scholarly journals A Unilateral Robotic Knee Exoskeleton to Assess the Role of Natural Gait Assistance in Hemiparetic Patients

2021 ◽  
Author(s):  
Julio Salvador Lora-Millan ◽  
Francisco José Sanchez-Cuesta ◽  
Juan Pablo Romero ◽  
Juan C. Moreno ◽  
Eduardo Rocon
Keyword(s):  
Control Strategies ◽  
Gait Pattern ◽  
Lower Limbs ◽  
Motor Deficits ◽  
Compensatory Mechanisms ◽  
Gait Symmetry ◽  
Paretic Limb ◽  
Hemiparetic Gait ◽  
Preliminary Validation ◽  
Technical Validation

Abstract Background: Hemiparetic gait is characterized by strong asymmetries that could severely affect the quality of life of stroke survivors. This asymmetry is due to motor deficits in the paretic leg and the resulting compensations in the non-paretic limb. In this study, we aim to evaluate the effect of actively promoting gait symmetry in hemiparetic patients by assessing the behavior of both paretic and non-paretic lower limbs. This paper introduces the design and validation of the REFLEX prototype, a unilateral active Knee-Ankle-Foot Orthosis able to naturally assist the paretic limb of hemiparetic patients during gait.Methods: REFLEX uses an Adaptive Frequency Oscillator to estimate the continuous gait phase of the non-paretic limb. Based on this estimation, the device synchronically assists the paretic leg following two different control strategies: (1) Replicating the movement of the sound leg or (2) Inducing a healthy gait pattern on the paretic leg. Technical validation of the system was implemented on three healthy subjects, while the effect of the generated assistance was assessed in three stroke patients. Results: Preliminary results proved the feasibility of the REFLEX prototype to assist gait by reinforcing symmetry. They also pointed out that the assistance of the paretic leg resulted in a decrease of the compensatory strategies developed by the non-paretic limb to achieve a functional gait. Notably, better results were attained when the assistance was provided according to a standard healthy pattern, which initially might suppose a lower symmetry but enabled a healthier evolution of the motion of the non-paretic limb.Conclusions: This work presents the preliminary validation of the REFLEX prototype, a unilateral knee exoskeleton for gait assistance in hemiparetic patients. The experimental results indicate that assisting the paretic leg of hemiparetic patients based on the movement of their non-paretic one is a valuable strategy for reducing the compensatory mechanisms developed by their sound limb.

Hemiparetic Gait Parameters in Overground Versus Treadmill Walking

2001 ◽  
Vol 15 (2) ◽  
pp. 105-112 ◽  
Author(s):  
Michelle L. Harris-Love ◽  
Larry W. Forrester ◽  
Richard F. Macko ◽  
Kenneth H. C. Silver ◽  
Gerald V. Smith
Keyword(s):  
Gait Pattern ◽  
Supporting Evidence ◽  
Gait Symmetry ◽  
Paretic Limb ◽  
Hemiparetic Gait ◽  
Gait Parameters ◽  
Stance Time ◽  
Hemiparetic Stroke ◽  
Chronic Hemiparetic Stroke ◽  
Sparse Methods

Objective: Hemiparetic gait is characterized by high stride-cycle variability, di minished stance time, single-limb stance time, and stance/swing ratio in the paretic limb. Recent studies suggest treadmill (TM) training may improve the motor control underlying these variables, but supporting evidence is sparse. Methods: This study compared gait patterns of untrained chronic hemiparetic stroke patients (n = 18; mean, 39.5 months poststroke) during overground (OG) and TM walking at matched velocities. Variables included relative stance time, relative single-limb stance time, stance/swing ratio, peak force, and impulse. Within-subject variability of these meas ures (CV) was used to assess gait pattern stability. Results: OG and TM cycle dura tions were similar, but CVs differed (TM < OG, p < 0.05). In the paretic limb, dif ferences were seen in relative stance time, relative single-limb stance time, and stance/swing ratio, respectively (TM > OG, p < 0.05). These variables decreased in the nonparetic limb during TM walking (p < 0.05 for all). Improved interlimb sym metry and coordination were evidenced by decreased between-limb differences and improved relative temporal phasing, respectively, in the TM condition (p < 0.05). Conclusions: Collectively, these results demonstrate that the TM induces an imme diate alteration toward a more consistent and symmetric gait pattern. Further inves tigation is needed to determine whether TM training leads to motor relearning and neuroplasticity in chronic hemiparetic subjects. Key Words: Stroke—Rehabilitation— Hemiparetic gait-Treadmill-Gait symmetry.

scholarly journals Mental state space visualization for interactive modeling of personalized BCI control strategies

2019 ◽  
Author(s):  
Ilya Kuzovkin ◽  
Konstantin Tretyakov ◽  
Andero Uusberg ◽  
Raul Vicente
Keyword(s):  
State Space ◽  
Mental State ◽  
Control Strategies ◽  
Muscular Activity ◽  
Mental States ◽  
Learning System ◽  
Self Organizing Map ◽  
Preliminary Validation ◽  
Som Algorithm ◽  
Mental Actions

AbstractObjectiveNumerous studies in the area of BCI are focused on the search for a better experimental paradigm – a set of mental actions that a user can evoke consistently and a machine can discriminate reliably. Examples of such mental activities are motor imagery, mental computations, etc. We propose a technique that instead allows the user to try different mental actions in the search for the ones that will work best.ApproachThe system is based on a modification of the self-organizing map (SOM) algorithm and enables interactive communication between the user and the learning system through a visualization of user’s mental state space. During the interaction with the system the user converges on the paradigm that is most efficient and intuitive for that particular user.Main resultsResults of the two experiments, one allowing muscular activity, another permitting mental activity only, demonstrate soundness of the proposed method and offer preliminary validation of the performance improvement over the traditional closed-loop feedback approach.SignificanceThe proposed method allows a user to visually explore their mental state space in real time, opening new opportunities for scientific inquiry. The application of this method to the area of brain-computer interfaces enables more efficient search for the mental states that will allow a user to reliably control a BCI system.

scholarly journals Human Gait Cycle Analysis Using Kinect V2 Sensor

2020 ◽  
Vol 15 (3) ◽  
pp. 3-14
Author(s):  
Péter Müller ◽  
Ádám Schiffer
Keyword(s):  
Gait Cycle ◽  
Medical Condition ◽  
Measurement Data ◽  
Human Movement ◽  
Gait Pattern ◽  
Lower Limbs ◽  
Human Gait ◽  
Skeleton Model ◽  
Kinect V2 ◽  
Reduced Mobility

Examining a human movement can provide a wealth of information about a patient’s medical condition. The examination process can be used to diagnose abnormal changes (lesions), ability development and monitor the rehabilitation process of people with reduced mobility. There are several approaches to monitor people, among other things with sensors and various imaging and processing devices. In this case a Kinect V2 sensor and a self-developed LabView based application was used, to examine the movement of the lower limbs. The ideal gait pattern was recorded in the RoboGait training machine and the measured data was used to identify the phases of the human gait. During the evaluation, the position of the skeleton model, the associated body joints and angles can be calculated. The pre-recorded ideal and natural gait cycle can be compared.With the self-developed method the pre-recorded ideal and natural gait cycle can be compared and processed for further evaluation. The evaluated measurement data confirm that a reliable and mobile solution for gait analysis has been created.

scholarly journals Measurement of Human Gait Symmetry using Body Surface Normals Extracted from Depth Maps

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 891 ◽  
Author(s):  
Trong-Nguyen Nguyen ◽  
Huu-Hung Huynh ◽  
Jean Meunier
Keyword(s):  
Body Surface ◽  
Lower Limbs ◽  
Upper Body ◽  
Whole Body ◽  
Human Gait ◽  
Gait Symmetry ◽  
Symmetry Index ◽  
Depth Maps ◽  
Abnormal Gait ◽  
3D Information

In this paper, we introduce an approach for measuring human gait symmetry where the input is a sequence of depth maps of subject walking on a treadmill. Body surface normals are used to describe 3D information of the walking subject in each frame. Two different schemes for embedding the temporal factor into a symmetry index are proposed. Experiments on the whole body, as well as the lower limbs, were also considered to assess the usefulness of upper body information in this task. The potential of our method was demonstrated with a dataset of 97,200 depth maps of nine different walking gaits. An ROC analysis for abnormal gait detection gave the best result ( AUC = 0.958 ) compared with other related studies. The experimental results provided by our method confirm the contribution of upper body in gait analysis as well as the reliability of approximating average gait symmetry index without explicitly considering individual gait cycles for asymmetry detection.

Modified Brain Activations of the Nondamaged Hemisphere During Ipsilesional Upper-Limb Movement in Persons With Initial Severe Motor Deficits Poststroke

2017 ◽  
Vol 32 (1) ◽  
pp. 34-45 ◽  
Author(s):  
Liesjet E. H. van Dokkum ◽  
Emmanuelle le Bars ◽  
Denis Mottet ◽  
Alain Bonafé ◽  
Nicolas Menjot de Champfleur ◽  
...  
Keyword(s):  
Upper Limb ◽  
Control Strategies ◽  
Block Design ◽  
Middle Temporal Gyrus ◽  
Motor Deficits ◽  
Activation Patterns ◽  
Severe Stroke ◽  
Flexion Extension ◽  
Before And After ◽  
Stroke Group

Background. Poststroke, the ipsilesional upper limb shows slight but substantial and long-term motor deficits. Objective. To define brain activation patterns during a gross motor flexion/extension task of the ipsilesional elbow early poststroke before and after rehabilitation, in relation to the corresponding kinematic characteristics at each time point. Method. Simultaneous analysis of kinematic features (amplitude, frequency, smoothness, and trajectory of movement) and of corresponding functional magnetic resonance imaging activations (block-design). A total of 21 persons with subacute initial severe stroke (Fugl-Meyer score <30/66) participated twice: within the first 2 months poststroke (V0) and after 6 weeks of rehabilitation (V1). Results at both time points were compared with activation patterns and kinematics of 13 healthy controls. Results. Compared with controls ( a) movements of the ipsilesional upper-limb poststroke were smaller (V0 + V1) and less smooth (V0 + V1) and ( b) participants poststroke showed additional recruitment of the contralesional middle temporal gyrus (V0) and rolandic opercularis involved in movement visualization (V0 + V1), whereas they lacked activation of the supramarginal gyrus (V0 + V1). Over time, participants poststroke showed an extended activation of the contralesional sensorimotor cortex at V0. Conclusion. Movements of the ipsilesional upper limb within an initially severe stroke group were not only atypical in motor outcome, but seemed to be controlled differently. Together the observed changes pointed toward an overall disturbance of the bihemispheric motor network poststroke, marked by ( a) a possible despecialization of the nondamaged hemisphere and ( b) the employment of alternative control strategies to ensure optimal task execution.

scholarly journals Ultrasonic Measurement of Dynamic Muscle Behavior for Poststroke Hemiparetic Gait

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Xin Chen ◽  
Xudong Zhang ◽  
Wenxiu Shi ◽  
Jun Wang ◽  
Yun Xiang ◽  
...  
Keyword(s):  
Muscle Contraction ◽  
Gait Cycle ◽  
Joint Angle ◽  
Pennation Angle ◽  
Ultrasonic Measurement ◽  
Lower Limbs ◽  
Morphological Parameter ◽  
Change Pattern ◽  
Hemiparetic Gait ◽  
Morphological Index

Quantitative evaluation of the hemiparesis status for a poststroke patient is still challenging. This study aims to measure and investigate the dynamic muscle behavior in poststroke hemiparetic gait using ultrasonography. Twelve hemiparetic patients walked on a treadmill, and EMG, joint angle, and ultrasonography were simultaneously recorded for the gastrocnemius medialis muscle. Pennation angle was automatically extracted from ultrasonography using a tracking algorithm reported previously. The characteristics of EMG, joint angle, and pennation angle in gait cycle were calculated for both (affected and unaffected) sides of lower limbs. The results suggest that pennation angle could work as an important morphological index to continuous muscle contraction. The change pattern of pennation angle between the affected and unaffected sides is different from that of EMG. These findings indicate that morphological parameter extracted from ultrasonography can provide different information from that provided by EMG for hemiparetic gait.

scholarly journals Biomechanics of Lower Limbs during Walking among Candidates for Total Knee Arthroplasty with and without Low Back Pain

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
David R. Burnett ◽  
Naira H. Campbell-Kyureghyan ◽  
Robert V. Topp ◽  
Peter M. Quesada
Keyword(s):  
Low Back Pain ◽  
Back Pain ◽  
Reaction Force ◽  
Lower Limbs ◽  
Low Back ◽  
Vertical Ground Reaction Force ◽  
Gait Patterns ◽  
Gait Symmetry ◽  
Group I ◽  
Group Ii

The effect of joint pathologies, such as unilateral knee osteoarthritis (UKOA) or low back pain (LBP), on bilateral gait symmetry has gained increased attention during the past decade. This study is the first to compare gait patterns between patients with UKOA and LBP in combination and with UKOA only. Temporal, kinematic, and kinetic variables were measured bilaterally during gait stance phase in 31 subjects with UKOA and LBP (Group I) and 11 subjects with only UKOA (Group II). Group I patients exhibited less hip rotation in the affected limb (A) than in the nonaffected (NA) limb during walking in contrast to Group II patients. Group I patients had minimal bilateral differences in hip abduction and flexion, but Group II patients displayed significantly larger values in the NA limb compared to the A limb for both parameters. Hip flexion patterns were significantly different between Groups I and II. Subjects in both groups adapted gait patterns that minimized vertical ground reaction force, knee flexion motion, and stance time on the UKOA affected limb. The distinct kinematic gait patterns that were revealed in this study may provide clinical value for assessment of patients with UKOA in conjunction with LBP.

A Novel Dynamic Ankle-Supinating Device

2010 ◽  
Vol 26 (1) ◽  
pp. 114-121 ◽  
Author(s):  
Gregory M. Gutierrez ◽  
Thomas Kaminski
Keyword(s):  
Ankle Instability ◽  
Control Strategies ◽  
Neuromuscular Control ◽  
Biomechanical Analysis ◽  
Ankle Sprains ◽  
Compensatory Mechanisms ◽  
Lateral Ankle ◽  
History Of ◽  
Underlying Causes ◽  
Insight Into

Lateral ankle sprains (LAS) are among the most common joint injuries, and although most are resolved with conservative treatment, others develop chronic ankle instability (AI). Considerable attention has been directed toward understanding the underlying causes of this pathology; however, little is known concerning the neuromuscular mechanisms behind AI. A biomechanical analysis of the landing phase of a drop jump onto a device that simulates the mechanism of a LAS may give insight into the dynamic restraint mechanisms of the ankle by individuals with AI. Furthermore, work evaluating subjects who have a history of at least one lateral ankle sprain, yet did not develop AI, may help elucidate compensatory mechanisms following a LAS event. Identifying proper neuromuscular control strategies is crucial in reducing the incidence of AI.

Effect of PNF technique for knee muscles on lower limb performance in subacute stroke – an experimental study

2016 ◽  
Vol 15 (1) ◽  
Author(s):  
Sanjiv Kumar ◽  
Shiva Prasad Tiwari
Keyword(s):  
Lower Limb ◽  
Lower Limbs ◽  
Motor Deficits ◽  
Sit To Stand ◽  
Subacute Stroke ◽  
Intervention Treatment ◽  
Proprioceptive Neuromuscular Facilitation ◽  
Agonist And Antagonist ◽  
Stabilization Technique ◽  
Functional Ambulation Profile

AbstractApproximately two-thirds of stroke survivors have sequel of neurological impairments. Although all sequels have direct impact on the performance of activities of daily living, motor deficits of the lower limbs have the most important impact on an individual’s functioning. The objective was to study the effect of proprioceptive neuromuscular facilitation (PNF) technique on lower limb performance in subjects with subacute stroke.Thirteen participants with subacute strokes were recruited. Participants were treated with PNF rhythmic stabilization technique. All participants received 10 days of intervention. Treatment sessions consisted of PNF rhythmic stabilization exercises for knee that utilizes alternating isometric contractions of agonist and antagonist against resistance. Lower limb performances were measured with Modified Emory Functional Ambulation Profile, Five Time Sit To Stand Test and Postural Assessment Scale For Stroke.Lower limb performances were improved after 10 days of intervention as compared to baseline assessment in all the outcome measures.This study suggests that the rhythmic stabilization technique is an effective method to improve lower limb function that can be used as an adjunct with other therapies.

Sign in / Sign up

Export Citation Format

Share Document