Gait Asymmetry in Community-Ambulating Stroke Survivors

Buyang Huanwu decoction improves motor function by enhancing internal capsule reorganization through inhibiting Notch signaling after ischemic stroke

ETHNOPHARMACOLOGICAL RELEVANCE

Buyang Huanwu Decoction (BHD) is a common traditional Chinese medicine formula that has been used for the treating post-stroke disability for centuries. Nevertheless, the impact of BHD on internal capsule injury following stroke remains unknown and warrants further investigation.

AIM OF THE STUDY

This study aimed to assess the efficacy of BHD on post-stroke internal capsule integrity by using an in vivo magnetic resonance imaging (MRI) technique and further explore the potential mechanisms by which BHD facilitates internal capsule reorganization after ischemic stroke.

MATERIALS AND METHODS

Male Sprague-Dawley rats were subjected to permanent occlusion of the middle cerebral artery (MCAO) to induce focal cerebral ischemia. BHD was intragastrically administered at doses of 16.6 g/kg and 8.3 g/kg to rats once daily for 30 consecutive days. Subsequently, an automated Digi gait system was utilized to assess the motor function. MRI examinations, including T2 relaxometry mapping and diffusion tensor imaging (DTI), were conducted to detect structural alterations in the internal capsule. Moreover, diffusion tractography was performed to evaluate internal capsule remodeling. Pearson correlation analysis was conducted between the gait and MRI parameters. Additionally, luxol fast blue (LFB) staining was performed for pathological assessment of the internal capsule. Double immunofluorescence staining was carried out to evaluate remyelination and Notch signaling activation in the injured internal capsule.

RESULTS

The gait analysis revealed that BHD treatment significantly decreased stance time while elevating swing time, stride length, and paw area of the MCAO rats. T2 mapping indicated obvious infarction and an elevated T2 value, and DTI detected reduced fractional anisotropy but increased radial diffusivity in the internal capsule following MCAO. LFB staining further confirmed demyelination in the injured internal capsule. However, BHD interventions effectively reversed these MRI abnormalities and demyelination, and improved fiber density and length of the internal capsule. Notably, the gait performances were strongly correlated to the T2 value, fiber density, and fiber length of the internal capsule. Particularly, BHD treatments facilitated oligodendrogenesis in the internal capsule by elevating the numbers of Ki67/NG2, Ki67/Oligo2, and Ki67/CNPase positive cells. Furthermore, BHD effectively inhibited the activation of Notch signaling in the oligodendrocyte precursor cells (OPCs), as evidenced by reduced numbers of NG2/Notch1, NG2/NICD, and NG2/Hes5 positive cells.

CONCLUSION

The present study demonstrated that BHD could promote post-stroke motor recovery by alleviating structural damage to the internal capsule and facilitating internal capsule reorganization. Notably, BHD treatment enhanced oligodendrogenesis and subsequent remyelination by inhibiting Notch signaling activation in the OPCs.

The Relation Between Hemiparetic Gait Patterns and Walking Function After Stroke, as Measured with Wearable Sensors

PURPOSE

After stroke, walking is characterized by hemiparetic patterns, quantified with force sensitive walkways and motion capture systems. Some joint-level kinematic patterns of walking also can be obtained with wearable sensors. The purpose of this project was to measure joint-level kinematic patterns during walking with wearable sensors and determine the association with walking speed and endurance in individuals with chronic stroke.

METHODS

In this cross-sectional observational study, participants donned APDM Opal wearable sensors during walking tests (10-meter walk test or 6-min walk test). We extracted joint-level kinematic variables of elevation at midswing, circumduction, foot strike angle, and toe-off angle. Associations of each variable with walking speed and endurance were tested, and significantly associated variables were entered into a regression model.

RESULTS

68 individuals with chronic stroke were included. We found that the less affected foot strike angle, less affected toe-off angle, and more affected toe-off angle were significant predictors of walking speed (R2 ≥ 0.71, p < 0.001). Less affected toe-off angle, more affected foot strike angle, and more affected toe-off angle were significant predictors of walking endurance (R2 ≥ 0.67, p < 0.001).

CONCLUSION

We found consistent evidence that greater toe-off angle (may reflect greater push-off) and lesser foot strike angle (may reflect lesser foot drop) were important predictors of greater walking speed and endurance. Our results suggest that wearable sensors can provide important information about joint-level kinematic patterns that are important for walking function. This information could help therapists target interventions toward specific deficits or compensatory patterns to improve walking.

Age and self-selected walking speed impact the generalization of locomotor memories across contexts

Previous work has shown that compared with young adults, older adults generalize their walking patterns more across environments that impose different motor demands (i.e., split-belt treadmill vs. overground). However, in this previous study, all participants walked at a speed that was more comfortable for older adults than young participants, which leads to the question of whether young adults would generalize more their walking patterns than older adults when exposed to faster speeds that are more comfortable for them. To address this question, we examined the interaction between healthy aging and walking speed on the generalization of a pattern learned on a split-belt treadmill (i.e., legs moving at different speeds) to overground. We hypothesized that walking speed during split-belt walking regulates the generalization of walking patterns in an age-specific manner. To this end, groups of young (<30 yr old) and older (65+ yr old) adults adapted their gait on a split-belt treadmill at either slower or faster walking speeds. We assessed the generalization of movements between the groups by quantifying their aftereffects during overground walking, where larger overground aftereffects represent more generalization, and zero aftereffects represent no generalization. We found an interaction between age and walking speed in the generalization of walking patterns. More specifically, older adults generalized more when adapted at slower speeds, whereas younger adults did so when adapted at faster speeds. These results suggest that comfortable walking speeds lead to more generalization of newly acquired motor patterns beyond the training contexts.NEW & NOTEWORTHY The generalization of motor learning in humans depends on both internal factors, such as age, and external factors imposed by experimenters, like treadmill speeds. However, the interaction between these factors remains unclear. Our study revealed that older adults showed increased generalization when adapting to slower speeds, whereas younger adults exhibited this behavior at faster speeds. This implies that walking at unusual speeds acts as a contextual cue, restricting the generalization of motor patterns.

Discrepant Spatiotemporal Characteristics of Gait Impairments in Thalamic Infarction Patients

BACKGROUND AND OBJECTIVES

Thalamic infarction (TI) can lead to gait disturbances (GDs), even in the absence of significant motor impairments. Understanding the characteristics of GDs in TI patients is crucial for developing targeted rehabilitation strategies. Nonetheless, very little is known about the detailed gait changes in TI patients. This study aimed to investigate and characterize these parameters in TI patients.

METHODS

Ninety participants, including 45 subacute TI patients and 45 age-sex-matched healthy controls, were cross-sectionally and consecutively included from West China Hospital, Sichuan University. A detailed set of spatiotemporal gait analyses was performed with forty-one parameters as output, evaluated using the "ReadyGo" three-dimensional motion balance testing system. Additionally, we analyzed the correlation between cerebral small vessel disease (CSVD) and gait parameters in TI and healthy controls (HC) and performed a Fisher z-test to determine whether there was a significant difference.

RESULTS

Variability, stride length, stride speed, and swing velocity significantly differed in the affected and unaffected sides of TI patients. TI patients exhibited differences in thirty-eight gait parameters compared to controls. Coordination analysis revealed impairments in the timed up and go test, with longer total time, turn time, stand-up time, and reduced stride speed. Additionally, deficits were noted in the Heel-Knee-Shin test and Finger-Nose test. However, no differences were found in Romberg's test. Balance assessment showed variations in sit time, torso rocking degree, torso forward roll degree, and walking speed. The correlation between gait parameters and CSVD in TI and HC is presented. Additionally, it was found that total burden leads to a decrease in step width in TI patients and increases trunk sway degree in the tandem stance test in TI.

CONCLUSION

This study demonstrates distinct spatiotemporal gait impairment patterns, coordination, and balance deficits in TI patients. Additionally, our findings suggest that the mechanisms underlying GDs may differ between TI patients and HC in relation to CSVD. These findings emphasize the need for personalized rehabilitation strategies to target these specific GDs in TI patients.

The effect of transcranial direct current stimulation combined with task-specific training on spatio-temporal gait parameters and functional mobility in individuals with stroke: a systematic review and meta-analysis

INTRODUCTION

Transcranial direct current stimulation (tDCS) has a priming effect on post- stroke motor rehabilitation.

OBJECTIVE

We verified whether tDCS combined with task-specific training was superior to nonintervention, task-specific training, or simulated intervention in improving spatio-temporal gait parameters and functional mobility in stroke patients.

METHODS

We searched MEDLINE, EMBASE, CINAHL, Scopus, Cochrane Central, Web of Science, and LILACS for articles published until May 2024, using terms related to stroke, tDCS, and task-specific training. The risk of bias was assessed using the PEDro scale. The Grading of Recommendations, Assessment, Development, and Evaluation methodology was used to classify the certainty of the evidence for each outcome. Meta-analysis was performed using a random-effects model.

RESULTS

A total of 1,685 studies were identified, of which 18 were included in the qualitative analysis. Seven studies were included in the meta-analysis; all outcomes were classified as "very low quality." Improvements in walking speed only were associated with tDCS combined with task-specific training (mean difference [MD], 0.06; 95% confidence interval [CI]: 0.04, 0.07; p < 0.001; I  = 0%). There were no differences in other spatio-temporal gait parameters or functional mobility.

CONCLUSION

This systematic review provides low-quality evidence that tDCS, in combination with task-specific training, increases speed in individuals after stroke. Both interventions, tDCS and task-specific training, are inexpensive and easy to implement; therefore, the mean estimate may be considered clinically worthwhile, although the CIs spans both clinically trivial and worthwhile effects.

REGISTRATION

International Prospective Register of Systematic Reviews (PROSPERO; number CRD42023396021).

Evidence of sensory error threshold in triggering locomotor adaptations in humans

Changing body biomechanics or external conditions trigger neural adaptations to optimize motor behavior. While the adaptations appear to be constantly minimizing movement errors, not all errors necessarily initiate sensorimotor adaptations. The locomotor control system may resist changes since exploratory modifications can lead to critical failures in walking. Theoretically, this implies the presence of an error threshold to trigger the adaptation mechanism. Here, kinematic and kinetic asymmetries were imposed as conditions on stepping using a passive orthosis (kinematic asymmetry) and real-time feedback about limb loading (kinetic asymmetry) to vary sensorimotor error during locomotion on a treadmill. Healthy participants adapted to asymmetric conditions while walking on a tied-belt treadmill. The asymmetry in leading and trailing double stance captured the presence of aftereffects, and consequently adaptation, in two conditions: i) only kinematic constraints, or ii) kinematic and kinetic constraints. We tested the hypothesis that the presence of adaptation depends on the magnitude of locomotor asymmetry. Kinematic asymmetry alone did not induce persistent locomotor adaptation; however, the addition of asymmetric interlimb loading triggered the expected adaptation. This result suggests that uninjured locomotor systems can cope with a range of kinematic asymmetries without initiating persistent adaptations, and that loading may be a key variable for triggering the adaptation. The error threshold within the adaptation mechanism may mitigate possible disruption of locomotion when adaptation is not necessary. These insights elucidate the mechanism of neural plasticity and have implications for rehabilitation.

A wearable ankle-assisted robot for improving gait function and pattern in stroke patients

BACKGROUND

Hemiplegic gait after a stroke can result in a decreased gait speed and asymmetrical gait pattern. Normal gait patterns and speed are typically the ultimate goals of gait function in stroke rehabilitation. The purpose of this study was to investigate the immediate effects of the Gait Enhancing and Motivating System-Ankle (GEMS-A) on gait function and pattern in stroke patients with hemiplegia.

METHODS

A total of 45 eligible participants was recruited for the study. The experimental protocol consisted of overground gait at a comfortable speed under 2 conditions: free gait (FG) without robot assistance and robot-assisted gait (RAG). All measurement data were collected using a 3D motion capture system with 8 infrared cameras and 2 force plates.

RESULTS

Patients in the RAG condition had significantly increased gait speed, cadence, gait symmetry, and peak flexion angle and moment of the paretic ankle joint compared to the FG condition. Moreover, the RAG resulted in higher propulsive forces by altering peak ankle force generation compared with the FG.

CONCLUSION

The findings of this study provide evidence that a newly developed wearable ankle-assist robot, the GEMS-A, is a potentially useful walking assist device for improving gait function and pattern in stroke patients with hemiplegia.

TRIAL REGISTRATION

NCT03767205 (first registration date: 02/12/2018, URL: https://register.

CLINICALTRIALS

gov ).

Understanding the implication of task conditions on asymmetry in gait of post-stroke individuals using an Integrated Wearable System

Hemiplegic individuals often demonstrate gait abnormality causing asymmetry in lower-limb muscle activation-related (implicit) and gait-related (explicit) measures (offering complementary information on one's gait) while walking. Added to hemiplegia, such asymmetry can be aggravated while walking under varying task conditions, namely, walking without speaking (single task), walking while counting backwards (dual task), and walking while holding an object and counting backwards (multiple task). This emphasizes the need to quantify the extent of aggravated implication of multiple-task and dual-task on gait asymmetry compared to single task. Here, we used Integrated Wearable System and carried out a study with a group of age-matched hemiplegic (Grp_S) and healthy (Grp_H) individuals to understand the potential of our system in quantifying asymmetry in explicit and implicit measures of gait, implication of hemiplegic condition and varying task conditions on these asymmetry measures along with their clinical relevance. Results showed the potential of our system in quantifying asymmetry in both explicit and implicit measures of gait, and these measures were statistically higher (p-value < 0.05) in Grp_S than Grp_H irrespective of the task conditions. Also, for Grp_S, these asymmetry measures became more pronounced as task demand increased, and again, these measures have shown a correlation with their risk of fall specifically during more attention-demanding tasks that could be clinically relevant.

Mapping Trajectories of Gait Recovery in Clinical Stroke Rehabilitation

BackgroundHow gait changes during the early stages of stoke rehabilitation, and which patient characteristics are associated with these changes is still largely unknown.Objectivehe first objective was to describe the changes in gait during stroke rehabilitation. Secondly, we determined how various patient characteristics were associated with the rate of change of gait over time.MethodsParticipants were measured every 3 weeks during stroke rehabilitation. The assessment consisted of an inertial measurement unit (IMU) based 2-minute walk test (2MWT), 3 IMU-based balance tests, and standard clinical tests. In the 2MWT, participants were equipped with 3 IMUs, from which speed, variability, asymmetry, and smoothness were calculated. The changes in gait were examined from admission to discharge at an individual level. The effect of patient characteristics on the rate of change of the gait features over time was assessed with growth models.ResultsA total of 81 Trajectories from 72 participants were analyzed. On an individual basis, speed increased in 32 trajectories. Only a few trajectories exhibited significant changes in variability, asymmetry, and smoothness over the clinical rehabilitation period. The growth models revealed a significant increase in speed and decrease in variability and smoothness. Only the Berg Balance Scale and gait speed at onset were (negatively) associated with the rates of change of speed and smoothness, respectively.ConclusionWe found a substantial variability in the gait-feature outcomes and their progression in individuals after stroke during clinical rehabilitation. The patient characteristics studied had limited associations with the rate of change of gait features over time.

Flexible exoskeleton-assisted training enhances lower limb motor function after stroke: a systematic review and meta-analysis

BACKGROUND

Recent advances in flexible exoskeleton technology have broadened its application in stroke rehabilitation, particularly for improving motor functions in the affected lower limb. This review examines the impact of flexible exoskeleton-assisted training (FEAT) compared to conventional therapy on balance, motor functions, and gait parameters in post-stroke patients.

METHODS

We conducted a meta-analysis using data from randomized controlled trials (RCTs) identified through database searches and manual screening, focusing on outcomes such as balance (Berg Balance Scale, BBS), lower limb motor functions (Ten-Meter Walk Test, 10MWT; Six-Minute Walk Test, 6MWT; Functional Ambulation Category, FAC), and gait parameters (walking speed, step length, cadence, and symmetry).

RESULTS

This meta-analysis included 6 studies with 213 patients. FEAT significantly enhanced BBS scores, and performances on the 10MWT and 6MWT, along with other gait parameters; however, FAC scores did not improve significantly. Subgroup analyses revealed that FEAT with hip assistance significantly improved step length, cadence, and gait symmetry ratio, while ankle assistance improved performance on the 10MWT and 6MWT. FEAT was especially effective in improving step length, cadence, and gait symmetry ratio in patients with a post-stroke duration exceeding three months.

CONCLUSION

Compared to the conventional therapy, FEAT markedly improves the balance, walking ability, and gait parameters in stroke rehabilitation. These findings support the value of FEAT in lower extremity rehabilitation post-stroke, suggesting its integration into clinical programs could enhance the therapy effectiveness or efficiency. In addition, the appropriate type of FEAT needs to be selected in the rehabilitation program based on the patient's specific impairment. For example, FEAT with hip assistance may be recommended for stroke patients with severe gait asymmetry, aiding the development of personalized interventions.

Buyang Huanwu decoction promotes gray and white matter remyelination by inhibiting Notch signaling activation in the astrocyte and microglia after ischemic stroke

ETHNOPHARMACOLOGICAL RELEVANCE

Ischemic stroke causes damages to both gray and white matter, resulting in long-term motor impairments. Myelin repair is a promising strategy for poststroke motor rehabilitation. Buyang Huanwu Decoction (BHD) is a classical traditional Chinese medicine formula for managing the sequelae of ischemic stroke. Whether BHD benefits gray and white matter remyelination following stroke remains to be elucidated.

AIM OF THE STUDY

The present study aimed to investigate the effects of BHD on the gray and white matter remyelination following ischemic stroke and further explore the underlying mechanisms by combining magnetic resonance imaging (MRI) and histological experiments.

MATERIALS AND METHODS

The ischemic stroke model was established in male Sprague-Dawley rats by permanently occluding the middle cerebral artery (MCAO). BHD (16.6 g/kg and 8.3 g/kg) was intragastrically administered to rats for 30 days. The motor function was assessed by an automated Digi gait system. The structural integrity of the motor cortex and external capsule was monitored by MRI, including T2 mapping and diffusion tensor imaging (DTI). The remyelination was examined by Olig2/Ki67, 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase)/Ki67 double immunofluorescence staining and Luxol fast blue (LFB) staining. Subsequently, the Notch signaling activation in astrocytes and microglia was assessed by double immunofluorescence staining with JAG1/Notch1/Notch intracellular domain (NICD) and glial fibrillary acidic protein (GFAP)/ionized calcium binding adaptor molecule 1 (Iba1).

RESULTS

BHD treatments remarkably improved motor function of the MCAO rats by reducing steps, swing time and ataxia coefficient of the left forelimb. The MRI examinations found that BHD treatments significantly reduced infarct volume and preserved the motor cortex and external capsule integrity, as reflected by decreased T2 values, RD, and increased FA. Notably, the gait parameters of the left forelimb were correlated to the MRI index obtained from the perilesional motor cortex and external capsule to varying degrees. Furthermore, BHD treatments enhanced gray and matter remyelination by elevating the numbers of Olig2+/Ki67+, CNPase+/Ki67+ cells, and the integrated optical density of LFB. Finally, BHD effectively inhibited the activation of Notch signaling in the astrocytes and microglia of the corresponding gray and white matter, as evidenced by decreased numbers of cells co-expressing JAG1/Notch1/NICD and GFAP/Iba1.

CONCLUSION

This study demonstrated that BHD treatment could promote poststroke motor recovery by preserving the structural integrity of the gray and white matter and facilitating their remyelination. Notably, the pro-remyelination effects of BHD treatment might be attributed to suppressed activation of Notch signaling within the reactive astrocytes and microglia.

Identifying impairments and compensatory strategies for temporal gait asymmetry in post-stroke persons

In post-stroke persons, temporal gait asymmetry (TGA) during comfortable gait involves a combination of pure impairments and compensatory strategies. In this study, we aimed to differentiate between pure impairments and compensatory strategies underlying TGA in post-stroke individuals and identify associated clinical factors. We examined 39 post-stroke individuals who participated in comfortable walking speed (CWS) and rhythmic auditory cueing (RAC). Gait evaluation included spatiotemporal parameters and trunk acceleration, while clinical evaluation comprised motor paralysis severity, sensory disturbances, spasticity, balance ability, and gait efficacy. The participants were classified by clustering based on the symmetry index during CWS and RAC. TGA during CWS or RAC gait showed no association (ρ = 0.062, p = 0.707). Clustering yielded four optimal clusters. Cluster 1 was asymmetric during CWS but symmetric during RAC condition (over-compensatory strategies); these participants had a poor score on the modified gait efficacy scale, and despite mild functional impairments, they lacked the confidence to walk safely. Cluster 2 showed impairment-driven asymmetry during CWS and RAC, with severe impairments and instability. Participants showing improved TGA under auditory cueing compared with comfortable speed demonstrate strong compensatory strategies associated with low gait efficacy. This suggests a need for targeted interventions to enhance gait self-efficacy and maximize residual function.

A Faster Walking Speed Is Important for Improving Biomechanical Function and Walking Performance in Stroke Survivors

This study compares joint kinematics and kinetics of young stroke survivors who walk <0.79 m/s (slow) or >0.80 m/s (fast) with reference to a healthy able-bodied group and provides clinical recommendations for guiding the gait rehabilitation of stroke survivors. Twenty-two young stroke survivors (18-55 y) were recruited from 6 hospital sites in the United Kingdom. Stroke participants were classified by walking speed as slow (<0.79) or fast (>0.80 m/s), and joint kinematics and kinetics at the pelvis, hip, knee, and ankle were measured during walking on level ground at self-selected speed. Ten walking biomechanical parameters correlated to walking speed (ρ ≥ .550). Stroke survivors in the slow group walked with significantly greater range of sagittal plane pelvic motion (P < .009), reduced range of hip adduction and abduction (P < .011), and smaller peak hip extension angle (P < .011) and hip flexion moment (P < .029) for the paretic limb. For the nonparetic limb, a significantly reduced hip flexion moment (P < .040) was observed compared with the fast group and control. We are the first to report how biomechanical function during walking is compromised in young stroke survivors classified by walking speed as slow (<0.79 m/s) or fast (>0.80 m/s) and propose that these biomechanical parameters be used to inform rehabilitation programs to improve walking for stroke survivors.

Gait asymmetry assessment through Eigen-Gait components on dissimilarity maps

Motor impairments caused by neurological diseases have an important impact on gait, particularly on the coordination between left and right lower limbs. Deviation from normal gait is often measured to assess this impact on gross motor functions, and to monitor the progress of patients during rehabilitation. The concept of gait dissimilarity map is introduced to represent bilateral raw gait signals, while accounting for their respective spatiotemporal dynamics. A model of gait for the healthy population is constructed through Singular Value Decomposition, considering both lower limbs. The obtained eigenvectors synthesize the symmetry present in gait. Then, by projecting the dissimilarity maps of patients with gait disorders on the space formed by such eigenvectors, we compute their associated Eigen-Gait Asymmetry Index (EGAI) relatively to an average normal gait reference vector. For the knee joint in the sagittal plane, EGAI values of patients are higher (9.73 ±2.16) than those of healthy controls (3.86 ±0.9), reflecting the asymmetry induced by neurological diseases. Patients with hemiparesis show the highest EGAI (10.4 ±1.8), followed by patients with paraparesis (9.9 ±1.8) and patients with tetraparesis (8.6 ±2.5). Indeed, patients with hemiparesis show a more asymmetrical gait since only one side of the body is affected. EGAI for hip, ankle and pelvis joints in the sagittal plane show similar trends. Our innovative method characterizes bilateral gait, enriching traditional unilateral assessments. Our method yields a comprehensive score reflecting both asymmetry and gait deviations, aiming to provide clinicians with an effective and precise monitoring tool.

We Will, We Will Shock You: Adaptive Versus Conventional Functional Electrical Stimulation in Individuals Post-Stroke

Functional electrical stimulation (FES) is often used in poststroke gait rehabilitation to address decreased walking speed, foot drop, and decreased forward propulsion. However, not all individuals experience clinically meaningful improvements in gait function with stimulation. Previous research has developed adaptive functional electrical stimulation (AFES) systems that adjust stimulation timing and amplitude at every stride to deliver optimal stimulation. The purpose of this work was to determine the effects of a novel AFES system on functional gait outcomes and compare them to the effects of the existing FES system. Twenty-four individuals with chronic poststroke hemiparesis completed 64-min walking trials on an adaptive and fixed-speed treadmill with no stimulation, stimulation from the existing FES system, and stimulation from the AFES system. There was no significant effect of stimulation condition on walking speed, peak dorsiflexion angle, or peak propulsive force. Walking speed was significantly faster and peak propulsive force was significantly larger on the adaptive treadmill (ATM) than the fixed-speed treadmill (both p < 0.0001). Dorsiflexor stimulation timing was similar between stimulation conditions, but plantarflexor stimulation timing was significantly improved with the AFES system compared to the FES system (p = 0.0059). Variability between and within subjects was substantial, and some subjects experienced clinically meaningful improvements in walking speed, peak dorsiflexion angle, and peak propulsive force. However, not all subjects experienced benefits, suggesting that further research to characterize which subjects exhibit the best instantaneous response to FES is needed to optimize poststroke gait rehabilitation using FES.

Immediate Effects of Two Different Methods of Trunk Elastic Taping on Pelvic Inclination, Trunk Impairment, Balance, and Gait in Stroke Patients

Background and Objectives: Stroke patients often experience changes in their pelvic tilt, trunk impairments and decreased gait and balance. While various therapeutic interventions have been attempted to improve these symptoms, there is a need for interventions that are easy to apply and reduce the physical labor of physical and occupational therapists. We aimed to investigate the immediate effects of two different methods of trunk elastic taping on the pelvic inclination, trunk impairment, balance, and gait in chronic stroke patients. Materials and Methods: We performed a single-blind randomized controlled trial involving 45 patients with chronic stroke. Participants were randomly assigned to one of three groups: forward rotation with posterior pelvic tilt taping (FRPPT, n = 14), backward rotation with posterior pelvic tilt taping (BRPPT, n = 14), or placebo taping (PT = 14). This study was conducted from December 2023 to January 2024. All the measurements were performed twice: before the intervention and immediately after the intervention. The pelvic inclination was assessed using the anterior pelvic tilt angle. The trunk impairment scale (TIS) was used to measure the trunk impairment. The balance and gait were evaluated using a force plate and walkway system. Results: The pelvic inclination was significantly different in the FRPPT and BRPPT groups compared to the PT group (p < 0.05, p < 0.001). The TIS and gait were significantly increased in the FRPPT group compared to the PT group (p < 0.05). The balance significantly improved in the FRPPT and BRPPT within groups (p < 0.05). Conclusions: Two different methods of posterior pelvic tilt taping improved the anterior pelvic tilt in chronic hemiplegic stroke patients compared with PT, and the FRPPT method also improved the trunk impairment and gait. Therefore, posterior pelvic tilt taping can be used as an intervention with immediate effect.

Serial engagement of distinct motor learning mechanisms to alter walking after stroke

This study asked if combining different motor learning mechanisms-adaptation and reinforcement-could produce immediate improvements in over ground walking after stroke. Fifteen adults with stroke engaged in three conditions: (1) reinforcement following adaptation, (2) reinforcement alone, and (3) adaptation alone. Adaptation involved split-belt treadmill walking to produce after-effects that reduce step asymmetry. Reinforcement involved the use of real-time auditory feedback about step length asymmetry. Auditory feedback was binary, signaling whether steps were asymmetric or equal, but not whether to shorten or lengthen either step. Change in step length asymmetry was the outcome assessed during over ground walking. Reinforcement following adaptation led to reductions in step length asymmetry that persisted into an immediate retention period. Importantly, it led to the desired pattern of lengthening the shorter step in a majority of participants. Reinforcement alone led to no significant change in step length asymmetry, and sometimes produced a non-optimal pattern of shortening the longer step. Our control condition of adaptation alone led to more transient reductions in step length asymmetry. These findings reveal the potential for utilizing serial delivery of adaptation and reinforcement to influence a complex movement in the real-world context of over ground walking, in people with stroke.

Development of a Gait Analysis Application for Assessing Upper and Lower Limb Movements to Detect Pathological Gait

Pathological gait in patients with Hakim's disease (HD, synonymous with idiopathic normal-pressure hydrocephalus; iNPH), Parkinson's disease (PD), and cervical myelopathy (CM) has been subjectively evaluated in this study. We quantified the characteristics of upper and lower limb movements in patients with pathological gait. We analyzed 1491 measurements of 1 m diameter circular walking from 122, 12, and 93 patients with HD, PD, and CM, respectively, and 200 healthy volunteers using the Three-Dimensional Pose Tracker for Gait Test. Upper and lower limb movements of 2D coordinates projected onto body axis sections were derived from estimated 3D relative coordinates. The hip and knee joint angle ranges on the sagittal plane were significantly smaller in the following order: healthy > CM > PD > HD, whereas the shoulder and elbow joint angle ranges were significantly smaller, as follows: healthy > CM > HD > PD. The outward shift of the leg on the axial plane was significantly greater, as follows: healthy < CM < PD < HD, whereas the outward shift of the upper limb followed the order of healthy > CM > HD > PD. The strongest correlation between the upper and lower limb movements was identified in the angle ranges of the hip and elbow joints on the sagittal plane. The lower and upper limb movements during circular walking were correlated. Patients with HD and PD exhibited reduced back-and-forth swings of the upper and lower limbs.

Modeling the Heterogeneity of Post-Stroke Gait Control in Free-Living Environments Using a Personalized Causal Network

Post-stroke gait control is a complex, often fail to account for the heterogeneity and continuity of gait in existing gait models. Precisely evaluating gait speed adjustability and gait instability in free-living environments is important to understand how individuals with post-stroke gait dysfunction approach diverse environments and contexts. This study aimed to explore individual causal interactions in the free-living gait control of persons with stroke. To this end, fifty persons with stroke wore an accelerometer on the fifth lumbar vertebra (L5) for 24 h in a free-living environment. Individually directed acyclic graphs (DAGs) were generated based on the spatiotemporal gait parameters at contemporaneous and temporal points calculated from the acceleration data. Spectral clustering and Bayesian model comparison were used to characterize the DAGs. Finally, the DAG patterns were interpreted via Bayesian logistic analysis. Spectral clustering identified three optimal clusters from the DAGs. Cluster 1 included persons with moderate stroke who showed high gait asymmetry and gait instability and primarily adjusted gait speed based on cadence. Cluster 2 included individuals with mild stroke who primarily adjusted their gait speed based on step length. Cluster 3 comprised individuals with mild stroke who primarily adjusted their gait speed based on both step length and cadence. These three clusters could be accurately classified based on four variables: Ashman's D for step velocity, Fugl-Meyer Assessment, step time asymmetry, and step length. The diverse DAG patterns of gait control identified suggest the heterogeneity of gait patterns and the functional diversity of persons with stroke. Understanding the theoretical interactions between gait functions will provide a foundation for highly tailored rehabilitation.

Differences in Trunk Acceleration-Derived Gait Indexes in Stroke Subjects with and without Stroke-Induced Immunosuppression

Background: Stroke-induced immunosuppression (SII) represents a negative rehabilitative prognostic factor associated with poor motor performance at discharge from a neurorehabilitation unit (NRB). This study aims to evaluate the association between SII and gait impairment at NRB admission. Methods: Forty-six stroke patients (65.4 ± 15.8 years, 28 males) and 42 healthy subjects (HS), matched for age, sex, and gait speed, underwent gait analysis using an inertial measurement unit at the lumbar level. Stroke patients were divided into two groups: (i) the SII group was defined using a neutrophil-to-lymphocyte ratio ≥ 5, and (ii) the immunocompetent (IC) group. Harmonic ratio (HR) and short-term largest Lyapunov's exponent (sLLE) were calculated as measures of gait symmetry and stability, respectively. Results: Out of 46 patients, 14 (30.4%) had SII. HR was higher in HS when compared to SII and IC groups (p < 0.01). HR values were lower in SII when compared to IC subjects (p < 0.01). sLLE was lower in HS when compared to SII and IC groups in the vertical and medio-lateral planes (p ≤ 0.01 for all comparisons). sLLE in the medio-lateral plane was higher in SII when compared to IC subjects (p = 0.04). Conclusions: SII individuals are characterized by a pronounced asymmetric gait and a more impaired dynamic gait stability. Our findings underline the importance of devising tailored rehabilitation programs in patients with SII. Further studies are needed to assess the long-term outcomes and the role of other clinical features on gait pattern.

Characterizing the Longitudinal Impact of Backward Locomotor Treadmill Training on Walking and Balance Outcomes in Chronic Stroke Survivors: A Randomized Single Center Clinical Trial

Background and Purpose

Walking and balance impairments after stroke are a global health concern, causing significant morbidity and mortality. However, effective strategies for achieving meaningful recovery in the chronic stages are limited. Backward locomotor treadmill training (BLTT) is a novel walking rehabilitation protocol that is safe, feasible, and likely beneficial in stroke survivors; however, its efficacy has not been tested. This single-center, randomized, assessor-blind clinical trial aims to test the preliminary efficacy of BLTT compared to forward locomotor treadmill training (FLTT) on walking speed, symmetry, and postural stability.

Methods

Forty stroke survivors [BLTT (N=19), FLTT (N=21); mean age= 56.3 ± 8.6 years; 53% Female; 30% Non-Hispanic Black] with mild-moderate walking impairment were enrolled. Participants underwent nine 30-minute BLTT or FLTT sessions over three weeks. The primary outcome was the mean change in the 10-meter walk test (10 MWT) at 24 hours post-training (24 hr POST). Secondary outcome measures were changes in spatiotemporal walking symmetry and postural stability during quiet standing at 24 hr POST. Retention was explored at Days 30- and 90 POST.

Results

We report clinically meaningful (≥ 0.16 m/s) improvements in overground walking speed at 24 hr POST, with retention up to Day 90 POST with BLTT and FLTT. However, contrary to our working hypothesis, no between-group differences in walking speed were observed. Nonetheless, we found that BLTT resulted in offline improvements in spatial symmetry and retention of subcomponents of the modified clinical test of sensory interaction on balance (mCTSIB), including the testing of proprio-vestibular integration up to Day 30 POST.

Conclusion

Among chronic stroke patients with mild-moderate walking impairment, BLTT and FLTT both resulted in long-lasting and clinically meaningful improvement in walking speed. However, preliminary findings suggest that BLTT may better comprehensively target walking asymmetry and sensory systems processing and integration.

The relationship between the ratio of the supraspinatus muscle thickness measured by ultrasound imaging and glenohumeral subluxation in stroke patients: a cross-sectional study

Introduction

Glenohumeral subluxation (GHS) is a common complication in stroke patients with hemiplegia, occurring in approximately 17-81% of cases. This study aims to evaluate the relationship between shoulder muscle thickness and the degree of subluxation using ultrasound imaging.

Methods

A cross-sectional study of 61 stroke patients with hemiplegia was conducted, measuring supraspinatus muscle thickness, deltoid muscle thickness, and acromion-greater tuberosity (AGT). Logistic regression and ROC analyses were used. ROC curves, calibration plots, and decision curves were drawn on the training and validation sets.

Results

According to logistic regression analysis, the ratio of supraspinatus muscle thickness was statistically significant (OR: 0.80; 95% CI: 0.70-0.92; p < 0.01), and it was an independent factor for evaluating the presence or absence of GHS. An AUC of 0.906 (95% CI, 0.802-1.000) was found in the training set; meanwhile, the AUC in the validation set was 0.857 (95% CI, 0.669-1.000), indicating good performance. According to the training set ROC curve, the most effective statistical threshold was 93%, with a sensitivity of 84% and a specificity of 96%.

Discussion

The ratio of supraspinatus muscle thickness is a valuable criterion for evaluating GHS risk, supporting targeted rehabilitation interventions.

Single-belt vs. split-belt treadmill symmetry training: is there a perfect choice for gait rehabilitation post-stroke?

Post-stroke gait asymmetry leads to inefficient gait and a higher fall risk, often causing limited home and community ambulation. Two types of treadmills are typically used for training focused on symmetry: split-belt and single belt treadmills, but there is no consensus on which treadmill is superior to improve gait symmetry in individuals with stroke. To comprehensively determine which intervention is superior, we considered multiple spatial and temporal gait parameters (step length, stride time, swing time, and stance time) and their symmetries. Ten individuals with stroke underwent a single session of split-belt treadmill training and single belt treadmill training on separate days. The changes in step length, stride time, swing time, stance time and their respective symmetries were compared to investigate which training improves both spatiotemporal gait parameters and symmetries immediately after the intervention and after 5 min of rest. Both types of treadmill training immediately increased gait velocity (0.08 m/s faster) and shorter step length (4.15 cm longer). However, split-belt treadmill training was more effective at improving step length symmetry (improved by 27.3%) without sacrificing gait velocity or step length. However, this step length symmetry effect diminished after a 5-min rest period. Split-belt treadmill training may have some advantages over single belt treadmill training, when targeting step length symmetry. Future research should focus on comparing the long-term effects of these two types of training and examining the duration of the observed effects to provide clinically applicable information.

Unraveling stroke gait deviations with movement analytics, more than meets the eye: a case control study

Background

This study aimed to identify and quantify the kinematic and kinetic gait deviations in post-stroke hemiplegic patients with matched healthy controls using Statistical Parametric Mapping (SPM).

Methods

Fifteen chronic stroke patients [4 females, 11 males; age 53.7 (standard deviation 12.2) years; body mass 65.4 (10.4) kg; standing height 168.5 (9.6) cm] and 15 matched healthy controls [4 females, 11 males; age 52.9 (11.7) years; body weight 66.5 (10.7) years; standing height 168.3 (8.8) cm] were recruited. In a 10-m walking task, joint angles, ground reaction forces (GRF), and joint moments were collected, analyzed, and compared using SPM for an entire gait cycle.

Results

Generally, when comparing the stroke patients' affected (hemiplegic) and less-affected (contralateral) limbs with the control group, SPM identified significant differences in the late stance phase and early swing phase in the joint angles and moments in bilateral limbs (all p < 0.005). In addition, the vertical and anteroposterior components of GRF were significantly different in various periods of the stance phase (all p < 0.005), while the mediolateral component showed no differences between the two groups.

Conclusion

SPM was able to detect abnormal gait patterns in both the affected and less-affected limbs of stroke patients with significant differences when compared with matched controls. The findings draw attention to significant quantifiable gait deviations in the less-affected post-stroke limb with the potential impact to inform gait retraining strategies for clinicians and physiotherapists.

Cautious Gait during Navigational Tasks in People with Hemiparesis: An Observational Study

Locomotor and balance disorders are major limitations for subjects with hemiparesis. The Timed Up and Go (TUG) test is a complex navigational task involving oriented walking and obstacle circumvention. We hypothesized that subjects with hemiparesis adopt a cautious gait during complex locomotor tasks. The primary aim was to compare spatio-temporal gait parameters, indicators of cautious gait, between the locomotor subtasks of the TUG (Go, Turn, Return) and a Straight-line walk in people with hemiparesis. Our secondary aim was to analyze the relationships between TUG performance and balance measures, compare spatio-temporal gait parameters between fallers and non-fallers, and identify the biomechanical determinants of TUG performance. Biomechanical parameters during the TUG and Straight-line walk were analyzed using a motion capture system. A repeated measures ANOVA and two stepwise ascending multiple regressions (with performance variables and biomechanical variables) were conducted. Gait speed, step length, and % single support phase (SSP) of the 29 participants were reduced during Turn compared to Go and Return and the Straight-line walk, and step width and % double support phase were increased. TUG performance was related to several balance measures. Turn performance (R2 = 63%) and Turn trajectory deviation followed by % SSP on the paretic side and the vertical center of mass velocity during Go (R2 = 71%) determined TUG performance time. People with hemiparesis adopt a cautious gait during complex navigation at the expense of performance.

AI in evaluating ambulation of stroke patients: severity classification with video and functional ambulation category scale

BACKGROUND

The evaluation of gait function and severity classification of stroke patients are important to determine the rehabilitation goal and the level of exercise. Physicians often qualitatively evaluate patients' walking ability through visual gait analysis using naked eye, video images, or standardized assessment tools. Gait evaluation through observation relies on the doctor's empirical judgment, potentially introducing subjective opinions. Therefore, conducting research to establish a basis for more objective judgment is crucial.

OBJECTIVE

To verify a deep learning model that classifies gait image data of stroke patients according to Functional Ambulation Category (FAC) scale.

METHODS

Gait vision data from 203 stroke patients and 182 healthy individuals recruited from six medical institutions were collected to train a deep learning model for classifying gait severity in stroke patients. The recorded videos were processed using OpenPose. The dataset was randomly split into 80% for training and 20% for testing.

RESULTS

The deep learning model attained a training accuracy of 0.981 and test accuracy of 0.903. Area Under the Curve(AUC) values of 0.93, 0.95, and 0.96 for discriminating among the mild, moderate, and severe stroke groups, respectively.

CONCLUSION

This confirms the potential of utilizing human posture estimation based on vision data not only to develop gait parameter models but also to develop models to classify severity according to the FAC criteria used by physicians. To develop an AI-based severity classification model, a large amount and variety of data is necessary and data collected in non-standardized real environments, not in laboratories, can also be used meaningfully.

Stroke walking and balance characteristics via principal component analysis

Balance impairment is associated gait dysfunction with several quantitative spatiotemporal gait parameters in patients with stroke. However, the link between balance impairments and joint kinematics during walking remains unclear. Clinical assessments and gait measurements using motion analysis system was conducted in 44 stroke patients. This study utilised principal component analysis to identify key joint kinematics characteristics of patients with stroke during walking using average joint angles of pelvis and bilateral lower limbs in every gait-cycle percentile related to balance impairments. Reconstructed kinematics showed the differences in joint kinematics in both paretic and nonparetic lower limbs that can be distinguished by balance impairment, particularly in the sagittal planes during swing phase. The impaired balance group exhibited greater joint variability in both the paretic and nonparetic limbs in the sagittal plane during entire gait phase and during terminal swing phase respectively compared with those with high balance scores. This study provides a more comprehensive understanding of stroke hemiparesis gait patterns and suggests considering both nonparetic and paretic limb function, as well as bilateral coordination in clinical practice. Principal component analysis can be a useful assessment tool to distinguish differences in balance impairment and dynamic symmetry during gait in patients with stroke.

Towards meaningful community ambulation in individuals post stroke through use of a smart hip exoskeleton: A preliminary investigation

Stroke is the leading cause of long-term disability in the United States, leaving survivors with profound mobility challenges that impact independent community ambulation. Evidence shows assistance at the hip during walking may be beneficial for stroke survivors. In this cross-over design study, we examine the impact of a novel hip exoskeleton on both functional and patient reported outcomes measuring speed, fall risk, gait symmetry, energy expenditure and perceived walking ability during both indoors and outdoors in single and serial counting dual task paradigms. Nine ambulatory stroke survivors with hemiplegia were included. No differences were seen between the exoskeleton and baseline conditions for any outcomes. Only the patient reported outcome in which subjects were asked to rate their ability to walk outdoors approached statistical significance (p = 0.051) with greater improvement reported for the exoskeleton condition. When asked to rate several key factors about the exoskeleton, weight and assistance emerged as primary perceived negative factors of the exoskeleton underscoring the need for improvements to the technology in this area. Despite lack of differences across groups, some individuals responded positively to the exoskeleton for several functional outcomes measured, highlighting the need for additional exploration into the use of personalized hip exoskeletons for post-stroke rehabilitation.

Effect of using an 8-figure shoulder brace on arm swing angle and gait parameters in chronic stroke patients: a pilot randomized controlled study

BACKGROUND

The 8-figure shoulder brace during treadmill training (8-FSBTT) intervention can stabilize the shoulder joint, improve the upright of the thoracic spine, induces a change in the angle of the arm during walking, and consequently improve walking ability in stroke patients.

OBJECTIVES

Our objective is to compare the effects of a 4-week program of 8-FSBTT with those of only treadmill training (OT) on arm swing angle, and gait parameters (gait speed, cadence, and both side stride lengths) in chronic stroke patients.

METHODS

Participants were randomized to either the 8-FSBTT (n = 11) or OT (n = 11) group. Patients in both groups underwent standard physiotherapy for 30 min per session. In addition, 8-FSBTT and OT interventions were performed 10 min, 5 times per week for 4 weeks. Arm swing angle, gait speed, cadence, and both side stride lengths were measured after 4 weeks of training.

RESULTS

After 4 weeks of training, the 8-FSBTT group showed significant improvement in all outcome measures compared with baseline (p < 0.05). Furthermore, Arm swing angle, gait speed, cadence, and both side stride lengths showed greater improvement in the 8-FSBTT group compared to the OT group (p < 0.05).

CONCLUSIONS

This study demonstrated that 8-FSBTT training, combined with standard physiotherapy, improved Arm swing angle, gait speed, cadence, and both side stride lengths in the chronic stroke patients.

Validity and reliability of inertial measurement units for gait assessment within a post stroke population

BACKGROUND

The ability to objectively measure spatiotemporal metrics within individuals post-stroke is integral to plan appropriate intervention, track recovery, and ultimately improve efficacy of rehabilitation programs. Inertial measurement units (IMUs) provide a means to systematically collect gait-specific metrics that could not otherwise be obtained from clinical outcomes. However, the use of IMUs to measure spatiotemporal parameters in stroke survivors has yet to be validated. The purpose of this study is to determine the validity and reliability of IMU-recorded spatiotemporal gait metrics as compared to a motion capture camera system (MCCS) in individuals post-stroke.

METHODS

Participants (n = 23, M/F = 12/11, mean (SD) age = 50.2(11.1) spatiotemporal data were collected simultaneously from a MCCS and APDM Opal IMUs during a five-minute treadmill walking task at a self-selected speed. Criterion validity and test-retest reliability were assessed using Lin's concordance correlation coefficients (CCCs) and intraclass correlation coefficients (ICCs), respectively. Spatiotemporal values from MCCS and IMU were used to calculate gait asymmetry, and a t-test was used to assess the difference between asymmetry values.

RESULTS

There were fair-to-excellent agreement between IMU and MCCS of temporal parameters (CCC 0.56-0.98), excellent agreement of spatial parameters (CCC >0.90), and excellent test-retest reliability for all parameters (ICC >0.90).

CONCLUSIONS

Compared to motion capture, the APDM Opal IMUs produced accurate and reliable measures of spatiotemporal parameters. Findings support the use of IMUs to assess spatiotemporal parameters in individual's post-stroke.

Concurrent ankle-assisted movement, biofeedback, and proprioceptive stimulation reduces lower limb motor impairment and improves gait in persons with stroke

BACKGROUND

Persons with stroke live with residual sensorimotor impairments in their lower limbs (LL), which affects their gait.

PURPOSE

We investigated whether these residual impairments and resulting gait deficits can be reduced through concurrently applied assisted movement, biofeedback, and proprioceptive stimulation.

METHODS

A robotic device provided impairment-oriented training to the affected LL of 24 persons with stroke (PwS) with moderate-to-severe LL impairment. Participants were given 22-30 training sessions over 2-3 months. During training, the interventional device cyclically dorsiflexed and plantarflexed the ankle at 5 deg/s through ±15 deg for 30 min while the participant assisted with the imposed movement. Concurrently, participants received visual biofeedback of assistive joint torque or agonist EMG while mechanical vibration was applied to the currently lengthening (i.e. antagonist) tendon.

RESULTS

Sensorimotor impairment significantly decreased over the training period, which was sustained over 3 months, based on the Fugl-Meyer Assessment (FMA-LL) (p < .001), modified Ashworth scale in dorsiflexors (p < .05), and an ankle strength test (dorsiflexors and plantarflexors) (p < .05). Balance and gait also improved, based on the Tinetti Performance Oriented Mobility Assessment (POMA) (p < .05).

CONCLUSION

Impairment-oriented training using a robotic device capable of applying assisted movement, biofeedback, and proprioceptive stimulation significantly reduces LL impairment and improves gait in moderately-to-severely impaired PwS.

Clinical gait analysis using video-based pose estimation: Multiple perspectives, clinical populations, and measuring change

Gait dysfunction is common in many clinical populations and often has a profound and deleterious impact on independence and quality of life. Gait analysis is a foundational component of rehabilitation because it is critical to identify and understand the specific deficits that should be targeted prior to the initiation of treatment. Unfortunately, current state-of-the-art approaches to gait analysis (e.g., marker-based motion capture systems, instrumented gait mats) are largely inaccessible due to prohibitive costs of time, money, and effort required to perform the assessments. Here, we demonstrate the ability to perform quantitative gait analyses in multiple clinical populations using only simple videos recorded using low-cost devices (tablets). We report four primary advances: 1) a novel, versatile workflow that leverages an open-source human pose estimation algorithm (OpenPose) to perform gait analyses using videos recorded from multiple different perspectives (e.g., frontal, sagittal), 2) validation of this workflow in three different populations of participants (adults without gait impairment, persons post-stroke, and persons with Parkinson's disease) via comparison to ground-truth three-dimensional motion capture, 3) demonstration of the ability to capture clinically relevant, condition-specific gait parameters, and 4) tracking of within-participant changes in gait, as is required to measure progress in rehabilitation and recovery. Importantly, our workflow has been made freely available and does not require prior gait analysis expertise. The ability to perform quantitative gait analyses in nearly any setting using only low-cost devices and computer vision offers significant potential for dramatic improvement in the accessibility of clinical gait analysis across different patient populations.

Comparison between prefabricated ankle-foot orthoses, Dyna Ankle and UD Flex, in patients with hemiplegia

OBJECTIVE

To compare the kinematic effects of two widely-used prefabricated ankle-foot orthoses (AFOs), the Dyna Ankle (DA) and UD Flex (UD), on the gait cycle of patients with hemiplegia due to cerebral palsy or acquired brain injury.

METHODS

This was a retrospective cohort study involving 29 patients. Gait analysis results were assessed under three conditions: barefoot, with the DA, and with the UD. Friedman tests and post hoc analysis with Bonferroni correction were performed to assess differences between the three conditions.

RESULTS

The DA significantly improved ankle dorsiflexion during the mid-swing phase, making it more effective in correcting foot drop compared with the UD (DA: 2.28°, UD: 0.44°). Conversely, the UD was more effective in preventing knee flexion during the loading response (DA: 28.11°, UD: 26.72°).

CONCLUSIONS

The DA improved ankle dorsiflexion during the swing phase significantly more than that with the UD in patients with hemiplegia. Compared with the DA, the UD more effectively prevented increased knee flexion during the loading response. The choice to prescribe these orthoses should consider individual patient characteristics.

Quantitative EEG for the Monitoring of Walking Recovery in Chronic Stroke Patients Receiving Action Observation Training

The current study aimed to evaluate the effects of action observation on the walking ability and oscillatory brain activity of chronic stroke patients. Fourteen chronic stroke patients were allocated randomly to the action observation (AO) or sham observation (SO) groups. Both groups received 12 sessions of intervention. Each session composed of 12 min of observational training, which depicted exercises for the experimental group but nature pictures for the sham group and 40 min of occupational therapy, which was the same for the both groups. Walking ability was assessed by a motion analysis system and brain activity was monitored using quantitative electroencephalography (QEEG) before and after the intervention. Brain asymmetry at alpha frequency, the percentage of stance phase, and step length showed significant changes in the AO group. Only the change in global alpha power was significantly correlated with the change in velocity after the intervention in AO group. Despite more improvements in walking and brain activity of patients in the AO group, our study failed to show significant correlations between the brain activity changes and functional improvements after the intervention, which might be mainly due to the small sample size in our study. Trial registration: IRCT20181014041333N1.

Gait Adaptation to Asymmetric Hip Stiffness Applied by a Robotic Exoskeleton

Wearable exoskeletons show significant potential for improving gait impairments, such as interlimb asymmetry. However, a more profound understanding of whether exoskeletons are capable of eliciting neural adaptation is needed. This study aimed to characterize how individuals adapt to bilateral asymmetric joint stiffness applied by a hip exoskeleton, similar to split-belt treadmill training. Thirteen unimpaired individuals performed a walking trial on the treadmill while wearing the exoskeleton. The right side of the exoskeleton acted as a positive stiffness torsional spring, pulling the thigh towards the neutral standing position, while the left acted as a negative stiffness spring pulling the thigh away from the neutral standing position. The results showed that this intervention applied by a hip exoskeleton elicited adaptation in spatiotemporal and kinetic gait measures similar to split-belt treadmill training. These results demonstrate the potential of the proposed intervention for retraining symmetric gait.

Comparative efficacy of different repetitive transcranial magnetic stimulation protocols for lower extremity motor function in stroke patients: a network meta-analysis

Background

Lower extremity motor dysfunction is one of the most severe consequences after stroke, restricting functional mobility and impairing daily activities. Growing evidence suggests that repetitive transcranial magnetic stimulation (rTMS) can improve stroke patients' lower extremity motor function. However, there is still controversy about the optimal rTMS protocol. Therefore, we compared and analyzed the effects of different rTMS protocols on lower extremity motor function in stroke patients using network meta-analysis (NMA).

Methods

We systematically searched CNKI, WanFang, VIP, CBM, PubMed, Embase, Web of Science, and Cochrane Library databases (from origin to 31 December 2023). Randomized controlled trials (RCTs) or crossover RCTs on rTMS improving lower extremity motor function in stroke patients were included. Two authors independently completed article screening, data extraction, and quality assessment. RevMan (version 5.4) and Stata (version 17.0) were used to analyze the data.

Results

A total of 38 studies with 2,022 patients were eligible for the NMA. The interventions included HFrTMS-M1, LFrTMS-M1, iTBS-Cerebellum, iTBS-M1, dTMS-M1, and Placebo. The results of NMA showed that LFrTMS-M1 ranked first in FMA-LE and speed, and HFrTMS-M1 ranked first in BBS, TUGT, and MEP amplitude. The subgroup analysis of FMA-LE showed that HFrTMS-M1 was the best stimulation protocol for post-stroke time > 1 month, and LFrTMS-M1 was the best stimulation protocol for post-stroke time ≤ 1 month.

Conclusion

Considering the impact of the stroke phase on the lower extremity motor function, the current research evidence shows that HFrTMS-M1 may be the preferred stimulation protocol to improve the lower extremity motor function of patients for post-stroke time > 1 month, and LFrTMS-M1 for post-stroke time ≤ 1 month. However, the above conclusion needs further analysis and validation by more high-quality RCTs.Systematic Review Registration:www.crd.york.ac.uk/prospero/, identifier (CRD42023474215).

Determination of Gait Events and Temporal Gait Parameters for Persons with a Knee-Ankle-Foot Orthosis

Gait event detection is essential for controlling an orthosis and assessing the patient's gait. In this study, patients wearing an electromechanical (EM) knee-ankle-foot orthosis (KAFO) with a single IMU embedded in the thigh were subjected to gait event detection. The algorithm detected four essential gait events (initial contact (IC), toe off (TO), opposite initial contact (OIC), and opposite toe off (OTO)) and determined important temporal gait parameters such as stance/swing time, symmetry, and single/double limb support. These gait events were evaluated through gait experiments using four force plates on healthy adults and a hemiplegic patient who wore a one-way clutch KAFO and a pneumatic cylinder KAFO. Results showed that the smallest error in gait event detection was found at IC, and the largest error rate was observed at opposite toe off (OTO) with an error rate of -2.8 ± 1.5% in the patient group. Errors in OTO detection resulted in the largest error in determining the single limb support of the patient with an error of 5.0 ± 1.5%. The present study would be beneficial for the real-time continuous monitoring of gait events and temporal gait parameters for persons with an EM KAFO.

Determinants of Gait Parameters in Patients With Severe Hip Osteoarthritis

OBJECTIVE

To investigate the characteristics and symptoms of patients with hip osteoarthritis that are associated with spatiotemporal gait parameters, including their variability and asymmetry.

DESIGN

A retrospective, cross-sectional study.

SETTING

University hospital.

PARTICIPANTS

The study analyzed the gait analysis data of 155 patients (N=155) with hip osteoarthritis who were admitted to a university hospital for total hip replacement and were able to walk on a treadmill without a handrail.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The dependent variables were gait parameters during treadmill walking. These included gait speed, stride length, cadence, coefficient of variation of stride length and stride time, swing time symmetry index, and step symmetry index. Single and multiple regression analyses were conducted using independent variables of the characteristics and symptoms of the patients, including age, sex, height, pain, leg-length discrepancy, and muscle strength of the affected and normal sides measured with a hand-held dynamometer (iliopsoas, gluteus medius, and quadriceps).

RESULTS

In the analysis, gait speed and stride were the dependent variables, whereas age, height, and muscle strength on the affected side were the significant independent variables (P<.05). Additionally, pain demonstrated a marginal association with gait speed (P=.053). Only the leg-length discrepancy correlated with cadence. When the coefficient of variation of the stride length was the dependent variable, age and muscle strength on the affected side were significant. For the swing time symmetry index, only the muscle strength on the affected side was significant. Furthermore, the step symmetry index only correlated with leg-length discrepancy. The muscle strength on the affected side was the only significant independent variable for the coefficient of variation of the stride time.

CONCLUSIONS

The results revealed that each of the frequent clinical symptoms of hip osteoarthritis, such as pain, muscle weakness, and leg-length discrepancy, can explain different aspects of gait performance.

Human Gait Entrainment to Soft Robotic Hip Perturbation During Simulated Overground Walking

Entraining human gait with a periodic mechanical perturbation has been proposed as a potentially effective strategy for gait rehabilitation, but the related studies have mostly depended on the use of a fixed-speed treadmill (FST) due to various practical constraints. However, imposing a constant treadmill speed on participants becomes a critical problem because this speed constraint prohibits the participants from adjusting the gait speed, resulting in significant alterations in natural biomechanics as the entrainment alters the stride frequency. In this study, we hypothesized that the use of a variable-speed treadmill (VST), which enables the participants to continuously adjust their speed, can improve the success rate of gait entrainment and preserve natural gait biomechanics. To test this hypothesis, we recruited 15 young and healthy adults and let them walk on a conventional FST and a self-paced VST while wearing a soft robotic hip exosuit, which applied hip flexion perturbations at various frequencies, ranging from the preferred walking frequency to a 30% increased value. Kinematics and kinetics of the participants' walking under the two treadmill conditions were measured on two separate days. Experimental results demonstrated a higher success rate of entrainment during VST walking compared to FST walking, particularly at faster perturbation frequencies. Furthermore, walking on VST facilitated the maintenance of natural biomechanics, such as stride length and normalized propulsive impulse, better than walking on FST. The observed improvement, primarily attributed to allowing an increase in walking speed following the increase in the perturbation frequency, suggests that using a self-paced VST is a viable method for exploiting the potentially beneficial therapeutic effects of entrainment in gait rehabilitation.

The Development of a Wearable Biofeedback System to Elicit Temporal Gait Asymmetry using Rhythmic Auditory Stimulation and an Assessment of Immediate Effects

Temporal gait asymmetry (TGA) is commonly observed in individuals facing mobility challenges. Rhythmic auditory stimulation (RAS) can improve temporal gait parameters by promoting synchronization with external cues. While biofeedback for gait training, providing real-time feedback based on specific gait parameters measured, has been proven to successfully elicit changes in gait patterns, RAS-based biofeedback as a treatment for TGA has not been explored. In this study, a wearable RAS-based biofeedback gait training system was developed to measure temporal gait symmetry in real time and deliver RAS accordingly. Three different RAS-based biofeedback strategies were compared: open- and closed-loop RAS at constant and variable target levels. The main objective was to assess the ability of the system to induce TGA with able-bodied (AB) participants and evaluate and compare each strategy. With all three strategies, temporal symmetry was significantly altered compared to the baseline, with the closed-loop strategy yielding the most significant changes when comparing at different target levels. Speed and cadence remained largely unchanged during RAS-based biofeedback gait training. Setting the metronome to a target beyond the intended target may potentially bring the individual closer to their symmetry target. These findings hold promise for developing personalized and effective gait training interventions to address TGA in patient populations with mobility limitations using RAS.

Lower limb vertical stiffness and frontal plane angular impulse during perturbation-induced single limb stance and their associations with gait in individuals post-stroke

After stroke, deficits in paretic single limb stance (SLS) are commonly observed and affect walking performance. During SLS, the hip abductor musculature is critical in providing vertical support and regulating balance. Although disrupted paretic hip abduction torque production has been identified in individuals post-stroke, interpretation of previous results is limited due to the discrepancies in weight-bearing conditions. Using a novel perturbation-based assessment that could induce SLS by removing the support surface underneath one limb, we aim to investigate whether deficits in hip abduction torque production, vertical body support, and balance regulation remain detectable during SLS when controlling for weight-bearing, and whether these measures are associated with gait performance. Our results showed that during the perturbation-induced SLS, individuals post-stroke had lower hip abduction torque, less vertical stiffness, and increased frontal plane angular impulse at the paretic limb compared to the non-paretic limb, while no differences were found between the paretic limb and healthy controls. In addition, vertical stiffness during perturbation-induced SLS was positively correlated with single support duration during gait at the paretic limb and predicted self-selected and fast walking speeds in individuals post-stroke. The findings indicate that reduced paretic hip abduction torque during SLS likely affects vertical support and balance control. Enhancing SLS hip abduction torque production could be an important rehabilitation target to improve walking function for individuals post-stroke.

Immediate effects of insoles applied to the sound side lower extremity of patients with chronic hemiplegia during walking

Background

Asymmetric gait patterns are mostly observed in hemiplegic stroke patients. These abnormal gait patterns resulting in abnormal speed, and decreased ability in daily of activity living.

Objective

This study aimed to determine the immediate changes in gait parameters and plantar pressure during elevation by wearing an insole on the sound side lower extremity of patients with hemiplegia.

Methods

Thirty-six participants were recruited, comprising those with a post-stroke follow-up of ≥3 months and a functional ambulation category score of ≥2. The participants were asked to walk with and without a 1 cm insole in the shoe of their sound side, and the order of wearing or not wearing the insole was randomized. Gait parameters, bilateral gait parameters, and dynamic plantar pressure were measured using the GAITRite Walkway System.

Results

Paired t-test was used to examine immediate changes in gait parameters and plantar pressure with and without insoles during walking in the same group. Overall, gait velocity and step length significantly decreased (p < 0.05), whereas step time significantly increased (p < 0.05). The swing phase of the affected sidelower extremities significantly increased (p < 0.05), and the stance phase significantly decreased (p < 0.05). Double-support unloading phase (pre-swing phase) significantly increased (p < 0.05). The changes in plantar pressure were significantly increased in some lateral zones and significantly decreased in the medial zone of the mid-hindfoot, both in terms of pressure per time and peak pressure (p < 0.05).

Conclusion

Although this study did not show immediate positive effects on gait parameters and gait cycle, it is expected that sensory input from the sole of the foot through changes in plantar pressure may help improve gait asymmetry and regulate postural symmetry.

The MT1 receptor as the target of ramelteon neuroprotection in ischemic stroke

Stroke is the leading cause of death and disability worldwide. Novel and effective therapies for ischemic stroke are urgently needed. Here, we report that melatonin receptor 1A (MT1) agonist ramelteon is a neuroprotective drug candidate as demonstrated by comprehensive experimental models of ischemic stroke, including a middle cerebral artery occlusion (MCAO) mouse model of cerebral ischemia in vivo, organotypic hippocampal slice cultures ex vivo, and cultured neurons in vitro; the neuroprotective effects of ramelteon are diminished in MT1-knockout (KO) mice and MT1-KO cultured neurons. For the first time, we report that the MT1 receptor is significantly depleted in the brain of MCAO mice, and ramelteon treatment significantly recovers the brain MT1 losses in MCAO mice, which is further explained by the Connectivity Map L1000 bioinformatic analysis that shows gene-expression signatures of MCAO mice are negatively connected to melatonin receptor agonist like Ramelteon. We demonstrate that ramelteon improves the cerebral blood flow signals in ischemic stroke that is potentially mediated, at least, partly by mechanisms of activating endothelial nitric oxide synthase. Our results also show that the neuroprotection of ramelteon counteracts reactive oxygen species-induced oxidative stress and activates the nuclear factor erythroid 2-related factor 2/heme oxygenase-1 pathway. Ramelteon inhibits the mitochondrial and autophagic death pathways in MCAO mice and cultured neurons, consistent with gene set enrichment analysis from a bioinformatics perspective angle. Our data suggest that Ramelteon is a potential neuroprotective drug candidate, and MT1 is the neuroprotective target for ischemic stroke, which provides new insights into stroke therapy. MT1-KO mice and cultured neurons may provide animal and cellular models of accelerated ischemic damage and neuronal cell death.

Concurrent validity of walking speed measured by a wearable sensor and a stopwatch during the 10-meter walk test in individuals with stroke

BACKGROUND

Walking speed is often measured with a stopwatch throughout stroke recovery. Wearable sensors also have been used recently to measure walking speed and provide information about spatiotemporal characteristics of walking.

RESEARCH QUESTION

Do walking speeds measured with stopwatch and APDM wearable sensors have concurrent validity?

METHODS

Individuals with chronic stroke (n = 62) performed the 10-meter walk test at comfortable and maximal speeds. Walking speeds were measured with a stopwatch and APDM Opal wireless wearable sensors (3-unit). Tests of concurrent validity between stopwatch and APDM (Bland-Altman plots, systematic and proportional bias, and intraclass correlations) and test-retest reliability between trials (intraclass correlations, standard error of measurement, and minimal detectable change) were performed.

RESULTS

Walking speeds measured with APDM were ∼0.07 m/s slower than those measured with stopwatch (systematic bias; t ≥ 13.1, p < 0.001). Intraclass correlations ranged from poor to excellent. There were greater differences in walking speeds between APDM and stopwatch for individuals with faster walking speeds (proportional bias). Test-retest reliability was excellent for both APDM and stopwatch (intraclass correlation≥0.94). Standard error of measurement ranged from 0.04 to 0.07 m/s and minimal detectable change ranged from 0.10 to 0.19 m/s.

SIGNIFICANCE

It may be inappropriate to use walking speed measurements from APDM sensors and stopwatch interchangeably in individuals with chronic stroke. Differences in walking speeds may reflect stopwatch error or the derivation of walking speed from wearable sensors. Test-retest reliability was excellent for both stopwatch and APDM, but minimal detectable change values were large. Large changes in walking speed may be required to be confident that the change is a true and clinically meaningful change and not measurement error. The validity and reliability of measuring walking speed with wearable sensors in individuals with chronic stroke has important implications for determining community ambulation, assessing improvements after rehabilitation, and developing exercise prescriptions.

Robotic exoskeleton embodiment in post-stroke hemiparetic patients: an experimental study about the integration of the assistance provided by the REFLEX knee exoskeleton

Hemiparetic gait is the most common motor-disorder after stroke and, in spite of rehabilitation efforts, it is persistent in 50% of community dwelling stroke-survivors. Robotic exoskeletons have been proposed as assistive devices to support impaired joints. An example of these devices is the REFLEX knee exoskeleton, which assists the gait of hemiparetic subjects and whose action seems to be properly embodied by stroke survivors, who were able to adapt the motion of their non-assisted limbs and, therefore, reduce their compensation mechanisms. This paper presents an experimental validation carried out to deepen into the effects of REFLEX's assistance in hemiparetic subjects. Special attention was paid to the effect produced in the muscular activity as a metric to evaluate the embodiment of this technology. Significant differences were obtained at the subject level due to the assistance; however, the high dispersion of the measured outcomes avoided extracting global effects at the group level. These results highlight the need of individually tailoring the action of the robot to the individual needs of each patient to maximize the beneficial outcomes. Extra research effort should be done to elucidate the neural mechanisms involved in the embodiment of external devices by stroke survivors.

Gait adaptation to asymmetric hip stiffness applied by a robotic exoskeleton

Wearable exoskeletons show significant potential for improving gait impairments, such as interlimb asymmetry. However, a more profound understanding of whether exoskeletons are capable of eliciting neural adaptation is needed. This study aimed to characterize how individuals adapt to bilateral asymmetric joint stiffness applied by a hip exoskeleton, similar to split-belt treadmill training. Thirteen unimpaired individuals performed a walking trial on the treadmill while wearing the exoskeleton. The right side of the exoskeleton acted as a positive stiffness torsional spring, pulling the thigh towards the neutral standing position, while the left acted as a negative stiffness spring pulling the thigh away from the neutral standing position. The results showed that this intervention applied by a hip exoskeleton elicited adaptation in spatiotemporal and kinetic gait measures similar to split-belt treadmill training. These results demonstrate the potential of the proposed intervention for retraining symmetric gait.

Effects of Training with a Powered Exoskeleton on Cortical Activity Modulation in Hemiparetic Chronic Stroke Patients: A Randomized Controlled Pilot Trial

OBJECTIVES

To investigate the effects of exoskeleton-assisted gait training in stroke patients.

DESIGN

Prospective randomized controlled trial.

SETTING

Rehabilitation department in a single tertiary hospital.

PARTICIPANTS

Thirty (N=30) chronic stroke patients with Functional Ambulatory Category scale (FAC) between 2 and 4.

INTERVENTION

Patients were randomly assigned to 1 of 2 groups: training with Healbot G, a wearable powered exoskeleton (Healbot G group; n=15), or treadmill training (control group; n=15). All participants received 30 minutes of training, 10 times per week, for 4 weeks.

OUTCOME MEASUREMENTS

The primary outcome was oxyhemoglobin level changes, representing cortical activity in both motor cortices using functional near-infrared spectroscopy. The secondary outcomes included FAC, Berg Balance Scale, Motricity Index for the lower extremities (MI-Lower), 10-meter walk test, and gait symmetry ratio (spatial step and temporal symmetry ratio).

RESULTS

Compared to the control group, during the entire training session, the pre-training and post-training mean cortical activity, and the amount of increment between pre- and post-training were significantly higher in the Healbot G group (∆mean ± SD; pre-training, 0.245±0.119, post-training, 0.697±0.429, between pre- and post-training, 0.471±0.401μmol, P<.001). There was no significant difference in cortical activity between affected- and unaffected hemispheres after Healbot G training. FAC (∆mean ± SD; 0.35 ± 0.50, P=.012), MI-Lower (∆mean ± SD; 7.01 ± 0.14, P=.001), and spatial step gait symmetry ratio (∆mean ± SD; -0.32 ± 0.25, P=.049) were improved significantly in the Healbot G group.

CONCLUSION

Exoskeleton-assisted gait training induces cortical modulation effect in both motor cortices, a balanced cortical activation pattern with improvements in spatial step symmetry ratio, walking ability, and voluntary strength.

Discovering individual-specific gait signatures from data-driven models of neuromechanical dynamics

Locomotion results from the interactions of highly nonlinear neural and biomechanical dynamics. Accordingly, understanding gait dynamics across behavioral conditions and individuals based on detailed modeling of the underlying neuromechanical system has proven difficult. Here, we develop a data-driven and generative modeling approach that recapitulates the dynamical features of gait behaviors to enable more holistic and interpretable characterizations and comparisons of gait dynamics. Specifically, gait dynamics of multiple individuals are predicted by a dynamical model that defines a common, low-dimensional, latent space to compare group and individual differences. We find that highly individualized dynamics-i.e., gait signatures-for healthy older adults and stroke survivors during treadmill walking are conserved across gait speed. Gait signatures further reveal individual differences in gait dynamics, even in individuals with similar functional deficits. Moreover, components of gait signatures can be biomechanically interpreted and manipulated to reveal their relationships to observed spatiotemporal joint coordination patterns. Lastly, the gait dynamics model can predict the time evolution of joint coordination based on an initial static posture. Our gait signatures framework thus provides a generalizable, holistic method for characterizing and predicting cyclic, dynamical motor behavior that may generalize across species, pathologies, and gait perturbations.

Ankle stiffness asymmetry is associated with balance function in individuals with chronic stroke

Ankle joint is one of important contributors on balance in stroke survivors. This study aimed to investigate the relationships of ankle stiffness symmetry ratios along the talocrural and subtalar axes with clinical balance measures and weight distribution during quiet standing in ambulatory chronic post-stroke survivors. The clinical trials involved 15 ambulatory elderly with chronic post-stroke hemiparesis and 15 healthy controls. Ankle stiffness was evaluated during non-weight-bearing isokinetic passive biaxial ankle movements, and ankle stiffness symmetry ratios between paretic and non-paretic ankle stiffness (SR: Inversion/Eversion SRIE & Dorsi-/Plantarflexion SRDP) were measured. A certified physiotherapist evaluated the Berg Balance Scale (BBS) and weight-distribution ratio (WDR) on bilateral force plates during quiet standing. Correlation coefficients, the factor analysis, and Pearson linear multiple regression were assessed with measured parameters. Correlation coefficients showed significances in-betweens; BBS and SRDP (r = -0.543, p = 0.022), WDR and SRIE (r = -0.667, p = 0.004), SRIE and SRDP (r = -0.604, p = 0.011). The exploratory factor analysis suggested four extracted factors; (1) Balance & Gait, (2) Stroke, (3) Symmetry and (4) Dimension. The first and second factors include general and pathological characteristics in stoke participants respectively. The third factor is associated with symmetrical characteristics explaining up to 99.9% of the variance. Multiple regression analysis showed ankle stiffness ratios predict BBS up to 60% of variance. The biaxial ankle stiffness ratio is a useful clinical variable that assesses balance function, in ambulatory chronic stroke survivors.

Efficacy of stumble recovery assistance in a knee exoskeleton for individuals with simulated mobility impairment: A pilot study

Falls due to stumbles are a major cause of injury for many populations, and as such interventions to reduce fall risk have been a key focus of rehabilitation research. However, dedicated stumble recovery assistance in a powered lower-limb exoskeleton has yet to be explored as a fall mitigation intervention. Thus young, healthy adults () were recruited for a stumble recovery experiment to test the efficacy of knee exoskeleton stumble recovery assistance in improving an impaired stumble recovery response (i.e., the elevating strategy response). Leg weights were attached unilaterally to each participant's shank to simulate walking and stumble recovery impairment, and a unilateral powered knee exoskeleton was worn on the same leg for walking and stumble recovery assistance. Ultimately, knee exoskeleton stumble recovery assistance served to improve participants' elevating limb kinematics (i.e., increase thigh and knee motion) and reduce overall fall risk (i.e., reduce trunk motion and improve foot placement) during responses relative to their impaired response (i.e., with the leg weights and no assistance), and relative to their response while receiving only walking assistance. This initial exploration provides a first indication that knee exoskeleton stumble recovery assistance is a viable approach to improving an impaired stumble recovery response, which could serve two important use cases: (1) a safety mechanism for existing exoskeleton wearers, who may be less capable of recovering from stumbles due to the added weight or joint impedance of the device; (2) an external stumble recovery aid for fall-prone populations, such as the elderly or stroke survivors.