Non-paretic Side Research Articles

Physical Activity, Physical Function, and Quadriceps Muscle Thickness in Male Patients with Sub-Acute Stroke during Hospitalization: A Pilot Study

Increasing physical activity (PA) is an important rehabilitation target for patients with sub-acute stroke during hospitalization in order to recover physical function and prevent stroke recurrence. However, the characteristics of low PA in stroke patients during hospitalization who were targets for increased intervention have not been reported. The purpose of this study was to investigate the relationship between the daily number of steps and physical function and quadriceps muscle thickness (QMT) in patients with sub-acute stroke during hospitalization for convalescence rehabilitation. Twenty-nine patients with ischemic or haemorrhagic stroke (mean age, 69 ± 11 years) hospitalized for inpatient convalescent rehabilitation were included. PA was measured using a three-dimensional accelerometer that calculates the daily number of steps taken. Physical function was measured by a short physical performance battery (SPPB; 0–12 points) and the leg motor selectivity score (6 motor stages defined by Brunnstrom), and the QMT of both legs was measured using ultrasonography. PA was significantly correlated with the SPPB score (r = 0.63, p = 0.0002), QMT on the paretic side (r = 0.41, p = 0.02), and QMT on non-paretic side (r = 0.56, p = 0.002). There were no significant effects of the leg motor selectivity score on daily PA (F = 1.37, p = 0.27). In the multiple regression analysis, only the SPPB score showed significant linear regression (β = 0.44, p = 0.02). PA in male patients with sub-acute stroke during hospitalization was related to physical function and QMT and not with the severity of paresis.

Quantitative analysis of structure–function relationship between ocular motility and superior oblique muscle hypoplasia in unilateral superior oblique palsy

AimsTo determine the structure–function relationship between the degree of superior oblique (SO) hypoplasia and ocular motility in unilateral SO palsy.MethodsA total of 166 patients with unilateral SO palsy were divided...

Do functional hamstring to quadriceps ratio differ between men and women with and without stroke?

ABSTRACTBackground: The functional hamstrings/quadriceps ratio (FH/Q) is useful to detect muscle imbalances after stroke. However, is necessary to investigate possible differences between men and women affected by stroke and controls.Objectives: To compare the FH/Q between men and women with stroke and matched controls.Method: Cross-sectional study. Fifty-six participants (10 men – MSTK and 18 women – WSTK with stroke; and 10 men – MCONT and 18 women – WCONT, matched controls) were recruited. The concentric knee extension (conc) and eccentric flexion exercises (ecc) were performed, and peak torque (PT) was used to calculate the FH/Q. Comparisons of PT between sexes (MSTK vs WSTK; MCONT vs WCONT) and comparisons of FH/Q between sexes and groups (MSTK vs MCONT; WSTK vs WCONT), considering dominant vs non-paretic side and non-dominant vs paretic side were performed by ANOVA and Kruskal–Wallis test, when applicable.Results: No significant FH/Q differences were found between STK vs CONT and sexes (non-paretic vs dominant). The paretic FH/Q was significantly higher than the non-dominant (CONT), for both sexes. PTconc and PTecc were significant higher for men, considering limbs comparisons. No significant PTecc an PTconc differences were found between STK vs CONT, for men’s non-paretic and paretic limb’s. However, men’s non-dominant limb presented a higher PTconc compared to men’s paretic limbs.Conclusions: Our study demonstrated that individuals affected by stroke had a higher FH/Q in the paretic limb compared to the non-dominant limb of the control group, for both men and women. One interesting finding was the absence of significant FH/Q differences between men and women with stroke.

Nature, reliability, and predictive value of muscle performance measures in patients with hemiparesis following stroke.

The purposes of this investigation were to examine among a sample of hemiparetic stroke patients the nature and reliability of selected muscle performance measures and the correlation between the measures and gait speed. Fourteen subjects who met specific entry criteria participated. The Lido Active Rehabilitation System was used to obtain bilaterally all muscle performance measures of knee extension (velocity, isometric torque-peak and time specific, and time to peak torque and 90% peak torque). Gait speed was measured under both "comfortable" and "maximum safe" conditions. In addition to lower torques, the subjects demonstrated slower knee extension speeds and longer times to peak torque and 90% peak torque on the paretic than on the nonparetic side. High intrasession reliabilities were demonstrated for all muscle performance measures except the torque at 0.1 sec on the nonparetic side and the time to peak torque and 90% peak torque measures. Significant correlations were demonstrated between both gait speeds and paretic knee extension torque (except at 0.1 sec), nonparetic knee extension torque at 0.1 sec and 0.2 sec, and time to nonparetic peak torque. Muscle performance measures other than peak torque appeared to offer little advantage (alone) over paretic peak torque for predicting gait speed. Over 74% of the variance in gait speed, however, could be predicted by the peak isometric peak torque of the paretic side and the time to peak torque on the nonparetic side, together. Thus, there may be benefits to testing the muscle performance of both lower extremities when examining patients with stroke.

Muscle force strategies for poststroke hemiparetic patients during gait

ABSTRACTBackground and Objective: Individuals who survive a stroke often display considerable gait impairments that occur in part due to inadequate muscle force production. This study aimed to investigate lower limb muscle forces in poststroke patients during walking.Methods: Kinematics, kinetics, and electromyographic (EMG) measurements were performed on nine poststroke and healthy individuals walking at natural speed in a cross-sectional study. Recorded parameters were used in an EMG-driven model to estimate the forces exerted by the muscles around the knee and ankle joints during the stance (braking and propulsion) and swing phases.Results: For hemiparetic patients, in comparison to healthy controls, the paretic side exhibited (i) lower forces generated by plantar-flexors and quadriceps respectively during the braking and propulsion phases, but (ii) higher knee-flexors forces during the propulsion phase. Regarding the non-paretic side, it displayed (i) higher forces generated by knee-flexors and quadriceps (only for the propulsion phase) forces during the stance phase, and (iii) higher plantar-flexors forces during the swing phase, in comparison to controls.Conclusion: Reduced forces exerted by the plantar-flexors and the knee-extensors along with increased force generated by the knee-flexors on the paretic side give possible explanation for hemiparetic gait abnormalities. Increased muscle forces exerted by the non-paretic side might be a compensatory strategy to better support body weight and properly adjust the center of mass forward.

Reshaping of Bilateral Gait Coordination in Hemiparetic Stroke Patients After Early Robotic Intervention

Hemiparetic gait is a common condition after stroke which alters importantly the quality of life of stroke survivors. In recent years, several robotic interventions have been developed to support and enhance rehabilitation strategies for such population. The Hybrid Assistive Limb® (HAL) robot suit is a unique device able to collect in real time bioelectric signals from the patient to support and enhance voluntary gait. HAL has been used before in early stages of stroke showing gait improvement after the intervention. However, evaluation of the coordination of gait has not been done yet. Coordination is a key factor for an adequate gait performance; consequently, its changes may be closely related to gait recovery. In this study, we used planar covariation to evaluate coordination changes in hemiparetic stroke patients after early HAL intervention. Before starting, impaired intersegmental coordination for the paretic and non-paretic side was evident. HAL intervention was able to induce recovery of the covariation loop shape and deviation from the covariation plane improving intersegmental coordination. Also, there was a tendency of recovery for movement range evidenced by comparison of peak elevation angles of each limb segment of the patients before and after HAL intervention, and also when compared to healthy volunteers. Our results suggest that early HAL intervention contributed to the improvement of gait coordination in hemiparetic stroke patients by reinforcing central pattern generators and therefore reshaping their gait pattern.Trial registration: UMIN000022410 2016/05/23.

Shear Waves Reveal Viscoelastic Changes in Skeletal Muscles After Hemispheric Stroke.

We investigated alterations in material properties such as elasticity and viscoelasticity of stroke-affected muscles using ultrasound induced shear waves and mechanical models. We used acoustic radiation force to generate shear waves along fascicles of biceps muscles and measured their propagation velocity. The shear wave data were collected in muscles of 13 hemiplegic stroke survivors under passive conditions at 90°, 120°, and 150° elbow flexion angles. In a viscoelastic medium, as opposed to a purely elastic medium, the shear wave propagation velocity depends on the frequency content of the induced wave. Therefore, in addition to the shear wave group velocity (GpV), we also estimated a frequency-dependent phase velocity (PhV). We found significantly higher GpVs and PhVs in stroke-affected muscles ( ). The velocity data were used to estimate shear elasticity and viscosity using an elastic and viscoelastic material models. A pure elastic model showed increased shear elasticity in stroke-affected muscles ( ). The Voigt model estimates of viscoelastic properties were also significantly different between the stroke-impaired and non-impaired muscles. We observed significantly larger model-estimated viscosity values on the stroke-affected side at elbow flexion angles of 120° and 150°. Furthermore, the creep behavior (tissue strain resulting from the application of sudden constant stress) of the model was also different between muscles of the paretic and non-paretic side. We speculate that these changes are associated with the structural disruption of muscles after stroke and may potentially affect force generation from muscle fibers as well as transmission of force to tendons.

Mirror therapy for improving motor function after stroke.

Mirror therapy is used to improve motor function after stroke. During mirror therapy, a mirror is placed in the person's midsagittal plane, thus reflecting movements of the non-paretic side as if it were the affected side. To summarise the effectiveness of mirror therapy compared with no treatment, placebo or sham therapy, or other treatments for improving motor function and motor impairment after stroke. We also aimed to assess the effects of mirror therapy on activities of daily living, pain, and visuospatial neglect. We searched the Cochrane Stroke Group's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, CINAHL, AMED, PsycINFO and PEDro (last searched 16 August 2017). We also handsearched relevant conference proceedings, trials and research registers, checked reference lists, and contacted trialists, researchers and experts in our field of study. We included randomised controlled trials (RCTs) and randomised cross-over trials comparing mirror therapy with any control intervention for people after stroke. Two review authors independently selected trials based on the inclusion criteria, documented the methodological quality, assessed risks of bias in the included studies, and extracted data. We assessed the quality of the evidence using the GRADE approach. We analysed the results as standardised mean differences (SMDs) or mean differences (MDs) for continuous variables, and as odds ratios (ORs) for dichotomous variables. We included 62 studies with a total of 1982 participants that compared mirror therapy with other interventions. Of these, 57 were randomised controlled trials and five randomised cross-over trials. Participants had a mean age of 59 years (30 to 73 years). Mirror therapy was provided three to seven times a week, between 15 and 60 minutes for each session for two to eight weeks (on average five times a week, 30 minutes a session for four weeks).When compared with all other interventions, we found moderate-quality evidence that mirror therapy has a significant positive effect on motor function (SMD 0.47, 95% CI 0.27 to 0.67; 1173 participants; 36 studies) and motor impairment (SMD 0.49, 95% CI 0.32 to 0.66; 1292 participants; 39 studies). However, effects on motor function are influenced by the type of control intervention. Additionally, based on moderate-quality evidence, mirror therapy may improve activities of daily living (SMD 0.48, 95% CI 0.30 to 0.65; 622 participants; 19 studies). We found low-quality evidence for a significant positive effect on pain (SMD -0.89, 95% CI -1.67 to -0.11; 248 participants; 6 studies) and no clear effect for improving visuospatial neglect (SMD 1.06, 95% CI -0.10 to 2.23; 175 participants; 5 studies). No adverse effects were reported. The results indicate evidence for the effectiveness of mirror therapy for improving upper extremity motor function, motor impairment, activities of daily living, and pain, at least as an adjunct to conventional rehabilitation for people after stroke. Major limitations are small sample sizes and lack of reporting of methodological details, resulting in uncertain evidence quality.

Study of bone mineral density in stroke survivors

Osteoporosis after stroke differs from age-related and other causes of osteoporosis. Stroke is frequently followed by extensive bone loss, precipitating the increased fracture risk in survivors. It is more evident on the paretic side and that too in the upper extremities. The present study is to assess the Bone Mineral Density (BMD) in hip, spine and wrist and to assess BMD difference between paretic and non-paretic side in ambulatory stroke survivors. The study design is Cross-sectional observational study. Forty individuals attending the OPD of Department of Physical Medicine and Rehabilitation, VMMC & Safdarjung hospital, New Delhi with the diagnosis of stroke, fulfilling inclusion criteria were enrolled. Tools of measurement used were: –BMD using dual energy X-ray absorptiometry (DEXA) by OSTEOSCORE-3 (Digital 2D Densitometer) at spine, forearm and hip; –Biochemical markers (S.Ca, Phosphorous, ALP); –X-ray of spine, bilateral hip and wrist. Our study involved total 40 subjects having 33 (82.5%) males and 7 (17.5%) females. Mean age of study group was found to be 53.9 ± 10.9 years. The T score for forearm was found to be significantly higher in non-paretic side (Mean = −4.11 ± 2.46) compared to paretic side (Mean = −4.85 ± 2.01) ( P = 0.04). The T score for hip on non-paretic side was found to be higher (Mean = −1.96 ± 1.74) compared to that of paretic side (Mean = −2.14 ± 1.57) ( P = 0.4). Fifteen (37.5%) subjects were found to be osteoporotic on DEXA scanning of spine. Most of the patients who presented after one year of stroke had low T-score at hip and forearm on paretic side in comparison to non-paretic side.

Can a novel rehabilitation robot device change the muscle synergy patterns during walking in individuals after stroke?

Rehabilitation Robots for improvement of gait dysfunction with neurological deficits have been developed to regain the adequate gait control Motor relearning with repetition of assisted motion by robotic devices is assumed to be able to make the efficient motor kinematics and kinetics However, it is not clear what changes with the motor control via motor relearning process with using robot devices occur during walking in this population In general, the nerve system was considered to control the motion using a low-dimensional modular organization of muscle activation We aimed to clarify the effect of the robots for muscle synergy control using non-negative matrix factorization. Robot Knee Ankle Foot Orthosis (RKAFO) that can control the knee motion during gait was used as robot device to assist to normalize gait kinematics In 8 participants after stroke, EMG signals from ten leg muscles on both sides were measured before and after robot assist walking for 3 minutes at self-selected speed. The number of modules on paretic side was less than that on non-paretic side Furthermore, fewer modules were needed to be account for muscle activation in walking before robot assist than after robot assist The number of fractionated synergy from before to after assisted gait related to the increase of gait speed by using RKAFO. Our results suggest the muscle synergy coordination during walking was changed with normal motion induced by using robot assist in post-stroke subjects And also, increase in number of fractionated synergy was related with higher gait function.

Gait training with a powered exoskeleton improve gait coordination in acute stroke patients

Stroke is a leading cause of acquired disability in adults Despite rehabilitation, some patients cannot achieve a functional motor recovery The Hybrid Assistive Limb (HAL) robot is an exoskeleton able to support and enhance the lower extremities performance of patients using their own bioelectrical signals We think HAL may help acute stroke patients achieve an adequate motor recovery. Eight hemiparetic patients underwent 9 sessions of HAL A motion capture system (VICON MX, 100 Hz) was used to record segmental kinematics regarding the elevation angles described for the thigh, shank and foot before the first and after the last session Data from 9 healthy volunteers was used for comparison. Reduction of the percentage of variance was observed for the paretic (par) side of patients reaching similar levels to healthy (h) volunteers (P-value: pre-par Vs post-par: 0.039, pre-par Vs h: 0.018, post-par Vs h: 0.49) Tendency of recovery for the non-paretic side also was observed but was still significantly different from healthy group after HAL ( P -value < 0.01) HAL improved significantly the planarity of coordination in hemiparetic acute stroke patients This novel intervention offers a new approach to improve motor recovery in this population.

Regulation of quasi-joint stiffness by combination of activation of ankle muscles in midstances during gait in patients with hemiparesis

BackgroundThe regulation of ankle joint stiffness by combination of activation of plantarflexor and dorsiflexor during gait has not been investigated in patients with hemiparesis. The objective of the present study was to examine the relationship between combination of activation of ankle muscles and quasi-joint stiffness (QJS) during the stance phase of gait. MethodsThe activation of the medial head of the gastrocnemius (MG), soleus, and tibialis anterior, gait parameters were collected from 19 patients with hemiparesis due to stroke and from 12 healthy controls using a three-dimensional motion analysis system. The indexes of reciprocal activation and coactivation were calculated from the ratio of plantarflexor to dorsiflexor activation and magnitude of coactivation (MC), which is computed by multiplying an index of simultaneous activation of ankle muscles by plantarflexor activation. ResultsQJS was significantly correlated with MC of MG on the paretic side, whereas it correlated with the ratio of MG (r = 0.63, p < 0.05) in healthy controls and the ratio of MG (r = 0.67, p < 0.05) and soleus (r = 0.61, p < 0.05) on the non-paretic side in midstance. Furthermore, QJS on the paretic side was lower than that on the non-paretic side and in healthy controls (p < 0.05). SignificanceOur findings support that the regulation of QJS in midstance by reciprocal activation is altered on the paretic side, whereas it may be regulated by reciprocal activation and enhanced by relatively high activity of plantarflexor on the non-paretic side and in healthy controls.

Use of whole body vibration in individuals with chronic stroke: Transmissibility and signal purity

This study examined (1) the influence of whole body vibration (WBV) frequency (20 Hz, 30 Hz, 40 Hz), amplitude (low: 0.8 mm and high: 1.5 mm) and body postures (high-squat, deep-squat, tip-toe standing) on WBV transmissibility and signal purity, and (2) the relationship between stroke motor impairment and WBV transmissibility/signal purity. Thirty-four participants with chronic stroke were tested under 18 different conditions with unique combinations of WBV frequency, amplitude, and body posture. Lower limb motor function and muscle spasticity were assessed using the Fugl-Meyer Assessment and Modified Ashworth Scale respectively. Nine tri-axial accelerometers were used to measure acceleration at the WBV platform, and the head, third lumbar vertebra, and bilateral hips, knees, and ankles. The results indicated that WBV amplitude, frequency, body postures and their interactions significantly influenced the vibration transmissibility and signal purity among people with chronic stroke. In all anatomical landmarks except the ankle, the transmissibility decreased with increased frequency, increased amplitude or increased knee flexion angle. The transmissibility was similar between the paretic and non-paretic side, except at the ankle during tip-toe standing. Less severe lower limb motor impairment was associated with greater transmissibility at the paretic ankle, knee and hip in certain WBV conditions. Leg muscle spasticity was not significantly related to WBV transmissibility. In clinical practice, WBV amplitude, frequency, body postures need to be considered regarding the therapeutic purpose. Good contact between the feet and vibration platform and symmetrical body-weight distribution pattern should be ensured.

Cognitive-motor dual-task interference modulates mediolateral dynamic stability during gait in post-stroke individuals

Gait asymmetry and dynamic balance impairments observed in post-stroke individuals increase their risk of fall. Moreover, walking while performing a cognitive task (i.e. dual-task) disturbs the control of balance in post-stroke individuals. Here we investigated the mediolateral dynamic stability in twenty-two community-dwelling participants (12 post-strokes and 10 healthy controls) while walking in single-task (normal gait) and four different dual-tasks (cognitive-motor interference). Positions of the extrapolated center of mass and mediolateral widths of both margin of stability and base of support were extracted from 35 marker trajectories. Post-stroke participants presented larger margin of stability and base of support than controls during single-task (both p < 0.01), with a larger margin of stability on the non-paretic side than on the paretic side at ipsilateral foot-strike (p < 0.05). No significant effect of the dual-task was found between groups. In post-stroke participants, dual-task induced slight modification of the mediolateral stability strategy, as the margin of stability was not different between the two limbs at foot-strike, and significantly reduced the performance in every cognitive task. Post-stroke participants increased their dynamic stability in the frontal plane in single-task by extending their base of support and mainly relying on their non-paretic limb. Under cognitive-motor interference (dual-task), post-stroke participants prioritized dynamic stability over cognitive performance to ensure a safe locomotion. Thus, rehabilitation programs should consider both dynamic balance and dual-task training, even at a chronic delay following stroke, to reduce the risk of fall in post-stroke individuals.

Bilateral changes in afterhyperpolarization duration of spinal motoneurones in post-stroke patients.

This paper extends the observations presented in the previously published work on the afterhyperpolarization (AHP) duration changes in motoneurones (MNs) on the paretic (more affected) side of 11 post-stroke patients by the same analysis on the non-paretic (less-affected) side. The estimated AHP duration for patients’ MNs supplying more-affected muscles was significantly longer than control values and the elongation decreased with patient age and disorder duration. For MNs supplying less-affected muscles, dependency of AHP duration on age was closer to the control data, but the scatter was substantially bigger. However, the AHP duration estimate of less-affected MNs tended to be longer than that of controls in the short time elapsed since the stroke, and shorter than controls in the long time. Our results thus suggest that the spinal MNs on both sides respond to the cerebral stroke rapidly with prolongation of AHP duration, which tends to normalize with time, in line with functional recovery. This suggestion is in concert with the published research on post-stroke changes in brain hemispheres. To our knowledge, these dependencies have never been investigated before. Since the number of our data was limited, the observed trends should be verified in a larger sample of patients and such a verification could take into account the suggestions for data analysis that we provide in this paper. Our data are in line with the earlier published research on MN firing characteristics post-stroke and support the conclusion that the MUs of the muscles at the non-paretic side are also affected and cannot be considered a suitable control for the MUs on the paretic side.

Do Performance Measures of Strength, Balance, and Mobility Predict Quality of Life and Community Reintegration After Stroke?

ObjectiveTo investigate the extent to which physical performance measures of strength, balance, and mobility taken at discharge from inpatient stroke rehabilitation can predict health-related quality of life (HRQoL) and community reintegration after 6 months. DesignLongitudinal study. SettingUniversity laboratory. ParticipantsAdults (N=75) recruited within 1 month of discharge home from inpatient stroke rehabilitation. InterventionsNot applicable. Main Outcome Measures36-Item Short Form Health Survey (SF-36) for HRQoL and Subjective Index of Physical and Social Outcome (SIPSO) for community reintegration. Physical performance measures were the 6-minute walk test, timed Up and Go (TUG) test, Berg Balance Scale, Community Balance and Mobility Scale, and isokinetic torque and power of hip, knee, and ankle on the paretic and nonparetic sides. Other prognostic variables included age, sex, stroke type and location, comorbidities, and motor FIM score. ResultsSeparate stepwise linear regressions were performed using the SF-36 and SIPSO as dependent variables. The total paretic lower limb torque and 6-minute walk test predicted the SF-36 Physical Component Summary (adjusted R2=.30). The total paretic lower limb torque and TUG test predicted the SIPSO physical component (adjusted R2=.47). The total paretic lower limb torque significantly predicted the SF-36 Mental Component Summary, but the adjusted R2 was low (.06). Similarly, the TUG test significantly predicted the SIPSO social component, but again the adjusted R2 was low (.09). ConclusionsMeasures of physical performance including muscle strength and mobility at discharge can partially predict HRQoL and community reintegration 6 months later. Further research is necessary for more accurate predictions.

Effect of mirror use on lower extremity muscle strength of patients with chronic stroke.

[Purpose] This study examines the effect on muscle strength of lower extremity muscle strength exercise while using a mirror on the non-paretic side in patients with chronic stroke. [Subjects and Methods] Subjects were randomly assigned to a non-mirror lower extremity exercise group (n=10), a mirror lower extremity exercise group (n=10), or a mirror lower extremity muscle strength exercise group (n=10). Subjects were asked to do the exercise assigned to their group (5 sets 30 times a day, 5 times weekly for 4 weeks) with general physical therapy in the hospital. Muscle strength in the knee extensor and flexor of paretic and non-paretic side were measured using electrical muscle testing device before and after the intervention. [Results] Muscle strength significantly increased within each group after intervention. No significant differences were found among the three groups. [Conclusion] This study showed that the lower extremity muscle strength exercise of the non-paretic side using a mirror has a positive effect on muscle strength in patient with chronic stroke.

Muscle Thickness and Echo Intensity of the Abdominal and Lower Extremity Muscles in Stroke Survivors.

Background and PurposeThis study compared the muscle thickness (MT) and echo intensity (EI) of the abdominal, thigh, and lower leg muscles between the paretic and nonparetic sides in chronic stroke survivors.MethodsThirty-two stroke survivors living in the community participated in this study. The MT and EI, which are indicators of muscle mass and intramuscular fat or connective tissue, were assessed in the rectus abdominis, external oblique, internal oblique, transversus abdominis, rectus femoris, vastus intermedius, vastus lateralis, vastus medialis, tibialis anterior, gastrocnemius, and soleus via transverse ultrasound imaging. In addition, a possible indicator of physical activity—the frequency of going out per week—was evaluated.ResultsAll quadriceps muscles and the tibialis anterior were significantly thinner and the EI values of the vastus intermedius, vastus lateralis, vastus medialis, and soleus were significantly higher in the paretic limb than the nonparetic limb. The MT and EI values of abdominal muscles did not differ significantly between the two sides. The MT values of the paretic rectus femoris, vastus lateralis, and vastus medialis were significantly associated with the frequency of going out after adjusting confounding factors. The MT of the nonparetic vastus lateralis was significantly associated with latency from stroke onset after adjusting confounding factors.ConclusionsOur results indicate that quantitative and qualitative changes on the paretic side in stroke survivors were the most robust in the thigh muscles, whereas such changes might not occur in the abdominal muscles.

Comparison of neuromuscular fatigue in chronic stroke patients with healthy controls

Background and Introduction: Fatigue has been defined as a feeling of early exhaustion, weariness, lack of energy and aversion to effort. Glader et al suggest that survivors of stroke with fatigue have a higher fatality rate three years after stroke due to its association with sedentary lifestyle. Neuromuscular fatigue is defined as an activity induced impairment in the ability to exert force, and is quantified by the reduction in force that a muscle or muscles can exert following or during an activity. Fatigue of the paretic leg muscles is likely to greatly impact walking function post-stroke. Therefore, quantitative measures of neuromuscular fatigue of the paretic leg muscles are expected to be associated with walking function in people post-stroke. There is scant research, which specifically investigates neuromuscular fatigue following stroke. The purpose of the study was to assess and compare the contribution of neuromuscular fatigue in patients following stroke with age and gender matched healthy participants. Methodology: Subjects (N=80) were divided into experimental group (N=40) and control group (N=40) by purposive sampling. Patients who were already been diagnosed with chronic stroke (>6months) by Registered Medical Practitioner (RMP) were included in the study. The muscle activity of the quadriceps and hamstrings on the subject’s paretic as well as non-paretic side were recorded using Dual Bio Amp/Stimulator. Pre- fatigue inducing exercise (Electromyography) EMG signals (integral mean values in mVs) were recorded by performing Maximal Voluntary Contraction (MVC) of both the muscles. Post-fatigue inducing exercise EMG signals (integral mean values in mVs) by performing Sit-To-Stand test (STS). Visual Analog Fatigue Scale (VAFS) was used to assess the subjective levels of fatigue pre and post exercise while Fatigue Severity Scale (FSS) was used to assess chronic fatigue. Results: In paretic, non-paretic and control study group, the mean pre-fatigue EMG activity of hamstrings is significantly higher compared to mean post-fatigue EMG activity of hamstrings (P-value<0.001). In paretic, non-paretic and control study group, the mean pre-fatigue EMG activity of quadriceps is significantly higher compared to mean post-fatigue EMG activity of quadriceps (P-value<0.001). Conclusion: It was concluded that there is a difference seen in the peripheral neuromuscular fatigue in the chronic stroke individuals when compared with age and gender matched control group.

Dynamic structure of lower limb joint angles during walking post-stroke

BackgroundVariability in joint kinematics is necessary for adaptability and response to everyday perturbations; however, intrinsic neuromotor changes secondary to stroke often cause abnormal movement patterns. How these abnormal movement patterns relate to joint kinematic variability and its influence on post-stroke walking impairments is not well understood. ObjectiveThe purpose of this study was to evaluate the movement variability at the individual joint level in the paretic and non-paretic limbs of individuals post-stroke. MethodsSeven individuals with hemiparesis post-stroke walked on a treadmill for two minutes at their self-selected speed and the average speed of the six-minute walk test while kinematics were recorded using motion-capture. Variability in hip, knee, and ankle flexion/extension angles during walking were quantified with the Lyapunov exponent (LyE). Interlimb differences were evaluated. ResultsThe paretic side LyE was higher than the non-paretic side at both self-selected speed (Hip: 50%; Knee: 74%), and the average speed of the 6-min walk test (Hip: 15%; Knee: 93%). ConclusionDifferences in joint kinematic variability between limbs of persons post-stroke supports further study of the source of non-paretic limb deviations as well as the clinical implications of joint kinematic variability in persons post-stroke. The development of bilaterally-targeted post-stroke gait interventions to address variability in both limbs may promote improved outcomes.