Real-Time Visual Kinematic Feedback During Overground Walking Improves Gait Biomechanics in Individuals Post-Stroke

Treadmill-based gait rehabilitation protocols have shown that real-time visual biofeedback can promote learning of improved gait biomechanics, but previous feedback work has largely involved treadmill walking and not overground gait. The objective of this study was to determine the short-term response to hip extension visual biofeedback, with individuals post-stroke, during unconstrained overground walking. Individuals post-stroke typically have a decreased paretic propulsion and walking speed, but increasing hip extension angle may enable the paretic leg to better translate force anteriorly during push-off. Fourteen individuals post-stroke completed overground walking, one 6-min control bout without feedback, and three 6-min training bouts with real-time feedback. Data were recorded before and after the control bout, before and after the first training bout, and after the third training bout to assess the effects of training. Visual biofeedback consisted of a display attached to eyeglasses that showed one horizontal bar indicating the user's current hip angle and another symbolizing the target hip extension to be reached during training. On average, paretic hip extension angle (p = 0.014), trailing limb angle (p = 0.025), and propulsion (p = 0.011) were significantly higher after training. Walking speed increased but was not significantly higher after training (p = 0.089). Individuals demonstrated a greater increase in their hip extension angle (p = 0.035) and propulsion (p = 0.030) after the walking bout with feedback compared to the control bout, but changes in walking speed did not significantly differ (p = 0.583) between a control walking bout and a feedback bout. Our results show the feasibility of overground visual gait feedback and suggest that feedback regarding paretic hip extension angle enabled many individuals post-stroke to improve parameters important for their walking function.

An integrated review of music cognition and rhythmic stimuli in sensorimotor neurocognition and neurorehabilitation

This work reviews the growing body of interdisciplinary research on music cognition, using biomechanical, kinesiological, clinical, psychosocial, and sociological methods. The review primarily examines the relationship between temporal elements in music and motor responses under varying contexts, with considerable relevance for clinical rehabilitation. After providing an overview of the terminology and approaches pertinent to theories of rhythm and meter from the musical-theoretical and cognitive fields, this review focuses on studies on the effects of rhythmic sensory stimulation on gait, rhythmic cues' effect on the motor system, reactions to rhythmic stimuli attempting to synchronize mobility (i.e., musical embodiment), and the application of rhythm for motor rehabilitation for individuals with Parkinson's disease, stroke, mild cognitive impairment, Alzheimer's disease, and other neurodegenerative or neurotraumatic diseases. This work ultimately bridges the gap between the musical-theoretical and cognitive science fields to facilitate innovative research in which each discipline informs the other.

Evaluation of a carepartner-integrated telehealth gait rehabilitation program for persons with stroke: study protocol for a feasibility study

BACKGROUND

Despite family carepartners of individuals post-stroke experiencing high levels of strain and reduced quality of life, stroke rehabilitation interventions rarely address carepartner well-being or offer training to support their engagement in therapeutic activities. Our group has developed creative intervention approaches to support families during stroke recovery, thereby improving physical and psychosocial outcomes for both carepartners and stroke survivors. The purpose of this study is to test the feasibility of an adapted, home-based intervention (Carepartner Collaborative Integrative Therapy for Gait-CARE-CITE-Gait) designed to facilitate positive carepartner involvement during home-based training targeting gait and mobility.

METHODS

This two-phased design will determine the feasibility of CARE-CITE-Gait, a novel intervention that leverages principles from our previous carepartner-focused upper extremity intervention. During the 4-week CARE-CITE-Gait intervention, carepartners review online video-based modules designed to illustrate strategies for an autonomy-supportive environment during functional mobility task practice, and the study team completes two 2-h home visits for dyad collaborative goal setting. In phase I, content validity, usability, and acceptability of the CARE-CITE-Gait modules will be evaluated by stroke rehabilitation content experts and carepartners. In phase II, feasibility (based on measures of recruitment, retention, intervention adherence, and safety) will be measured. Preliminary effects of the CARE-CITE-Gait will be gathered using a single-group, quasi-experimental design with repeated measures (two baseline visits 1 week apart, posttest, and 1-month follow-up) with 15 carepartner and stroke survivor dyads. Outcome data collectors will be blinded. Outcomes include psychosocial variables (family conflict surrounding stroke recovery, strain, autonomy support, and quality of life) collected from carepartners and measures of functional mobility, gait speed, stepping activity, and health-related quality of life collected from stroke survivors.

DISCUSSION

The findings of the feasibility testing and preliminary data on the effects of CARE-CITE-Gait will provide justification and information to guide a future definitive randomized clinical trial. The knowledge gained from this study will enhance our understanding of and aid the development of rehabilitation approaches that address both carepartner and stroke survivor needs during the stroke recovery process.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT05257928. Registered 25 February 2022.

TRIAL STATUS

This trial was registered on ClinicalTrials.gov (NCT05257928) on March 25, 2022. Recruitment of participants was initiated on May 18, 2022.

The Effects of Stroke and Stroke Gait Rehabilitation on Behavioral and Neurophysiological Outcomes:: Challenges and Opportunities for Future Research

Stroke continues to be a leading cause of adult disability, contributing to immense healthcare costs. Even after discharge from rehabilitation, post-stroke individuals continue to have persistent gait impairments, which in turn adversely affect functional mobility and quality of life. Multiple factors, including biomechanics, energy cost, psychosocial variables, as well as the physiological function of corticospinal neural pathways influence stroke gait function and training-induced gait improvements. As a step toward addressing this challenge, the objective of the current perspective paper is to outline knowledge gaps pertinent to the measurement and retraining of stroke gait dysfunction. The paper also has recommendations for future research directions to address important knowledge gaps, especially related to the measurement and rehabilitation-induced modulation of biomechanical and neural processes underlying stroke gait dysfunction. We posit that there is a need for leveraging emerging technologies to develop innovative, comprehensive, methods to measure gait patterns quantitatively, to provide clinicians with objective measure of gait quality that can supplement conventional clinical outcomes of walking function. Additionally, we posit that there is a need for more research on how the stroke lesion affects multiple parts of the nervous system, and to understand the neuroplasticity correlates of gait training and gait recovery. Multi-modal clinical research studies that can combine clinical, biomechanical, neural, and computational modeling data provide promise for gaining new information about stroke gait dysfunction as well as the multitude of factors affecting recovery and treatment response in people with post-stroke hemiparesis.

Evaluation of a Carepartner-Integrated Telehealth Gait Rehabilitation Program for Persons with Stroke : Study Protocol for a Feasibility Study

Background

Despite family carepartners of individuals post-stroke experiencing high levels of strain and reduced quality of life, stroke rehabilitation interventions rarely address carepartner well-being or offer training to support their engagement in therapeutic activities. Our group has developed creative intervention approaches to support families during stroke recovery, thereby improving physical and psychosocial outcomes for both carepartners and stroke survivors. The purpose of this preliminary clinical trial is to test the feasibility of an adapted, home-based intervention (Carepartner Collaborative Integrative Therapy for Gait-CARE-CITE-Gait) designed to facilitate positive carepartner involvement during home-based training targeting gait and mobility.

Methods

This two-phased study will determine the feasibility of CARE-CITE-Gait, a novel intervention developed by our team that leverages principles from our previous carepartner-focused upper extremity intervention. During the 4-week CARE-CITE-Gait intervention, carepartners review online video-based modules designed to illustrate strategies for an autonomy-supportive environment during functional mobility task practice, and the study team completes two 2-hour (home-based) visits for dyad collaborative goal setting. In Phase I, the usability and acceptability of the CARE-CITE-Gait modules will be evaluated by stroke rehabilitation content experts and carepartners. In Phase II, feasibility (based on measures of recruitment, retention, and intervention adherence) will be measured. Preliminary effects of the CARE-CITE-Gait will be gathered using a single-group, evaluator blinded, quasi-experimental design with repeated measures (two baseline visits one week apart, post-test, and one-month follow-up) with 15 carepartner and stroke survivor dyads. Outcomes include psychosocial variables (strain, family conflict surrounding stroke recovery, autonomy support and life changes) collected from carepartners, and measures of functional mobility, gait speed, stepping activity, and health-related quality of life collected from stroke survivors.

Discussion

The findings of the feasibility testing and preliminary data on the effects of CARE-CITE-Gait will provide justification and information to guide a future definitive randomized clinical trial. The knowledge gained from this study will enhance our understanding of and aid the development of rehabilitation approaches that address both carepartner and stroke survivor needs during the stroke recovery process.

Trial Registration

ClinicalTrials.gov, NCT05257928. Registered 25 February 2022, https://clinicaltrials.gov/ct2/show/NCT05257928.

Commentary: Remote assessments of gait and balance - Implications for research during and beyond Covid-19

The COVID-19 pandemic has disrupted non-essential in-person research activities that require contact with human subjects. While guidelines are being developed for ramping up human subjects research, one component of research that can be performed remotely is participant screening for lower limb function and gait impairments. In this commentary, we summarize evidence-supported clinical assessments that have potential to be conducted remotely in a safe manner, to make an initial determination of the functional mobility status of persons with neurological disorders. We present assessments that do not require complex or costly equipment, specialized software, or trained personnel to administer. We provide recommendations to implement remote functional assessments for participant recruitment and continuation of lower limb neurorehabilitation research as a rapid response to the COVID-19 pandemic and for utilization beyond the current pandemic. We also highlight critical research gaps related to feasibility and measurement characteristics of remote lower limb assessments, providing opportunities for future research to advance tele-assessment and tele-rehabilitation.

Comparison of the effects of real-time propulsive force versus limb angle gait biofeedback on gait biomechanics

BACKGROUND

Reduced forward propulsion during gait, measured as the anterior component of the ground reaction force (AGRF), may contribute to slower walking speeds in older adults and gait dysfunction in individuals with neurological impairments. Trailing limb angle (TLA) is a clinically important gait parameter that is associated with AGRF generation. Real-time gait biofeedback can induce modifications in targeted gait parameters, with potential to modulate AGRF and TLA. However, the effects of real-time TLA biofeedback on gait biomechanics have not been studied thus far.

RESEARCH QUESTION

What are the effects of unilateral, real-time, audiovisual trailing limb angle biofeedback on gait biomechanics in able-bodied individuals?

METHODS

Ten able-bodied adults participated in one session of treadmill-based gait analyses comprising 60-second walking trials under three conditions: no biofeedback, AGRF biofeedback, and TLA biofeedback. Biofeedback was provided unilaterally to the right leg. Dependent variables included AGRF, TLA, ankle moment, and ankle power. One-way repeated measures ANOVA with post-hoc tests were conducted to determine the effect of the biofeedback conditions on gait parameters.

RESULTS

Compared to no biofeedback, both AGRF and TLA biofeedback induced significant increases in targeted leg AGRF without concomitant changes to the non-targeted leg AGRF. Targeted leg TLA was significantly larger during TLA biofeedback compared to AGRF biofeedback. Only AGRF biofeedback induced significant increases in ankle power; and only the TLA biofeedback condition induced increases in the non-targeted leg TLA.

SIGNIFICANCE

Our novel findings provide support for the feasibility and promise of TLA as a gait biofeedback target. Our study demonstrates that comparable magnitudes of feedback-induced increases in AGRF in response to AGRF and TLA biofeedback may be achieved through divergent biomechanical strategies. Further investigation is needed to uncover the effects of TLA biofeedback on gait parameters in individuals with neuro-pathologies such as spinal cord injury or stroke.

Effects of downslope walking on Soleus H-reflexes and walking function in individuals with multiple sclerosis: A preliminary study

BACKGROUND

Downslope walking (DSW) is an eccentric-based exercise intervention that promotes neuroplasticity of spinal reflex circuitry by inducing depression of Soleus Hoffman (H)-reflexes in young, neurologically unimpaired adults.

OBJECTIVE

The objective of the study was to evaluate the effects of DSW on spinal excitability (SE) and walking function (WF) in people with multiple sclerosis (PwMS).

METHODS

Our study comprised two experiments on 12 PwMS (11 women; 45.3±11.8 years). Experiment 1 evaluated acute effects of a single 20-minute session of treadmill walking at three different walking grades on SE, 0% or level walking (LW), - 7.5% DSW, and - 15% DSW. Experiment 2 evaluated the effects of 6 sessions of DSW, at - 7.5% DSW (with second session being - 15% DSW) on SE and WF.

RESULTS

Experiment 1 showed significantly greater acute % H-reflex depression following - 15% DSW compared to LW (p = 0.02) and - 7.5% DSW (p = 0.05). Experiment 2 demonstrated significant improvements in WF. PwMS who showed greater acute H-reflex depression during the - 15% DSW session also demonstrated greater physical activity, long-distance WF, and the ability to have greater H-reflex depression after DSW training. Significant changes were not observed in regards to SE.

CONCLUSIONS

Though significant changes were not observed in SE after DSW training, we observed an improvement in WF which merits further investigation of DSW in PwMS.

The Short-Term Effect of Slope Walking on Soleus H-Reflexes in People with Multiple Sclerosis

Downslope walking (DSW) causes H-reflex depression in healthy adults, and thus may hold promise for inducing spinal reflex plasticity in people with Multiple Sclerosis (PwMS). The study purpose was to test the hypothesis that DSW will cause acute depression of spinal excitability in PwMS. Soleus H-reflexes were measured in PwMS (n = 18) before and after 20 min of treadmill walking during three visits. Participants walked on a different slope each visit [level: 0% level walking (LW), upslope: +7.5% treadmill walking with an upslope (USW) or downslope: -7.5% (DSW)]. The soleus H_max/M_max ratio was used to measure spinal excitability. Heart rate and ratings of perceived exertion (RPE) were measured during walking. DSW induced the largest change in spinal excitability (a 26.7% reduction in soleus H_max/M_max (p = 0.001)), although LW also reduced H_max/M_max (-5.3%, p = 0.05). Heart rate (p < 0.001) was lowest for DSW, and RPE for DSW did not exceed "Fairly light". DSW evokes short-term spinal plasticity in PwMS, while requiring no greater effort than LW. Our results suggest that PwMS retain the capacity for DSW-induced short-term spinal reflex modulation previously found in healthy adults. These results may provide a foundation for further investigation of long-term effects of DSW on spinal reflex plasticity and functional ability in PwMS.

Abstract T P112: The Effect of Monoaminergic Drugs on Motor Cortex Excitability, Motor Performance and Psychophysics

INTRODUCTION: The benefit of pharmacologic augmentation of stroke recovery remains unclear. As post-stroke motor recovery depends on training-dependent plasticity, we wanted to test the effect of these drugs on the excitability of primary motor cortex (M1), kinematic and psychophysical measures.

METHODS: Nine able-bodied individuals (4 males) participated in 4 test sessions at least 1 week apart during which they were administered one oral dose of 4 different medications: placebo (P), amphetamine 10mg (A), methylphenidate 20mg (M), carbidopa/levodopa 25/100mg (D). We used transcranial magnetic stimulation (TMS) to measure the effects of the different drugs on M1 excitability. Motor evoked potentials (MEP) were elicited using TMS at intensities of 35-80% of maximum stimulator output. The Boltzmann function was calculated for MEP amplitudes and compared across the 4 drug conditions. The effects of the drugs on psychophysics and movement kinematics were captured by a 2d accelerometer mounted on the dorsum of the hand. We measured the reaction time and the peak acceleration and dispersion of directions of auditory paced ballistic wrist extension movements.

RESULTS: Comparison of the 4 different equations for the Boltzmann sigmoid curve where R max represents the maximum MEP amplitude; k, the slope of the curve; and S50, the intensity that produced half of the maximum MEP amplitude revealed significant differences between drug conditions. Compared to P, A led to a significant decrease in the maximum MEP amplitude (p= 0.00015), while D increased it (p=0.013). The other two parameters were similar to placebo. M had no effect on any of the three parameters. The different drugs had no statistically significant effect on the kinematic measures or reaction time.

CONCLUSIONS: These results indicate that the neuromodulatory effect of drugs on M1 excitability differs, which may point to different mechanisms mediating the beneficial effects of these drugs on functional recovery after stroke. It would also support the notion that the beneficial effect of the drugs on recovery is likely due to improved kinematics or psychophysics of executions during training.

Effects of stimulation frequency versus pulse duration modulation on muscle fatigue

During functional electrical stimulation (FES), both the frequency and intensity can be increased to increase muscle force output and counteract the effects of muscle fatigue. Most current FES systems, however, deliver a constant frequency and only vary the stimulation intensity to control muscle force. This study compared muscle performance and fatigue produced during repetitive electrical stimulation using three different strategies: (1) constant pulse-duration and stepwise increases in frequency (frequency-modulation); (2) constant frequency and stepwise increases in pulse-duration (pulse-duration-modulation); and (3) constant frequency and pulse-duration (no-modulation). Surface electrical stimulation was delivered to the quadriceps femoris muscles of 12 healthy individuals and isometric forces were recorded. Muscle performance was assessed by measuring the percent changes in the peak forces and force-time integrals between the first and the last fatiguing trains. Muscle fatigue was assessed by measuring percent declines in peak force between the 60Hz pre- and post-fatigue testing trains. The results showed that frequency-modulation showed better performance for both peak forces and force-time integrals in response to the fatiguing trains than pulse-duration-modulation, while producing similar levels of muscle fatigue. Although frequency-modulation is not commonly used during FES, clinicians should consider this strategy to improve muscle performance.

Effect of frequency and pulse duration on human muscle fatigue during repetitive electrical stimulation

Different combinations of stimulation frequency and intensity can generate a targeted force during functional electrical stimulation (FES). This study compared isometric performance and muscle fatigue during repetitive stimulation with three different combinations of frequency and pulse duration that produced the same initial peak forces: protocol 1 used long pulse duration (fixed at 600 micros) and 11.5 +/- 1.2 Hz (low frequency); protocol 2 used 30 Hz (medium frequency) and medium pulse duration (150 +/- 21 micros); and protocol 3 used 60 Hz (high frequency) and short pulse duration (131 +/- 24 micros). Twenty and 60 Hz pre- and postfatigue testing trains were delivered at the pulse duration used by the fatiguing trains and at 600 micros pulse duration. The percentage decline in peak force between the first and last fatiguing train of each protocol was the measure of muscle performance. The declines in peak force of the 60 Hz testing trains were used to measure muscle fatigue. The 20 Hz:60 Hz peak force ratio was used as a measure of low-frequency fatigue. The results showed that protocol 1 produced the least decline in peak force in response to the fatiguing trains, as well as the least muscle fatigue and low-frequency fatigue when the pulse duration was maintained at the level used by the fatiguing trains. Interestingly, protocol 2 produced the least muscle fatigue, and there were no differences in the levels of low-frequency fatigue across protocols when a comparable motor unit population was tested using 600 micros pulse duration. The results suggest that if the frequency and intensity are kept constant during FES, using the lowest frequency and longest pulse duration may maximize performance.

Catchlike property of skeletal muscle: Recent findings and clinical implications

The catchlike property of skeletal muscle is the force augmentation produced by the inclusion of an initial, brief, high-frequency burst of two to four pulses at the start of a subtetanic low-frequency stimulation train. Catchlike-inducing trains take advantage of the catchlike property of skeletal muscle and augment muscle performance compared with constant-frequency trains, especially in the fatigued state. Literature spanning more than 30 years has provided comprehensive information about the catchlike property of skeletal muscle. The pattern of the catchlike-inducing train that maximizes muscle performance is fairly similar across different muscles of different species and under various stimulation conditions. This review summarizes the mechanisms of the catchlike property, factors affecting force augmentation, techniques used to identify patterns of catchlike-inducing trains that maximize muscle performance, and potential clinical applications to provide a historical and current perspective of our understanding of the catchlike property.