Lower Limb Coordination in Hemiparetic Subjects: Impact of Botulinum Toxin Injections Into Rectus Femoris

Anatomical landmarks for ultrasound-guided rectus femoris diagnostic nerve block in post-stroke spasticity

Introduction/Purpose

To determine the location of the rectus femoris (RF) motor branch nerve, as well as its coordinates with reference to anatomical and ultrasound landmarks.

Methods

Thirty chronic stroke patients with stiff knee gait (SKG) and RF hyperactivity were included. The motor nerve branch to the RF muscle was identified medially to the vertical line from anterior superior iliac spine and the midpoint of the superior margin of the patella (line AP) and vertically to the horizontal line from the femoral pulse and its intersection point with the line AP (line F). The point of the motor branch (M) was located with ultrasound, and nerve depth and subcutaneous tissue thickness (ST) were calculated.

Results

The coordinates of the motor branch to the RF were 2.82 (0.47) cm medially to the line AP and 4.61 (0.83) cm vertically to the line F. Nerve depth and subcutaneous tissue thickness were 2.71 (0.62) cm and 1.12 (0.75) cm, respectively.

Conclusion

The use of specific coordinates may increase clinicians' confidence when performing RF motor nerve block. This could lead to better decision-making when assessing SKG in chronic stroke patients.

The Effect of Botulinum Toxin Type A Injection in the Rectus Femoris in Stroke Patients Walking With a Stiff Knee Gait: A Randomized Controlled Trial

BACKGROUND

Over activity of the rectus femoris is often cited as a main cause for stiff knee gait (SKG). Botulinum toxin (BoNT) can be used to reduce this over activity. Inconsistent results for the effect of BoNT injections were found in literature which can possibly be explained by the study design as these were uncontrolled or non-randomized studies.

OBJECTIVE

To conduct a randomized controlled trial (RCT) to investigate the effect of botulinum toxin type A (BoNT-A) injections in the rectus femoris on gait kinematics and functional outcome in adult stroke patients.

METHODS

Twenty-six participants were included in this triple-blind cross-over RCT. The intervention consisted of an injection with BoNT-A. Placebo is an injection with saline. Besides knee and hip kinematics, functional outcomes were measured.

RESULTS

Comparison of the effect of BoNT-A injection to placebo injection showed a significant increase in peak knee flexion and knee range of motion of 6.7° and 4.8° respectively. There was no difference in hip kinematics. In functional outcomes, only the 6 Minute Walking Test showed a significant increase of 18.3 m.

CONCLUSIONS

BoNT-A injections in the rectus femoris is a valuable treatment option for stroke patients walking with a SKG to improve knee kinematics. To study the effect on functional outcome more research is necessary with different functional outcome measures that can capture the effect in kinematics. It is important to use kinematic measurements to demonstrate effects in quality of movement that are not captured by commonly used functional outcome measurements post stroke.Clinical Trial Registration: https://trialsearch.who.int/Trial2.aspx?TrialID=NTR2169.

Does higher knee hyperextension in patients with hemiplegia affect lateral and medial meniscus volume in the paretic leg? A cross-sectional study

BACKGROUND

After stroke, an abnormal gait pattern gradually leads to knee pain and joint lesions, resulting the gait instability. However, the correlation between the knee hyperextension and gait pattern, the meniscus volume, and the water content of meniscus in paretic and non-paretic legs has not been fully investigated. Moreover, most of physicians tend to ignore this knee hyperextension. This study attempted to emphasize the importance of knee hyperextension using gait analysis and Magnetic resonance imaging (Trial registration number ChiCTR2000039641, date of registration 04/11/2020).

METHODS

Eight patients with chronic hemiplegic (6 male, 2 female) volunteered to participate in this study. Participants was recruited if they had a hemiplegia following a stroke occurring more than 6 months, had an ability to walk 10 m without aids, had a Function Ambulation Category level at least 3 and above, and had a hemiplegic lower extremity identified as Brunnstrom state III or above identification. The spatial-temporal gait parameters and kinematic parameters in the paretic and the non-paretic legs and the percentage of free water content in deep and shallow layers.

RESULTS

Longer time since hemiplegia led to larger angles of knee hyperextension (R = 0.56, p = 0.016), larger angles of knee hyperextension led to more tears in meniscus (R =  - 0.53, - 0,57 and - 0.70), and larger angles of knee hyperextension decreased water content of the lateral meniscus in the non-paretic leg (R =  - 0.91) but increased water content of the medial meniscus (R = 0.53 and 0.63).

CONCLUSIONS

The knee hyperextension could not be ignored by physicians and needed to be diagnosed and treated as early as possible, the time since hemiplegia could be an indicator of sign of knee hyperextension.

The effectiveness of botulinum toxin on spasticity and gait of hemiplegic patients after stroke: A systematic review and meta-analysis

The aim of the study is to evaluate the evidence supporting the efficacy of botulinum toxin type A (BTA) injections in lower limb of hemiplegic patients, after stroke or cerebrovascular accident, and their gait analysis. This study included: randomized controlled trials (RCTs), non-randomized or controlled clinical trials (CCTs) or cluster trials, clinical trials of various phases (I-III), interrupted time series (ITS) studies with at least three data points before and after the intervention, controlled before and after (CBA) studies, prospective and retrospective comparative cohort studies, case-control and multicentred studies. The patients included in these studies had similar characteristics: age over 18 years, history of stroke and following hemiplegia, minimum modified Ashworth scale (MAS) score of 2 and duration since stroke over 6 months. The number of studies included in this review was 21. A meta-analysis was performed on a fraction of them depending on the reported index and the methodology as reported in detail in the results section. MAS score, following BTA injections, was significantly improved (Hedges' g: -1.17; 95% CI: -1.66, 0.67; p < 0.001). The same applied for the 10 Meter Walk Test (MWT) (-0.35; 95% CI: -0.68, -0.02; p = 0.016). The gait velocity showed improvement, yet without statistical significance (0.27; 95% CI: -0.09, 0.63; p = 0.285). We concluded that botulinum toxin injections showed effectiveness on lower limb hypertonia reduction of hemiplegic patients after stroke. Apart from significantly reducing the MAS scores, 10 MWT was also improved. However, more research is required in order to determine the advancement in specific gait and posture parameters.

Investigating Inducible Muscle Overactivity in Acquired Brain Injury and the Impact of Botulinum Toxin A

OBJECTIVE

To investigate the pattern of change in muscle overactivity during repetitive grasp/release using dynamic computerized dynamometry (DCD; objective 1) and the effect of botulinum toxin A (BTX-A; objective 2).

DESIGN

Secondary analysis of an observational cohort study.

SETTING

Hospital outpatient spasticity management service.

PARTICIPANTS

A convenience sample (N=65), comprising adults with upper motor neuron syndrome affecting the arm after acquired brain injury (ABI; n=38) and participants without ABI (n=27).

INTERVENTIONS

After clinical assessment, a subgroup of participants with ABI (n=28) underwent BTX-A injections as part of their spasticity management.

MAIN OUTCOME MEASURES

Post hoc DCD data processing extracted the values of minimum force generation between 10 sequential contractions. The pattern of change was analyzed.

RESULTS

The ABI injected group exerted greater force at baseline than both other groups (ABI injected=1.04 kg, ABI noninjected=0.74 kg, participants without ABI=0.53 kg; P=.011). After the first contraction, minimum force values increased for all groups and were greatest in the ABI injected group. With subsequent cycles, the group without ABI showed a linear pattern of decreasing force generation, whereas both ABI groups showed a quadratic increasing pattern, which was of greater magnitude in the ABI injected group. After injection, values for the ABI injected group showed a 51% reduction in inducible muscle overactivity (P=.003) to magnitudes similar to those of the ABI noninjected group.

CONCLUSIONS

This study showed that hand relaxation deteriorated during repetitive movements in people with spasticity, a feature hypothesized to adversely influence everyday hand function. After BTX-A injection, the magnitude but not the pattern of this inducible muscle overactivity improved.

Rectus Femoris Characteristics in Post Stroke Spasticity: Clinical Implications from Ultrasonographic Evaluation

In stroke survivors, rectus femoris (RF) spasticity is often implicated in gait pattern alterations such as stiff knee gait (SKG). Botulinum toxin type A (BoNT-A) is considered the gold standard for focal spasticity treatment. However—even if the accuracy of injection is crucial for BoNT-A efficacy—instrumented guidance for BoNT-A injection is not routinely applied in clinical settings. In order to investigate the possible implications of an inadequate BoNT-A injection on patients’ clinical outcome, we evaluated the ultrasound-derived RF characteristics (muscle depth, muscle thickness, cross-sectional area and mean echo intensity) in 47 stroke survivors. In our sample, we observed wide variability of RF depth in both hemiparetic and unaffected side of included patients (0.44 and 3.54 cm and between 0.25 and 3.16 cm, respectively). Moreover, our analysis did not show significant differences between treated and non-treated RF in stroke survivors. These results suggest that considering the inter-individual variability in RF muscle depth and thickness, injection guidance should be considered for BoNT-A treatment in order to optimize the clinical outcome of treated patients. In particular, ultrasound guidance may help the clinicians in the long-term follow-up of muscle quality.

Gait kinematics and physical function that most affect intralimb coordination in patients with stroke

BACKGROUND

Disturbed lower limb coordination is thought to limit gait ability in patients with stroke. However, the relationship of lower limb coordination with gait kinematics and physical function has not yet been clarified.

OBJECTIVE

The purpose of the study was to clarify the gait kinematic and physical function variables that most affect intralimb coordination by using the continuous relative phase (CRP) between the thigh and shank.

METHODS

Fifteen participants with stroke were enrolled in this study. Kinematic and kinetic measurements were recorded during gait at preferred speeds. CRP was defined as the difference between the thigh and shank phase angles.

RESULTS

Stepwise analysis revealed that non-paretic CRP during the propulsive phase was a determinant of gait speed. The paretic knee extension and flexion angles were determinants of the CRP during the propulsive phase in the non-paretic limb. Stepwise analysis showed that the paretic knee extension angle was a determinant of the CRP during the propulsive phase in the paretic limb. Stepwise analysis revealed that the paretic knee extensor muscle strength was a determinant of the CRP during the propulsive phase in both limbs.

CONCLUSIONS

Our study indicates that improvement in knee movement during the stance phase may improve coordination.

Botulinum Toxin Type A for the Treatment of Lower Limb Spasticity after Stroke

Post-stroke lower limb spasticity impairs balance and gait leading to reduced walking speed, often increasing wheelchair use and caregiver burden. Several studies have shown that appropriate treatments for lower limb spasticity after stroke include injections of botulinum toxin type A (BoNT-A), phenol or alcohol, surgical correction and a rehabilitation program. In the present article, we review the safety and effectiveness of BoNT-A for the treatment of lower limb spasticity after stroke, with a focus on higher doses of BoNT-A. The cumulative body of evidence coming from the randomized clinical trials and open-label studies selected in the article suggest BoNT-A to be safe and efficacious in reducing lower limb spasticity after stroke. Studies of high doses of BoNT-A also showed a greater reduction of severe post-stroke spasticity. In stroke survivors with spasticity of the ankle plantar-flexor muscles, a combined approach between surgery and BoNT-A can be indicated. However, controversy remains about improvement in motor function relative to post-stroke spasticity reduction after BoNT-A treatment.

Motion analysis for the evaluation of muscle overactivity: A point of view

Muscle overactivity is a general term for pathological increases in muscle activity such as spasticity. It is caused by damage to the central nervous system at the cortical, subcortical or spinal levels, leading to an upper motor neuron syndrome. In routine clinical practice, muscle overactivity, which induces abnormal muscle tone, is usually evaluated by using the Modified Ashworth Scale or the Tardieu Scale. However, both of these scales involve testing in passive conditions that do not always reflect muscle activity during dynamic tasks such as gait or reaching. To determine appropriate treatment strategies, muscle overactivity should be evaluated by using objective measures in dynamic conditions. Instrumental motion analysis systems that include 3-D motion analysis and electromyography are very useful for this purpose. The method can be used to identify patterns of abnormal muscle activity that can be related to abnormal kinematic patterns. It allows for objective and accurate assessment of the effects of treatments to reduce muscle overactivity on the movement to be improved. The aim of this point-of-view article is to describe the utility of instrumental motion analysis and to outline both its numerous advantages in evaluating muscle overactivity and to present the current limitations for its use (e.g., cost, the need for an engineer, errors relating to marker placement and cross talk between electromyography sensors).

Botulinum toxin A injection in the management of shoulder muscle overactivity: A scoping review

The majority of studies examining botulinum toxin A (BTX-A) in the management of upper limb muscle overactivity and pain focus on the distal arm and hand. Research has begun to look at BTX-A efficacy in more proximal upper limb muscles, with literature showing equivocal findings. This scoping review identified 15 studies meeting inclusion criteria whose data were examined against three outcome variables: muscle overactivity, range of movement and pain. Overall, while the majority of injected participants improved on these variables, between-study methodological variability such as research design potentially underpowered studies and arbitrary decision making gave a high likelihood of influencing the interpretation of their results. Future research is warranted, with a robust focus on functional anatomy, a critical appraisal of how BTX-A may help the individual being studied and utilising individualised rather than protocol-driven research paradigms.

Beyond speed: Gait changes after botulinum toxin injections in chronic stroke survivors (a systematic review)

BACKGROUND

The mechanisms by which spasticity reductions after botulinum toxin A (BoNT) affect gait in stroke are not well understood. We systematically reviewed the effects of BoNT on spatiotemporal, kinematic, kinetic and electromyographic (EMG) measures during gait.

QUESTION

What are the effects of botulinum toxin on gait mechanics in stroke patients?

METHODS

Systematic search using PubMed and Web of Science. We considered all studies that reported laboratory-based and instrumented gait measures as primary or secondary outcomes to determine the effects of BoNT on walking performance in stroke populations only. Selected studies were classified and analysed based on the injection sites.

RESULTS

A total of 240 articles were identified of which 22 were selected for analysis. Overall, 91% of the studies reported spatiotemporal, 64% kinematics, 23% kinetics, 32% EMG and 23% other gait measures. All but one study found significant effects of BoNT on gait measures using instrumented assessments even when clinical measures (i.e. speed) did not significantly improve. However, the majority of the studies had a high risk of bias. Overall, BoNT improved: a) dorsiflexion during stance, propulsive forces and timing and activity of more proximal musculature with injections in the plantarflexors; b) hip, knee and ankle angles and velocities, coordination and energetic cost with injections in the rectus femoris; c) segmental coordination and energetic cost when several lower limb muscles were injected; and, d) elbow and trunk angles when upper limb muscles were injected.

CONCLUSION

Instrumented and laboratory measures of gait improve after BoNT injections in different muscle groups even in the absence of clinical changes.

Effect of botulinum toxin injection on length and force of the rectus femoris and triceps surae muscles during locomotion in patients with chronic hemiparesis (FOLOTOX)

Background

After stroke, spasticity of the rectus femoris (RF) and triceps surae (TS) muscles frequently alters the gait pattern. Knee flexion and ankle dorsiflexion in swing are often reduced, respectively called Stiff Knee Gait (SKG) and equinus. A preliminary uncontrolled study suggested that botulinum toxin type A (BTX-A) injections could improve muscle length and force generated during gait, improving inter-segmental coordination.

The aim of this randomised controlled study is thus to evaluate changes in the length of the RF and TS muscles during gait 1 month after either BTX-A or placebo injection in patients with chronic stroke, SKG and spastic equinus. The secondary aims are to evaluate peak length and peak force generated during gait, as well inter-segmental coordination assessed using the continuous relative phase method initially described by Barela et al. in patients with stroke.

Methods

This is a prospective, three-centre, randomised, placebo-controlled, triple blind study over 3 months with 4 visits. Forty patients will be included. During visits V1, V3 and V4, length and force generated by RF and TS during gait will be assessed using musculoskeletal models (MSM). Muscle force will also be assessed using an isokinetic dynamometer. Inter segmental coordination will be evaluated using 3D gait analysis and functional tests will be performed. During V2, patients will receive either an injection of BTX-A in the RF and TS muscles or a placebo injection of saline solution.

Discussion

We expect an increase in peak length and a decrease in peak force generated by the RF and TS muscles in the BTX-A group 1 month post injection. Moreover, we expect these parameters to be more improved in the BTX-A than the Control group. This is the first study to assess these parameters in a randomised, controlled trial using instrumented methods (isokinetic evaluation and 3D gait analysis). The results should help to improve understanding of the mechanism(s) underlying improvements in inter-segmental coordination that have been found in many previous uncontrolled studies.

Trial registration

ClinicalTrials.gov: NCT01821573, First received: March 27, 2013 Last updated: September 14, 2016 Last verified: September 2016 Other Study ID Numbers: P110136 AOM11223.

Comparative effects of robotic-assisted gait training combined with conventional physical therapy on paretic hip joint stiffness and kinematics between subacute and chronic hemiparetic stroke

BACKGROUND

Robotic-assisted gait training (RAGT) has been proposed as a novel, promising intervention paradigm to improve gait function in subacute or chronic stroke neurorehabilitation. However, the benefits of RAGT combined with conventional physical therapy for gait recovery in patients with subacute and chronic hemiparetic stroke remain unclear.

OBJECTIVES

The aim of the present study was to compare the effect of RAGT combine with conventional physical therapy on hip joint kinetics, kinematics, and clinical function characteristics between subacute and chronic hemiparetic stroke.

METHODS

Seventeen patients with hemiparetic stroke (nine subacute and eight chronic patients) performed progressive RAGT (session 1, 40 min) combined with conventional physical therapy (session 1, 40 min) 5 days per week, for an average of 86 sessions over 8 weeks. The clinical outcomes included the Functional Ambulation Category (FAC), modified Rankin scale (mRS), Korean version of the modified Barthel index (K-MBI), and modified Ashworth scale, in addition to hip joint kinetics and kinematics before and after intervention.

RESULTS

The mean change in active torque, resistive torque, and stiffness in the paretic hip joint did not differ significantly between the two groups. However, Cohen's effect size suggested a moderate difference between the groups in the hip flexion phase (d = 0.58, d = 0.70, and d = 0.70). The mean change in maximal hip flexion kinematics in the chronic group was significantly greater than that in the subacute group (p = 0.04, d = -0.70). The mean change in the clinical function test results between the groups was not statistically significant. However, both groups showed significantly improved FAC, mRS, and K-MBI scores.

CONCLUSIONS

RAGT combine with conventional physical therapy may be useful when selecting therapeutic interventions to improve the active torque, resistive torque, and stiffness in the paretic hip flexion phase in patients with chronic hemiparetic stroke who reached a plateau in the maximum locomotor recovery after conventional locomotor training.

Biomechanical gait characteristics of naturally occurring unsuccessful foot clearance during swing in individuals with chronic stroke

BACKGROUND

Altered gait mechanics are common following stroke and may increase the risk of falls. Paretic gait impairments have been previously compared to the non-paretic limb or control participants. Unfortunately, the biomechanical parameters underlying instances of naturally occurring unsuccessful foot clearance (trips) have yet to be examined in individuals with chronic stroke.

METHODS

Gait data from 26 participants with chronic stroke were obtained on a dual-belt instrumented treadmill. Instances of successful and unsuccessful foot swing were identified. Temporal, kinematic, and kinetic measures of the paretic limb occurring during late stance, toe-off, and swing were compared between trip and non-trip steps using paired samples t-tests. An α = 0.004 was used to adjust for multiple comparisons.

FINDINGS

In the paretic limb, the ankle angle at toe off (P = 0.003; d = 0.64), knee flexion velocity at toe off (P < 0.001; d = 0.73), and peak knee extension moment during terminal stance (P < 0.001; d = 0.74) were significantly different between trips and non-trip steps. During trip steps, ankle plantarflexion at toe-off was 1.0° greater, knee flexion velocity was reduced by 17.6°/sec, and peak knee extension moment was increased by 0.011 Nm/kg · m compared to non-trip steps.

INTERPRETATION

It appears to take only minor changes in the movement of the paretic limb to result in a trip in individuals with chronic stroke. Although small, the multi-joint biomechanical changes occurring in the paretic limb during unsuccessful foot clearance result in a functionally longer limb. Thus, interventions targeting multiple joints in the paretic limb may be needed to reduce the risk of trips following stroke.

Intersegmental coordination scales with gait speed similarly in men and women

We applied principal component analysis (PCA) to thigh, shank, and foot elevation angles to examine the impact of speed on intra-limb coordination during gait. The specific aims were to (1) determine speed-related changes in segment loadings on three principal components (PCs) and (2) examine differences between men and women. The subjects (26 women, 21 men) walked overground at five self-selected paces (very slow, slow, normal, fast, very fast). PCA yielded percent variation (PV) explained by each PC and thigh, shank, and foot loadings on PC1-PC3. These parameters were regressed against the speed normalized to body height (BH/s) to derive individual and aggregate slopes and P values, separately for men and women. PV1 increased with speed, whereas PV2 and PV3 decreased (all P < 0.001). The loadings of thigh and foot segments on PC1 increased with speed (0.14 and 0.04 per BH/s, P < 0.001, respectively), and the loading of shank decreased (-0.10, P < 0.001). Compared to PC1, the changes in segment loadings on PC3 were the opposite (thigh -0.18, shank 0.09, foot -0.04 per BH/s, P < 0.001). The changes in segment loadings on PC2 were inconsistent and generally small. The only significance (P = 0.006), albeit a minor difference between men and women, was in the slope of thigh loading on PC2 (-0.005 ± 0.019 and 0.015 ± 0.026 per BH/s, respectively). We conclude that intersegmental coordination during gait scales with speed, with the greatest impact on the thigh segment, but no differently between men and women.

Relationship between hip flexion and ankle dorsiflexion during swing phase in chronic stroke patients

BACKGROUND

During the clinical examination of stroke patients, it is common to observe that involuntary hip flexion occurs during voluntary ankle dorsiflexion (synkinesia). This suggests that there is a relationship between these two joints. We hypothesized that there may be a relationship between hip and ankle flexion during swing phase of the gait cycle. The objective of this study was to determine if there is a biomechanical relationship between peak hip flexion and peak ankle dorsiflexion during the swing phase of the gait cycle following stroke.

METHOD

The paretic lower limbs of 60 patients with stroke were evaluated using clinical tests and 3D-gait analysis. The clinical assessment included muscle strength, spasticity and passive range of ankle motion. The gait analysis focused on sagittal frontal and transverse kinematic gait parameters during swing.

FINDINGS

A stepwise-linear-regression indicated that peak hip flexion and gait speed were the only 2 parameters which accounted for peak ankle dorsiflexion. There was also a significant negative correlation between peak hip flexion and peak ankle dorsiflexion during swing, and a significant positive correlation between hip flexor and ankle dorsiflexor muscle strength.

INTERPRETATION

These results suggest that the biomechanical behaviour of hip and ankle joints during the swing phase of the gait cycle is linked in patients with stroke. They also suggest that two strategies exist: if sufficient ankle dorsiflexion is present, less hip flexion is required (distal-strategy) whereas if dorsiflexion is reduced, it is compensated for by an increase in peak hip flexion (proximal-strategy).

Energy cost of obstacle crossing in stroke patients

OBJECTIVE

The purpose of this study was to analyze the effects of clearing and skirting obstacles during the gait on the energetic cost of walking (ECW) of patients with chronic hemiplegia. The hypothesis was that hemiplegia would have a greatest increase in the ECW than in the healthy group.

DESIGN

Fifteen healthy subjects and 17 patients with chronic hemiplegia completed two 6-min walking sessions: one with obstacles and the other without obstacles. During both sessions, the patients were equipped with a portable gas analyzer to measure oxygen uptake (V˙o2). Gait velocity and ECW were calculated.

RESULTS

In both groups, gait velocity was lower in the with-obstacles condition and the ECW was significantly higher. V˙o2 was greater in the with-obstacles condition for the healthy group, whereas it remained unchanged for the group with hemiplegia.

CONCLUSIONS

Results demonstrated that the addition of obstacles during gait increased the ECW and decreased mean walking speed in both the healthy subjects and the patients with hemiplegia. More interestingly, the authors found differences in adaptation strategies between the healthy subjects and the patients with hemiplegia. During the with-obstacles condition, the oxygen uptakes of the healthy subjects increased and mean walking speed decreased, whereas, in the subjects with hemiplegia, only mean walking speed decreased.

Effect of Intrathecal Baclofen Bolus Injection on Ankle Muscle Activation During Gait in Patients With Acquired Brain Injury

Background. Intrathecal baclofen (ITB) bolus injection effectively decreases spinal excitability but the impact on lower limb muscle activation during gait has not been thoroughly investigated. Objective. Examine activation of medial gastrocnemius (MG) and tibialis anterior (TA) muscles during gait before and after ITB bolus injection in patients with resting hypertonia after acquired brain injury. Methods. Lower extremity Ashworth score, temporospatial gait parameters, characteristics of the linear relationship between electromyogram (EMG) and lengthening velocity (LV) in MG during stance, and the duration and magnitude of TA-MG coactivation were assessed before and at 2, 4, and 6 hours after a 50-µg ITB injection via lumbar puncture in 8 hemorrhagic stroke and 11 traumatic brain injury subjects. Results. Temporospatial gait parameters did not significantly differ across the evaluation points ( P ≥ .170). However, Ashworth score ( P < .001), frequency and gain of significant positive EMG-LV slope ( P ≤ .020), and duration of TA-MG coactivation ( P ≤ .013) significantly decreased in the more-affected leg after ITB bolus. EMG changes were not significantly different between patients who did (n = 10) and did not (n = 9) increase gait speed after the injection. The timing of the largest decrease in Ashworth score and the largest decrease in EMG parameters coincided in 36% of cases, on average. Conclusions. ITB bolus injection alters the activation of MG and TA during gait. However, the changes in muscle activation are not closely related to the changes in gait speed or resting muscle hypertonia. The analysis of ankle muscle activation during gait better characterizes the response to ITB bolus injection than gait kinematics.

Effects of quadriceps muscle fatigue on stiff-knee gait in patients with hemiparesis

The relationship between neuromuscular fatigue and locomotion has never been investigated in hemiparetic patients despite the fact that, in the clinical context, patients report to be more spastic or stiffer after walking a long distance or after a rehabilitation session. The aim of this study was to evaluate the effects of quadriceps muscle fatigue on the biomechanical gait parameters of patients with a stiff-knee gait (SKG). Thirteen patients and eleven healthy controls performed one gait analysis before a protocol of isokinetic quadriceps fatigue and two after (immediately after and after 10 minutes of rest). Spatiotemporal parameters, sagittal knee and hip kinematics, rectus femoris (RF) and vastus lateralis (VL) kinematics and electromyographic (EMG) activity were analyzed. The results showed that quadriceps muscle weakness, produced by repetitive concentric contractions of the knee extensors, induced an improvement of spatiotemporal parameters for patients and healthy subjects. For the patient group, the increase in gait velocity and step length was associated with i) an increase of sagittal hip and knee flexion during the swing phase, ii) an increase of the maximal normalized length of the RF and VL and of the maximal VL lengthening velocity during the pre-swing and swing phases, and iii) a decrease in EMG activity of the RF muscle during the initial pre-swing phase and during the latter 2/3 of the initial swing phase. These results suggest that quadriceps fatigue did not alter the gait of patients with hemiparesis walking with a SKG and that neuromuscular fatigue may play the same functional role as an anti-spastic treatment such as botulinum toxin-A injection. Strength training of knee extensors, although commonly performed in rehabilitation, does not seem to be a priority to improve gait of these patients.

Effect of a robotic restraint gait training versus robotic conventional gait training on gait parameters in stroke patients

Kinematic and kinetic gait parameters have never been assessed following robotic-assisted gait training in hemiparetic patients. Previous studies suggest that restraint of the non-paretic lower limb during gait training could be a useful rehabilitation approach for hemiparetic patients. The aim of this study is to compare a new Lokomat(®) asymmetrical restraint paradigm (with a negative kinematic constraint on the non-paretic limb and a positive kinematic constraint on the paretic limb) with a conventional symmetrical Lokomat(®) training in hemiparetic subjects. We hypothesized that hip and knee kinematics on paretic side would be more improved after the asymmetrical Lokomat(®) training than after the conventional training. In a prospective observational controlled study, 26 hemiparetic subjects were randomized to one of the two groups Lokomat(®) experimental gait training (LE) or Lokomat(®) conventional gait training (LC). They were assessed using 3D gait analysis before, immediately after the 20 min of gait training and following a 20-min rest period. There was a greater increase in peak knee flexion on the paretic side following LE than LC (p = 0.04), and each type of training induced different changes in vertical GRF during single-support phase on the paretic side. Several other spatiotemporal, kinematic and kinetic gait parameters were similarly improved after both types of training. Lokomat(®) restrained gait training with a negative kinematic constraint on the non-paretic limb and a positive kinematic constraint on the paretic limb appears to be an effective approach to specifically improve knee flexion in the paretic lower limb in hemiparetic patients. This study also highlights spatiotemporal, kinematic and kinetic improvements after Lokomat(®) training, in hemiparetic subjects, rarely investigated before.

Variations in kinematics during clinical gait analysis in stroke patients

In addition to changes in spatio-temporal and kinematic parameters, patients with stroke exhibit fear of falling as well as fatigability during gait. These changes could compromise interpretation of data from gait analysis. The aim of this study was to determine if the gait of hemiplegic patients changes significantly over successive gait trials. Forty two stroke patients and twenty healthy subjects performed 9 gait trials during a gait analysis session. The mean and variability of spatio-temporal and kinematic joint parameters were analyzed during 3 groups of consecutive gait trials (1-3, 4-6 and 7-9). Principal component analysis was used to reduce the number of variables from the joint kinematic waveforms and to identify the parts of the gait cycle which changed during the gait analysis session. The results showed that i) spontaneous gait velocity and the other spatio-temporal parameters significantly increased, and ii) gait variability decreased, over the last 6 gait trials compared to the first 3, for hemiplegic patients but not healthy subjects. Principal component analysis revealed changes in the sagittal waveforms of the hip, knee and ankle for hemiplegic patients after the first 3 gait trials. These results suggest that at the beginning of the gait analysis session, stroke patients exhibited phase of adaptation,characterized by a "cautious gait" but no fatigue was observed.

Spatio-temporal parameters and intralimb coordination patterns describing hemiparetic locomotion at controlled speed

Background

Comparison between healthy and hemiparetic gait is usually carried out while subjects walk overground at preferred speed. This generates bias due to the lack of uniformity across selected speeds because they reflect the great variability of the functional level of post-stroke patients. This study aimed at examining coordinative adaptations during walking in response to unilateral brain damage, while homologous participants walked at two fixed speeds.

Methods

Five patients with left and five with right chronic hemiparesis, characterized by similar level of motor functioning, were enrolled. Ten non-disabled volunteers were recruited as matched control group. Spatio-temporal parameters, and intralimb thigh-leg and leg-foot coordination patterns were used to compare groups while walking on a treadmill at 0.4 and 0.6 m/s. The likelihood of Continuous Relative Phase patterns between healthy and hemiparetic subjects was evaluated by means of the root mean square of the difference and the cross correlation coefficient. The effects of the group (i.e., healthy vs. hemiparetics), side (i.e., affected vs.unaffected), and speed (e.g., slow vs. fast) were analyzed on all metrics using the Analysis of Variance.

Results

Spatio-temporal parameters of all hemiparetic subjects did not significantly differ from those of healthy subjects nor showed any asymmetry between affected and unaffected limbs. Conversely, both thigh-leg and foot-leg coordination patterns appeared to account for pathology related modifications.

Conclusion

Comparisons between hemiparetic and healthy gait should be carried out when all participants are asked to seek the same suitable dynamic equilibrium led by the same external (i.e., the speed) and internal (i.e., severity of the pathology) conditions. In this respect, biomechanical adaptations reflecting the pathology can be better highlighted by coordinative patterns of coupled segments within each limb than by the spatio-temporal parameters. Accordingly, a deep analysis of the intralimb coordination may be helpful for clinicians while designing therapeutic treatments.

Effect of botulinum toxin injection on length and lengthening velocity of rectus femoris during gait in hemiparetic patients

BACKGROUND

In hemiparetic patients, rectus femoris spasticity is one of the main causes of reduced knee flexion in swing phase, known as stiff knee gait. Botulinum toxin is often used to reduce rectus femoris spasticity and to increase knee flexion during swing phase. However, the mechanisms behind these improvements remain poorly understood. The aim of this study was (1) to quantify maximal rectus femoris length and lengthening velocity during gait in ten adult hemiparetic subjects with rectus femoris spasticity and stiff knee gait and to compare these parameters with those of ten healthy subjects and (2) to study the effect of botulinum toxin injection in the rectus femoris muscle on the same parameters.

METHODS

10 patients with stiff knee gait and rectus femoris spasticity underwent 3D gait analysis before and one month after botulinum toxin injection of the rectus femoris (200 U Botox, Allergan Inc., Markham, Ontario, CANADA). Rectus femoris length and lengthening velocity were quantified using a musculoskeletal model (SIMM, MusculoGraphics, Inc., Santa Rosa, California, USA).

FINDINGS

Maximal length and lengthening velocity of the rectus femoris were significantly reduced on the paretic side. There was a significant increase in muscle length as well as lengthening velocity during gait following botulinum toxin injection.

INTERPRETATION

This study showed that botulinum toxin injection in the spastic rectus femoris of hemiparetic patients improves muscle kinematics during gait. However maximal rectus femoris length did not reach normal values following injection, suggesting that other mechanisms are likely involved.

Effects of a knee-ankle-foot orthosis on gait biomechanical characteristics of paretic and non-paretic limbs in hemiplegic patients with genu recurvatum

BACKGROUND

A knee-ankle-foot orthosis may be prescribed for the prevention of genu recurvatum during the stance phase of gait. It allows also to limit abnormal plantarflexion during swing phase. The aim is to improve gait in hemiplegic patients and to prevent articular degeneration of the knee. However, the effects of knee-ankle-foot orthosis on both the paretic and non-paretic limbs during gait have not been evaluated. The aim of this study was to quantify biomechanical adaptations induced by wearing a knee-ankle-foot orthosis, on the paretic and non-paretic limbs of hemiplegic patients during gait.

METHODS

Eleven hemiplegic patients with genu recurvatum performed two gait analyses (without and with the knee-ankle-foot orthosis). Spatio-temporal, kinematic and kinetic gait parameters of both lower limbs were quantified using an instrumented gait analysis system during the stance and swing phases of the gait cycle.

FINDINGS

The knee-ankle-foot orthosis improved spatio-temporal gait parameters. During stance phase on the paretic side, knee hyperextension was reduced and ankle plantarflexion and hip flexion were increased. During swing phase, ankle dorsiflexion increased in the paretic limb and knee extension increased in the non-paretic limb. The paretic limb knee flexion moment also decreased.

INTERPRETATION

Wearing a knee-ankle-foot orthosis improved gait parameters in hemiplegic patients with genu recurvatum. It increased gait velocity, by improving cadence, stride length and non-paretic step length. These spatiotemporal adaptations seem mainly due to the decrease in knee hyperextension during stance phase and to the increase in paretic limb ankle dorsiflexion during both phases of the gait cycle.

The promise of mHealth: daily activity monitoring and outcome assessments by wearable sensors

Mobile health tools that enable clinicians and researchers to monitor the type, quantity, and quality of everyday activities of patients and trial participants have long been needed to improve daily care, design more clinically meaningful randomized trials of interventions, and establish cost-effective, evidence-based practices. Inexpensive, unobtrusive wireless sensors, including accelerometers, gyroscopes, and pressure-sensitive textiles, combined with Internet-based communications and machine-learning algorithms trained to recognize upper- and lower-extremity movements, have begun to fulfill this need. Continuous data from ankle triaxial accelerometers, for example, can be transmitted from the home and community via WiFi or a smartphone to a remote data analysis server. Reports can include the walking speed and duration of every bout of ambulation, spatiotemporal symmetries between the legs, and the type, duration, and energy used during exercise. For daily care, this readily accessible flow of real-world information allows clinicians to monitor the amount and quality of exercise for risk factor management and compliance in the practice of skills. Feedback may motivate better self-management as well as serve home-based rehabilitation efforts. Monitoring patients with chronic diseases and after hospitalization or the start of new medications for a decline in daily activity may help detect medical complications before rehospitalization becomes necessary. For clinical trials, repeated laboratory-quality assessments of key activities in the community, rather than by clinic testing, self-report, and ordinal scales, may reduce the cost and burden of travel, improve recruitment and retention, and capture more reliable, valid, and responsive ratio-scaled outcome measures that are not mere surrogates for changes in daily impairment, disability, and functioning.

Walking velocity and lower limb coordination in hemiparesis

BACKGROUND/OBJECTIVE

Gait training at fast speed has been suggested as an efficient rehabilitation method in hemiparesis. We investigated whether maximal speed walking might positively impact inter-segmental coordination in hemiparetic subjects.

METHODS

We measured thigh-shank and shank-foot coordination in the sagittal plane during gait at preferred (P) and maximal (M) speed using the continuous relative phase (CRP), in 20 healthy and 27 hemiparetic subjects. We calculated the root-mean square (CRP(RMS)) and its variability (CRP(SD)) over each phase of the gait cycle. A small CRP(RMS) indicates in-phasing, i.e. high level of synchronization between two segments along the gait cycle. A small CRP(SD) indicates high stability of the inter-segmental coordination across gait cycles.

RESULTS

Increase from preferred to maximal speed was 57% in healthy and 49% in hemiparetic subjects (difference NS). In healthy subjects, the main change was shank-foot in-phasing at stance (CRP(Shank-Foot/RMS), P, 98±10; M, 67±12, p<0.001). In hemiparetic subjects, we also found shank-foot in-phasing at late stance bilaterally (non-paretic CRP(Shank-Foot/RMS), P, 37±9; M, 29±8, p<0.001; paretic CRP(Shank-Foot/RMS), P, 38±13; M, 32±12, p<0.001), and thigh-shank in-phasing at mid-stance in the non-paretic limb (CRP(Thigh-Shank/RMS), P, 57±9; M, 49±9, p<0.001). CRP(Thigh-Shank) variability diminished in the paretic limb (CRP(Thigh-Shank/SD), P, 18.3±6.3; M, 16.1±5.2, p<0.001).

CONCLUSION

During gait velocity increase in hemiparesis, there is improvement of thigh-shank coordination stability in the paretic limb and of shank-foot synchronization at late stance bilaterally, which optimizes the propulsive phase similarly to healthy subjects. These findings may add incentive for rehabilitation clinicians to explore maximal velocity gait training in hemiparesis.

Botulinum Toxin Effect on Voluntary and Stretch Reflex–Related Torque Produced by the Quadriceps

Background. An understanding of the mechanical effects of botulinum toxin type A (BoNT A) on spastic and voluntary muscle contraction may help predict functional responders. Objective. To compare the effect of BoNT A on the voluntary and stretch reflex–related torques produced by activation of the rectus femoris (RF). Methods. This was a prospective open study where 15 incomplete spinal cord injury patients, impaired by a stiff-knee gait, with RF hyperactivity in mid-swing quantified by formal gait analysis (GA), were assessed before and after RF BoNT A injection (Botox, 200 UI). Main outcome measures included isokinetic peak torque (and angle at peak torque) at 0° (supine) and 90° (seated) during passive stretch (10 deg/s, 90 deg/s, and 150 deg/s), and voluntary contraction (60 deg/s) of the quadriceps. Secondary measures included impairment by Modified Tardieu Scale (MTS), peak knee flexion and spatial-temporal data by GA, activity (6-minute walking test, timed stair climbing), and discomfort (Verbal Rating Scale). Results. Voluntary torque decreased (−16%; P = .0004) but with only a trend toward a decrease in stretch reflex–related torque. The angle at spastic torque increased at 90 deg/s (+5°; P = .03), whereas MTS, peak knee flexion (+4°; P = .01), spatial-temporal data, timed stair climbing test (25%; P = .02), and discomfort were significantly improved. Conclusion. BoNT A appeared to delay the stretch-reflex angle at peak torque, whereas the voluntary torque decreased. After strict patient selection, BoNT A injection into the RF muscle led to improvements in impairment, activity, and discomfort.

Lower limb coordination patterns in hemiparetic gait: factors of knee flexion impairment

BACKGROUND

The mechanisms altering knee flexion in hemiparetic gait may be neurological (muscle overactivity) or orthopedic (soft tissue contracture) in nature, a distinction which is difficult to ascertain clinically during gait. This study aimed to distinguish the 2 mechanisms in evaluating thigh-shank coordination, which may show instability across the gait cycle in the case of bursting rectus femoris overactivity.

METHODS

We measured thigh-shank coordination in the sagittal plane using the continuous relative phase during gait in 15 healthy subjects without and with an orthotic knee constraint (control and constrained) and 14 subjects with hemiparesis and rectus femoris overactivity before (pre) and after botulinum toxin injection.

FINDINGS

Compared with the control group, both orthopedic and neurological knee flexion limitations were associated with decreased root-mean square of continuous relative phase over swing (control, 72.9; constrained, 26.0, P<0.001; pre, 31.3, P<0.001). However, only the neurological limitation was characterized by a higher number of continuous relative phase reversals over swing (control, 2.3; pre, 4.0; P=0.001) and late stance (control, 0.6; pre, 1.7; P<0.001). Botulinum toxin injection was associated with a 40% increase in root-mean square of continuous relative phase during swing and a 41% decrease in number of continuous relative phase reversals during late stance, while peak knee flexion was increased by 31%.

INTERPRETATION

In hemiparesis, rectus femoris overactivity at swing phase is associated with alternating thigh-shank coordination in swing and late stance, which improves after botulinum toxin injection. Coordination analysis may help to distinguish neurological from orthopedic factors in knee flexion impairment.