Intrinsic muscle strength and voluntary activation of both lower limbs and functional performance after stroke

Recovery of walking ability using a robotic device in subacute stroke patients: a randomized controlled study

PURPOSE

This study investigates the effectiveness of Lokomat + conventional therapy in recovering walking ability in non-ambulatory subacute stroke subjects involved in inpatient rehabilitation.

METHOD

Thirty first-ever stroke patients completed 8 weeks of intervention. One group (n = 16) received Lokomat therapy twice a week, combined with three times 30 min a week of conventional overground therapy. The second group (n = 14) received conventional assisted overground therapy only, during a similar amount of time (3.5 h a week). The intervention was part of the normal rehabilitation program. Primary outcome measure was walking speed. Secondary outcome measures assessed other walking- and mobility-related tests, lower-limb strength and quality of life measures. All outcome measures were assessed before and after the intervention and at wk 24 and wk 36 after start of the intervention.

RESULTS

Patients showed significant (p < 0.05) gains in walking speed, other walking- and mobility related tests, and strength of the paretic knee extensors relative to baseline at all assessments. However, there were no significant differences in improvements in any of the variables between groups at any time during the study.

CONCLUSION

These results indicate that substituting Lokomat therapy for some of conventional therapy is as effective in recovering walking ability in non-ambulatory stroke patients as conventional therapy alone. Implications for Rehabilitation Recovery of walking after stroke is important. Robot-assisted therapy is currently receiving much attention in research and rehabilitation practice as devices such as the Lokomat seem to be promising assistive devices. Technical developments, sub-optimal study designs in literature and new therapy insights warrant new effectiveness studies. RESULTS of a financially and practically feasible study indicate that substituting Lokomat therapy for some of conventional therapy is as effective in recovering walking ability in non-ambulatory stroke patients as compared to conventional overground therapy alone.

Physical fitness training for stroke patients

BACKGROUND

Levels of physical fitness are low after stroke. It is unknown whether improving physical fitness after stroke reduces disability.

OBJECTIVES

To determine whether fitness training after stroke reduces death, dependence, and disability. The secondary aims were to determine the effects of training on physical fitness, mobility, physical function, quality of life, mood, and incidence of adverse events.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (last searched January 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 12: searched January 2013), MEDLINE (1966 to January 2013), EMBASE (1980 to January 2013), CINAHL (1982 to January 2013), SPORTDiscus (1949 to January 2013), and five additional databases (January 2013). We also searched ongoing trials registers, handsearched relevant journals and conference proceedings, screened reference lists, and contacted experts in the field.

SELECTION CRITERIA

Randomised trials comparing either cardiorespiratory training or resistance training, or both, with no intervention, a non-exercise intervention, or usual care in stroke survivors.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed quality, and extracted data. We analysed data using random-effects meta-analyses. Diverse outcome measures limited the intended analyses.

MAIN RESULTS

We included 45 trials, involving 2188 participants, which comprised cardiorespiratory (22 trials, 995 participants), resistance (eight trials, 275 participants), and mixed training interventions (15 trials, 918 participants). Nine deaths occurred before the end of the intervention and a further seven at the end of follow-up. No dependence data were reported. Diverse outcome measures made data pooling difficult. Global indices of disability show a tendency to improve after cardiorespiratory training (standardised mean difference (SMD) 0.37, 95% confidence interval (CI) 0.10 to 0.64; P = 0.007); benefits at follow-up and after mixed training were unclear. There were insufficient data to assess the effects of resistance training.Cardiorespiratory training involving walking improved maximum walking speed (mean difference (MD) 7.37 metres per minute, 95% CI 3.70 to 11.03), preferred gait speed (MD 4.63 metres per minute, 95% CI 1.84 to 7.43), walking capacity (MD 26.99 metres per six minutes, 95% CI 9.13 to 44.84), and Berg Balance scores (MD 3.14, 95% CI 0.56 to 5.73) at the end of the intervention. Mixed training, involving walking, increased preferred walking speed (MD 4.54 metres per minute, 95% CI 0.95 to 8.14), walking capacity (MD 41.60 metres per six minutes, 95% CI 25.25 to 57.95), and also pooled balance scores but the evidence is weaker (SMD 0.26 95% CI 0.04 to, 0.49). Some mobility benefits also persisted at the end of follow-up. The variability and trial quality hampered the assessment of the reliability and generalisability of the observed results.

AUTHORS' CONCLUSIONS

The effects of training on death and dependence after stroke are unclear. Cardiorespiratory training reduces disability after stroke and this may be mediated by improved mobility and balance. There is sufficient evidence to incorporate cardiorespiratory and mixed training, involving walking, within post-stroke rehabilitation programs to improve the speed and tolerance of walking; improvement in balance may also occur. There is insufficient evidence to support the use of resistance training. Further well-designed trials are needed to determine the optimal content of the exercise prescription and identify long-term benefits.

Understanding compensatory strategies for muscle weakness during gait by simulating activation deficits seen post-stroke

Musculoskeletal simulations have been used to explore compensatory strategies, but have focused on responses to simulated atrophy in a single muscle or muscle group. In a population such as stroke, however, impairments are seen in muscle activation across multiple muscle groups. The objective of this study was to identify available compensatory strategies for muscle weakness during gait by simulating activation deficits in multiple muscle groups. Three dimensional dynamics simulations were created from 10 healthy subjects (48.8 ± 13.3 years, self-selected speed 1.28 ± 0.17 m/s) and constraints were set on the activation capacity of the plantar flexor, dorsiflexor, and hamstrings muscle groups to simulate activation impairme nts seen post-stroke. When the muscle groups are impaired individually, the model requires that the plantar flexor, dorsiflexor, and hamstrings muscle groups are activated to at least 55%, 64%, and 18%, respectively, to recreate the subjects' normal gait pattern. The models were unable to recreate the normal gait pattern with simultaneous impairment of all three muscle groups. Other muscle groups are unable to assist the dorsiflexor muscles during early swing, which suggests that rehabilitation or assistive devices may be required to correct foot drop. By identifying how muscles can interact, clinicians may be able to develop specific strategies for using gait retraining and orthotic assistance to best address an individual's needs.

Towards more effective robotic gait training for stroke rehabilitation: a review

Background

Stroke is the most common cause of disability in the developed world and can severely degrade walking function. Robot-driven gait therapy can provide assistance to patients during training and offers a number of advantages over other forms of therapy. These potential benefits do not, however, seem to have been fully realised as of yet in clinical practice.

Objectives

This review determines ways in which robot-driven gait technology could be improved in order to achieve better outcomes in gait rehabilitation.

Methods

The literature on gait impairments caused by stroke is reviewed, followed by research detailing the different pathways to recovery. The outcomes of clinical trials investigating robot-driven gait therapy are then examined. Finally, an analysis of the literature focused on the technical features of the robot-based devices is presented. This review thus combines both clinical and technical aspects in order to determine the routes by which robot-driven gait therapy could be further developed.

Conclusions

Active subject participation in robot-driven gait therapy is vital to many of the potential recovery pathways and is therefore an important feature of gait training. Higher levels of subject participation and challenge could be promoted through designs with a high emphasis on robotic transparency and sufficient degrees of freedom to allow other aspects of gait such as balance to be incorporated.

Differential Effects of Power Training Versus Functional Task Practice on Compensation and Restoration of Arm Function After Stroke

Background. Improved upper-extremity (UE) movement with stroke rehabilitation may involve restoration of more normal or development of compensatory movement patterns. Objective. The authors investigated the differential effects of functional task practice (FTP) and dynamic resistance training (POWER) on clinical function and reaching kinematics in an effort to distinguish between mechanisms of gains. Methods. A total of 14 hemiparetic individuals were randomly assigned to 10 weeks of either FTP or POWER and then crossed over to 10 weeks of the alternate treatment. Treatment order A was FTP followed by POWER, whereas treatment order B was POWER followed by FTP. Evaluation before and after each treatment block included a battery of clinical evaluations and kinematics of paretic UE functional reach to grasp. Results. Both FTP and POWER improved movement accuracy, as revealed by a shift toward normal, including fewer submovements and reduced reach-path ratio. However, active range of motion revealed differential treatment effects. Shoulder flexion and elbow extension decreased with FTP and were associated with increased trunk displacement. In contrast, shoulder flexion and elbow extension excursion increased with POWER and were associated with significantly reduced trunk displacement. Treatment order B (POWER followed by FTP) revealed greater overall improvements. Conclusion. FTP increases compensatory movement patterns to improve UE function. POWER leads to more normal movement patterns. POWER prior to FTP may enhance the benefits of repetitive task practice.

Stroke-related changes in neuromuscular fatigue of the hip flexors and functional implications

OBJECTIVE

The aim of this study was to compare stroke-related changes in hip flexor neuromuscular fatigue of the paretic leg during a sustained isometric submaximal contraction with those of the nonparetic leg and controls and to correlate fatigue with clinical measures of function.

DESIGN

Hip torques were measured during a fatiguing hip flexion contraction at 20% of the hip flexion maximal voluntary contraction in the paretic and nonparetic legs of 13 people with chronic stroke and 10 age-matched controls. In addition, the participants with stroke performed a fatiguing contraction of the paretic leg at the absolute torque equivalent to 20% maximal voluntary contraction of the nonparetic leg and were tested for self-selected walking speed (10-m Walk Test) and balance (Berg).

RESULTS

When matching the nonparetic target torque, the paretic hip flexors had a shorter time to task failure compared with the nonparetic leg and controls (P < 0.05). The time to failure of the paretic leg was inversely correlated with the reduction of hip flexion maximal voluntary contraction torque. Self-selected walking speed was correlated with declines in torque and steadiness. Berg-Balance scores were inversely correlated with the force fluctuation amplitude.

CONCLUSIONS

Fatigue and precision of contraction are correlated with walking function and balance after stroke.

Physical fitness training for stroke patients

BACKGROUND

Levels of physical fitness are low after stroke. It is unknown whether improving physical fitness after stroke reduces disability.

OBJECTIVES

To determine whether fitness training after stroke reduces death, dependence, and disability. The secondary aims were to determine the effects of training on physical fitness, mobility, physical function, quality of life, mood, and incidence of adverse events.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (last searched April 2010), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, July 2010), MEDLINE (1966 to March 2010), EMBASE (1980 to March 2010), CINAHL (1982 to March 2010), SPORTDiscus (1949 to March 2010), and five additional databases (March 2010). We also searched ongoing trials registers, handsearched relevant journals and conference proceedings, screened reference lists, and contacted experts in the field.

SELECTION CRITERIA

Randomised trials comparing either cardiorespiratory training or resistance training, or both, with no intervention, a non-exercise intervention, or usual care in stroke survivors.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed quality, and extracted data. We analysed data using random-effects meta-analyses. Diverse outcome measures limited the intended analyses.

MAIN RESULTS

We included 32 trials, involving 1414 participants, which comprised cardiorespiratory (14 trials, 651 participants), resistance (seven trials, 246 participants), and mixed training interventions (11 trials, 517 participants). Five deaths were reported at the end of the intervention and nine at the end of follow-up. No dependence data were reported. Diverse outcome measures made data pooling difficult. The majority of the estimates of effect were not significant. Cardiorespiratory training involving walking improved maximum walking speed (mean difference (MD) 8.66 metres per minute, 95% confidence interval (CI) 2.98 to 14.34), preferred gait speed (MD 4.68 metres per minute, 95% CI 1.40 to 7.96) and walking capacity (MD 47.13 metres per six minutes, 95% CI 19.39 to 74.88) at the end of the intervention. These training effects were retained at the end of follow-up. Mixed training, involving walking, increased preferred walking speed (MD 2.93 metres per minute, 95% CI 0.02 to 5.84) and walking capacity (MD 30.59 metres per six minutes, 95% CI 8.90 to 52.28) but effects were smaller and there was heterogeneity amongst the trial results. There were insufficient data to assess the effects of resistance training. The variability in the quality of included trials hampered the reliability and generalizability of the observed results.

AUTHORS' CONCLUSIONS

The effects of training on death, dependence, and disability after stroke are unclear. There is sufficient evidence to incorporate cardiorespiratory training involving walking within post-stroke rehabilitation programmes to improve speed, tolerance, and independence during walking. Further well-designed trials are needed to determine the optimal exercise prescription and identify long-term benefits.

Neuromuscular performance of paretic versus non-paretic plantar flexors after stroke

The objective of this study was to compare the neuromuscular function of the paretic and non-paretic plantar flexors (i.e. soleus, gastrocnemius medialis, lateralis) in chronic stroke patients. It was hypothesized that the contractile rate of force development (RFD) and neural activation, assessed by electromyogram (EMG) and V-waves normalized to the M-wave, and voluntary activation (twitch interpolation) would be reduced during plantar flexor maximum voluntary isometric contraction and that the evoked muscle twitch properties would be reduced in the paretic limb. Ten chronic stroke survivors completed the study. The main findings were that the paretic side showed deteriorated function compared to the non-paretic leg in terms of (1) RFD in all analyzed time windows from force onset to 250 ms, although relative RFD (i.e. normalized to maximum voluntary force) was similar; (2) fast neural activation (for most analyzed time windows), assessed by EMG activity in time windows from EMG onset to 250 ms; (3) V-wave responses (except for gastrocnemius medialis); (4) voluntary activation; (5) the evoked peak twitch force, although there was no evidence of intrinsic muscle slowing; (6) EMG activity obtained at maximal voluntary force. In conclusion, this study demonstrates considerable neuromuscular asymmetry of the plantar flexors in chronic stroke survivors. Effective rehabilitation regimes should be investigated.

Corticospinal tract integrity correlates with knee extensor weakness in chronic stroke survivors

OBJECTIVE

Muscle weakness develops rapidly after stroke, adversely affecting motor performance, and contributing to reduced functional ability. While the contributions of structural and functional alterations in skeletal muscle to post-stroke weakness have been well described, the relationship between motor pathway integrity, measured using both radiological and electrophysiological techniques, and post-stroke muscle weakness is not clear. This study sought to determine the role of corticospinal tract (CST) integrity on knee extensor weakness in chronic stroke survivors.

METHODS

Knee extensor strength and activation testing were performed at 90° of knee flexion using an interpolated triplet technique. CST integrity was evaluated using data obtained from Diffusion Tensor Imaging and transcranial magnetic stimulation.

RESULTS

Recordings in nine stroke subjects indicated substantial knee extensor weakness and activation deficits in the paretic legs of the stroke survivors. Regression analysis revealed that asymmetry in CST integrity was strongly related to between-leg differences in knee strength.

CONCLUSIONS

The results of this study suggest a strong link between CST integrity and lower extremity strength, and add to the growing evidence of substantial knee extensor weakness and activation impairments in stroke survivors.

SIGNIFICANCE

The findings from this study further our understanding of the anatomical and neurophysiological contributions to motor impairments after stroke, which may benefit clinicians and researchers in the field of stroke rehabilitation.

5-repetition sit-to-stand test in subjects with chronic stroke: reliability and validity

OBJECTIVES

To examine the (1) intrarater, interrater, and test-retest reliability of the 5-repetition sit-to-stand test (5-repetition STS test) scores, (2) correlation of 5-repetition STS test scores with lower-limb muscle strength and balance performance, and (3) cut-off scores among the 3 groups of subjects: the young, the healthy elderly, and subjects with stroke.

DESIGN

Cross-sectional study.

SETTING

University-based rehabilitation center.

PARTICIPANTS

A convenience sample of 36 subjects: 12 subjects with chronic stroke, 12 healthy elderly subjects, and 12 young subjects.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

5-Repetition STS test time scores; hand-held dynamometer measurements of hip flexors, and knee flexors and extensors; ankle dorsiflexors and plantarflexors muscle strength; Berg Balance Scale (BBS); and limits of stability (LOS) test using dynamic posturography.

RESULTS

Excellent intrarater reliability of intraclass correlation coefficient (ICC) (range, .970-.976), interrater reliability (ICC=.999), and test-retest reliability (ICC range, .989-.999) were found. Five-repetition STS test scores were also found to be significantly associated with the muscle strength of affected and unaffected knee flexors (rho=-.753 to -.830; P<.00556) of the subjects with stroke. No significant associations were found between 5-repetition STS test and BBS and LOS tests in subjects with stroke. Cut-off scores of 12 seconds were found to be discriminatory between healthy elderly and subjects with stroke at a sensitivity of 83% and specificity of 75%.

CONCLUSIONS

The 5-repetition STS test is a reliable measurement tool that correlates with knee flexors muscle strength but not balance ability in subjects with stroke.

Intrinsic properties of the knee extensor muscles after subacute stroke

Horstman AM, Gerrits KH, Beltman MJ, Koppe PA, Janssen, TW, de Haan A. Intrinsic properties of the knee extensor muscles after subacute stroke.

OBJECTIVE

To characterize muscle properties of paretic lower-limb (PL) and nonparetic lower-limb (NL) knee extensors in patients with subacute stroke.

DESIGN

Case-control study.

SETTING

Rehabilitation center research laboratory.

PARTICIPANTS

Patients with subacute stroke (n=14) and able-bodied age-matched control subjects (n=12).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Half relaxation times (HRTs) and maximal rates of torque development (MRTDs) were assessed as indicators of contractile speed using both voluntary and electrically evoked contractions. Moreover, changes in torque were measured during a fatigue protocol (35 electrically evoked intermittent contractions; 1.5s on, 2s off) and recovery.

RESULTS

No differences among groups were found for normalized MRTDs during electrically evoked contractions (P=.117). However, during voluntary contractions both PLs (53% of control, P=.022) and NL (71% of control, P<.001) had significantly lower MRTD compared with control. Both PL (134% of control, P=.001) and NL (123% of control, P=.032) had significantly higher HRTs than control, indicating muscle slowing in patients with subacute stroke. PLs fatigued more and faster than control (P=.011) and both PL and NL recovered slower (P<.001).

CONCLUSIONS

The changes in HRTs and fatigue suggest adaptations in muscle properties toward slower, more fatigable muscle shortly after stroke. The inability to make use of contractile speed because of impaired neural activation seems the most limiting factor during the initial phase of torque development in PL. Thus, besides strengthening, muscle endurance and speed should also be addressed during rehabilitation.

Exercise therapy and cognitive behavioural therapy to improve fatigue, daily activity performance and quality of life in postpoliomyelitis syndrome: the protocol of the FACTS-2-PPS trial

Background

Postpoliomyelitis Syndrome (PPS) is a complex of late onset neuromuscular symptoms with new or increased muscle weakness and muscle fatigability as key symptoms. Main clinical complaints are severe fatigue, deterioration in functional abilities and health related quality of life. Rehabilitation management is the mainstay of treatment. Two different therapeutic interventions may be prescribed (1) exercise therapy or (2) cognitive behavioural therapy (CBT). However, the evidence on the effectiveness of both interventions is limited. The primary aim of the FACTS-2-PPS trial is to study the efficacy of exercise therapy and CBT for reducing fatigue and improving activities and quality of life in patients with PPS. Additionally, the working mechanisms, patients' and therapists' expectations of and experiences with both interventions and cost-effectiveness will be evaluated.

Methods/Design

A multi-centre, single-blinded, randomized controlled trial will be conducted. A sample of 81 severely fatigued patients with PPS will be recruited from 3 different university hospitals and their affiliate rehabilitation centres. Patients will be randomized to one of three groups i.e. (1) exercise therapy + usual care, (2) CBT + usual care, (3) usual care. At baseline, immediately post-intervention and at 3- and 6-months follow-up, fatigue, activities, quality of life and secondary outcomes will be assessed. Costs will be based on a cost questionnaire, and statistical analyses on GEE (generalized estimated equations). Analysis will also consider mechanisms of change during therapy. A responsive evaluation will be conducted to monitor the implementation process and to investigate the perspectives of patients and therapists on both interventions.

Discussion

A major strength of the FACTS-2-PPS study is the use of a mixed methods design in which a responsive and economic evaluation runs parallel to the trial. The results of this study will generate new evidence for the rehabilitation treatment of persons with PPS.

Trial registration

Dutch Trial Register NTR1371.

Fitness and Mobility Exercise (FAME) Program for stroke

Given the potential of exercise to positively influence so many physical and psychosocial domains, the Fitness and Mobility Exercise (FAME) Program was developed to address the multiple impairments arising from the chronic health condition of stroke. We present the details of this exercise program and the evidence which has shown that the FAME Program can improve motor function (muscle strength, balance, walking), cardiovascular fitness, bone density, executive functions and memory. The FAME Program can help to improve the physical and cognitive abilities of people living with a stroke and reduce the risk of secondary complications such as falls, fractures and heart disease.

A comparison of functional electrical and magnetic stimulation for propelled cycling of paretic patients

OBJECTIVE

To compare isometric torque and cycling power, smoothness and symmetry using repetitive functional magnetic stimulation (FMS) and functional electrical stimulation (FES) in patients with paretic legs with preserved sensibility and in patients without sensibility.

DESIGN

Repeated-measures design.

SETTING

Laboratory setting.

PARTICIPANTS

Eleven subjects with complete spinal cord injury (SCI) and 29 subjects with chronic hemiparesis (16.6+/-5.5mo poststroke) volunteered.

INTERVENTIONS

Using a tricycle testbed, participants were exposed to isometric measurements and ergometric cycling experiments, performed during both 20Hz FMS and FES stimulation. Subjects with hemiparesis and with complete SCI were stimulated at maximally tolerable level and maximal intensity, respectively.

MAIN OUTCOME MEASURES

Maximal isometric pedaling torque and mean ergometric power, smoothness, and symmetry were recorded for voluntary, FES, and FMS conditions.

RESULTS

Two different patterns of the efficacy of FMS were identified. (1) Patients with complete SCI did not benefit (less torque and power was evoked with FMS than with FES, P<.003 and 10(-4) respectively). (2) Patients with hemiplegia and preserved sensibility could improve their torque output (P<.05), smoothness, and symmetry of pedaling (P<.05) with FMS more than with FES.

CONCLUSIONS

FMS is a potential alternative to surface FES of the large thigh musculature in stimulation-supported cycling of patients with partially or completely preserved sensibility.

Functional electrical stimulation assisted cycling of patients with subacute stroke: kinetic and kinematic analysis

BACKGROUND

Cycling is a safe and functionally effective exercise for patients with early post-stroke and poor balance. Such exercise is considered even more effective when functional electrical stimulation is added. Our principal aim was to determine the biomechanically quantifiable parameters of cycling that can be improved in patients with subacute hemiparesis by incorporating functional electrical stimulation. These parameters were defined as objective goals that can be achieved in clinical applications. A secondary aim was to determine whether they could be used to identify subjects who would benefit from such therapy.

METHODS

Using a tricycle testbed, we tested 39 subacute (mean 10.9 weeks post-stroke (SD 5.9)), hemiplegic subjects. During isometric measurements we recorded volitional and electrically evoked crank torques, the latter at maximal tolerable intensity. During ergometric measurements, volitional pedaling was alternated with combined pedaling (volitional supported by stimulation), performed at 30-s intervals. Power, smoothness, and symmetry of cycling were evaluated.

FINDINGS

Twenty-six percent of the subjects significantly improved the smoothness of their cycling with functional electrical stimulation. Only 8% and 10% significantly increased their power and symmetry, respectively. The improvement in smoothness significantly correlated with the capability of the individual to generate electrical torque (Spearman's rank correlation coefficient=0.66 at P=0.001).

INTERPRETATION

The smoothness of cycling was the most sensitive parameter improved by functional electrical stimulation. This improvement depended on the amount of torque evoked, and the torque achieved, in turn, correlated with the tolerated intensity of stimulation.