Gait Asymmetry Research Articles

Treadmill Training Plus Semi-Immersive Virtual Reality in Parkinson's Disease: Results from a Pilot Study.

Parkinson's disease (PD) is one of the most common neurodegenerative disorders that causes postural instability and gait alterations, such as reduced walking speed, shorter step length, and gait asymmetry, exposing patients to a higher risk of falling. Recently, virtual reality (VR) was added to a treadmill, in order to promote motor functional recovery and neuroplastic processes. Twenty PD patients were enrolled and randomly assigned to two groups: the experimental group (EG) and the control group (CG). In particular, patients in the EG were trained with the C-Mill, an innovative type of treadmill, which is equipped with semi-immersive VR, whereas the CG performed conventional physiotherapy. Patients in both groups were evaluated through a specific motor assessment battery at baseline (T0) and after the training (T1). Comparing pre-(T0) and post-(T1) treatment scores, in the EG, we found statistical significances in the following outcome measures: 6 Minutes Walking Test (6MWT) (p < 0.0005), Timed up and go (TUG right) (p < 0.03), Berg Balance Scale (BBS) (p < 0.006), Tinetti Scale (TS) (p < 0.002), Falls Efficacy Scale- International (FES-I), (p < 0.03) Unified PD Rating Scale-III (UPDRS) (p < 0.002), and Functional Independence Measure (FIM) (p < 0.004). Also, the CG showed statistical significances after the training. Between-group (EG and CG) analysis showed significative statistical differences in 6MWT (p < 0.006), BBS (p < 0.006), TS (p < 0.008), FES-I (p < 0.01), and FIM (p < 0.009). From our results it emerges that both groups (EG and CG) achieved better outcome scores after the treatment, suggesting that both physiotherapy interventions were effective. However, the EG training using VR seemed to have induced more improvements, especially in gait and balance skills. Then, C-Mill could be a valid adjunctive treatment in the context of gait and balance disturbances, which are very common in the PD population.

A Comparative Analysis of Symmetry Indices for Spatiotemporal Gait Features in Early Parkinson's Disease.

This study compared the five most commonly used equations for calculating gait symmetry in discrete variables among Parkinson's disease patients. Twelve patients (five women and seven men) performed ten consecutive gait trials on a 10 m walkway. Gait data were collected using eight optoelectronic cameras (100 fr/s). The analysis focused on various spatiotemporal parameters, including cadence, step time, stride time, single support, double support, walking speed, step length, stride length, step width, and foot angle. Five symmetry indices were calculated for each trial rather than averaging the ten recorded trials. The variability in and reliability of each symmetry equation were assessed using the coefficient of variation (CV) and intraclass correlation coefficient (ICC), respectively. Additionally, Bland-Altman plots were produced to visualize the agreement between each pair of methods for each spatiotemporal parameter. The results revealed that the symmetry ratio method exhibited lower variability and higher reliability compared with the other four indices across all spatiotemporal gait parameters. However, it was found that the reliability of a single trial was generally poor, regardless of the symmetry calculation formula used. Therefore, we recommend basing measurements of gait asymmetry in Parkinson's disease on multiple trials.

Attempted symmetry affects dynamic gait stability in individuals with lower-limb amputation

BackgroundGait in people with lower limb amputation (LLA) is typically asymmetrical. Reducing this asymmetry is often attempted to minimise the impact of secondary health issues. However, temporal-spatial asymmetry in gait of people with LLA has also been shown to underpin dynamic stability. Research questionThe current study aimed to identify the effects of acute attempts to achieve temporal-spatial symmetry on the dynamic stability of people with unilateral transtibial amputation (UTA). The secondary aim of this study was to identify the corresponding biomechanical adaptations during attempted symmetrical gait. MethodsEleven people with UTA walked along a 15 m walkway in four different conditions: normal (NORM), attempted symmetrical step length and step frequency (SYMSL+SF) attempted symmetrical step length (SYMSL) and attempted symmetrical step frequency (SYMSF). Dynamic stability was measured using the backward (BW) and medio-lateral (ML) margins of stability (MoS). ResultsResults indicate that attempting SYMSF had a positive effect on gait stability in BW and ML directions, while attempting SYMSL had a potentially negative effect, although these results did not appear to be significant. The absence of clustering in principal component analysis, supported the lack of significant results, indicating no features differentiating between conditions of attempted symmetry. Conversely, there was clustering by limbs which were associated with differences in knee and ankle joint angles between the prosthetic and non-prosthetic limbs, and clustering by individuals highlighting the importance of patient-specific analysis. ConclusionThe data suggests that attempted symmetrical gait reduces asymmetry but also affects dynamic stability.

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

ABSTRACT 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.

Absent loading response knee flexion: The impact on gait kinetics and centre of mass motion in individuals with unilateral transfemoral amputation, and the effect of microprocessor controlled knee provision

BackgroundIndividuals with unilateral transfemoral amputation walk with increased levels of asymmetry, and this is associated with reduced gait efficiency, back pain and overuse of the intact limb. This study investigated the effect of walking with a unilateral absence of loading response knee flexion on the symmetry of anterior-posterior kinetics and centre of mass accelerations. MethodsA retrospective cohort study design was used, assessing three-dimensional gait data from individuals with unilateral transfemoral amputation (n = 56). The anterior-posterior gait variables analysed included; peak ground reaction forces, impulse, centre of mass acceleration, as well as rate of vertical ground reaction force increase in early stance. With respect to these variables, this study assessed the symmetry between intact and prosthetic limbs, compared intact limbs against a healthy unimpaired control group, and evaluated effect on symmetry of microprocessor controlled knee provision. FindingsSignificant between-limb asymmetries were found between intact and prosthetic limbs across all variables (p < 0.0001). Intact limbs showed excessive loading when compared with control group limbs after speed normalisation across all variables (p < 0.0001). No improvement in kinetic symmetry following microprocessor controlled knee provision was found. InterpretationThe gait asymmetries for individuals with transfemoral amputation identified in this study suggest that more should be done by developers to address the resultant overloading of the intact limb, as this is thought to have negative long-term effects. The provision of microprocessor controlled knees did not appear to improve the asymmetries faced by individuals with transfemoral amputation, and clinicians should be aware of this when managing patient expectations.

Electrocortical activity correlated with locomotor adaptation during split-belt treadmill walking.

Locomotor adaptation is crucial for daily gait adjustments to changing environmental demands and obstacle avoidance. Mobile brain imaging with high-density electroencephalography (EEG) now permits quantification of electrocortical dynamics during human locomotion. To determine the brain areas involved in human locomotor adaptation, we recorded high-density EEG from healthy, young adults during split-belt treadmill walking. We incorporated a dual-electrode EEG system and neck electromyography to decrease motion and muscle artefacts. Voluntary movement preparation and execution have been linked to alpha (8-13Hz) and beta band (13-30Hz) desynchronizations in the sensorimotor and posterior parietal cortices, whereas theta band (4-7Hz) modulations in the anterior cingulate have been correlated with movement error monitoring. We hypothesized that relative to normal walking, split-belt walking would elicit: (1) decreases in alpha and beta band power in sensorimotor and posterior parietal cortices, reflecting enhanced motor flexibility; and (2) increases in theta band power in anterior cingulate cortex, reflecting instability and balance errors that will diminish with practice. We found electrocortical activity in multiple regions that was associated with stages of gait adaptation. Data indicated that sensorimotor and posterior parietal cortices had decreased alpha and beta band spectral power during early adaptation to split-belt treadmill walking that gradually returned to pre-adaptation levels by the end of the adaptation period. Our findings emphasize that multiple brain areas are involved in adjusting gait under changing environmental demands during human walking. Future studies could use these findings on healthy, young participants to identify dysfunctional supraspinal mechanisms that may be impairing gait adaptation. KEY POINTS: Identifying the location and time course of electrical changes in the brain correlating with gait adaptation increases our understanding of brain function and provides targets for brain stimulation interventions. Using high-density EEG in combination with 3D biomechanics, we found changes in neural oscillations localized near the sensorimotor, posterior parietal and cingulate cortices during split-belt treadmill adaptation. These findings suggest that multiple cortical mechanisms may be associated with locomotor adaptation, and their temporal dynamics can be quantified using mobile EEG. Results from this study can serve as a reference model to examine brain dynamics in individuals with movement disorders that cause gait asymmetry and reduced gait adaptation.

Gait asymmetry in children with Duchenne muscular dystrophy: evaluated through kinematic synergies and muscle synergies of lower limbs

BackgroundGait is a complex, whole-body movement that requires the coordinated action of multiple joints and muscles of our musculoskeletal system. In the context of Duchenne muscular dystrophy (DMD), a disease characterized by progressive muscle weakness and joint contractures, previous studies have generally assumed symmetrical behavior of the lower limbs during gait. However, such a symmetric gait pattern of DMD was controversial. One aspect of this is criticized, because most of these studies have primarily focused on univariate variables, rather than on the coordination of multiple body segments and even less investigate gait symmetry under a motor synergy of view.MethodsWe investigated the gait pattern of 20 patients with DMD, compared to 18 typical developing children (TD) through 3D Gait Analysis. Kinematic and muscle synergies were extracted with principal component analysis (PCA) and non-negative matrix factorization (NNMF), respectively. The synergies extracted from the left and right sides were compared with each other to obtain a symmetry value. In addition, bilateral spatiotemporal variables of gait, such as stride length, percentage of stance and swing phase, step length, and percentage of double support phase, were used for calculating the symmetry index (SI) to evaluate gait symmetry as well.ResultsCompared with the TD group, the DMD group walked with decreased gait velocity (both p < 0.01), stride length (both p < 0.01), and step length (both p < 0.001). No significant difference was found between groups in SI of all spatiotemporal parameters extracted between the left and right lower limbs. In addition, the DMD group exhibited lower kinematic synergy symmetry values compared to the TD group (p < 0.001), while no such significant group difference was observed in symmetry values of muscle synergy.ConclusionsThe findings of this study suggest that DMD influences, to some extent, the symmetry of synergistic movement of multiple segments of lower limbs, and thus kinematic synergy appears capable of discriminating gait asymmetry in children with DMD when conventional spatiotemporal parameters are unchanged.

Walking speed differentially affects lower extremity biomechanics in individuals with anterior cruciate ligament reconstruction compared to uninjured controls

BackgroundWalking biomechanics are commonly affected after anterior cruciate ligament reconstruction and differ compared to uninjured controls. Manipulating task difficulty has been shown to affect the magnitude of walking impairments in those early after knee surgery but it is unclear if patients in later phases post-op are similarly affected by differing task demands. Here, we evaluated the effects of manipulating walking speed on between-limb differences in ground reaction force and knee biomechanics in those with and without anterior cruciate ligament reconstruction. MethodsWe recruited 28 individuals with anterior cruciate ligament reconstruction and 20 uninjured control participants to undergo walking assessments at three speeds (self-selected, 120%, and 80% self-selected speed). Main outcomes included sagittal plane knee moments, angles, excursions, and ground reaction forces (vertical and anterior-posterior). FindingsWe observed walking speed differentially impacted force and knee-outcomes in those with anterior cruciate ligament reconstruction. Between-limb differences increased at fast and decreased at slow speeds in those with anterior cruciate ligament reconstruction while uninjured participants maintained between-limb differences regardless of speed (partial η2 = 0.13–0.33, p < 0.05). Anterior cruciate ligament reconstruction patients underloaded the surgical limb relative to both the contralateral, and uninjured controls in GRFs and sagittal plane knee moments (partial η2 range = 0.13–0.25, p < 0.05). InterpretationOverall, our findings highlight the persistence of walking impairments in those with anterior cruciate ligament reconstruction despite completing formal rehabilitation. Further research should consider determining if those displaying larger changes in gait asymmetries in response to fast walking also exhibit poorer strength and/or joint health outcomes.

Bilateral Asymmetry in Knee and Hip Musculoskeletal Loading During Stair Ascending/Descending in Individuals with Unilateral Mild-to-Moderate Medial Knee Osteoarthritis

Most cases of unilateral knee osteoarthritis (OA) progress to bilateral OA within 10 years. Biomechanical asymmetries have been implicated in contralateral OA development; however, gait analysis alone does not consistently detect asymmetries in OA patient gait. Stair ambulation is a more demanding activity that may be more suited to reveal between-leg asymmetries in OA patients. The objective of this study was to investigate the between-leg biomechanical differences in patients with unilateral mild-to-moderate knee OA. Sixteen unilateral mild-to-moderate medial knee OA patients and 16 healthy individuals underwent kinematic and kinetic analysis of stair ascent and descent. Stair ascent produced higher loading and muscle forces in the unaffected limb compared to the OA limb, and stair descent produced lower loading on the OA limb compared to healthy subjects. These biomechanical differences were apparent in the ankle, knee, and hip joints. The implications of these findings are that OA patients rely more heavily on their unaffected sides than the affected side in stair ascent, a strategy that may be detrimental to the unaffected joint health. The reduction in affected limb loading in stair descent is thought to be related to minimizing pain.

The effects of gastrocnemius muscle spasticity on gait symmetry and trunk control in chronic stroke patients

BackgroundAlthough reduced gait asymmetry and trunk control are generally accepted outcomes in stroke patients after having a stroke, the number of studies examining the factors affecting gait symmetry and trunk control is limited in the literature. Research questionWhat are the effects of gastrocnemius muscle spasticity on trunk control and gait symmetry in chronic stroke patients? MethodThe sample of the study included 29 individuals aged 40–70 who were diagnosed with stroke at least six months ago. The sociodemographic information of the patients was collected using a descriptive information form. Their gastrocnemius muscle spasticity levels were assessed using the Modified Ashworth Scale (MAS), their trunk control was assessed using the Trunk Impairment Scale (TIS), and their gait symmetry was assessed using software developed for the Kinect V2 camera. ResultsThere was a numerical difference between the gait symmetry results of the patients who had a MAS score lower than 2 and those who had a MAS score of 2 or higher, where MAS scores corresponded to gastrocnemius muscle spasticity levels, but this difference was not statistically significant (p > 0.05). There was a statistically significant difference between the total TIS scores and TIS coordination subscale scores of the patients who had a MAS score lower than 2 and those who had a MAS score of 2 or higher (p < 0.05). A negative significant relationship was determined between total TIS and TIS coordination subscale scores and the severity of gastrocnemius muscle spasticity. SignificanceAccording to the results of our study, to improve trunk control and gait in stroke survivors, the management of gastrocnemius muscle spasticity should be included in rehabilitation programs. We believe that our study will be guiding for future interventional studies aiming to improve trunk control and gait in stroke patients.

Mechanical Asymmetries during Treadmill Running: Effects of Running Velocity and Hypoxic Exposure

Studies evaluating mechanical asymmetry across a range of running velocities during treadmill runs have yielded inconsistent findings, while the impact of additional hypoxic exposure has never been investigated. The aim of this study was to characterize the effects of manipulating running velocity and hypoxic exposure on gait asymmetry during treadmill running. Eleven trained individuals performed seven runs at different velocities (8, 10, 12, 14, 16, 18, and 20 km·h−1) in a randomized order, each lasting 45 s. The running took place on an instrumented treadmill for normoxia (FiO2 = 20.9%), moderate hypoxia (FiO2 = 16.1%), high hypoxia (FiO2 = 14.1%), and severe hypoxia (FiO2 = 13.0%). Vertical and antero-posterior ground reaction force recordings over 20 consecutive steps (i.e., after running ∼25 s) allowed the measurement of running mechanics. Lower-limb asymmetry was assessed from the ‘symmetry angle’ (SA) score. Two-way repeated-measures ANOVA (seven velocities × four conditions) was used. There was no significant difference in SA scores for any of the biomechanical variables for velocity (except contact time and braking phase duration; p = 0.003 and p = 0.002, respectively), condition, or interaction. Mean SA scores varied between ∼1% and 2% for contact time (1.5 ± 0.8%), flight time (1.6 ± 0.6%), step length (0.8 ± 0.2%), peak vertical force (1.2 ± 0.5%), and mean vertical loading rate (2.1 ± 1.0%). Mean SA scores ranged from ∼2% to 5% for duration of braking (1.6 ± 0.7%) and push-off phases (1.9 ± 0.6%), as well as peak braking (5.0 ± 1.9%) and push-off forces (4.8 ± 1.7%). In conclusion, the trained runners exhibited relatively even strides, with mechanical asymmetries remaining low-to-moderate across a range of submaximal, constant running velocities (ranging from 8 to 20 km·h−1) and varying levels of hypoxia severity (between normoxia and severe hypoxia).

Split-Belt Treadmill Adaptation Improves Spatial and Temporal Gait Symmetry in People with Multiple Sclerosis

Multiple sclerosis (MS) is a neurodegenerative disease characterized by degradation of the myelin sheath resulting in impaired neural communication throughout the body. As a result, most people with MS (PwMS) experience gait asymmetries between their legs leading to an increased risk of falls. Recent work indicates that split-belt treadmill adaptation, where the speed of each leg is controlled independently, can decrease gait asymmetries for other neurodegenerative impairments. The purpose of this study was to test the efficacy of split-belt treadmill training to improve gait symmetry in PwMS. In this study, 35 PwMS underwent a 10 min split-belt treadmill adaptation paradigm, with the faster paced belt moving under the more affected limb. Step length asymmetry (SLA) and phase coordination index (PCI) were the primary outcome measures used to assess spatial and temporal gait symmetries, respectively. It was predicted that participants with a worse baseline symmetry would have a greater response to split-belt treadmill adaptation. Following this adaptation paradigm, PwMS experienced aftereffects that improved gait symmetry, with a significant difference between predicted responders and nonresponders in both SLA and PCI change (p &lt; 0.001). Additionally, there was no correlation between SLA and PCI change. These findings suggest that PwMS retain the ability for gait adaptation, with those most asymmetrical at baseline demonstrating the greatest improvement, and that there may be separate neural mechanisms for spatial and temporal locomotor adjustments.

La récupération de la marche n’est pas corrélée à des lésions méniscales et/ou ligamentaires du genou après fracture du plateau tibial latéral. Une étude de cohorte prospective de 56 patients au recul de 3 ans

IntroductionThough associated meniscus and/or knee ligament injuries following lateral tibial plateau fractures (TPF) are common, the importance of development in gait recovery is unknown. This study aim to report the 12- and 36-month gait recovery in patients with lateral TPF divided into two groups presenting with and without associated meniscus and/or knee ligament injuries. (Associated meniscus and/or knee ligament injuries were grouped as: 1) missing, 2) lateral or medial menisci, 3) posterior and anterior cruciate ligament (PCL/ACL), and 4) lateral or medial collateral ligament.) HypothesisComparable results at the 12- and 36-month follow-up between groups presenting with and without soft tissue injuries. Patients and methodsStudy design: cohort study. Included were patients admitted following a lateral TPF (AO-type 41 B) between December 1, 2013 and November 30, 2016. The primary outcome score was gait sample. ResultsFifty-six patients were included. The mean age of the patients at the time of fracture was 56 years (range from 22 to 86). Female gender represents 75%. MRI-verified associated meniscus and/or knee ligament injuries were observed in 28 patients (50%). The average gait speed at the 12- and 36-month follow-up were 125.7 (SD31.3) and 127.7 (SD16.6) cm/sec. for patients with associated meniscus and/or knee ligament injuries and 125.2 (SD31.1) and 130.1 (SD15.6) cm/sec. for patients without associated meniscus and/or knee ligament injuries (p=0.96, p=0.17). Regardless of soft tissue injuries, the development in percent of gait asymmetry for step-length and single-support decrease significantly between the 12- and the 36-month follow-up. (p>0.002) DiscussionThis study indicates that gait recovery following lateral TPFs were not associated with associated meniscus and/or knee ligament injuries at the 12- and 36-month follow-up. Between the 12- and 36-month follow-up asymmetry of the gait function decline significantly indicating a prolonged recovery period of gait function following TPFs. Level of evidenceII; prospective cohort study.

Overground Robotic Gait Trainer mTPAD Improves Gait Symmetry and Weight Bearing in Stroke Survivors

Stroke is a leading cause of disability, impairing the ability to generate propulsive forces and causing significant lateral gait asymmetry. We aim to improve stroke survivors’ gaits by promoting weight-bearing during affected limb stance. External forces can encourage this; e.g., vertical forces can augment the gravitational force requiring higher ground reaction forces, or lateral forces can shift the center of mass over the stance foot, altering the lateral placement of the center of pressure. With our novel design of a mobile Tethered Pelvic Assist Device (mTPAD) paired with the DeepSole system to predict the user’s gait cycle percentage, we demonstrate how to apply three-dimensional forces on the pelvis without lower limb constraints. This work is the first result in the literature that shows that with an applied lateral force during affected limb stance, the center of pressure trajectory’s lateral symmetry is significantly closer to a 0% symmetry (5.5%) than without external force applied (−9.8%,p&lt;0.05). Furthermore, the affected limb’s maximum relative pressure (p) significantly increases from 233.7p to 234.1p (p&lt;0.05) with an applied downward force, increasing affected limb loading. This work highlights how the mTPAD increases weight-bearing and propulsive forces during gait, which is a crucial goal for stroke survivors.

Development of an Integrated Powered Hip and Microprocessor-Controlled Knee for a Hip-Knee-Ankle-Foot Prosthesis.

Hip-knee-ankle-foot prostheses (HKAF) are full lower-limb devices for people with hip amputations that enable individuals to regain their mobility and move freely within their chosen environment. HKAFs typically have high rejection rates among users, as well as gait asymmetry, increased trunk anterior-posterior lean, and increased pelvic tilt. A novel integrated hip-knee (IHK) unit was designed and evaluated to address the limitations of existing solutions. This IHK combines powered hip and microprocessor-controlled knee joints into one structure, with shared electronics, sensors, and batteries. The unit is also adjustable to user leg length and alignment. ISO-10328:2016 standard mechanical proof load testing demonstrated acceptable structural safety and rigidity. Successful functional testing involved three able-bodied participants walking with the IHK in a hip prosthesis simulator. Hip, knee, and pelvic tilt angles were recorded and stride parameters were analyzed from video recordings. Participants were able to walk independently using the IHK and data showed that participants used different walking strategies. Future development of the thigh unit should include completion of a synergistic gait control system, improved battery-holding mechanism, and amputee user testing.

Long-term locked knee ankle foot orthosis use: A perspective overview of iatrogenic biomechanical and physiological perils.

A knee ankle foot orthosis (KAFO) may be prescribed to the person with severe neuromusculoskeletal impairment of the lower limb to promote walking stability. The locked knee ankle foot orthosis (L-KAFO) is among the KAFO's routinely prescribed; however, long-term use of the L-KAFO is associated with musculoskeletal (arthrogenic and myogenic) and integumentary changes, and gait asymmetry with increased energy expenditure. Consequently, the risk of developing low back pain, osteoarthritis of the lower limbs and spinal joints, skin dermatitis, and ulceration increases, all of which impact quality of life. This article synthesizes the iatrogenic biomechanical and physiological perils of long-term L-KAFO use. It promotes using recent advances in rehabilitation engineering to improve daily activities and independence for proper patient groups.

The Transcallosal Highway: The ipsilateral silent period as a neural biomarker for impaired corpus callosum communication in multiple sclerosis

Multiple sclerosis is a neurodegenerative disease that damages myelin sheath within the central nervous system. This axonal demyelination impacts communication between the brain's hemispheres in persons with multiple sclerosis (PwMS). Changes in transcallosal communication impairs the coordination of movements requiring precise temporal and spatial components such as lower extremity function during gait. These bilateral movements require constant communication across the corpus callosum to excite and inhibit specific muscle groups. The ipsilateral silent period (iSP) is an indirect marker of the magnitude for transcallosal inhibition. We hypothesize that the iSP may also serve as a neural biomarker for transcallosal impairments originating from the more affected hemisphere and highlight underlying mechanisms for gait asymmetries in PwMS. Our ongoing study utilizes transcranial magnetic stimulation to assess the inhibitory capacity between the brain's hemispheres (i.e., iSPs). A focal magnetic pulse is delivered to the first dorsal interosseous resulting in a suppression of muscle activity, thus reflecting inhibitory transcallosal communication. There is a lack of research analyzing directionality data between the more and less affected hemisphere in PwMS. Therefore, we evaluate outcome metrics dependent upon the individual's more affected hemisphere. Twenty-three PwMS completed the ongoing protocol and inhibitory metrics such as depth iSP% average, duration, depth iSP% max, transcallosal conduction time, and onset latency were collected. No statistically significant differences have been found between the two hemispheres in PwMS. However, beyond directionality data, our study is investigating gait coordination with overall inhibitory capacity. Walking coordination is quantified using a metric called phase coordination index (PCI). A greater PCI value reflects poorer gait coordination. We hypothesize those who demonstrate better gait coordination (lower PCI values), will have a greater iSP. These findings will determine the potential of iSPs as a neural biomarker to address gait asymmetries and stratify participants into individualized mobility rehabilitation protocols. Multiple sclerosis is a neurodegenerative disease that damages myelin sheath within the central nervous system. This axonal demyelination impacts communication between the brain's hemispheres in persons with multiple sclerosis (PwMS). Changes in transcallosal communication impairs the coordination of movements requiring precise temporal and spatial components such as lower extremity function during gait. These bilateral movements require constant communication across the corpus callosum to excite and inhibit specific muscle groups. The ipsilateral silent period (iSP) is an indirect marker of the magnitude for transcallosal inhibition. We hypothesize that the iSP may also serve as a neural biomarker for transcallosal impairments originating from the more affected hemisphere and highlight underlying mechanisms for gait asymmetries in PwMS. Our ongoing study utilizes transcranial magnetic stimulation to assess the inhibitory capacity between the brain's hemispheres (i.e., iSPs). A focal magnetic pulse is delivered to the first dorsal interosseous resulting in a suppression of muscle activity, thus reflecting inhibitory transcallosal communication. There is a lack of research analyzing directionality data between the more and less affected hemisphere in PwMS. Therefore, we evaluate outcome metrics dependent upon the individual's more affected hemisphere. Twenty-three PwMS completed the ongoing protocol and inhibitory metrics such as depth iSP% average, duration, depth iSP% max, transcallosal conduction time, and onset latency were collected. No statistically significant differences have been found between the two hemispheres in PwMS. However, beyond directionality data, our study is investigating gait coordination with overall inhibitory capacity. Walking coordination is quantified using a metric called phase coordination index (PCI). A greater PCI value reflects poorer gait coordination. We hypothesize those who demonstrate better gait coordination (lower PCI values), will have a greater iSP. These findings will determine the potential of iSPs as a neural biomarker to address gait asymmetries and stratify participants into individualized mobility rehabilitation protocols.

Splitting the Difference: Split-Belt Treadmill Training Improves Spatial and Temporal Gait Symmetry in People with Multiple Sclerosis

Multiple sclerosis (MS) is a neurodegenerative disease affecting two million people worldwide. This disease is characterized by degradation of the myelin sheath resulting in impaired neural communication throughout the body. As a result, most people with MS (PwMS) experience significant mobility impairments. Gait asymmetries between the two legs are prevalent leading to an increased risk of falls, musculoskeletal injury, and decreased quality of life. Recent work indicates that split-belt treadmill training, where the speed of each leg is controlled independently, can decrease gait asymmetries for other neurodegenerative impairments. In this study, 26 PwMS have undergone split-belt treadmill training, with the faster paced belt moving under the more affected limb. Phase coordination index (PCI), which measures temporal coordination to assess stepping accuracy and consistency, and limb excursion asymmetry (LEA), which measures spatial coordination by quantifying sagittal displacement from toe off to heel strike of the ipsilateral leg, are the primary outcome measures used to assess gait symmetry in the current study. Previous work has identified an average PCI for PwMS population to be 5.19%, thus we grouped participants based on their baseline PCI value as either 1) above (poor baseline symmetry) or 2) below (good baseline symmetry) the previously recorded MS mean PCI of 5.19%, predicting that participants with a baseline PCI greater than 5.19% would show a greater response to split-belt treadmill training. Preliminary results show a mean PCI change of -1.31% (SE=0.65) for the poor baseline symmetry group and a mean PCI change of 0.92% (SE: 0.32) (p=0.0062). Among participants with poor baseline symmetry, the mean LEA change is -13.02mm (SE: 5.25) compared to a mean LEA change of 0.83mm (SE=3.35) for participants with good baseline symmetry (p=0.037). These findings suggest that PwMS retain the ability for gait adaptation, and provide the template for a novel, targeted mobility intervention. Multiple sclerosis (MS) is a neurodegenerative disease affecting two million people worldwide. This disease is characterized by degradation of the myelin sheath resulting in impaired neural communication throughout the body. As a result, most people with MS (PwMS) experience significant mobility impairments. Gait asymmetries between the two legs are prevalent leading to an increased risk of falls, musculoskeletal injury, and decreased quality of life. Recent work indicates that split-belt treadmill training, where the speed of each leg is controlled independently, can decrease gait asymmetries for other neurodegenerative impairments. In this study, 26 PwMS have undergone split-belt treadmill training, with the faster paced belt moving under the more affected limb. Phase coordination index (PCI), which measures temporal coordination to assess stepping accuracy and consistency, and limb excursion asymmetry (LEA), which measures spatial coordination by quantifying sagittal displacement from toe off to heel strike of the ipsilateral leg, are the primary outcome measures used to assess gait symmetry in the current study. Previous work has identified an average PCI for PwMS population to be 5.19%, thus we grouped participants based on their baseline PCI value as either 1) above (poor baseline symmetry) or 2) below (good baseline symmetry) the previously recorded MS mean PCI of 5.19%, predicting that participants with a baseline PCI greater than 5.19% would show a greater response to split-belt treadmill training. Preliminary results show a mean PCI change of -1.31% (SE=0.65) for the poor baseline symmetry group and a mean PCI change of 0.92% (SE: 0.32) (p=0.0062). Among participants with poor baseline symmetry, the mean LEA change is -13.02mm (SE: 5.25) compared to a mean LEA change of 0.83mm (SE=3.35) for participants with good baseline symmetry (p=0.037). These findings suggest that PwMS retain the ability for gait adaptation, and provide the template for a novel, targeted mobility intervention.

Autonomous Control of Music to Retrain Walking After Stroke

Background Post-stroke care guidelines highlight continued rehabilitation as essential; however, many stroke survivors cannot participate in outpatient rehabilitation. Technological advances in wearable sensing, treatment algorithms, and care delivery interfaces have created new opportunities for high-efficacy rehabilitation interventions to be delivered autonomously in any setting (ie, clinic, community, or home). Methods We developed an autonomous rehabilitation system that combines the closed-loop control of music with real-time gait analysis to fully automate patient-tailored walking rehabilitation. Specifically, the mechanism-of-action of auditory-motor entrainment is applied to induce targeted changes in the post-stroke gait pattern by way of targeted changes in music. Using speed-controlled biomechanical and physiological assessments, we evaluate in 10 individuals with chronic post-stroke hemiparesis the effects of a fully-automated gait training session on gait asymmetry and the energetic cost of walking. Results Post-treatment reductions in step time (Δ: −12 ± 26%, P = .027), stance time (Δ: −22 ± 10%, P = .004), and swing time (Δ: −15 ± 10%, P = .006) asymmetries were observed together with a 9 ± 5% reduction (P = .027) in the energetic cost of walking. Changes in the energetic cost of walking were highly dependent on the degree of baseline energetic impairment (r =− .90, P < .001). Among the 7 individuals with a baseline energetic cost of walking larger than the normative value of healthy older adults, a 13 ± 4% reduction was observed after training. Conclusions The closed-loop control of music can fully automate walking rehabilitation that markedly improves walking after stroke. Autonomous rehabilitation delivery systems that can safely provide high-efficacy rehabilitation in any setting have the potential to alleviate access-related care gaps and improve long-term outcomes after stroke.

71 Lameness responses to a single exercise bout following dietary supplementation of Saccharomyces cerevisiae fermentation product in young horses

Yearling Quarter Horses (mean ± SEM; 561 ± 3 d; 373.3 ± 5 kg BW; 13 fillies, 14 colts) were used in a randomized complete block to test the hypothesis that dietary supplementation of a postbiotic Saccharomyces cerevisiae fermentation product (SCFP) mitigates lameness following a single exercise bout in young horses. For the 76-d trial, yearlings were fed a basal diet of 1% BW/d (as-fed) grain-based horse feed formulated without added microbials (SafeChoice® Original, Nutrena) twice daily plus ad libitum Coastal bermudagrass (Cynodon datylon) hay, and water. Horses were grouped by age, sex, and BW and randomly assigned to 1) concentrate only (CON; n = 10), 2) concentrate top dressed with 46 mg/kg SCFP (TRT 1; n = 8), or 3) concentrate top dressed with 92 mg/kg SCFP (TRT 2; n = 9). Objective lameness assessments were obtained by a wireless Inertial Sensor System (ISS) followed by a subjective evaluation performed by a licensed veterinarian. All horses underwent a baseline lameness assessment on d 0, followed by 2 lameness assessments on d 76 (pre-exercise, and post-exercise). Objective lameness evaluations were performed at the trot for 2 30 m, back-and-forth passes, wearing the wireless ISS lameness analysis system and evaluated in triplicate per assessment. For the subjective lameness analysis, horses were additionallytrotted in a circle in both directions within a 16 × 14 m area and evaluated by an individual licensed veterinarian using the American Association of Equine Practitioners (AAEP) lameness scale. Data were analyzed using PROC GLM in SAS v9.4 with diet and time included as fixed effects. When analyzing AAEP lameness evaluations, no differences were detected for dietary treatment or diet × time interactions related to primary (P = 0.55; P = 0.98), secondary (P = 0.43; P = 0.78), or tertiary (P = 0.77; P = 0.77) limbs. Additionally, no dietary treatment effects or diet × time interactions were detected using the wireless ISS for front Q score (P = 0.19; P = 0.92) or hind pushoff Q score (P = 0.53; P = 0.27). Furthermore, there was no effect of dietary treatment on hind impact Q score (P = 0.68). However, there tended to be a diet × time interaction (P = 0.06) whereby horses on TRT 2 tended to have a lower hind impact Q score. Additionally, post-exercise front Q scores increased over time (P ≤ 0.01) compared with both baseline and pre-exercise values regardless of dietary treatment. These results indicate the intensity of exercise may not have been sufficient to lead to dietary differences related to gait asymmetry.