Gait Symmetry Research Articles

Robust walking control of a lower limb rehabilitation exoskeleton coupled with a musculoskeletal model via deep reinforcement learning

BackgroundFew studies have systematically investigated robust controllers for lower limb rehabilitation exoskeletons (LLREs) that can safely and effectively assist users with a variety of neuromuscular disorders to walk with full autonomy. One of the key challenges for developing such a robust controller is to handle different degrees of uncertain human-exoskeleton interaction forces from the patients. Consequently, conventional walking controllers either are patient-condition specific or involve tuning of many control parameters, which could behave unreliably and even fail to maintain balance.MethodsWe present a novel, deep neural network, reinforcement learning-based robust controller for a LLRE based on a decoupled offline human-exoskeleton simulation training with three independent networks, which aims to provide reliable walking assistance against various and uncertain human-exoskeleton interaction forces. The exoskeleton controller is driven by a neural network control policy that acts on a stream of the LLRE’s proprioceptive signals, including joint kinematic states, and subsequently predicts real-time position control targets for the actuated joints. To handle uncertain human interaction forces, the control policy is trained intentionally with an integrated human musculoskeletal model and realistic human-exoskeleton interaction forces. Two other neural networks are connected with the control policy network to predict the interaction forces and muscle coordination. To further increase the robustness of the control policy to different human conditions, we employ domain randomization during training that includes not only randomization of exoskeleton dynamics properties but, more importantly, randomization of human muscle strength to simulate the variability of the patient’s disability. Through this decoupled deep reinforcement learning framework, the trained controller of LLREs is able to provide reliable walking assistance to patients with different degrees of neuromuscular disorders without any control parameter tuning.Results and conclusionA universal, RL-based walking controller is trained and virtually tested on a LLRE system to verify its effectiveness and robustness in assisting users with different disabilities such as passive muscles (quadriplegic), muscle weakness, or hemiplegic conditions without any control parameter tuning. Analysis of the RMSE for joint tracking, CoP-based stability, and gait symmetry shows the effectiveness of the controller. An ablation study also demonstrates the strong robustness of the control policy under large exoskeleton dynamic property ranges and various human-exoskeleton interaction forces. The decoupled network structure allows us to isolate the LLRE control policy network for testing and sim-to-real transfer since it uses only proprioception information of the LLRE (joint sensory state) as the input. Furthermore, the controller is shown to be able to handle different patient conditions without the need for patient-specific control parameter tuning.

Photobiomodulation therapy mitigates cardiovascular aging and improves survival.

Photobiomodulation (PBM) therapy, a form of low-dose light therapy, has been noted to be effective in several age-associated chronic diseases such as hypertension and atherosclerosis. Here, we examined the effects of PBM therapy on age-associated cardiovascular changes in a mouse model of accelerated cardiac aging. Fourteen months old Adenylyl cyclase type VIII (AC8) overexpressing transgenic mice (n = 8) and their wild-type (WT) littermates (n = 8) were treated with daily exposure to Near-Infrared Light (850 nm) at 25 mW/cm2 for 2 min each weekday for a total dose of 1 Einstein (4.5 p.J/cm2 or fluence 3 J/cm2 ) and compared to untreated controls over an 8-month period. PBM therapy was administered for 3.5 months (Early Treatment period), paused, due to Covid-19 restrictions for the following 3 months, and restarted again for 1.5 months. Serial echocardiography and gait analyses were performed at monthly intervals, and serum TGF-β1 levels were assessed following sacrifice. During the Early Treatment period PBM treatments: reduced the age-associated increases in left ventricular (LV) mass in both genotypes (p = 0.0003), reduced the LV end-diastolic volume (EDV) in AC8 (p = 0.04); and reduced the left atrial dimension in both genotypes (p = 0.02). PBM treatments substantially increased the LV ejection fraction (p = 0.03), reduced the aortic wall stiffness (p = 0.001), and improved gait symmetry, an index of neuro-muscular coordination (p = 0.005). The effects of PBM treatments, measured following the pause, persisted. Total TGF-β1 levels were significantly increased in circulation (serum) in AC8 following PBM treatments (p = 0.01). We observed a striking increase in cumulative survival in PBM-treated AC8 mice (100%; p = 0.01) compared to untreated AC8 mice (43%). PBM treatment mitigated age-associated cardiovascular remodeling and reduced cardiac function, improved neuromuscular coordination, and increased longevity in an experimental animal model. These responses correlate with increased TGF-β1 in circulation. Future mechanistic and dose optimization studies are necessary to assess these anti-aging effects of PBM, and validation in future controlled human studies is required for effective clinical translation.

Differences between Sexes and Speed Levels in Pelvic 3D Kinematic Patterns during Running Using an Inertial Measurement Unit (IMU).

This study aimed to assess the 3D kinematic pattern of the pelvis during running and establish differences between sexes using the IMU sensor for spatiotemporal outcomes, vertical acceleration symmetry index, and ranges of motion of the pelvis in the sagittal, coronal, and transverse planes of movement. The kinematic range in males was 5.92°-6.50°, according to tilt. The range of obliquity was between 7.84° and 9.27° and between 9.69° and 13.60°, according to pelvic rotation. In females, the results were 6.26°-7.36°, 7.81°-9.64°, and 13.2°-16.13°, respectively. Stride length increased proportionally to speed in males and females. The reliability of the inertial sensor according to tilt and gait symmetry showed good results, and the reliability levels were excellent for cadence parameters, stride length, stride time, obliquity, and pelvic rotation. The amplitude of pelvic tilt did not change at different speed levels between sexes. The range of pelvic obliquity increased in females at a medium speed level, and the pelvic rotation range increased during running, according to speed and sex. The inertial sensor has been proven to be a reliable tool for kinematic analysis during running.

The Effect of Kinesio Taping Over the Gluteal Muscles on Activity and Participation in Children with Unilateral Cerebral Palsy: A Preliminary Randomized Controlled Study

Background: Insufficiencies of gluteus medius and maximus muscles in children with unilateral cerebral palsy (CP) may restrict activity and participation by affecting gait, gross motor functions, and balance. Objectives: The present study aimed to elucidate the effect of Kinesio taping (KT) applied to the gluteus medius and maximus muscles on activity and participation in children with CP. Methods: The study was completed with 20 children with unilateral CP who were randomly divided into 2 groups: The KT group received KT and physiotherapy (n = 11), and the control group received only physiotherapy (n = 9). The KT application was administered for 4 weeks. The activity was evaluated with a BTS G-Walk Spatiotemporal Gait Analysis System, Timed Up and Go test (TUG), Functional Mobility Scale (FMS), Gross Motor Function Measure (GMFM), and Pediatric Balance Scale (PBS); in addition, participation was evaluated using the Canadian Occupational Performance Measure (COPM). Results: The KT group showed significant improvements in the gait parameter (cadence; P = 0.009), pelvic tilt symmetry (P = 0.017), pelvic rotation symmetry (P = 0.018), gait symmetry (P < 0.001), FMS (P = 0.07), TUG, GMFM, PBS, and COPM scores (P < 0.001) in the medium-term compared to the control group. It was also found that gait (cadence; P = 0.004) and functional mobility (P < 0.001) improved in the immediate term than in the KT group. Conclusions: KT combined with conventional physiotherapy can improve cadence and functional mobility in the immediate term, as well as gait and pelvic symmetry, functional mobility, gross motor function, balance, and participation in the medium term in children with unilateral CP. Further randomized controlled studies addressing large samples and long-term effects are warranted.

The Effect of Kinesio Taping Over the Gluteal Muscles on Activity and Participation in Children with Unilateral Cerebral Palsy: A Preliminary Randomized Controlled Study

Background: Insufficiencies of gluteus medius and maximus muscles in children with unilateral cerebral palsy (CP) may restrict activity and participation by affecting gait, gross motor functions, and balance. Objectives: The present study aimed to elucidate the effect of Kinesio taping (KT) applied to the gluteus medius and maximus muscles on activity and participation in children with CP. Methods: The study was completed with 20 children with unilateral CP who were randomly divided into 2 groups: The KT group received KT and physiotherapy (n = 11), and the control group received only physiotherapy (n = 9). The KT application was administered for 4 weeks. The activity was evaluated with a BTS G-Walk Spatiotemporal Gait Analysis System, Timed Up and Go test (TUG), Functional Mobility Scale (FMS), Gross Motor Function Measure (GMFM), and Pediatric Balance Scale (PBS); in addition, participation was evaluated using the Canadian Occupational Performance Measure (COPM). Results: The KT group showed significant improvements in the gait parameter (cadence; P = 0.009), pelvic tilt symmetry (P = 0.017), pelvic rotation symmetry (P = 0.018), gait symmetry (P < 0.001), FMS (P = 0.07), TUG, GMFM, PBS, and COPM scores (P < 0.001) in the medium-term compared to the control group. It was also found that gait (cadence; P = 0.004) and functional mobility (P < 0.001) improved in the immediate term than in the KT group. Conclusions: KT combined with conventional physiotherapy can improve cadence and functional mobility in the immediate term, as well as gait and pelvic symmetry, functional mobility, gross motor function, balance, and participation in the medium term in children with unilateral CP. Further randomized controlled studies addressing large samples and long-term effects are warranted.

Effect of galvanic vestibular stimulation applied at the onset of stance on muscular activity and gait cycle duration in healthy individuals.

Locomotion requires the complex involvement of the spinal and supraspinal systems. So far, the role of vestibular input in gait has been assessed mainly with respect to gait stability. The noninvasive technique of galvanic vestibular stimulation (GVS) has been reported to decrease gait variability and increase gait speed, but the extent of its effect on spatiotemporal gait parameters is not fully known. Objective: Characterize vestibular responses during gait and determine the influence of GVS on cycle duration in healthy young participants. Methods: Fifteen right-handed individuals participated in the study. Electromyography (EMG) recordings of the bilateral soleus (SOL) and tibialis anterior muscles (TA) were performed. First, to determine stimulation intensity, an accelerometer placed on the vertex recorded the amplitude of the head tilts evoked by the GVS (1-4 mA, 200 ms) to establish a motor threshold (T). Second, while participants walked on a treadmill, GVS was applied at the onset of the stance phase during the treadmill gait with an intensity of 1 and 1.5 T with the cathode behind the right (RCathode) or left ear (LCathode). EMG traces were rectified, averaged (n = 30 stimuli), and analyzed. Latency, duration, and amplitude of vestibular responses as well as the mean duration of the gait cycles were measured. Results: GVS mainly induced long-latency responses in the right SOL, right TA and left TA. Only short-latency responses were triggered in the left SOL. Responses in the right SOL, left SOL and left TA were polarity dependent, being facilitatory with RCathode and inhibitory with LCathode, whereas responses in the right TA remained facilitatory regardless of the polarity. With the RCathode configuration, the stimulated cycle was prolonged compared with the control cycle at both 1 and 1.5 T, due to prolonged left SOL and TA EMG bursts, but no change was observed in right SOL and TA. With LCathode, GVS did not modify the cycle duration. Conclusion: During gait, a brief, low-intensity GVS pulse delivered at the right stance onset induced mainly long-latency polarity-dependent responses. Furthermore, a RCathode configuration increased the duration of the stimulated gait cycle by prolonging EMG activity on the anodic side. A similar approach could be explored to influence gait symmetry in individuals with neurological impairment.

Spatiotemporal Parameters of Gait in terms of Symmetry in Asymptomatic Individuals

Context: Human gait, or the way people walk, is a complicated motor activity involving coordinated movements of different parts of the body. It is crucial in everyday activities and is influenced by a variety of factors such as age, health status, and musculoskeletal and neurological disorders. Understanding the many characteristics of gait, especially symmetry and asymmetry, is critical for getting insights into normal locomotion patterns and recognising potential deviations associated with certain conditions. Aims: The current study aims to understand the different aspects of gait such as symmetry and asymmetry of gait to develop a deeper understanding of the underpinnings of human gait. Settings and Design: Convenience sampling was used. This was a cross-sectional observational study. Subjects and Methods: A cross-sectional study was done on 72 healthy adults between the age group of 20 and 80 according to the criteria. Convenience sampling was used. Subjects were divided into six groups having 12 subjects in each group. Gait analysis was done using GAITRite. Subjects were asked to walk three times on the walkway at their preferred speed. Since all the variables are continuous, all the data have been processed in terms of the mean. Statistical Analysis: The Statistical Software, namely Jamovi 0.9.5.12 (jamovi.org), was used for statistical analysis. Results: It was observed that step time and cycle time can be considered parameters representing symmetry and parameters such as step length, stride length, H-H base of support, swing (% of gait cycle) stance (% of gait cycle), single support (% of gait cycle), and double support (% of gait cycle) represent gait asymmetry. Conclusions: This study establishes the asymmetric parameters of gait across the age span the minimum detectable difference in all the parameters were calculated.

Assessment of the effects of white cane variables on step symmetry of blind individuals.

Step symmetry is an important feature of human gait and is often regarded as a key index of healthy individuals' walking. This study evaluated the effects of height, white cane technique, and cane tip on symmetrical gait in blind individuals. Twenty blind and ten sighted subjects, aged 15-38 years, participated in this study. The harmonic ratio (HR) and improved HR (iHR) were measured by trunk accelerometer as gait symmetry index in three axes: anteroposterior (AP), vertical, and mediolateral of the body. These parameters were measured in the sighted group in open-eye conditions and in the blind group in five experimental conditions with different two heights (standard and long), two tips (pencil and roller), and two techniques (two-point touch and constant contact) of white cane when they walked in the 6-m path. There was a significant difference between HR and iHR of the blind and sighted group, which indicates a significant reduction of symmetry loss in the blind group. Among the five different conditions studied in the group of blind people, an increase was observed in the HR and the iHR on the AP axis during the application of a standard cane with a roller tip, which indicated an increase in symmetry. Based on the results, a long cane with a pencil tip and a standard cane with a roller tip in the constant contact technique can increase step symmetry.

Design, Manufacture, and Experimental Validation of a Hydraulic Semi-Active Knee Prosthesis.

In this article, a new hydraulic semi-active knee (HSAK) prosthesis is proposed. Compared with knee prostheses driven by hydraulic-mechanical coupling or electromechanical systems, we novelly combine independent active and passive hydraulic subsystems to solve the incompatibility between low passive friction and high transmission ratio of current semi-active knees. The HSAK not only has the low friction to follow the intentions of users, but also performs adequate torque output. Moreover, the rotary damping valve is meticulously designed to effectively control motion damping. The experimental results demonstrate the HSAK combines the advantages of both passive and active prostheses, including the flexibility of passive prostheses, as well as the stability and the sufficient active torque of active prostheses. The maximum flexion angle in level walking is about 60°, and the peak output torque in stair ascent is greater than 60Nm. Relative to the daily use of prosthetics, the HSAK improves gait symmetry on the affected side and contributes to the amputees better maintain daily activities.

Obesity Is Associated With Gait Alterations and Gait Asymmetry in Older Adults.

The prevalence of obesity (OB) has increased in the older adult (OA) population. However, it is not quite clear whether OB exaggerates gait instability and leads to a higher risk of falls in OAs. The first goal of this study was to investigate whether OB is associated with gait alterations and gait asymmetry in OAs. The second goal of this study was to examine relationships between various OB measures with gait measures and gait symmetry measures in OAs. A total of 30 OAs were included and categorized according to their body mass index (BMI) values into groups of persons with normal weight (NW), overweight (OW), and OB. Participants were required to complete an anthropometric assessment, a body composition assessment, and overground walking tests. The group with OB had shorter swing phase, longer stance phase, and shorter single support phase than the NW group. Increased body weight, BMI, visceral adipose tissue mass, and android fat had correlations with shorter swing phase, longer stance phase, and shorter single support phase. Increased body weight and BMI had significantly positive correlations with symmetry index of knee range of motion. OB may impair gait automation capacity in OAs. Both body weight and BMI remain good measures in terms of establishing correlations with gait stability in OAs. However, the amount of fat mass surrounding the abdomen could be vital to interpreting the alterations in the gait of OAs with obesity.

Evaluation of a Vibrotactile Biofeedback System Targeting Stance Time Symmetry Ratio of Individuals With Lower-Limb Amputation: A Pilot Study

Individuals with lower-limb amputation (LLA) often exhibit atypical gait patterns and asymmetries. These patterns can be corrected using biofeedback (BFB). Real-time BFB strategies have demonstrated to be effective to various degrees in BFB systems. However, no studies have evaluated the use of corrective vibrotactile BFB strategies to improve temporal gait symmetry of LLA. The aim of this study was to evaluate a wearable vibrotactile BFB system to improve stance time symmetry ratio (STSR) of LLA, and compare two corrective BFB strategies that activate either one or two vibrating motors at two different frequency and amplitude levels, based on a pre-set STSR target. Gait patterns of five unilateral LLA were assessed with and without BFB. Spatiotemporal and kinematic gait parameters were measured and assessed using a wearable motion capture system. Usability and workload were assessed using the System Usability Scale and NASA Task Load Index questionnaires, respectively. Results showed that participants significantly (p<0.001) improved STSR with BFB; however, this coincided with a reduction in gait speed and cadence compared to walking without feedback. Knee and hip flexion angles improved and changes in other parameters were variable. Immediate post-test retention effects were observed, suggesting that gait changes due to BFB were preserved for at least a short-time after feedback was withdrawn. System usability was found to be acceptable while using BFB. The outcomes of this study provide new insights into the development and implementation of clinically practical and viable BFB systems. Future work should focus on assessing the long-term use and retention effects of BFB outside controlled-laboratory conditions.

A Cable-driven Exoskeleton with Personalized Assistance Improves the Gait Metrics of People in Subacute Stroke.

Most stroke survivors have mobility deficits and show a pathological gait pattern. Seeking to enhance the gait performance among this population, we have developed a hybrid cable-driven lower limb exoskeleton (called SEAExo). This study aimed to determine the effects of SEAExo with personalized assistance on immediate changes in gait performance of people after stroke. Gait metrics (i.e., the foot contact angle, knee flexion peak, temporal gait symmetry indices) and muscle activities were the primary outcomes to evaluate the assistive performance. Seven subacute stroke survivors participated and completed the experiment with three comparison sessions, i.e., walking without SEAExo (served as baseline) and without/with personalized assistance, at their preferred walking speeds. Compared to the baseline, we observed increases in the foot contact angle and knee flexion peak by 70.1% (p < 0.05) and 60.0% (p < 0.05) with personalized assistance. Personalized assistance contributed to the improvements in temporal gait symmetry of more impaired participants (p < 0.05), and it led to a 22.8% and 51.3% (p < 0.05) reduction in the muscle activities of ankle flexor muscles. These results demonstrate that SEAExo with personalized assistance has the potential to enhance post-stroke gait rehabilitation in real-world clinical settings.

Concurrent locomotor adaptation and retention to visual and split-belt perturbations.

Gait asymmetry is a common symptom in groups with neurological disorders and significantly reduces gait efficiency. To develop efficient training for gait rehabilitation, we propose a novel gait rehabilitation paradigm that combines two distinct perturbation strategies: visual feedback distortion (VFD) and split-belt treadmill (SBT) walking. In SBT walking, spatiotemporal gait adaptation can be readily achieved, but it quickly fades after training. Gait adaptation to implicit VFD in an unconscious manner tends to persist longer, potentially due to a greater engagement of implicit learning during training. Thus, we investigated whether the combined strategies would lead to more effective changes in symmetric gait patterns with longer retention periods. We compared the retention of the preserved asymmetric pattern acquired by "implicit VFD+SBT walking" with "SBT-only walking" and with "SBT walking with conscious correction". In the implicit VFD+SBT walking, the speed of the two belts was gradually changed, the visual representation of gait symmetry was implicitly distorted, and no instructions were given to subjects except to watch the visual feedback. In the SBT walking with conscious correction, subjects were instructed to consciously correct their steps with the help of visual feedback while SBT walking. The SBT-only walking consisted of SBT walking with no visual feedback. After the 7-minute adaptation period, we removed the visual feedback and the split-belt perturbations, and we assessed the retention of the preserved asymmetric pattern while subjects continued walking for the 15-minute post-adaptation period. In a group of subjects who spontaneously showed visuomotor adaptation in response to the implicit VFD (16 out of 27 subjects), we found a greater retention rate during the implicit VFD+SBT walking trial than the SBT-only walking or the SBT walking with conscious correction trials. The implicit visual distortion paradigm delivered in an attention-independent (unconscious) manner can be utilized and integrated into SBT walking to improve the efficacy of symmetric gait adaptation by producing longer-lasting effects on the retention of a newly learned motor pattern.

Gait asymmetry in stroke patients with unilateral spatial neglect

The recovery of independent gait represents one of the main functional goals of the rehabilitative interventions after stroke but it can be hindered by the presence of unilateral spatial neglect (USN). The aim of the paper is to study if the presence of USN in stroke patients affects lower limb gait parameters between the two body sides, differently from what could be expected by the motor impairment alone, and to explore whether USN is associated to specific gait asymmetry. Thirty-five stroke patients (right or left lesion and ischemic or hemorrhagic etiology) who regained independent gait were assessed for global cognitive functioning and USN. All patients underwent a gait analysis session by using a wearable inertial system, kinematic parameters were computed. Enrolled patients presented altered motion parameters. Stroke patients with USN showed specific asymmetries in the following parameters: stance phase, swing phase, and knee range of motion. No differences in the clinical scores were found as the presence of USN. The presence of USN was associated with a specific form of altered gait symmetry. These findings may help clinicians to develop more tailored rehabilitative training to enhance gait efficacy of patients with motor defects complicated by the presence of selected cognitive impairments. Overview of the experiment setup. The workflow shows: diagnosis of unilateral spatial neglect by the neuropsychologist, sensors placement, gait analysis protocol and evaluation of the gait asymmetry together with the statistically significant features.

Superior Gait Symmetry and Postural Stability among Yoga Instructors-Inertial Measurement Unit-Based Evaluation.

This study investigates gait symmetry and single-leg stance balance of professional yoga instructors versus age-matched typically developed controls using inertial measurement unit (IMU)-based evaluation. We recruited twenty-five yoga instructors and twenty-five healthy control subjects to conduct the walking experiments and single-leg stance tests. Kinematic data were measured by attaching IMUs to the lower limbs and trunk. We assessed the asymmetry of swing phases during the normal-walk and tandem-walk tests with eyes open and closed, respectively. The subjects subsequently conducted four single-leg stance tests, including a single-leg stance on both legs with eyes open and closed. Two balance indexes regarding the angular velocities of the waist and chest were defined to assess postural stability. The gait asymmetry indexes of yoga instructors were significantly lower than those of the typically developed controls. Similarly, the yoga instructors had better body balance in all four single-leg stance tests. This study's findings suggest that yoga improves gait asymmetry and balance ability in healthy adults. In the future, further intervention studies could be conducted to confirm the effect of yoga training.

Reliability of a Global Gait Symmetry Index Based on Linear Joint Displacements

Gait symmetry is commonly used as an informal measure to assess functional gait recovery. As other outcome measures used for the evaluation of clinical change over time, gait symmetry indices must be reliable. However, studies assessing the reliability of symmetry indices are scarce and focused on discrete and local indices (i.e., peak joint angle, step length), which fail to assess overall gait symmetry. On the other hand, the repeatability of global symmetry indices (using multiple continuous waveforms) based on joint angles may be hampered by the sensitivity of these variables to marker placement imprecision. The aim of this study is to evaluate the test–retest intra-rater reliability and measurement error of an alternative global symmetry index. Two 3D gait analyses were performed on separate days (a week interval) on twenty-three healthy adults. Reliability and measurement error were assessed by calculating the intraclass correlation coefficient and the 95% limits of agreement, standard error of measurement and smallest detectable change, respectively. The new symmetry index presented acceptable results in terms of reliability (ICC = 0.71, 95% CI 0.33–0.88) and measurement error (95% LOA between −30.2% and 29.1%, SEM = 10.7% and SDC = 29.7%), thus being a more promising tool to assess overall gait symmetry.

Cycling Power Symmetry in Patients Early Post-Stroke With and Without Feedback: A Pilot Study

<h3>Research Objectives</h3> To determine the safety and feasibility of a recumbent cycling program in individuals early post stroke when provided biofeedback (BFB) about power symmetry. <h3>Design</h3> Individuals were randomized to either a treatment group that received the intervention or a standard-of-care control group. Individuals in the intervention group pedaled for 10 days with faded BFB. <h3>Setting</h3> University Inpatient Rehabilitation Facility (IRF). <h3>Participants</h3> Five individuals, 3 females, mean 12-days post-stroke, mean age 47 years, completed the study. <h3>Interventions</h3> All individuals performed submaximal cycling assessments without BFB on days 1 and 12 to determine peak heart rate and resistance at exhaustion. Day 1 and day 12 allowed assessment on cycling symmetry. The intervention group performed ten 30-minute sessions of cycling on a recumbent cycle ergometer fitted with commercial power meter pedals and head unit. They were provided faded BFB visually on a screen in front of them about total percent power contribution of each limb. The standard of care group underwent usual rehabilitation interventions. <h3>Main Outcome Measures</h3> Safety was determined by all individuals completing the intervention without health concerns (e.g. cardiovascular or orthopedic). Feasibility was determined by the ability to perform this type of intervention in an IRF setting with individuals early post-stroke. The limb symmetry index was used to evaluate power symmetry which is equal to the hemiparetic limb power divided by the non-hemiparetic limb power times 100. <h3>Results</h3> The intervention was safe (no adverse events) and feasible. Participants in the treatment group presented an average increase of 13.76 in power symmetry compared to an average increase of 3.15 in the control group. <h3>Conclusions</h3> The results of this work have potential to improve gait symmetries in an individual's early post-stroke compared to traditional therapy. The subacute phase is the optimal time for capitalizing on neuroplasticity and preventing ingrained deficient habits. Additionally, improved power production capacity in the hemiparetic limb may directly result in improved gait symmetry by improving weight shift. <h3>Author(s) Disclosures</h3> The authors have nothing to disclose.

Walking asymmetry and its relation to patient-reported and performance-based outcome measures in individuals with unilateral lower limb loss

ABSTRACT Gait asymmetry persists for most people after lower limb amputation and is associated with slower walking speeds. However, the relationship between gait asymmetry and patient-reported function remains unclear because they are not commonly assessed together. The purpose of this study was to determine relationships between gait asymmetries in people with lower limb loss and (1) patient-reported outcomes and (2) performance-based prosthetic functional measures. This cross-sectional analysis included nine people with unilateral limb loss aged 48.2 ± 13.1 years of mixed amputation etiology. Patient-reported outcomes included the Prosthetic Evaluation Questionnaire mobility subscale and Activities-specific Balance Confidence scale. Performance outcomes included the Berg Balance Scale and the 30-second sit-to-stand test. Walking performance measures included the 2-Minute Walk Test, during which APDM Opal sensors recorded spatiotemporal gait parameters, and daily step-counts from StepWatch4 activity monitors. The study found that the most asymmetric gait symmetry ratios (prosthetic-limb divided by intact-limb) could be attributed to prosthetic foot dorsiflexion-plantarflexion and rotation motion limitations: prosthetic-limb trailing double support (0.789 ± 0.052), toe-off (0.760 ± 0.068) and toe-out angle (0.653 ± 0.256). Single limb stance, and stance and swing phase durations were most strongly associated with balance and walking performance measures. Notably, no symmetry ratio was significantly associated with patient-reported prosthetic function (unadjusted Pearson correlation coefficients r < 0.50, P > 0.05). More gait symmetry was associated with better balance and walking performance but had no significant relationship with patient-reported function. Although achieving gait symmetry after lower limb loss is a common walking goal, symmetry was unrelated to the perception of functional mobility for people with lower limb loss.

Gait variability predicts cognitive impairment in older adults with subclinical cerebral small vessel disease.

Advanced methods of gait research, including approaches to quantify variability, and orderliness/regularity/predictability, are increasingly used to identify patients at risk for the development of cognitive impairment. Cerebral small vessel disease (CSVD) is highly prevalent in older adults and is known to contribute to the development of vascular cognitive impairment and dementia (VCID). Studies in preclinical models demonstrate that subclinical alterations precede CSVD-related cognitive impairment in gait coordination. In humans, CSVD also associates with gait abnormalities. The present study was designed to test the hypothesis that increased gait variability and gait asymmetry predict a decline in cognitive performance in older adults with CSVD. To test this hypothesis, we compared cognitive performance and gait function in patients with CSVD (age: 69.8 ± 5.3 years; n = 11) and age- and sex-matched control participants (age: 70.7 ± 5.8 years; n = 11). Based on imaging findings, patients with CSVD were identified [presence of white matter hyperintensities plus silent brain infarcts and/or microhemorrhages on magnetic resonance imaging (MRI) assessment]. Cognitive performance was assessed using the Cambridge Neuropsychological Test Automated Battery (CANTAB). Gait parameters were measured during the single and dual tasks, during which participants, in addition to the motor task, completed a series of mental arithmetic calculations. Spatial and temporal parameters of gait variability, symmetry, and permutation entropy were determined using a pressure-sensitive gait mat during single and dual cognitive task conditions. Patients with CSVD exhibited lower performance in a visual learning test (p = 0.030) and in a sustained attention test (p = 0.007). CSVD also affected step time variability (p = 0.009) and step length variability (p = 0.017). Step lengths of CSVD participants were more asymmetric (p = 0.043) than that of controls, while the two groups were statistically similar regarding step time symmetry and entropy of step time and length. Gait variability was inversely associated with sustained attention, especially among CSVD patients, and this relationship was significantly different between the two groups. The association of sustained attention with gait symmetry was also significantly different between the two groups. Our findings provide additional evidence in support of the concept that increased gait variability and asymmetry may predict cognitive impairment in older adults with CSVD.

Short Communication: changes in gait after 12 wk of shoeing in previously barefoot horses.

Farriery can impact gait symmetry and lameness outcomes, but there is limited scientific data documenting these effects. We hypothesized that shoeing previously barefoot horses with plain stamp shoes on the hind hooves would increase gait symmetry, alter hock angles and increase range of motion, and improve lameness scores more than shoeing with traditional fullered shoes. At the start of the study, gait symmetry via wireless inertial motion sensors (IMS), kinematic gait analysis (hock angle and range of motion), and American Association for Equine Practitioner's (AAEP) lameness scoring were completed for 14 barefoot horses. Horses were then trimmed and hind hooves were shod (wk 0) in three-quarter fullered shoes or plain stamp style shoes. Horses were trimmed and re-shod at week 6. At the end of 12 wk, the IMS analysis, kinematic gait analysis, and lameness scoring were repeated. Differences between shod and barefoot values were calculated for each horse, and impact of shoe type was analyzed via t-test. Significance was determined at P ≤ 0.05. No differences were observed in the IMS scores, hock angles or range of motion, or AAEP lameness scores between horses shod in fullered or plain stamp shoes (P ≥ 0.08). As no variables were determined to be significantly different between the two shoe types, data from all horses were combined to analyze the differences between the barefoot and shod state. Shoeing increased the maximum angle of the right and left hocks (P ≤ 0.03) and the minimum angle of the left (P = 0.02) but not right hock (P = 0.23) relative to barefoot conditions. No differences in hock range of motion were observed in either hock. Lower AAEP lameness scores were observed in horses when shod compared with barefoot (P = 0.001). In conclusion, shoeing previously barefoot horses improved AAEP lameness scores and increased hock angles, regardless of the type of shoe.