Paretic Muscles Research Articles

High-Intensity Interval Training Improves Physical Function, Prevents Muscle Loss, and Modulates Macrophage-Mediated Inflammation in Skeletal Muscle of Cerebral Ischemic Mice.

Although skeletal muscle is the main effector organ largely accounting for disability after stroke, considerably less attention is paid to the secondary abnormalities of stroke-related skeletal muscle loss. It is necessary to explore the mechanism of muscle atrophy after stroke and further develop effective rehabilitation strategy. Here, we evaluated the effects of high-intensity interval (HIIT) versus moderate-intensity aerobic training (MOD) on physical function, muscle mass, and stroke-related gene expression profile of skeletal muscle. After the model of middle cerebral artery occlusion (MCAO) was successfully made, the blood lactate threshold corresponding speed (SLT) and maximum speed (Smax) were measured. Different intensity training protocols (MOD < SLT; SLT < HIIT < Smax) were carried out for 3 weeks beginning at 7 days after MCAO in the MOD and HIIT groups, respectively. We found that both HIIT and MOD prevented stroke-related gastrocnemius muscle mass loss in MCAO mice. HIIT was more beneficial than MOD for improvements in muscle strength, motor coordination, walking competency, and cardiorespiratory fitness. Furthermore, HIIT was superior to MOD in terms of reducing lipid accumulation, levels of IL-1β and IL-6 in paretic gastrocnemius, and improving peripheral blood CD4+/CD8+ T cell ratio, level of IL-10. Additionally, RNA-seq analysis revealed that the differentially expressed genes among HIIT, MOD, and MCAO groups were highly associated with signaling pathways involved in inflammatory response, more specifically the I-kappaB kinase/NF-kappaB signaling. Following the outcome, we further investigated the infiltrating immune cells abundant in paretic muscles. The results showed that HIIT modulated macrophage activation by downregulating CD86+ (M1 type) macrophages and upregulating CD163+ (M2 type) macrophages via inhibiting the TLR4/MyD88/NFκB signaling pathway and exerting an anti-inflammatory effect in paretic skeletal muscle. It is expected that these data will provide novel insights into the mechanisms and potential targets underlying muscle wasting in stroke.

TMS based lower extremity multi-muscle motor mapping in persons post-stroke with impaired muscle coordination

Abstract Co-excitation of normally independent muscle groups or modules can explain impaired motor coordination during walking. Mass flexion-extension co-excitation patterns (i.e., only two or three modules instead of the usually observed four modules) are often seen as a consequence of stroke. The corticospinal (CST) and corticoreticular (CRP) networks are major contributors to the production of modules during walking. A structural MRI-based analysis from our lab found that both CST and CRP are involved in locomotor recovery post-stroke and greater involvement of both ipsi- and contralesional CRP is associated with mass flexion-extension synergy leading to a two module pattern and poor walking ability. In the current study, we will further investigate the relationship between a two module pattern and ipsi- and contralesional cortical reorganization with TMS derived motor mapping during standing. Utilizing neuronavigation a 6x8 grid with 1.25 cm between grid points will be centered over individual participants’ T1 image. The motor threshold of the paretic tibialis anterior muscle will be determined during standing (functionally-relevant to walking) with a double-cone coil positioned over the vertex. Ten stimulations at an intensity of 140% of motor threshold will be delivered to each grid point over both hemispheres. Visual feedback will be provided to ensure equal weight distribution between the legs during standing. The average motor evoked potential amplitude and response latency from eight muscles of each leg will be used for motor mapping. We hypothesize that the individuals who have severely damaged CST and two module patterns of walking will have reorganization of leg motor representation in contralesional M1 and/or cortical regions associated with CRP (i.e., supplementary motor area and pre-motor cortex of the ipsi-and-contralesional hemispheres). This ongoing study will provide essential knowledge of the cortical contributions to modules and eventually be applicable to designing patient-specific neuromodulation rehabilitation techniques. Keywords: TMS, motor coordination, gait, Structural MRI

Intramuscular tetanus neurotoxin reverses muscle atrophy: a randomized controlled trial in dogs with spinal cord injury.

BackgroundMotor symptoms of spinal cord injury (SCI) considerably impair quality of life and are associated with a high risk of secondary diseases. So far, no pharmacological treatment is available for these symptoms. Therefore, we conducted a randomized, double‐blinded, placebo‐controlled study in dogs with spontaneous SCI due to disc herniation to test whether a reduction of spinal inhibitory activity by intramuscular injections of tetanus neurotoxin (TeNT) alleviates motor symptoms such as muscle atrophy or gait function.MethodsTo this end, 25 dogs were treated with injections of either TeNT or placebo into their paretic hindlimb muscles. Effects of TeNT on muscle thickness were assessed by ultrasound, while effects on gait function were measured using the modified functional scoring system in dogs.ResultsFour weeks after the TeNT injections, muscle thickness of the gluteus medius muscle (before median 1.56 cm [inter‐quartile range {IQR} 1.34–1.71 cm] and after median 1.56 cm [IQR 1.37–1.85 cm], P‐value 0.0133) as well as of the rectus femoris muscle (before median 0.76 cm [IQR 0.60–0.98 cm] and after median 0.93 cm [IQR 0.65–1.05 cm], P‐value 0.0033) significantly increased in the TeNT group. However, there was no difference in gait function between the TeNT and placebo groups. The treatment was well tolerated by all dogs without any signs of generalized tetanus symptoms or any spreading of effects beyond the lumbar level of the injected hindlimbs.ConclusionsWith regard to the beneficial effects on muscle thickness, intramuscular injections of TeNT represent the first pharmacological approach that focally reverses muscle atrophy in SCI. Moreover, the study data support the safety of this treatment when TeNT is used at low dose.

MUSCLE OXYGENATION BETWEEN THE PARETIC AND NONPARETIC LEG MEASURED DURING ARTERIAL OCCLUSION AND EXERCISE IN CHRONIC STROKE

<h3>BACKGROUND</h3> Oxygen delivery and demand are reduced in the paretic leg of individuals post-stroke, reflecting decreases of vascular function and reductions of muscle quantity and quality. However, it is unknown how muscle oxygenation, the balance between delivery and utilization of oxygen, at the muscle is altered post-stroke and how it relates to functional ambulation and aerobic exercise. The purpose of this study was to determine the difference in muscle oxygenation between the paretic and nonparetic leg of post-stroke individuals and determine if there is an association with the six-minute walk test (6MWT) distance. <h3>METHODS AND RESULTS</h3> This was a single group cross-sectional study and a sub-study of a larger two-arm parallel-group superiority trial. Skeletal muscle O2 saturation (SMO2) of the paretic and nonparetic vastus lateralis muscles were monitored continuously with two near-infrared spectroscopy (NIRS) devices, a non-invasive measure of muscle oxygenation. NIRS outcomes were measured at rest, during arterial occlusion, acute submaximal exercise and 6MWT. Muscle oxygenation was evaluated by the rate of SMO2 deoxygenation and reoxygenation during and after occlusion and exercise, and by SMO2 averages for rest and the 6MWT (see figure). Eleven subjects (91% male; 32.2±6.1 months post-stroke; age 62.9±13.6 years, with a Chedoke–McMaster Stroke Assessment score of 4.1±1.4 of the paretic leg; 7 representing normal movement) participated. There was no significant difference in SMO2 between legs at rest (p=0.13) or during the 6MWT (p=0.26). The arterial occlusion desaturation slope in the nonparetic leg (-0.70±0.36%/second) was significantly steeper than the paretic leg (-0.53±0.24%/second; p=0.03), suggesting impaired oxygen consumption in the paretic leg. The post-occlusion resaturation slope was significantly steeper in the nonparetic leg (5.7±1.6%/second) compared to the paretic leg (4.6±1.8%/second; p=0.04), indicating poorer microvascular function in the paretic leg. The exercise deoxygenation slope in the paretic leg (-0.6±0.6%/second) was significantly steeper than the non-paretic leg (-0.3±0.2%/second; p=0.047), indicating a greater mismatch between oxygen delivery and consumption at the onset of exercise, however, there was no significant difference between legs in the post-exercise resaturation slope (p=0.39). Average 6MWT SMO2 of each leg was not significantly correlated with 6MWT distance (Paretic: r=-0.06, p=0.85; Nonparetic: r=0.25, p=0.46). <h3>CONCLUSION</h3> Oxygen consumption and microvascular responsiveness are reduced in the paretic compared to the nonparetic leg. At the onset of exercise there is a mismatch between oxygen delivery and consumption in the paretic leg, which may require strategies to improve muscle oxygenation in this population.

Combined distal nerve and tendon transfer in drop wrist for treatment of high injuries of the radial nerve

The aim of direct distal selective nerve transfer close to the end organ with high radial nerve injury is restoration of the paretic function before irreversible atrophy of the target muscle. Simultaneous tendon transfer enables direct functional correction of wrist drop. Selective nerve and tendon transfer of the lower arm is indicated if a)the primary nerve lesion is located proximally distant and reinnervation by direct nerve repair would take too long to reach aparetic muscle because of the long distance involved, b)direct repair of the nerve lesion is impossible or c)there has been a substantial delay after the primary injury. Aviable donor nerve must be available. A) After final denervation of amuscle, which occurs approximately 1.5years after a nerve injury, the atrophy is irreversible and a nerve transfer can no longer restore the paretic muscle. Only younger patients under 30 years old might benefit from delayed nerve transfer. B) When no sufficient donor nerve is available only tendon transfer is possible. Direct nerve transfer from the median nerve to the radial nerve as well as direct functional correction of wrist drop by tendon transfer of the pronator teres muscle. Immobilization of the arm for 3 days, wrist orthosis for 6weeks for protection of the tendon transfer, ergotherapy and physiotherapy preferably by a hand therapist. Active wrist and finger extension 2years after transfer, with individualized extension of the thumb and index finger is possible, wrist drop reversed.

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.

Spasticité chez l’enfant paralysé cérébral : quelle définition pour quelle évaluation clinique ?

Spasticity is a common motor impairment in children with cerebral palsy (CP). Since the version of Lance in 1980, the definition of the term “spasticity” has been modified many times without becoming consensual. Since many years, spasticity is integrated in global concepts and defined as one of factors leading to an increase neuromuscular resistance of spastic and paretic muscle lengthening. The clinical assessment of spasticity is classically performed using ordinal scales, which psychometrics properties are limited. Distinguishing spasticity from others factors and accurate quantification of its level are majors’ difficulties. The objective of this article is (1) to clarify the sense of the term “spasticity” from a summary of the evolution of its definition since 1980 to nowadays, (2) describe psychometrics properties of the clinical scales assessing spasticity.

The role of kinesiotherapy in treating the symptoms of obstetric palsy

Obstetric palsy (OP) is the partial or total paralysis of the upper limb due to injury of the brachial plexus during childbirth. Early kinesiotherapy intervention helps to treat motor disorders faster and more effectively by reducing upper limb disability. The aim of this review is to describe recent research data on kinesiotherapy applications in patients with OP. The Google Scholar and PubMed databases were searched with the following keywords: obstetric palsy, kinesiotherapy, rehabilitation. This review included five articles. In conclusion, the application of kinesiotherapy contributes to the better treatment of motor and sensory disorders of the paretic muscles caused by OP as it helps to maintain the range of motion of the glenohumeral joint, to prevent stiffness, to maintain muscle tone, to increase muscle strength and endurance and, consequently, to improve function of the affected limb.

Corticospinal recruitment of spinal motor neurons in human stroke survivors.

Muscle weakness after stroke results from damage to corticospinal fibres that structurally and functionally connect cerebral cortex to the spinal cord. Here, we show an asymmetry in corticospinal recruitment of spinal motor neurons that is linked to maximal voluntary output of hand muscles weakened by stroke. Spike timing-dependent plasticity of synapses between corticospinal and spinal motor neurons transiently reversed recruitment failures in some survivors. These modulatory effects were strongly associated with recruitment asymmetry and hand impairment. Our findings highlight the functional relevance of spinal motor neuron recruitment by corticospinal inputs and the viability of corticospinal motor neuronal synapses for restoring activation of lower motor neurons after stroke. Corticospinal input to spinal motor neurons is structurally and functionally altered by hemiparetic stroke. The pattern and extent to which corticospinal recruitment of spinal motor neurons is reorganized and whether such changes are linked to the severity of motor impairments is not well understood. Here, we performed experiments using the triple stimulation technique to quantify corticospinal recruitment of spinal motor neurons serving paretic and non-paretic intrinsic hand muscles of humans with longstanding motor impairment secondary to stroke (n=13). We also examined whether recruitment failures could be transiently reversed by strengthening corticospinal-motoneuronal synaptic connectivity via targeted, temporally controlled non-invasive stimulation to elicit spike timing-dependent plasticity (STDP). Asymmetries were detected in corticospinal recruitment of spinal motor neurons, central conduction time and motor-evoked potential (MEP) latency. However, only recruitment asymmetry correlated with maximal voluntary motor output from the paretic hand. STDP-like effects were observed as an increase in spinal motor neuron recruitment. Control experiments to isolate the locus of plasticity demonstrated a modulation in MEPs elicited by electrical stimulation of primary motor cortex but not F-wave size or persistence, suggesting that plasticity was mediated through enhanced efficacy of residual corticospinal-motor neuronal synapses. The modulation in recruitment was strongly associated with baseline recruitment asymmetry and impairment severity. Our findings demonstrate that asymmetry in corticospinal recruitment of spinal motor neurons is directly related to impairments experienced by stroke survivors. These recruitment deficits may be partially and transiently reversed by spike timing-dependent plasticity of synapses between upper and lower motor neurons in the spinal cord, downstream of supraspinal circuits damaged by stroke.

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. SignificanceIschemic 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.

Drop foot due to lumbar degenerative disease: Painless drop foot is difficult to recover

ObjectiveTo evaluate the improvement of drop foot following lumbar decompression surgery and determine the prognostic factors that might influence the recovery of drop foot. Summary and background dateDrop foot is a common but serious problem that can lead to deteriorate patient’s daily activities. There are numerous studied regarding the prognostic factors for the recovery of drop foot. However a few reports have been described the pathophysiological etiology of not only drop foot but also Trendelenburg’s sign due to the L5 nerve root palsy. Therefore, there is a possibility drop foot caused by peroneal nerve palsy is included. In addition, none have evaluated the presence or absence of radicular leg pain with drop foot patients. The purpose of this study was to evaluate the improvement of paretic leg muscles and determine the prognostic factors that might influence the recovery of drop foot. MethodsFifty-five drop foot patients were included in the study. Prognostic factors were retrospectively studied.Patients were assessed in terms of 10 items: 1) age, 2) sex, 3) diagnosis (LDH or LSS), 4) muscle strength of tibialis anterior, 5) muscle strength of extensor halluces longus, 6) muscle strength of gluteus medius, 7) presence or absence of radicular leg pain, 8) duration before surgery, 9) surgical treatment (spinal fusion or not), 10) anamnesis of diabetes mellitus. ResultsThirty-two (58.2%) of 55 patients recovered from their drop foot (manual muscle test of tibialis anterior ≥ 4 at final follow-up), while 23 (41.8%) did not (manual muscle test of tibialis anterior ≤ 3 at final follow-up). The strength of all muscles that were innervated and controlled by the L5 nerve root had recovered at the final follow-up when evaluated as averages. Multivariate logistic regression analysis revealed significant differences in terms of 2 items: “duration before surgery” and “presence or absence of radicular leg pain”. Conclusions“Duration before surgery” and “presence or absence of radicular leg pain” are important to predict the recovery of drop foot. Painless drop foot patients with lumbar degenerative disease are difficult to recover their paralysis.

Repetitive peripheral magnetic stimulation for the assessment of wrist spasticity: reliability, validation and correlation with clinical measures

Purpose To determine feasibility and reliability of using repetitive peripheral magnetic stimulation (rPMS) to induce wrist extension movement for the assessment of spasticity in wrist flexors, instead of the passive stretch used in the modified Tardieu scale. Methods Spasticity was assessed with the index of movement restriction (iMR), calculated as the difference between the range of maximum wrist passive movement and the rPMS-induced movement, in 12 healthy subjects (HS), 12 acute stroke patients without spasticity (AS) and 12 chronic stroke patients with spasticity (CS). Test-retest reliability and clinical correlation were assessed in CS patients before Botulinum neurotoxin type A (BoNT-A) treatment. Results In comparison to HS and AS patients, CS patients showed statistically significant reduction of rPMS-induced movement amplitude, velocity, and acceleration. The mean iMR was 2.8 (SD = 2.6) in HS, 13.0 (SD = 11.2) in AS and 59.2 (SD = 23.4) in CS. This score significantly reduced to 41.1 (SD = 19.7) in CS after BoNT-A (p < 0.01). Test-retest reliability was very good, with an intraclass correlation coefficient ranging between 0.85 and 0.99 for the variables analysed. Conclusions We have shown good reliability and feasibility of a new method providing quantifiable data for the assessment of spasticity and its response to BoNT-A treatment. IMPLICATIONS FOR REHABILITATION The muscle contraction induced by repetitive peripheral magnetic stimulation (rPMS) in paretic muscles of post-stroke patients was used to assess spasticity. The index of movement restriction (iMR), calculated as the difference between the maximum passive range of movement and the rPMS induced movement, improved after botulinum toxin treatment. Measuring spastic reactions to rPMS provides quantifiable and reliable data for follow-up and assessment of therapeutic benefits.

Functional synergy recruitment index as a reliable biomarker of motor function and recovery in chronic stroke patients

Objective. Stroke affects the expression of muscle synergies underlying motor control, most notably in patients with poorer motor function. The majority of studies on muscle synergies have conventionally approached this analysis by assuming alterations in the inner structures of synergies after stroke. Although different synergy-based features based on this assumption have to some extent described pathological mechanisms in post-stroke neuromuscular control, a biomarker that reliably reflects motor function and recovery is still missing. Approach. Based on the theory of muscle synergies, we alternatively hypothesize that functional synergy structures are physically preserved and measure the temporal correlation between the recruitment profiles of healthy modules by paretic and healthy muscles, a feature hereafter reported as the FSRI. We measured clinical scores and extracted the muscle synergies of both ULs of 18 chronic stroke survivors from the electromyographic activity of 8 muscles during bilateral movements before and after 4 weeks of non-invasive BMI controlled robot therapy and physiotherapy. We computed the FSRI as well as features quantifying inter-limb structural differences and evaluated the correlation of these synergy-based measures with clinical scores. Main results. Correlation analysis revealed weak relationships between conventional features describing inter-limb synergy structural differences and motor function. In contrast, FSRI values during specific or combined movement data significantly correlated with UL motor function and recovery scores. Additionally, we observed that BMI-based training with contingent positive proprioceptive feedback led to improved FSRI values during the specific trained finger extension movement. Significance. We demonstrated that FSRI can be used as a reliable physiological biomarker of motor function and recovery in stroke, which can be targeted via BMI-based proprioceptive therapies and adjuvant physiotherapy to boost effective rehabilitation.

Quantification and Monitoring of the Effect of Botulinum Toxin A on Paretic Calf Muscles of Children With Cerebral Palsy With MRI: A Preliminary Study.

Background: Muscles from patients with cerebral palsy (CP) are often spastic and form contractures that limit the range of motion. Injections of botulinum toxin A (BTX) into the calf muscles are an important treatment for functional equinus; however, improvement in gait function is not always achieved. BTX is also used to test muscle weakening for risk evaluation of muscle lengthening surgery. Our aim was to assess the effect of BTX over time on calf muscle properties in pediatric CP patients with MRI.Material and Methods: Six toe-walking CP patients (mean age 11.6 years) with indication for lengthening surgery were prospectively enrolled and received BTX injections into the gastrocnemius and soleus muscles. MRI scans at 3T of the lower legs and clinical examinations were performed pre-BTX, 6 weeks (6w), and 12 weeks (12w) post-BTX. A fat-suppressed 2D multi-spin-echo sequence was used to acquire T2 maps and for segmentation. Fat fraction maps were calculated from 3D multi-echo Dixon images. Diffusion tensor imaging (DTI) with a 2D echo-planar imaging (EPI) sequence yielded maps of the mean apparent diffusion coefficient (ADC) and of the fractional anisotropy (FA). Hyperintense regions of interest (ROIs) on the T2-weighted (T2w) images at 6w were segmented in treated muscles. Mean values of T2, fat fraction, ADC, and FA were calculated in hyperintense ROIs and in reference ROIs in non-treated muscles.Results: Hyperintensity on T2w scans and increased T2 (group mean ± standard deviation: 35 ± 1 ms pre-BTX, 45 ± 2 ms at 6w, and 44 ± 2 ms at 12w) were observed in all patients at the injection sites. The T2 increase was spatially limited to parts of the injected muscles. FA increased (0.30 ± 0.03 pre-BTX, 0.34 ± 0.02 at 6w, and 0.36 ± 0.03 at 12w) while ADC did not change in hyperintense ROIs, indicating a BTX-induced increase in extracellular space and a simultaneous decrease of muscle fiber diameter. Fat fraction showed a trend for increase at 12w. Mean values in reference ROIs remained unchanged.Conclusion: MRI showed limited spatial distribution of the BTX-induced effects in pediatric CP patients. It could be a promising non-invasive tool for future studies to test BTX treatment protocols.

Immediate effects of stance and swing phase training on gait in patients with stroke.

To compare the effects of gait trainings targeting the stance (stance training) and the swing phases (swing training) among the subjects with stroke, and quantify the characteristics in the subjects who benefitted from either the stance training or the swing training. Sixteen subjects with stroke performed the stance training, which focused on the center of pressure to move from the heel to the forefoot, and the swing training, which focused on the improvement of hip flexion in the swing phase. To investigate the immediate effects of the stance training and the swing training, the instrumented gait analysis was performed before and after training. To quantify the characteristics, subjects were divided into two groups based on the gait speed change. These two groups were compared using clinical examinations. After the stance training, the center of pressure displacement of the paretic limb was increased compared with the swing training. Subjects who benefitted from the stance training had slower Timed Up and Go and weaker paretic hip muscle strength than those who benefitted from the swing training. Stance training may be more effective in subjects with slower Timed Up and Go outcomes and weaker hip muscles.

Wavelet coherence analysis of muscle coupling during reaching movement in stroke

Agonist-antagonist coordination is essential to ensure the accuracy and stability of voluntary movement, which can be presented by time-varying coupling between agonist-antagonist electromyographic (EMG) signals. To discover the stroke-induced neurological change in paretic muscles, the wavelet coherence is firstly compared with coherence by simulated data and is utilized to represent the time-varying coupling of experimental data during elbow-tracking tasks. The simulation in this study demonstrates that the wavelet coherence is superior to coherence in the detection of short-time coupling between simulated signals. In addition, the experiment in this study is designed to explore the coupling between agonist-antagonist activations during the dynamic process. In the experiment, 10 post-stroke patients and 10 age-matched adults serving as controls were recruited and asked to perform elbow sinusoidal trajectory tracking tasks. Both the elbow angle and EMG signals of biceps and triceps were recorded simultaneously. Experimental results showed that wavelet coherence could represent the time-varying coupling between two EMG signals in the time-frequency domain, and its dynamic character was appropriate in the dynamic process to discover the functional coupling. According to the time and frequency analysis, the lower functional coupling in the post-stroke group and the obvious wavelet coherence difference between the two groups in the lower frequency range suggested a possible hypothesis mechanism that the weakening of coupling between agonist-antagonist muscles in the affected sides might in fact be stroke-induced damage in the direct corticospinal pathways.

Comparative Study on Overground Gait of Stroke Survivors With a Conventional Cane and a Haptic Cane.

The conventional cane (single cane) is widely used to promote gait ability of stroke survivors as it provides postural stability by extending the base of support. However, its use can reduce muscle activity in the user's paretic side and cause upper limb neuropathies due to the intermittent and excessive loading of the upper limb. The provision of low magnitude support and speed regulation may result in collective improvement of gait parameters such as symmetry, balance and muscle activation. In this paper, we developed a robotic Haptic Cane (HC) that is composed of a tilted structure with motorized wheels and sensors to allow continuous haptic contact with the ground while moving at a regulated speed, and carried out gait experiments to compare the HC with an Instrumented conventional Cane (IC). The results show that use of the HC involved more continuous ground support force of a comparatively lesser magnitude than the IC, and resulted in greater improvements in the swing symmetry ratio and significant improvements in the step length symmetry ratio. Percentage of Non-Paretic Activity (%NPA) of paretic muscles (vastus medialis obliquus (VMO), semitendinosus (SMT), tibialis anterior (TBA) and gastrocnemius medialis (GCM)) in swing phase was significantly improved by the use of either device at fast speed. However, the use of HC improved %NPA of paretic VMO and SMT more than the use of IC at both preferred and fast speeds. It also significantly improved %NPA of paretic GCM in stance phase. Furthermore, comfortable speed with the HC was higher than with the IC and exhibited better RMS of anteroposterior (AP) tilt. Thus, the developed device with a simple and intuitive mechanism can provide efficient assistance for overground gait of stroke patients with a high possibility of widespread use.

Therapeutic effects of mirror therapy in patients after stroke

To evaluate the effect of mirror therapy on the regression of motor disorders in the paretic arm, functional and psychological disorders, the patient's functioning and quality of life, risk factors for recurrent stroke in the early recovery period of stroke. We examined 219 patients after stroke, including 154 patients after ischemic stroke (IS) and 65 patients after hemorrhagic stroke (HS) in the early recovery period (21 days to 6 months). All patients received a standard medical rehabilitation course including medications, physical rehabilitation, and physiotherapeutic treatment. Patients were divided into four groups depending on the stroke type and the medical rehabilitation course received: two study treatment groups (post-IS and post-HS groups), which consisted of patients receiving the standard medical rehabilitation course and mirror therapy, and two comparison groups (post-IS and post-HS), in which patients received only the standard medical rehabilitation course. All patients before and after the medical rehabilitation course were evaluated for neurological disorders (NIHSS, Ashworth scale of muscle spasticity, Medical Research Council (MRC) Scale and handgrip test), functional limitations (Frenchay Arm Test, Hauser Ambulation Index, Rivermead Mobility Index, Functional Independence Measure (FIM), ICF), mental status («Visual Memory» and «10 Word Memory» methods, Schulte-Platonoff tables, Lüscher color test, Hospital Anxiety and Depression Scale (HADS), Locus of Control Recovery Questionnaire), quality of life (EQ-5D), arterial hypertension (Arterial Hypertension in Adults. Clinical Guidelines, 2020). Addition of the mirror therapy to the standard course provided additional therapeutic effects: in patients with IS, the high tone of the paretic muscles of the arm significantly decreased (by 46%); the target blood pressure was achieved in 96% of patients; severe disorders of functional independence and depression regressed; significant changes of mental functions parameters (visual memory, shifting attention); improvement of activity and participation parameters (carrying in the hands, self-care, housekeeping). In patients with HS, the muscle strength of the paretic arm significantly increased (by 35%); the target blood pressure was achieved in all patients; improvement of mental functions (motivation, shifting attention, visual memory), activity and participation parameters (objects moving and manipulation, self-care), and decreased level of depression were observed. The addition of mirror therapy to the standard of care for patients after stroke resulted in regression of neurological deficit, motor disorders in the paretic arm, improvement of emotions and motivation, mitigation of recurrent stroke risk factors, as well as significant impact on the cognitive functions and enhancement of patients' capabilities of self-care.

Insulin Resistance in Skeletal Muscle of Chronic Stroke.

A stroke can lead to reduced mobility affecting skeletal muscle mass and fatty infiltration which could lead to systemic insulin resistance, but this has not been examined and the mechanisms are currently unknown. The objective was to compare the effects of in vivo insulin on skeletal muscle glycogen synthase (GS) activity in paretic (P) and nonparetic (NP) skeletal muscle in chronic stroke, and to compare to nonstroke controls. Participants were mild to moderately disabled adults with chronic stroke (n = 30, 60 ± 8 years) and sedentary controls (n = 35, 62 ± 8 years). Insulin sensitivity (M) and bilateral GS activity were determined after an overnight fast and during a hyperinsulinemic-euglycemic clamp. Stroke subjects had lower aerobic capacity than controls, but M was not significantly different. Insulin-stimulated activities of GS (independent, total, fractional), as well as absolute differences (insulin minus basal) and the percent change (insulin minus basal, relative to basal) in GS activities, were all significantly lower in P versus NP muscle. Basal GS fractional activity was 3-fold higher, and the increase in GS fractional activity during the clamp was 2-fold higher in control versus P and NP muscle. Visceral fat and intermuscular fat were associated with lower M. The effect of in vivo insulin to increase GS fractional activity was associated with M in control and P muscle. A reduction in insulin action on GS in paretic muscle likely contributes to skeletal muscle-specific insulin resistance in chronic stroke.

Main Stages in the Development of Kinesitherapy (Lecture)

The authors present their own views on the development of therapeutic gymnastics methods for the rehabilitation of motor neurological disorders. The long and ambiguous process of physical therapy evolution from the use of passive movements to modern kinesitherapy based on the laws of neurophysiology is described. It took more than half a century for the elementary passive gymnastics,originally used in the treatment of motor neurological disorders, to become modern kinesitherapy. The gradual accumulation of clinical experience and scientific knowledge made it possible to first introduce empirically found methods of excitation of some paretic muscles into rehabilitation practice, and then supply them with methods of including individual parts of the body in the motor activity due to the forced contraction of adjacent surviving muscle groups. The Soviet physiologists had developed functional systems doctrine and the concept of voluntary movements multilevel organization based on inborn and acquired motor programs. This investigation helped to understand that the skillful use of preserved motor abilities is the key to successful reconstruction of the basic functions, as well as every day and working skills (reflexes, synkinesis, mechanical coordination and reactive forces). In this case, the process of voluntary movement development is always associated with the patient’s volitional inhibition ability. So, it possible to counton impaired functions compensation in a reduced form long before the complete mobilization of all components of the movement. In chronological order, a critical review of several well-known kinesitherapy techniques is given (sisters Kenny, G. Kabat, S. Brunnström,spouses Bobat, etc.).