrid fibers was increased in the EDC muscle (p = 0.038). ER bilaterally increased EDC (p = 0.046), but not TBL, muscle size; EDC muscle fiber type was unchanged by ER. While the modified ER did not promote forelimb motor recovery, it does appear to have utility for studying the role of skeletal muscle plasticity in post-stroke recovery.

Pathophysiological changes of muscle after ischemic stroke: a secondary consequence of stroke injury

Sufficient clinical evidence suggests that the damage caused by ischemic stroke to the body occurs not only in the acute phase but also during the recovery period, and that the latter has a greater impact on the long-term prognosis of the patient. However, current stroke studies have typically focused only on lesions in the central nervous system, ignoring secondary damage caused by this disease. Such a phenomenon arises from the slow progress of pathophysiological studies examining the central nervous system. Further, the appropriate therapeutic time window and benefits of thrombolytic therapy are still controversial, leading scholars to explore more pragmatic intervention strategies. As treatment measures targeting limb symptoms can greatly improve a patient's quality of life, they have become a critical intervention strategy. As the most vital component of the limbs, skeletal muscles have become potential points of concern. Despite this, to the best of our knowledge, there are no comprehensive reviews of pathophysiological changes and potential treatments for post-stroke skeletal muscle. The current review seeks to fill a gap in the current understanding of the pathological processes and mechanisms of muscle wasting atrophy, inflammation, neuroregeneration, mitochondrial changes, and nutritional dysregulation in stroke survivors. In addition, the challenges, as well as the optional solutions for individualized rehabilitation programs for stroke patients based on motor function are discussed.

Multi-Modal versus Uni-Modal Treatment for the Recovery of Lower Limb Motor Function in Patients after Stroke: A Systematic Review with Meta-Analysis

The aim of this study is to evaluate whether the multimodal treatment based on both resistance and endurance training for the recovery of lower limb function in post-stroke patients is more effective than unimodal treatment. Six electronic databases were searched. The included articles were firstly analysed for methodological quality and then quantitatively analysed for the following outcomes: endurance, knee-extensor muscle strength, gait speed, and aerobic capacity. The treatment effect was analysed with the mean difference (MD) or standardised mean difference (SMD). From a total of 4439 records, 10 studies met the inclusion criteria for the qualitative analysis, whereas 7 studies were included in the quantitative analysis. There is a significant difference favourable to the group with multimodal treatment for knee-extensor muscle strength (SMD = 1.25; 95% CI 0.97, 1.53, I2 = 42%), both for the affected and the unaffected side. Multimodal treatments are a valid choice in the field of post-stroke rehabilitation. In particular, the combination of resistance and endurance training is useful to maximise the recovery of knee-extensor muscle strength, which in turn could be beneficial for achieving upright position and walking, allowing patients to improve independence levels in their activities of daily life.

Intensity-effects of strengthening exercise on thigh muscle volume, pro- or anti-inflammatory cytokines, and immunocytes in the older adults: A randomized controlled trial

BACKGROUND

This study investigated the intensity-effects of strength training on thigh muscle mass, cytokines, and immunocytes in the older adults.

MATERIALS AND METHODS

A total of 81 participated in this study. Participants were assigned randomly to four groups: control group (CON), low- (LSE), moderate- (MSE), and high-intensity strength exercise (HSE) groups. Three exercise groups worked out for 50 min/day, 3 days/week for 12 weeks.

RESULTS

In the thigh volume analyzed by computed tomography, the exercise groups showed a significant increase in the muscle mass, with a clear pattern of change observed in the groups who exercised with moderate to high intensity. The lowest levels of interleukin (IL)-6 in the MSE group (-20.94%) and tumor necrosis factor-α in the HSE group (-28.75%) were observed. Notably, IL-10 showed a significant increase (35.72%) only in the MSE group. In the CON group, natural killer (NK) cells showed a decrease, while in the exercise groups, their levels increased. The highest levels of NK cells were observed in the HSE group. Similar patterns of change were observed in CD4 T cells and CD19 B cells. CD3 and CD8 T cells exhibited significant increases in the MSE and HSE groups.

CONCLUSIONS

This study presents evidence that engaging in moderate to high-intensity exercise may have a positive impact on cytokines and immunocytes by increasing muscle mass in older adults who may have sarcopenia.

SIMPLE SUMMARY

Engaging in strength training exercises is considered crucial for maintaining the health of older individuals who are susceptible to sarcopenia. When resistance exercises are performed at a moderate to strenuous intensity, it is anticipated that positive changes can occur in cytokines and immunocytes. These changes can be observed through improvements in thigh muscle volumes as measured by computed tomography.

Differences in Skeletal Muscle Fiber Characteristics Between Affected and Nonaffected Limbs in Individuals With Stroke: A Scoping Review

OBJECTIVE

The objective of this scoping review was to characterize and identify knowledge gaps about the changes in skeletal muscle fiber type proportion and cross-sectional area (CSA) after stroke.

METHODS

This scoping review followed previously proposed frameworks. A systematic search was conducted for articles examining muscle fiber type proportion and CSA in individuals with stroke in EMBASE, MEDLINE, PsycINFO, CINAHL, SPORTDiscus, and Web of Science databases from inception to December 20, 2022. Two independent authors screened and extracted the data. Results were discussed using theories proposed by the authors of the included studies.

RESULTS

Of 13 studies (115 participants), 6 (46%) were case studies or case series, 6 (46%) were cross-sectional studies, and 1 (8%) was an experimental study. Studies had small sample sizes (1-23 participants) and various muscle sampling sites (6 different muscles). All 13 studies examined muscle fiber type distributions, and 6 (46%) examined CSA. Ten (77%) studies examined differences between paretic and nonparetic muscles, and 5 (38%) compared people with stroke to people without stroke. Results from 9 of 13 studies (69%) supported a greater proportion of type II muscle fibers in the paretic limb. Of those, 4 studies (42 participants), 3 studies (17 participants), and 1 study (1 participant) saw no differences, preferential type II and type I CSA loss between limbs, respectively.

CONCLUSION

Of the limited available evidence, stroke appears to result in a shift to a higher proportion of type II muscle fibers in the paretic muscles. There are mixed results for effects on muscle fiber CSA, but there is some evidence of specific atrophy of type II muscle fibers.

IMPACT

Changes in paretic skeletal muscle fibers of individuals with stroke may explain, in part, the substantial losses in strength and power in this population. Interventions to restore type II muscle fiber size may benefit people with stroke.

Structural and pathophysiological muscle changes up to one year after post-stroke hemiplegia: a systematic review

INTRODUCTION

Muscle changes after stroke cannot be explained solely on the basis of corticospinal bundle damage. Muscle-specific changes contribute to limited functional recovery but have been poorly characterized.

EVIDENCE ACQUISITION

We conducted a systematic review of muscular changes occurring at the histological, neuromuscular and functional levels during the first year after the onset of post-stroke hemiplegia. A literature search was performed on PubMed, Embase and CINHAL databases up to November 2022 using a keyword combination comprising cerebral stroke, hemiplegic, atrophy, muscle structure, paresis, skeletal muscle fiber type, motor unit, oxidative stress, strength, motor control.

EVIDENCE SYNTHESIS

Twenty-seven trial reports were included in the review, out of 12,798 articles screened. Structural modifications described on the paretic side include atrophy, transformation of type II fibers into type I fibers, decrease in fiber diameter and apparent myofilament disorganization from the first week post-stroke up to the fourth month. Reported biochemical changes comprise the abnormal presence of lipid droplets and glycogen granules in the subsarcolemmal region during the first month post-stroke. At the neurophysiological level, studies indicate an early decrease in the number and activity of motor units, correlated with the degree of motor impairment. All these modifications were present to a lesser degree on the non-paretic side. Although only sparse data concerning the subacute stage are available, these changes seem to appear during the first two weeks post-stroke and continue up to the third or fourth month.

CONCLUSIONS

Considering these early pathophysiological changes on both the paretic and non-paretic sides, it seems crucial to promptly stimulate central and also peripheral muscular activation after stroke through specific rehabilitation programs focused on the maintenance of muscle capacities associated with neurological recovery or plasticity.

Trunk training following stroke

BACKGROUND

Previous systematic reviews and randomised controlled trials have investigated the effect of post-stroke trunk training. Findings suggest that trunk training improves trunk function and activity or the execution of a task or action by an individual. But it is unclear what effect trunk training has on daily life activities, quality of life, and other outcomes.

OBJECTIVES

To assess the effectiveness of trunk training after stroke on activities of daily living (ADL), trunk function, arm-hand function or activity, standing balance, leg function, walking ability, and quality of life when comparing with both dose-matched as non-dose-matched control groups.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register, CENTRAL, MEDLINE, Embase, and five other databases to 25 October 2021. We searched trial registries to identify additional relevant published, unpublished, and ongoing trials. We hand searched the bibliographies of included studies.

SELECTION CRITERIA

We selected randomised controlled trials comparing trunk training versus non-dose-matched or dose-matched control therapy including adults (18 years or older) with either ischaemic or haemorrhagic stroke. Outcome measures of trials included ADL, trunk function, arm-hand function or activity, standing balance, leg function, walking ability, and quality of life.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Two main analyses were carried out. The first analysis included trials where the therapy duration of control intervention was non-dose-matched with the therapy duration of the experimental group and the second analysis where there was comparison with a dose-matched control intervention (equal therapy duration in both the control as in the experimental group).  MAIN RESULTS: We included 68 trials with a total of 2585 participants. In the analysis of the non-dose-matched groups (pooling of all trials with different training duration in the experimental as in the control intervention), we could see that trunk training had a positive effect on ADL (standardised mean difference (SMD) 0.96; 95% confidence interval (CI) 0.69 to 1.24; P < 0.001; 5 trials; 283 participants; very low-certainty evidence), trunk function (SMD 1.49, 95% CI 1.26 to 1.71; P < 0.001; 14 trials, 466 participants; very low-certainty evidence), arm-hand function (SMD 0.67, 95% CI 0.19 to 1.15; P = 0.006; 2 trials, 74 participants; low-certainty evidence), arm-hand activity (SMD 0.84, 95% CI 0.009 to 1.59; P = 0.03; 1 trial, 30 participants; very low-certainty evidence), standing balance (SMD 0.57, 95% CI 0.35 to 0.79; P < 0.001; 11 trials, 410 participants; very low-certainty evidence), leg function (SMD 1.10, 95% CI 0.57 to 1.63; P < 0.001; 1 trial, 64 participants; very low-certainty evidence), walking ability (SMD 0.73, 95% CI 0.52 to 0.94; P < 0.001; 11 trials, 383 participants; low-certainty evidence) and quality of life (SMD 0.50, 95% CI 0.11 to 0.89; P = 0.01; 2 trials, 108 participants; low-certainty evidence). Non-dose-matched trunk training led to no difference for the outcome serious adverse events (odds ratio: 7.94, 95% CI 0.16 to 400.89; 6 trials, 201 participants; very low-certainty evidence). In the analysis of the dose-matched groups (pooling of all trials with equal training duration in the experimental as in the control intervention), we saw that trunk training had a positive effect on trunk function (SMD 1.03, 95% CI 0.91 to 1.16; P < 0.001; 36 trials, 1217 participants; very low-certainty evidence), standing balance (SMD 1.00, 95% CI 0.86 to 1.15; P < 0.001; 22 trials, 917 participants; very low-certainty evidence), leg function (SMD 1.57, 95% CI 1.28 to 1.87; P < 0.001; 4 trials, 254 participants; very low-certainty evidence), walking ability (SMD 0.69, 95% CI 0.51 to 0.87; P < 0.001; 19 trials, 535 participants; low-certainty evidence) and quality of life (SMD 0.70, 95% CI 0.29 to 1.11; P < 0.001; 2 trials, 111 participants; low-certainty evidence), but not for ADL (SMD 0.10; 95% confidence interval (CI) -0.17 to 0.37; P = 0.48; 9 trials; 229 participants; very low-certainty evidence), arm-hand function (SMD 0.76, 95% CI -0.18 to 1.70; P = 0.11; 1 trial, 19 participants; low-certainty evidence), arm-hand activity (SMD 0.17, 95% CI -0.21 to 0.56; P = 0.38; 3 trials, 112 participants; very low-certainty evidence). Trunk training also led to no difference for the outcome serious adverse events (odds ratio (OR): 7.39, 95% CI 0.15 to 372.38; 10 trials, 381 participants; very low-certainty evidence). Time post stroke led to a significant subgroup difference for standing balance (P < 0.001) in non-dose-matched therapy. In non-dose-matched therapy, different trunk therapy approaches had a significant effect on ADL (< 0.001), trunk function (P < 0.001) and standing balance (< 0.001). When participants received dose-matched therapy, analysis of subgroup differences showed that the trunk therapy approach had a significant effect on ADL (P = 0.001), trunk function (P < 0.001), arm-hand activity (P < 0.001), standing balance (P = 0.002), and leg function (P = 0.002). Also for dose-matched therapy, subgroup analysis for time post stroke resulted in a significant difference for the outcomes standing balance (P < 0.001), walking ability (P = 0.003) and leg function (P < 0.001), time post stroke significantly modified the effect of intervention.  Core-stability trunk (15 trials), selective-trunk (14 trials) and unstable-trunk (16 trials) training approaches were mostly applied in the included trials.

AUTHORS' CONCLUSIONS

There is evidence to suggest that trunk training as part of rehabilitation improves ADL, trunk function, standing balance, walking ability, upper and lower limb function, and quality of life in people after stroke. Core-stability, selective-, and unstable-trunk training were the trunk training approaches mostly applied in the included trials. When considering only trials with a low risk of bias, results were mostly confirmed, with very low to moderate certainty, depending on the outcome.

Nondestructive ultrasound evaluation of microstructure-related material parameters of skeletal muscle: An in silico and in vitro study

Direct and nondestructive assessment of material properties of skeletal muscle in vivo shall advance our understanding of intact muscle mechanics and facilitate personalized interventions. However, this is challenged by intricate hierarchical microstructure of the skeletal muscle. We have previously regarded the skeletal muscle as a composite of myofibers and extracellular matrix (ECM), formulated shear wave propagation in the undeformed muscle using the acoustoelastic theory, and preliminarily demonstrated that ultrasound-based shear wave elastography (SWE) could estimate microstructure-related material parameters (MRMPs): myofiber stiffness μ_f, ECM stiffness μ_m, and myofiber volume ratio V_f. The proposed method warrants further validation but is hampered by the lack of ground truth values of MRMPs. In this study, we presented analytical and experimental validations of the proposed method using finite-element (FE) simulations and 3D-printed hydrogel phantoms, respectively. Three combinations of different physiologically relevant MRMPs were used in the FE simulations where shear wave propagations in the corresponding composite media were simulated. Two 3D-printed hydrogel phantoms with the MRMPs close to those of a real skeletal muscle (i.e., μ_f=2.02kPa, μ_m=52.42kPa, and V_f=0.675,0.832) for ultrasound imaging were fabricated by an alginate-based hydrogel printing protocol that we modified and optimized from the freeform reversible embedding of suspended hydrogels (FRESH) method in literature. Average percent errors of (μ_f,μ_m,V_f) estimates were found to be (2.7%,7.3%,2.4%)in silico and (3.0%,8.0%,9.9%)in vitro. This quantitative study corroborated the potential of our proposed theoretical model along with ultrasound SWE for uncovering microstructural characteristics of the skeletal muscle in an entirely nondestructive way.

Treatment of spasticity

Spasticity is characterized by an enhanced size and reduced threshold for activation of stretch reflexes and is associated with "positive signs" such as clonus and spasms, as well as "negative features" such as paresis and a loss of automatic postural responses. Spasticity develops over time after a lesion and can be associated with reduced speed of movement, cocontraction, abnormal synergies, and pain. Spasticity is caused by a combination of damage to descending tracts, reductions in inhibitory activity within spinal cord circuits, and adaptive changes within motoneurons. Increased tone, hypertonia, can also be caused by changes in passive stiffness due to, for example, increase in connective tissue and reduction in muscle fascicle length. Understanding the cause of hypertonia is important for determining the management strategy as nonneural, passive causes of stiffness will be more amenable to physical rather than pharmacological interventions. The management of spasticity is determined by the views and goals of the patient, family, and carers, which should be integral to the multidisciplinary assessment. An assessment, and treatment, of trigger factors such as infection and skin breakdown should be made especially in people with a recent change in tone. The choice of management strategies for an individual will vary depending on the severity of spasticity, the distribution of spasticity (i.e., whether it affects multiple muscle groups or is more prominent in one or two groups), the type of lesion, and the potential for recovery. Management options include physical therapy, oral agents; focal therapies such as botulinum injections; and peripheral nerve blocks. Intrathecal baclofen can lead to a reduction in required oral antispasticity medications. When spasticity is severe intrathecal phenol may be an option. Surgical interventions, largely used in the pediatric population, include muscle transfers and lengthening and selective dorsal root rhizotomy.

Effectiveness of hospital-based low intensity and inspected aerobic training on functionality and cardiorespiratory fitness in unconditioned stroke patients: Importance of submaximal aerobic fitness markers

INTRODUCTION

The purpose of our study was to evaluate the effectiveness of low-to moderate intensity aerobic training on cardiorespiratory functions in chronic unconditioned stroke patients. The oxygen uptake efficiency slope (OUES) and the ventilatory threshold (VO2-VT) could represent the aerobic capacity in submaximal test. Our study examined the application of the submaximal parameters for evaluating aerobic capacity of chronic stroke patients.

MATERIALS AND METHODS

In our assessor-blinded controlled pilot study 37 patients were randomized into 2 groups named: intervention group (IG, n: 21) and control group (CG, n:16), respectively. Cardiorespiratory functions were evaluated by ergospirometer before and after the 4-week (20 days) program. Both groups participated in daily occupational therapy (30 minutes) and conventional, customized physiotherapy CG (60 minutes), IG (30 minutes). Only IG performed aerobic training by bicycles (30 minutes) aiming to reach low-to moderate training intensity. Outcome measures included peak oxygen uptake (VO2 peak), OUES, VO2-VT, functional exercise capacity 6-Minute Walking Test (6MWT) and Functional Independence Measure.

RESULTS

Thirty-five subjects completed the study. The VO2 peak uptake was very low in both groups (IG: 11.9 mL/kg/min, CG: 12.45 mL/kg/min) and did not improve after the program, but submaximal parameters such as VO2-VT (P < .01) and OUES (P < .001) have shown significant improvement, but only in IG regardless of insufficient impact on VO2 peak. Each participant in both groups was unable to permanently reach the moderate intensity zone. Functional Independence Measure changed for the better in both groups, but 6MWT only in the IG.

DISCUSSION AND CONCLUSIONS

Four-week exercise training even at low intensity by lower limb cycle ergometer may provide benefit on aerobic and functional capacity without improvement of VO2 peak on unconditioned chronic stroke patients.

Preconditioning intensive training ameliorates reduction of transcription biofactors of PGC1α-pathway in paretic muscle due to cerebral ischemia

Exercise training increases fibronectin type III domain-containing protein 5 (FNDC5/irisin) via the peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α)-pathway. The PGC1α pathway induced FNDC5/irisin changes in response to exercise training and ischemic stroke are not entirely understood. We investigated the relation of the PGC-1α/FNDC5/irisin pathway to exercise training and to the pathophysiology of ischemic stroke in paretic muscles of stroke-induced rat models. We induced cerebral ischemia following completion of high-intensity interval training (HIIT) to evaluate PGC1α-pathway biofactors in paretic muscles. To define the underlying molecular mechanisms for improvement in paretic muscles following cerebral ischemia, we evaluated PCG-1α-pathway factors using immunofluorescence tracking and enzyme-linked immunosorbent assay (ELISA) immunoassay. We found that HIIT for 3 weeks produced increased expression and release of PGC-1α-pathway biomarkers in both the serum and paretic muscle of stroke-induced rats. We also found a close relation between the expression of PCG-1α-pathway factors in skeletal muscle and their concentration in blood. We found that PGC-1α-pathway biomarkers cause irisin up-regulation following induction of cerebral ischemia. The reduction in neurofunctional deficits following increased PGC-1α-pathway biomarkers suggests that these factors may act as markers of improvement in paretic muscle healing following cerebral ischemia.

Structural and passive mechanical properties of the medial gastrocnemius muscle in ambulatory individuals with chronic stroke

BACKGROUND

This study aimed to investigate the structural, morphological and passive mechanical properties of the medial gastrocnemius muscle among ambulating chronic stroke survivors using a computational model previously established in healthy individuals without stroke.

METHODS

Individuals with chronic stroke (n = 14, age = 63.4 ± 6.0 years) and healthy controls (n = 15, age = 59.6 ± 8.4 years) participated in the study. The mechanical properties of the medial gastrocnemius were measured during continuous passive ankle motion using ultrasound elastography and a corresponding muscle mechanical property-angle curve was estimated where slack angle and elasticity were determined. Muscle thickness, fascicle length, pennation angle, and echo intensity were also assessed using B-mode ultrasound.

FINDINGS

No significant differences in slack angle (paretic: -16.2° ± 6.13°, non-paretic: -16.93° ± 6.80°, p = 0.82), or slack elasticity (paretic: 4.36 ± 1.94 kPa, non-paretic: 4.54 ± 1.24 kPa, p = 0.64) were found between sides or groups. Lower muscle pennation angle (paretic: 13.6 ± 2.9°, non-paretic: 15.9 ± 2.0°, p = 0.019) and higher echo intensity (paretic: 80.5 ± 13.6, non-paretic: 63.4 ± 17.1, p = 0.003) were observed for paretic muscles. No significant between-sides differences were found for muscle thickness (paretic: 1.5 ± 0.3 cm, non-paretic: 1.6 ± 0.2 cm, p = 0.255) or fascicle length (paretic: 6.6 ± 1.9 cm, non-paretic: 7.1 ± 2.2 cm, p = 0.216). Significant between-groups difference was also observed for fascicle length [non-dominant side (control): 6.2 ± 0.8 cm, paretic side (stroke): 6.6 ± 1.9 cm, p = 0.017].

INTERPRETATION

Although muscle mechanical properties increased exponentially over the slack ankle, measures between paretic and non-paretic sides were similar in ambulating participants with chronic stroke. Side-to-side differences in structural and morphological measures suggest the impact of stroke was relatively more pronounced for these muscle parameters than for passive mechanical properties.

High Doses of Botulinum Toxin Type A for the Treatment of Post-Stroke Spasticity: Rationale for a Real Benefit for the Patients

In the past few years, there was a great interest in the use of higher doses of botulinum toxin type A, especially in case of upper and lower limb severe spasticity. To date, only one prospective, non-randomized, single-arm, multicenter, open-label, dose-titration study with the employment of incobotulinum toxin up to 800 U has been published, and the authors investigated safety and tolerability. Other researches showed efficacy in spasticity reduction, but there is a lack of evidence about the reasons to use high doses of botulinum toxin. This short communication highlights the benefits of higher doses for subjects with upper and lower limb spasticity.

Changes in Muscle Thickness and Echo Intensity in Chronic Stroke Survivors: A 2-Year Longitudinal Study

Background and Purpose

The objective of this study was to identify 2-year longitudinal changes in the muscle thickness (MT) and echo intensity (EI) of the abdominal, thigh, and lower limb muscles in chronic stroke survivors.

Methods

This study included 15 chronic stroke survivors aged 74.1±9.9 years. The MT, EI, and subcutaneous fat thickness values of the following muscles on the paretic and nonparetic sides were assessed on transverse ultrasound images: rectus abdominis, external oblique, internal oblique, transversus abdominis, rectus femoris (RF), vastus intermedius, vastus lateralis (VL), vastus medialis, tibialis anterior, gastrocnemius, and soleus. The ultrasound measurements were performed both at baseline and 2 years later.

Results

After 2 years, the VL on the paretic side showed a significant decrease in MT (p=0.031) and increase in EI (p=0.002), whereas the RF on the nonparetic side showed a significant decrease in EI (p=0.046). Correlation coefficient analyses showed that changes in MT (r=0.668, p=0.012) and EI (r=0.597, p=0.018) of the VL on the paretic side were significantly associated with a change in the body mass index.

Conclusions

The findings of this longitudinal study suggest that the VL on the paretic side is subject to deteriorations in muscle quantity and quality, and conversely that the RF on the nonparetic side shows an improvement in muscle quality after 2 years in chronic stroke survivors.

How Does Stroke Affect Skeletal Muscle? State of the Art and Rehabilitation Perspective

Long-term disability caused by stroke is largely due to an impairment of motor function. The functional consequences after stroke are caused by central nervous system adaptations and modifications, but also by the peripheral skeletal muscle changes. The nervous and muscular systems work together and are strictly dependent in their structure and function, through afferent and efferent communication pathways with a reciprocal “modulation.” Knowing how altered interaction between these two important systems can modify the intrinsic properties of muscle tissue is essential in finding the best rehabilitative therapeutic approach. Traditionally, the rehabilitation effort has been oriented toward the treatment of the central nervous system damage with a central approach, overlooking the muscle tissue. However, to ensure greater effectiveness of treatments, it should not be forgotten that muscle can also be a target in the rehabilitation process. The purpose of this review is to summarize the current knowledge about the skeletal muscle changes, directly or indirectly induced by stroke, focusing on the changes induced by the treatments most applied in stroke rehabilitation. The results of this review highlight changes in several muscular features, suggesting specific treatments based on biological knowledge; on the other hand, in standard rehabilitative practice, a realist muscle function evaluation is rarely carried out. We provide some recommendations to improve a comprehensive muscle investigation, a specific rehabilitation approach, and to draw research protocol to solve the remaining conflicting data. Even if a complete multilevel muscular evaluation requires a great effort by a multidisciplinary team to optimize motor recovery after stroke.

Effect of Walking Adaptability on an Uneven Surface by a Stepping Pattern on Walking Activity After Stroke

Real-world walking activity is important for poststroke patients because it leads to their participation in the community and physical activity. Walking activity may be related to adaptability to different surface conditions of the ground. The purpose of this study was to clarify whether walking adaptability on an uneven surface by step is related to daily walking activity in patients after stroke. We involved 14 patients who had hemiparesis after stroke (age: 59.4 ± 8.9 years; post-onset duration: 70.7 ± 53.5 months) and 12 healthy controls (age: 59.5 ± 14.2 years). The poststroke patients were categorized as least limited community ambulators or unlimited ambulators. For the uneven surface, the study used an artificial grass surface (7 m long, 2-cm leaf length). The subjects repeated even surface walking and the uneven surface walking trials at least two times at a comfortable speed. We collected spatiotemporal and kinematic gait parameters on both the even and uneven surfaces using a three-dimensional motion analysis system. After we measured gait, the subjects wore an accelerometer around the waist for at least 4 days. We measured the number of steps per day using the accelerometer to evaluate walking activity. Differences in gait parameters between the even and uneven surfaces were calculated to determine how the subjects adapted to an uneven surface while walking. We examined the association between the difference in parameter measurements between the two surface properties and walking activity (number of steps per day). Walking activity significantly and positively correlated with the difference in paretic step length under the conditions of different surface properties in the poststroke patients (r = 0.65, p = 0.012) and step width in the healthy controls (r = 0.68, p = 0.015). The strategy of increasing the paretic step length, but not step width, on an uneven surface may lead to a larger base of support, which maintains stability during gait on an uneven surface in poststroke patients, resulting in an increased walking activity. Therefore, in poststroke patients, an increase in paretic step length during gait on an uneven surface might be more essential for improving walking activity.

Sarcopenic Obesity in Individuals With Neurodisabilities: The SarcObeNDS Study

INTRODUCTION

Patients with neurodisabilities (NDS) are prone to alterations in body composition. Sarcopenic obesity (SO) is a condition characterized by increased adipose tissue accompanied by sarcopenia. The aim of this study was to investigate the prevalence of SO in patients with NDS, including stroke, spinal cord, and traumatic brain injuries.

METHODS

The study Sarcopenic Obesity in NeuroDisabled Subjects (acronym: SarcObeNDS) was a cross-sectional study of hospitalized patients (n = 82) and healthy controls (n = 32) with a mean age of 60.00 ± 14.22 years old. SO and sarcopenia were assessed through total body fat % (TBF %), fat mass index (fat mass to height²: FMI = FM/h²; kg/m²), and skeletal muscle index (appendicular skeletal muscle to height²: SMI = ASM/h²; kg/m²) via full-body dual-energy X-ray absorptiometry (DXA). This study was registered in the international database ClinicalTrials.gov with the unique identification number NCT03863379.

RESULTS

A statistically significant difference was found in SMI (7.18 ± 0.95 vs. 6.00 ± 1.13 kg/m², p < 0.001) between controls and patients with NDS. No statistical significance was found for TBF (p = 0.783) and FMI (p = 0.143) between groups. The results remained the same after controlling the results for gender and BMI. A strong positive correlation was demonstrated between BMI and TBF for the total population (r = 0.616, p < 0.001), the control group (r = 0.616, p < 0.001), and patients with NDS (r = 0.728, p < 0.001).

CONCLUSION

In summary, we observed significantly lower BMI and SMI scores in both genders compared to healthy controls. At the clinical level, a timely diagnosis and rapid treatment of sarcopenia and/or obesity in this population may prevent further metabolic repercussions accompanied by higher functional decline and lower quality of life.

Tensor electrical impedance myography identifies clinically relevant features in amyotrophic lateral sclerosis

Objective.Electrical impedance myography (EIM) shows promise as an effective biomarker in amyotrophic lateral sclerosis (ALS). EIM applies multiple input frequencies to characterise muscle properties, often via multiple electrode configurations. Herein, we assess if non-negative tensor factorisation (NTF) can provide a framework for identifying clinically relevant features within a high dimensional EIM dataset.Approach.EIM data were recorded from the tongue of healthy and ALS diseased individuals. Resistivity and reactivity measurements were made for 14 frequencies, in three electrode configurations. This gives 84 (2 × 14 × 3) distinct data points per participant. NTF was applied to the dataset for dimensionality reduction, termed tensor EIM. Significance tests, symptom correlation and classification approaches were explored to compare NTF to using all raw data and feature selection.Main Results.Tensor EIM provides highly significant differentiation between healthy and ALS patients (p< 0.001, AUROC = 0.78). Similarly tensor EIM differentiates between mild and severe disease states (p< 0.001, AUROC = 0.75) and significantly correlates with symptoms (ρ= 0.7,p< 0.001). A trend of centre frequency shifting to the right was identified in diseased spectra, which is in line with the electrical changes expected following muscle atrophy.Significance.Tensor EIM provides clinically relevant metrics for identifying ALS-related muscle disease. This procedure has the advantage of using the whole spectral dataset, with reduced risk of overfitting. The process identifies spectral shapes specific to disease allowing for a deeper clinical interpretation.

Noninvasive Assessment of In Vivo Passive Skeletal Muscle Mechanics as a Composite Material Using Biomedical Ultrasound

OBJECTIVE

This study develops a biomedical ultrasound imaging method to infer microstructural information (i.e., tissue level) from imaging mechanical behavior of skeletal muscle (i.e., organ level).

METHODS

We first reviewed the constitutive model of skeletal muscle by regarding it as a transversely isotropic (TI) hyperelastic composite material, for which a theoretical formula was established among shear wave speed, deformation, and material parameters (MPs) using the acoustoelasticity theory. The formula was evaluated by finite element (FE) simulations and experimentally examined using ultrasound shear wave imaging (SWI) and strain imaging (SI) on in vivo passive biceps brachii muscles of two healthy volunteers. The imaging sequence included 1) generation of SW in multiple propagation directions while resting the muscle at an elbow angle of 90; 2) generation of SW propagating along the myofiber direction during continuous uniaxial muscle extension by passively changing the elbow angle from 90 to 120. Ultrasound-quantified SW speeds and muscle deformations were fitted by the theoretical formula to estimate MPs of in vivo passive muscle.

RESULTS

Estimated myofiber stiffness, stiffness ratio of myofiber to extracellular matrix (ECM), ECM volume ratio all agreed with literature findings.

CONCLUSION

The proposed mathematical formula together with our in-house ultrasound imaging method enabled assessing microstructural material properties of in vivo passive skeletal muscle from organ-level mechanical behavior in an entirely noninvasive way.

SIGNIFICANCE

Noninvasive assessment of both micro and macro properties of in vivo skeletal muscle will advance our understanding of complex muscle dynamics and facilitate treatment and rehabilitation planning.

Muscle Fiber Diameter and Density Alterations after Stroke Examined by Single-Fiber EMG

This study presents single-fiber electromyography (EMG) analysis for assessment of paretic muscle changes after stroke. Single-fiber action potentials (SFAPs) were recorded from the first dorsal interosseous (FDI) muscle bilaterally in 12 individuals with hemiparetic stroke. The SFAP parameters, including the negative peak duration and the peak-peak amplitude, were measured and further used to estimate muscle fiber diameter through a model based on the quadratic function. The SFAP parameters, fiber density, and muscle fiber diameter derived from the model were compared between the paretic and contralateral muscles. The results show that SFAPs recorded from the paretic muscle had significantly smaller negative peak duration than that from the contralateral muscle. As a result, the derived muscle fiber diameter of the paretic muscle was significantly smaller than that of the contralateral muscle. The fiber density of the paretic muscle was significantly higher than that of the contralateral muscle. These results provide further evidence of remodeled motor units after stroke and suggest that paretic muscle weakness can be due to both complex central and peripheral neuromuscular alterations.

Advances in motion and electromyography based wearable technology for upper extremity function rehabilitation: A review

STUDY DESIGN

Scoping review.

INTRODUCTION

With the recent advances in technologies, interactive wearable technologies including inertial motion sensors and e-textiles are emerging in the field of rehabilitation to monitor and provide feedback and therapy remotely.

PURPOSE OF THE STUDY

This review article focuses on inertial measurement unit motion sensor and e-textiles-based technologies and proposes approaches to augment these interactive wearable technologies.

METHODS

We conducted a comprehensive search of relevant electronic databases (eg, PubMed, the Cumulative Index to Nursing and Allied Health Literature, Embase, PsycINFO, The Cochrane Central Register of Controlled Trial, and the Physiotherapy Evidence Database). The scoping review included all study designs.

RESULTS

Currently, there are a numerous research groups and companies investigating inertial motion sensors and e-textiles-based interactive wearable technologies. However, translation of these technologies to the clinic would need further research to increase ease of use and improve clinical validity of the outcomes of these technologies.

DISCUSSION

The current review discusses the limitations of the interactive wearable technologies such as, limited clinical utility, bulky equipment, difficulty in setting up equipment inertial motion sensors and e-textiles.

CONCLUSION

There is tremendous potential for interactive wearable technologies in rehabilitation. With the evolution of cloud computing, interactive wearable systems can remotely provide intervention and monitor patient progress using models of telerehabilitation. This will revolutionize the delivery of rehabilitation and make rehabilitation more accessible and affordable to millions of individuals.

Eccentric training effects for patients with post-stroke hemiparesis on strength and speed gait: A randomized controlled trial

BACKGROUND

In hemiparetic patients, the skeletal muscle is mainly affected with a combination of abnormalities (denervation, remodeling, spasticity, and eventually muscular atrophy).

OBJECTIVE

This study examined the role of eccentric exercise in strengthening muscles of the lower extremity and ultimately improving autonomy in patients with post-stroke hemiparesis during gait.

METHODS

Thirty-seven patients hemiparetic adults were recruited, randomized into a control group (n = 19) and an intervention group receiving eccentric muscle strengthening (n = 18). The protocol consisted of three sets of five repetitions of eccentric contraction of the paretic limb after determining the maximum repetition (1 MRI). Evaluation of the 1RM, 10 meters and 6WMT was performed before and after the exercise for each group. Manova test was used to compare the differences between the control and intervention groups.

RESULTS

The paretic limb showed significant increase in one-repetition maximum (1RM) between before and after rehabilitation (p≤0.00003). The two groups of Patients increased their walking speed (p≤0.0005), but we observed a significant difference between groups only for the 6MWT and not on the 10 meters Test.

CONCLUSIONS

Eccentric training can be useful in strengthening the muscles of the lower limbs, and promoting gait performance. Eccentric training could complement other methods of managing patients with post-stroke hemiparesis.

Gait synchronized neuromuscular electrical stimulation to the gluteus medius on a patient with right hemiparesis: a case report

Background and Purpose: Although the use of neuromuscular electrical stimulation (NMES) to return gait speed and function in patients poststroke is well documented, the use of NMES to the gluteus medius in patients with hemiparesis is not well described. The purpose of this case report is to describe the use of gait synchronized NMES to the right gluteus medius of a patient with right hemiparesis who had poor hip abduction control during the stance phase of the gait cycle and impaired balance.Case Description: A 72-year-old female presented to the emergency department with right-sided hemiparesis. During her fifteen day stay in in-patient rehabilitation she demonstrated a Trendelenburg gait pattern, indicating the use of functional NMES to the gluteus medius to help improve her hip abduction control during the stance phase of gait.Outcomes: After intervention which included traditional rehabilitation as well as functional NMES, the patient's gait speed increased from 0.22 m/s to 0.69 m/s and her Berg Balance Scale (BBS) increased from a 14/56 to 32/56 over a 14 day period indicating an improvement in dynamic balance and community ambulation.Discussion: This case report outlines the novel use of NMES to the gluteus medius during the stance phase of the gait cycle in a patient with poor hip abductor control.

Ultrasound Evaluation of the Rectus Femoris for Sarcopenia in Patients with Early Subacute Stroke

We investigated the ultrasound characteristics of the rectus femoris for sarcopenia detected by dual-energy X-ray absorptiometry (DEXA) in the early subacute stroke phase. Physical features (age, sex, body mass index, and circumference of thigh) and performances (modified Barthel index in Korean, functional ambulation categories, and mini-mental state examination in Korean) were measured. The thickness of the fat layer, the thickness of the rectus femoris (TRF), echo intensity (EI), EI to TRF ratio, and strain ratio of elastography (SRE) were measured by ultrasound in 30 patients with first-ever stroke (male: n = 20). Appendicular lean body mass was measured by DEXA. Sarcopenia was defined according to the Foundation for the National Institutes of Health Sarcopenia Project. In total, 14 patients were in the sarcopenia group, and 16 were in the non-sarcopenia group. Clinical characteristics were similar between the two groups. In the sarcopenia group, TRF was significantly decreased in the paretic (p < 0.026) and non-paretic sides (p < 0.01), and the EI to TRF ratio on the paretic side was significantly increased (p < 0.049). Multivariate binary logistic regression showed that TRF on the non-paretic side was independently and significantly associated with sarcopenia (OR = 0.616, 95% CI: 0.381-0.996). The EI and SRE were not significant between the two groups. In the early subacute stroke phase, TRF on the non-paretic side is a key factor for quantitative evaluation of sarcopenia, and the EI to TRF ratio on the paretic side is also a meaningful qualitative evaluation of sarcopenia.

Irisin-Associated Neuroprotective and Rehabilitative Strategies for Stroke

Irisin, a newly discovered protein hormone that is secreted in response to low frequency whole body vibration (LFV), could be a promising post-stroke rehabilitation therapy for patients who are frail and cannot comply with regular rehabilitation therapy. Irisin is generated from a membrane-bound precursor protein fibronectin type III domain-containing protein 5 (FNDC5). Aside from being highly expressed in muscle, FNDC5 is highly expressed in the brain. The cleaved form of FNDC5 was found in the cerebrospinal fluid as well as in various regions of the brain. Numerous studies suggest that irisin plays a key role in brain metabolism and inflammation regulation. Both the metabolism and inflammation govern stroke outcome, and in a published study, we demonstrated that LFV therapy following middle cerebral artery occlusion significantly reduced innate immune response, improved motor function and infarct volume in reproductively senescent female rats. The observed effect of LFV therapy could be working via irisin, therefore, the current review focuses to understand various aspects of irisin including its mechanism of action on the brain.

Aerobic Exercise After Left-Sided Stroke Improves Gait Speed and Endurance: A Prospective Cohort Study

OBJECTIVE

The aim of the study was to investigate the effects of aerobic exercise on individuals who have had a stroke and showed baseline scores lower than the standard scores for the 6-min and 10-meter walk tests.

DESIGN

Individuals were assigned to groups according to gait performance, defined by the standard values in the 6-min and 10-meter walk tests (standard baseline score and lower baseline score), and brain injury side. Aerobic exercise, 30 mins per day, 2 times a week, for a total of 12 wks. The 6-min and 10-meter walk tests in five assessments: initial, after 4, 8, 12 wks, and 4 wks of follow-up, analyzed by multivariate analysis, with P value of less than 0.05.

RESULTS

The 6-min walk test data showed an increase in endurance for lower baseline score and left-brain injury, during assessments 4, and follow-up, compared with standard baseline score (F4,84 = 14.64). Lower baseline score showed endurance increase for assessments 2, 3, 4, and follow-up compared with assessment 1 (F4,84 = 7.70). The 10-meter walk test data showed an increase in speed for lower baseline score and left-brain injury, during assessments 3, 4, and follow-up, compared with assessment 1, 4, and follow-up, compared with assessment 2 (F4,84 = 5.33).

CONCLUSIONS

Aerobic exercise increases gait endurance and speed in individuals who have had a stroke, with left-brain injury, and lower baseline score in the 6-min and 10-meter walk tests.

Ischemic stroke-induced polyaxonal innervation at the neuromuscular junction is attenuated by robot-assisted mechanical therapy

Ischemic stroke is a leading cause of disability world-wide. Mounting evidence supports neuromuscular pathology following stroke, yet mechanisms of dysfunction and therapeutic action remain undefined. The objectives of our study were to investigate neuromuscular pathophysiology following ischemic stroke and to evaluate the therapeutic effect of Robot-Assisted Mechanical massage Therapy (RAMT) on neuromuscular junction (NMJ) morphology. Using an ischemic stroke model in male rats, we demonstrated longitudinal losses of muscle contractility and electrophysiological estimates of motor unit number in paretic hindlimb muscles within 21 days of stroke. Histological characterization demonstrated striking pre- and postsynaptic alterations at the NMJ. Stroke prompted enlargement of motor axon terminals, acetylcholine receptor (AChR) area, and motor endplate size. Paretic muscle AChRs were also more homogenously distributed across motor endplates, exhibiting fewer clusters and less fragmentation. Most interestingly, NMJs in paretic muscle exhibited increased frequency of polyaxonal innervation. This finding of increased polyaxonal innervation in stroke-affected skeletal muscle suggests that reduction of motor unit number following stroke may be a spurious artifact due to overlapping of motor units rather than losses. Furthermore, we tested the effects of RAMT - which we recently showed to improve motor function and protect against subacute myokine disturbance - and found significant attenuation of stroke-induced NMJ alterations. RAMT not only normalized the post-stroke presentation of polyaxonal innervation but also mitigated postsynaptic expansion. These findings confirm complex neuromuscular pathophysiology after stroke, provide mechanistic direction for ongoing research, and inform development of future therapeutic strategies. SIGNIFICANCE: Ischemic stroke is a leading contributor to chronic disability, and there is growing evidence that neuromuscular pathology may contribute to the impact of stroke on physical function. Following ischemic stroke in a rat model, there are progressive declines of motor unit number estimates and muscle contractility. These changes are paralleled by striking pre- and postsynaptic maladaptive changes at the neuromuscular junction, including polyaxonal innervation. When administered to paretic hindlimb muscle, Robot-Assisted Mechanical massage Therapy - previously shown to improve motor function and protect against subacute myokine disturbance - prevents stroke-induced neuromuscular junction alterations. These novel observations provide insight into the neuromuscular response to cerebral ischemia, identify peripheral mechanisms of functional disability, and present a therapeutic rehabilitation strategy with clinical relevance.

An Exercise Mimetic Approach to Reduce Poststroke Deconditioning and Enhance Stroke Recovery

Evidence supports early rehabilitation after stroke to limit disability. However, stroke survivors are typically sedentary and experience significant cardiovascular and muscular deconditioning. Despite growing consensus that preclinical and clinical stroke recovery research should be aligned, there have been few attempts to incorporate cardiovascular and skeletal muscle deconditioning into animal models of stroke. Here, we demonstrate in rats that a hindlimb sensorimotor cortex stroke results in both cardiovascular and skeletal muscle deconditioning and impairments in gait akin to those observed in humans. To reduce poststroke behavioral, cardiovascular, and skeletal muscle perturbations, we then used a combinatorial intervention consisting of aerobic and resistance exercise in conjunction with administration of resveratrol (RESV), a drug with exercise mimetic properties. A combination of aerobic and resistance exercise mitigated decreases in cardiovascular fitness and attenuated skeletal muscle abnormalities. RESV, beginning 24 hours poststroke, reduced acute hindlimb impairments, improved recovery in hindlimb function, increased vascular density in the perilesional cortex, and attenuated skeletal muscle fiber changes. Early RESV treatment and aerobic and resistance exercise independently provided poststroke benefits, at a time when individuals are rapidly becoming deconditioned as a result of inactivity. Although no additive effects were observed in these experiments, this approach represents a promising strategy to reduce poststroke behavioral impairments and minimize deconditioning. As such, this treatment regime has potential for enabling patients to engage in more intensive rehabilitation at an earlier time following stroke when mechanisms of neuroplasticity are most prevalent.

Central activation deficits contribute to post stroke lingual weakness in a rat model

Lingual weakness frequently occurs after stroke and is associated with deficits in speaking and swallowing. Chronic weakness after stroke has been attributed to both impaired central activation of target muscles and reduced force-generating capacity within muscles. How these factors contribute to lingual weakness is not known. We hypothesized that lingual weakness due to middle cerebral artery occlusion (MCAO) would manifest as reduced muscle force capacity and reduced muscle activation. Rats were randomized into MCAO or sham surgery groups. Maximum volitional tongue forces were quantified 8 wk after surgery. Hypoglossal nerve stimulation was used to assess maximum stimulated force, muscle twitch properties, and force-frequency response. The central activation ratio was determined by maximum volitional/maximum stimulated force. Genioglossus muscle fiber type properties and neuromuscular junction innervation were assessed. Maximum volitional force and the central activation ratio were significantly reduced with MCAO. Maximum stimulated force was not significantly different. No significant differences were found for muscle twitch properties, unilateral contractile properties, muscle fiber type percentages, or fiber size. However, the twitch/tetanus ratio was significantly increased in the MCAO group relative to sham. A small but significant increase in denervated neuromuscular junctions (NMJs) and fiber-type grouping occurred in the contralesional genioglossus. Results suggest that the primary cause of chronic lingual weakness after stroke is impaired muscle activation rather than a deficit of force-generating capacity in lingual muscles. Increased fiber type grouping and denervated NMJs in the contralesional genioglossus suggest that partial reinnervation of muscle fibers may have preserved force-generating capacity, but not optimal activation patterns.NEW & NOTEWORTHY Despite significant reductions in maximum volitional forces, the intrinsic force-generating capacity of the protrusive lingual muscles was not reduced with unilateral cerebral ischemia. Small yet significant increases in denervated NMJs and fiber-type grouping of the contralesional genioglossus suggest that the muscle underwent denervation and reinnervation. Together these results suggest that spontaneous neuromuscular plasticity was sufficient to prevent atrophy, yet central activation deficits remain and contribute to chronic lingual weakness after stroke.

Association of obesity and diabetes with physical activity and fruit and vegetable consumption in stroke survivors

BACKGROUND

Engaging in unhealthy behaviours [poor diet, insufficient physical activity (PA)] increases risk for recurrent stroke and can be compounded by obesity and diabetes, but the association of obesity and diabetes with poor diet and insufficient PA in stroke survivors is unknown.

OBJECTIVE

The purpose of this study was to compare prevalences of low fruit and vegetable consumption (low FV consumption, <1 fruit and <1 vegetable daily) and low physical activity (low PA, <150 minutes of weekly moderate-intensity PA) in stroke survivors, stratified by obesity-diabetes status (neither condition, obesity only, diabetes only, both conditions).

METHODS

Cross-sectional data from 32 876 non-institutionalized, US stroke survivors aged ≥45 years from the 2015 and 2017 Behavioral Risk Factor Surveillance System were examined. Weighted, age-adjusted prevalence estimates and adjusted odds ratios (AORs) of the investigated unhealthy behaviours (adjusted for sex, age, race, income, education and marital status) and 95% confidence intervals (CIs) were calculated.

RESULTS

Prevalences of low FV consumption and low PA exceeded 50% across all obesity-diabetes categories. Compared with respondents with neither obesity nor diabetes, AORs for low PA were increased for respondents with both obesity and diabetes (2.02, 95% CI: 1.72-2.37) and respondents with obesity only (1.31, 1.13-1.53); AORs for low FV consumption did not differ across obesity-diabetes categories.

CONCLUSIONS

Results indicated a joint effect of obesity and diabetes with low PA among stroke survivors. Regardless of obesity-diabetes status, however, prevalence of low FV consumption and low PA exceeded 50%. Targeted interventions that modify these unhealthy behaviours among stroke survivors should be explored.

Clinical Practice Guideline to Improve Locomotor Function Following Chronic Stroke, Incomplete Spinal Cord Injury, and Brain Injury

BACKGROUND

Individuals with acute-onset central nervous system (CNS) injury, including stroke, motor incomplete spinal cord injury, or traumatic brain injury, often experience lasting locomotor deficits, as quantified by decreases in gait speed and distance walked over a specific duration (timed distance). The goal of the present clinical practice guideline was to delineate the relative efficacy of various interventions to improve walking speed and timed distance in ambulatory individuals greater than 6 months following these specific diagnoses.

METHODS

A systematic review of the literature published between 1995 and 2016 was performed in 4 databases for randomized controlled clinical trials focused on these specific patient populations, at least 6 months postinjury and with specific outcomes of walking speed and timed distance. For all studies, specific parameters of training interventions including frequency, intensity, time, and type were detailed as possible. Recommendations were determined on the basis of the strength of the evidence and the potential harm, risks, or costs of providing a specific training paradigm, particularly when another intervention may be available and can provide greater benefit.

RESULTS

Strong evidence indicates that clinicians should offer walking training at moderate to high intensities or virtual reality-based training to ambulatory individuals greater than 6 months following acute-onset CNS injury to improve walking speed or distance. In contrast, weak evidence suggests that strength training, circuit (ie, combined) training or cycling training at moderate to high intensities, and virtual reality-based balance training may improve walking speed and distance in these patient groups. Finally, strong evidence suggests that body weight-supported treadmill training, robotic-assisted training, or sitting/standing balance training without virtual reality should not be performed to improve walking speed or distance in ambulatory individuals greater than 6 months following acute-onset CNS injury to improve walking speed or distance.

DISCUSSION

The collective findings suggest that large amounts of task-specific (ie, locomotor) practice may be critical for improvements in walking function, although only at higher cardiovascular intensities or with augmented feedback to increase patient's engagement. Lower-intensity walking interventions or impairment-based training strategies demonstrated equivocal or limited efficacy.

LIMITATIONS

As walking speed and distance were primary outcomes, the research participants included in the studies walked without substantial physical assistance. This guideline may not apply to patients with limited ambulatory function, where provision of walking training may require substantial physical assistance.

SUMMARY

The guideline suggests that task-specific walking training should be performed to improve walking speed and distance in those with acute-onset CNS injury although only at higher intensities or with augmented feedback. Future studies should clarify the potential utility of specific training parameters that lead to improved walking speed and distance in these populations in both chronic and subacute stages following injury.

DISCLAIMER

These recommendations are intended as a guide for clinicians to optimize rehabilitation outcomes for persons with chronic stroke, incomplete spinal cord injury, and traumatic brain injury to improve walking speed and distance.

Relationship between Energy Intake and Changes in Thigh Echo Intensity during the Acute Phase of Stroke in Older Patients with Hemiplegia

OBJECTIVE

The aim of this study was to investigate the relationship between energy intake and changes in thigh echo intensity (TEI) during the acute phase of stroke in older patients with hemiplegia.

SUBJECTS AND METHODS

Older hemiplegic inpatients with stroke were enrolled in this post hoc analysis of a prospective observational study. Patients were divided into 2 groups according to energy intake during the 7 days after admission as follows: energy sufficient (ES) and energy insufficient (EIS) groups. The outcome was the rate of changes in TEI of the paralyzed and nonparalyzed sides between admission and after 4 weeks. A decrease in skeletal muscle quality is defined as an increase in intramuscular adipose tissues, which shows as an increase in echo intensity.

RESULTS

The study included 44 males and 39 females (median age 81 years). The rate of change of TEI in each group was as follows: +4.5% in the ES/paralyzed group, +6.7% in the EIS/paralyzed group, -0.9% in the ES/nonparalyzed group, and +4.4% in the EIS/nonparalyzed group. The univariate analyses showed no significant difference in the rate of change in TEI between ES and EIS groups in both paralyzed side (p = 0.190) and nonparalyzed side (p = 0.183). Multivariate analysis showed that higher energy intake was associated with a smaller increase in the rate of change in TEI on the nonparalyzed side (B = -4.115, 95% confidence interval, -7.127 to -1.103).

CONCLUSIONS

Higher energy intake during 7 days after admission was associated with a smaller increase in the rate of change in TEI on the nonparalyzed side upon admission and after 4 weeks.

Muscle and tendon properties of the spastic lower leg after stroke defined by ultrasonography: a systematic review

INTRODUCTION

Peripheral muscle and tendon changes after stroke can influence the functional outcome of patients. The aim of this systematic review was to summarize the evidence of ultrasonographic changes in morphological muscle and tendon properties of the spastic hemiparetic lower leg in patients with first ever stroke.

EVIDENCE ACQUISITION

A systematic search was conducted through PubMed, Embase, Scopus, Cinahl, Cochrane Library, and manual searches from inception until May 1, 2020. Observational case control or cohort studies were included. Risk of bias was evaluated by using the Newcastle-Ottawa Quality Assessment Scale. Outcome parameters of interest included muscle thickness, muscle and tendon length, fascicle length, pennation angle and echo-intensity.

EVIDENCE SYNTHESIS

Nine studies investigated outcome parameters beyond one-month after stroke. We are unable to make a comprehensive statement. Nevertheless, there are some arguments for reduced muscle thickness and reduced fascicle length of the hemiplegic, spastic leg.

CONCLUSIONS

Despite the fact that objective assessment by ultrasonography holds promise for diagnosis and follow-up of spastic hemiparesis after stroke, more evidence is needed to determine how changes in morphological muscle and tendon properties are related to muscle weakness, severity of spasticity and compensation strategies such as disuse or overuse in longitudinal studies starting early after stroke.

Anthropometrical Features of Para-Footballers According to Their Cerebral Palsy Profiles and Compared to Controls

Cerebral palsy (CP) football is a team para-sport practiced by para-athletes with eligible impairments of hypertonia, athetosis, and ataxia. This study aimed: (1) to describe the anthropometrical and body composition profiles of international CP para-footballers with different CP profiles (i.e., spastic diplegia, athetosis/ataxia, spastic hemiplegia, and minimum impairment); (2) to analyze the differences between both affected/nondominant and nonaffected/dominant sides; and (3) to compare the sample of international-level CP para-footballers (n = 141) with a sample of highly trained able-bodied footballers (n = 39). Anthropometric measures included four breadths, nine girths, and six skinfolds, while body composition was measured through fat mass (including Carter's, Faulkner's, and Withers' equations), muscle mass (Lee's equation), and bone mass (Rocha's and Martin's equations). This study found differences between the able-bodied footballers and the following impairment profiles: spastic diplegia (skinfolds); ataxia/athetosis (corrected calf of the nondominant side, and calf skinfolds for both sides); and spastic hemiplegia (all measurements excepting femur breadth, and thigh and ankle girths). No differences were found between para-athletes with minimum impairment and the able-bodied footballers. This study demonstrates that football players with or without physical impairments of hypertonia athetosis or ataxia may be considered homogeneous in shape when dominant size is compared. Besides, the study provides reference scores on anthropometric measures and body composition of international-level CP para-footballers that can help sports coaches and physical trainers to monitor physical fitness of their para-athletes.

Brain and Muscle: How Central Nervous System Disorders Can Modify the Skeletal Muscle

It is widely known that nervous and muscular systems work together and that they are strictly dependent in their structure and functions. Consequently, muscles undergo macro and microscopic changes with subsequent alterations after a central nervous system (CNS) disease. Despite this, only a few researchers have addressed the problem of skeletal muscle abnormalities following CNS diseases. The purpose of this review is to summarize the current knowledge on the potential mechanisms responsible for changes in skeletal muscle of patients suffering from some of the most common CSN disorders (Stroke, Multiple Sclerosis, Parkinson’s disease). With this purpose, we analyzed the studies published in the last decade. The published studies show an extreme heterogeneity of the assessment modality and examined population. Furthermore, it is evident that thanks to different evaluation methodologies, it is now possible to implement knowledge on muscle morphology, for a long time limited by the requirement of muscle biopsies. This could be the first step to amplify studies aimed to analyze muscle characteristics in CNS disease and developing rehabilitation protocols to prevent and treat the muscle, often neglected in CNS disease.

SWEAT2 study: effectiveness of trunk training on muscle activity after stroke. A randomized controlled trial

BACKGROUND

Trunk training after stroke is an effective method for improving trunk control, standing balance and mobility. The SWEAT² study attempts to discover the underlying mechanisms leading to the observed mobility carry-over effects after trunk training.

AIM

A secondary analysis investigating the effect of trunk training on muscle activation patterns, muscle synergies and motor unit recruitment of trunk and lower limbs muscles, aimed to provide new insights in gait recovery after stroke.

DESIGN

Randomized controlled trial.

SETTING

Monocentric study performed in the RevArte Rehabilitation Hospital (Antwerp, Belgium).

POPULATION

Forty-five adults diagnosed with first stroke within five months, of which 39 completed treatment and were included in the analysis.

METHODS

Participants received 16 hours of additional trunk training (N.=19) or cognitive training (N.=20) over the course of four weeks (1 hour, 4 times a week). They were assessed by an instrumented gait analysis with electromyography of trunk and lower limb muscles. Outcome measures were linear integrated normalized envelopes of the electromyography signal, the amount and composition of muscle synergies calculated by nonnegative matrix factorization and motor unit recruitment calculated, by mean center wavelet frequencies. Multivariate analysis with post-hoc analysis and statistical parametric mapping of the continuous curves were performed.

RESULTS

No significant differences were found in muscle activation patterns and the amount of muscle synergies. In 42% of the subjects, trunk training resulted in an additional muscle synergy activating trunk muscles in isolation, as compared to 5% in the control group. Motor unit recruitment of the of trunk musculature showed decreased fast-twitch motor recruitment in the erector spinae muscle after trunk training: for the hemiplegic (t[37]=2.44, P=0.021) and non-hemiplegic erector spinae muscle (t[37]=2.36, P=0.024).

CONCLUSIONS

Trunk training improves selective control and endurance of trunk musculature after sub-acute stroke.

CLINICAL REHABILITATION IMPACT

What is new to the actual clinical rehabilitation knowledge is that: trunk training does not alter muscle activation patterns or the amount of muscle synergies over time; a decrease in fast-twitch motor recruitment in the erector spinae muscle was found during walking after trunk training; trunk training seems to increase the fatigue-resistance of the back muscles and enables more isolated activation.

Lower Extremity Lymphatic Function in Nonambulatory Patients with Neuromuscular Disease

Background: Lymphedema results from inadequate lymphatic function causing swelling in subcutaneous tissues. Lymph is transported proximally through valved lymphatic channels and muscle contraction. The purpose of this study was to determine lymphatic function in nonambulatory patients with lower extremity neuromuscular disease. Methods and Results: Our Lymphedema Program database of 700 patients was reviewed for nonambulatory patients with lower extremity neuromuscular disease. Patient age, gender, disease, body mass index (BMI), and lymphoscintigram result were recorded. Eight patients were included in the study: myelomeningocele (n = 6), spinal muscle atrophy type 2 (n = 1), Charcot Marie Tooth (n = 1). Patient ages were between 15 and 36 years; five were female. BMI range for patients without swelling or a normal lymphoscintigram (n = 4) was 22-27. Four subjects with lymphatic dysfunction by lymphoscintigram all were obese (BMI 36-74; p = 0.03). Conclusions: Nonambulatory patients with lower extremity neuromuscular dysfunction and swelling can exhibit normal lymphatic function. Obesity is associated with abnormal lymphoscintigram result and lymphedema in this patient population. Individuals should be advised to maintain a normal BMI.

Neuromuscular Electrical Stimulation and High-Protein Supplementation After Subarachnoid Hemorrhage: A Single-Center Phase 2 Randomized Clinical Trial

INTRODUCTION

Aneurysmal subarachnoid hemorrhage (SAH) survivors live with long-term residual physical and cognitive disability. We studied whether neuromuscular electrical stimulation (NMES) and high-protein supplementation (HPRO) in the first 2 weeks after SAH could preserve neuromotor and cognitive function as compared to standard of care (SOC) for nutrition and mobilization.

METHODS

SAH subjects with a Hunt Hess (HH) grade > 1,modified Fisher score > 1 and BMI < 40 kg/m² were randomly assigned to SOC or NMES + HPRO. NMES was delivered to bilateral quadricep muscles daily during two 30-min sessions along with HPRO (goal:1.8 g/kg/day) between post-bleed day (PBD) 0 and 14. Primary endpoint was atrophy in the quadricep muscle as measured by the percentage difference in the cross-sectional area from baseline to PBD14 on CT scan. All subjects underwent serial assessments of physical (short performance physical battery, SPPB) cognitive (Montreal Cognitive Assessment Scale, MoCA) and global functional recovery (modified Rankin Scale, mRS) at PBD 14, 42, and 90.

RESULTS

Twenty-five patients (SOC = 13, NMES + HPRO = 12) enrolled between December 2017 and January 2019 with no between-group differences in baseline characteristics (58 years old, 68% women, 50% HH > 3). Median duration of interventions was 12 days (range 9-14) with completion of 98% of NMES sessions and 83% of goal HPRO, and no reported serious adverse events. There was no difference in caloric intake between groups, but HPRO + NMES group received more protein (1.5 ± 0.5 g/kg/d v 0.9 ± 0.4 g/kg/d, P < 0.01). Muscle atrophy was less in NMES + HPRO than the SOC group (6.5 ± 4.1% vs 12.5 ± 6.4%, P 0.01). Higher atrophy was correlated with lower daily protein intake (ρ = - 0.45, P = 0.03) and lower nitrogen balance (ρ = 0.47, P  = 0.02); and worse 3 month SPPB (ρ = -  0.31, P = 0.1) and mRS (ρ = 0.4, P  = 0.04). NMES + HPRO patients had a better median [25%,75] SPPB (12[10, 12] v. 9 [4, 12], P = 0.01) and mRS (1[0,2] v.2[1, 3], P = 0.04) than SOC at PBD 90.

CONCLUSIONS

NMES + HPRO appears to be feasible and safe acutely after SAH and may reduce acute quadriceps muscle wasting with a lasting benefit on recovery after SAH.

Factors Influencing Gait Velocity Improvement Following Botulinum Toxin Injection for Spasticity of the Plantar Flexors in Patients with Stroke

Objective:

In patients with hemiplegia, botulinum toxin type A injection for ankle spasticity of the plantar flexors reportedly improves walking speed. This improvement may be affected by background factors and patient baseline physical performance. This study aimed to clarify the factors affecting gait velocity improvement after botulinum toxin type A injection.

Methods:

Background and evaluation data were collected for 60 patients with stroke who received botulinum toxin type A injection for spasticity of the plantar flexors. The patients were divided into improvement (n=27) and non-improvement (n=33) groups based on the gait velocity change from before injection to 2 weeks after injection. Logistic regression analysis was performed with the improvement and non-improvement groups as response variables and background data and evaluation data at baseline as explanatory variables.

Results:

The presence or absence of physical therapy following botulinum toxin type A injection (odds ratio: 7.82) was the only significant explanatory variable for gait velocity change.

Conclusion:

Background factors and physical performance at baseline did not affect gait velocity improvement after botulinum toxin type A injection. If botulinum treatment of the ankle plantar flexors in patients with stroke is targeted at walking performance improvement, then physical therapy following botulinum toxin type A injection should be an essential part of the treatment strategy.

Focal brain ischemia in mice does not cause electrophysiological signs of critical illness neuropathy

OBJECTIVE

Critical illness polyneuropathy (CIP) is a common complication of severe systemic illness treated in intensive care medicine. Ischemic stroke leads to an acute critical injury of the brain with hemiparesis, immunosuppression and subsequent infections, all of which require extended medical treatment. Stroke-induced sarcopenia further contributes to poor rehabilitation and is characterized by muscle wasting and denervation in the paralytic, but also the unaffected limbs. Therefore, we asked whether stroke leads to an additional CIP-like neurodegeneration.

RESULTS

Focal brain ischemia was induced in adult mice by 60-min middle cerebral artery occlusion (MCAo) following reperfusion and led to functional deficits and marked hemispheric brain atrophy. Nerve conduction function and muscle potentials were measured in the ipsilateral sciatic nerve and gastrocnemius and quadriceps muscle with electroneurography/-myography on days 10, 22, 44 after stroke. An additional crush-injury to the sciatic nerve was included in two sham mice as positive control (sham +). We found no differences in nerve conduction function nor spontaneous electromyographic activity between MCAo and sham animals. Sham + mice developed marked reduction of the motor action potential amplitudes and conduction velocities with pathologic spontaneous activity. In conclusion, we found no peripheral nerve dysfunction/degeneration as signs of a CIP-like phenotype after MCAo.

Differences in muscle thickness and echo intensity between stroke survivors and age- and sex-matched healthy older adults

OBJECTIVE

The stroke survivors exhibit change in muscle quantity and quality compared to healthy older adults. This study aimed to compare the muscle thickness (MT) and echo intensity (EI) values of individual muscles between stroke survivors and age- and sex-matched healthy older adults.

METHODS

In total, 27 stroke survivors and 34 healthy older adults participated in this study. The MT and EI values of the following muscles were assessed from transverse ultrasound images: rectus abdominis (RA), external oblique, internal oblique, transversus abdominis, rectus femoris, vastus intermedius (VI), vastus lateralis (VL), vastus medialis (VM), tibialis anterior (TA), gastrocnemius (Gas), and soleus (Sol). The MT and EI values of these muscles were compared between stroke survivors and healthy older adults.

RESULTS

The MT values of the VL, VM, and RA on the non-paretic sides were significantly higher and those of the TA, Gas, and Sol on the paretic sides were significantly lower in the stroke survivors than in the healthy older adults (P < 0.05). The EI values of the VI, VL, VM, TA on the paretic sides and those of the Gas on both the paretic and non-paretic sides were significantly higher in the stroke survivors than in the healthy older adults (P < 0.05).

CONCLUSION

Stroke survivors seem to develop muscle hypertrophy of the non-paretic thigh muscles owing to a compensatory strategy. In addition, the lower-leg muscles on the paretic side of stroke survivors tend to show both quantitative and qualitative muscle changes.

Model-Based Sensitivity Analysis of EMG Clustering Index With Respect to Motor Unit Properties: Investigating Post-Stroke FDI Muscle

The objective of this study is to explore the diagnostic decision and sensitivity of the surface electromyogram (EMG) clustering index (CI) with respect to post-stroke motor unit (MU) alterations through a simulation approach by the existing motor neuron pool model and surface EMG model. In the simulation analysis, three patterns of diagnostic decisions were presented in 24 groups representing eight types in three degrees of MU alterations. Specifically, the CI decision exhibited an abnormally increased pattern for five types, an abnormally decreased pattern for two types, and an invariant pattern for one type. Furthermore, the CI diagnostic decision was found to be highly sensitive to three types because a 50% degree of alteration in these types resulted in a distinct deviation of 2.5 in the CI Z-score. The mixed CI patterns were confirmed in experimental data collected from the paretic muscles of 14 subjects with stroke, as compared to the healthy muscles of 10 control subjects. Given the simulation results as a guideline, the CI diagnostic decision could be interpreted from general neural or muscular changes into specific MU changes (in eight types). This can further promote clinical applications of the convenient surface EMG tool in examining and monitoring paretic muscle changes toward customized stroke rehabilitation.

Guidelines for the Evaluation of Cardiorespiratory Physiotherapy in Stroke Patients

Evaluation of stroke patients is prioritized over therapeutic interventions to restore cardiorespiratory capacity. This study aimed to develop a clinically applicable guideline to evaluate cardiorespiratory physiotherapy in stroke patients based on a literature review and a modified Delphi survey. The literature search included 13,498 articles in PubMed, EMBASE, CINAHL, and Cochrane Library electronic databases. We surveyed previous articles between January 2010 and June 2019. After the option elimination process, a total of 27 documents were selected and analyzed (draft: 18, modified Delphi survey: 9). The results of this research are roughly divided into two categories. First, 31 draft items were extracted, and a modified Delphi survey questionnaire was created from a literature review. Second, an expert was asked to make two modified Delphi surveys and to modify, delete, and supplement the entries in the statistical analysis at each level to finalize the steps to 20 items. The guidelines developed in this study reflect the selective use of cardiorespiratory physiotherapy evaluation methods in the clinical setting, based on the health status of individual patients. Moreover, the guidelines may help physiotherapists make informed decisions based on expert knowledge, thereby playing a crucial role in the patient-centered treatment planning process.

Transversus Abdominis Thickness at Rest and Exercise in Individuals with Poststroke Hemiparesis

The activity of the transverse abdominal (TrA) muscle affects the stabilization of the trunk. It is known that after a stroke, people experience problems in performing daily activities. The purpose of this study was to examine whether there are differences in the transversus abdominal thickness between the two sides of the body in individuals with hemiparesis and controls. Eight patients with hemiparesis and nine controls matched for age and body mass index were examined by musculoskeletal ultrasound in four conditions: a) At rest, b) abdominal hollowing maneuver from the supine position, c) bridge, and d) abdominal hollowing maneuver from the bridge position. In each of the above conditions, the symmetry index was calculated as the absolute value of the difference in thickness between the two sides. Analysis of variance showed a lower TrA thickness at rest and exercise in patients compared to the control group (p < 0.05). Further, patients showed a lower contraction thickness ratio during exercise compared to controls (p < 0.05). The absolute symmetry of the TrA thickness was 12.59 ± 6.43% to 19.31 ± 10.43% in patients and it was significantly greater than the control group (3.01 ± 2.47% to 4.47 ± 2.87%). According to the above results, it seems that transverse abdominal activation exercises are particularly useful for improving the stability of patients with hemiparesis, as long as they are located and adapted to the deficit of each patient.

Modifiable Factors Associated With Poststroke Physical Activity at Discharge From Rehabilitation: Prospective Cohort Study

BACKGROUND

People with stroke are not meeting recommended levels of physical activity. The modifiable factors associated with poststroke physical activity levels need to be identified to develop targeted interventions.

OBJECTIVE

The objective of this study was to investigate the factors at discharge from inpatient rehabilitation that are associated with physical activity levels at 3 months following discharge.

DESIGN

This was a prospective cohort study.

METHODS

Sixty-four people with stroke completed baseline assessments at discharge from inpatient rehabilitation and 55 completed the follow-up 3 months later. The candidate factors (ie, gait speed, balance, strength, cognition, mood, and motivation) were measured at discharge. The primary outcome measure at follow-up was walking-related activity (measured by wrist-worn accelerometer). Secondary outcome measures were physical activity participation (Activity Card Sort) and intensity of physical activity (International Physical Activity Questionnaire-Short 7 days). Adjusted separate multivariable linear regression models or proportional odds regression models were used to evaluate the associations between candidate factors and physical activity.

RESULTS

Gait speed and balance were associated with all aspects of physical activity. Higher level of intrinsic motivation was also associated with higher physical activity participation. Anxiety demonstrated a significant nonlinear relationship with physical activity participation.

LIMITATIONS

Inclusion of fatigue and individual muscle strength could have provided further insights into associations with steps per day.

CONCLUSION

The results demonstrated that better physical function at discharge from inpatient rehabilitation was associated with future increased levels of physical activity. Additionally, higher levels of motivation impacted on increased physical activity participation. The influence of anxiety on physical activity participation requires further exploration. Mixed-method study designs can be utilized to further understand the factors associated with poststroke physical activity.

Beyond the Brain: The Systemic Pathophysiological Response to Acute Ischemic Stroke

Stroke research has traditionally focused on the cerebral processes following ischemic brain injury, where oxygen and glucose deprivation incite prolonged activation of excitatory neurotransmitter receptors, intracellular calcium accumulation, inflammation, reactive oxygen species proliferation, and ultimately neuronal death. A recent growing body of evidence, however, points to far-reaching pathophysiological consequences of acute ischemic stroke. Shortly after stroke onset, peripheral immunodepression in conjunction with hyperstimulation of autonomic and neuroendocrine pathways and motor pathway impairment result in dysfunction of the respiratory, urinary, cardiovascular, gastrointestinal, musculoskeletal, and endocrine systems. These end organ abnormalities play a major role in the morbidity and mortality of acute ischemic stroke. Using a pathophysiology-based approach, this current review discusses the pathophysiological mechanisms following ischemic brain insult that result in end organ dysfunction. By characterizing stroke as a systemic disease, future research must consider bidirectional interactions between the brain and peripheral organs to inform treatment paradigms and develop effective, comprehensive therapeutics for acute ischemic stroke.

Obesity and diabetes are jointly associated with functional disability in stroke survivors

BACKGROUND

Stroke is the most common cause of complex disability. Obesity and diabetes increase risk for functional disability in the general population, but their contribution to functional disability in stroke survivors is unknown.

OBJECTIVE

To investigate the joint association of obesity and diabetes with functional disability in stroke survivors.

METHODS

Cross-sectional data from 34,376 stroke survivors from the 2015 and 2017 Behavioral Risk Factor Surveillance System (BRFSS) surveys were examined. Weighted and age-adjusted prevalence estimates and adjusted odds ratios (AOR, adjusted for sociodemographic characteristics) with 95% confidence intervals (CIs) were calculated to compare prevalence and odds for self-reported functional disability, stratified by obesity-diabetes status (i.e., neither condition, obesity only, diabetes only, both conditions).

RESULTS

Prevalence of functional disability increased across obesity-diabetes categories in the total sample: neither condition (45.4%, 95% CI: 43.4%-47.4%), obesity only (55.3%, 95% CI: 52.7%-58.0%), diabetes only (60.8%, 95% CI: 57.5%-64.1%), and both conditions (70.3%, 95% CI: 67.7%-72.9%). Compared to respondents with neither condition, those with both obesity and diabetes had 2.62 (95% CI: 2.23-3.08) higher odds for functional disability; odds were also increased for respondents with obesity only (1.52, 95% CI: 1.32-1.76) and diabetes only (1.71, CI: 1.45-2.01).

CONCLUSIONS

Our findings indicated a joint effect of obesity and diabetes on functional disability that exceeded either condition alone, placing stroke survivors with both health conditions at greatest risk for diminished functional capacity. Recognizing obesity and diabetes as modifiable risk factors may be useful for identifying stroke sub-populations that could benefit from lifestyle intervention.