Abnormal joint torque patterns exhibited by chronic stroke subjects while walking with a prescribed physiological gait pattern

Effects of ankle foot orthosis in stiff knee gait in adults with hemiplegia

Stroke survivors present a less efficient gait compared to healthy subjects due to abnormal knee flexion during the swing phase of gait, associated with spasticity of the rectus femoris muscle and overactivity of the ankle plantarflexors. It is relevant to understand the effect of the ankle foot orthosis (AFO) on gait in individuals with plantarflexor spasticity. The aim of this study was to compare the knee kinematics with an AFO/footwear combination and barefoot in post-stroke subjects with plantarflexor spasticity. Ten subjects with chronic hemiplegia were measured. Two kinematic variables were assessed during the swing phase of the paretic limb: knee flexion angle at toeoff and peak knee flexion angle. We also analyzed gait speed and step length of the non-paretic limb. All variables were obtained with and without the orthosis. Kinematic data were acquired using a motion capture system (ELITE). Subjects wearing an AFO showed significant improvements in gait speed (0.62 m/s (0.08 SD) vs. 0.47 m/s (0.13 SD) (p=0.007)), step length of the non-paretic limb (42 cm (5.9 SD) vs. 33.5 cm (6.6 SD) (p=0.005)) and peak knee flexion angle during the swing phase: 30.7° (14.1° SD) vs. 26.3° (11.7° SD) p=0.005. No significant differences were obtained in the knee flexion angle at toeoff between no AFO and AFO conditions. We described benefits with AFO/footwear use in the kinematics of the knee, the step length of the non-paretic limb, and the gait velocity in hemiplegic subjects after mild to moderate stroke. We conclude that the use of an AFO can improve the gait pattern and increase velocity in these subjects.

Towards more effective robotic gait training for stroke rehabilitation: a review

Background

Stroke is the most common cause of disability in the developed world and can severely degrade walking function. Robot-driven gait therapy can provide assistance to patients during training and offers a number of advantages over other forms of therapy. These potential benefits do not, however, seem to have been fully realised as of yet in clinical practice.

Objectives

This review determines ways in which robot-driven gait technology could be improved in order to achieve better outcomes in gait rehabilitation.

Methods

The literature on gait impairments caused by stroke is reviewed, followed by research detailing the different pathways to recovery. The outcomes of clinical trials investigating robot-driven gait therapy are then examined. Finally, an analysis of the literature focused on the technical features of the robot-based devices is presented. This review thus combines both clinical and technical aspects in order to determine the routes by which robot-driven gait therapy could be further developed.

Conclusions

Active subject participation in robot-driven gait therapy is vital to many of the potential recovery pathways and is therefore an important feature of gait training. Higher levels of subject participation and challenge could be promoted through designs with a high emphasis on robotic transparency and sufficient degrees of freedom to allow other aspects of gait such as balance to be incorporated.

Virtual reality and robotics for stroke rehabilitation: where do we go from here?

Promoting functional recovery after stroke requires collaborative and innovative approaches to neurorehabilitation research. Task-oriented training (TOT) approaches that include challenging, adaptable, and meaningful activities have led to successful outcomes in several large-scale multisite definitive trials. This, along with recent technological advances of virtual reality and robotics, provides a fertile environment for furthering clinical research in neurorehabilitation. Both virtual reality and robotics make use of multimodal sensory interfaces to affect human behavior. In the therapeutic setting, these systems can be used to quantitatively monitor, manipulate, and augment the users' interaction with their environment, with the goal of promoting functional recovery. This article describes recent advances in virtual reality and robotics and the synergy with best clinical practice. Additionally, we describe the promise shown for automated assessments and in-home activity-based interventions. Finally, we propose a broader approach to ensuring that technology-based assessment and intervention complement evidence-based practice and maintain a patient-centered perspective.

Principal component analysis of gait kinematics data in acute and chronic stroke patients

We present the joint angles analysis by means of the principal component analysis (PCA). The data from twenty-seven acute and chronic hemiplegic patients were used and compared with data from five healthy subjects. The data were collected during walking along a 10-meter long path. The PCA was applied on a data set consisting of hip, knee, and ankle joint angles of the paretic and the nonparetic leg. The results point to significant differences in joint synergies between the acute and chronic hemiplegic patients that are not revealed when applying typical methods for gait assessment (clinical scores, gait speed, and gait symmetry). The results suggest that the PCA allows classification of the origin for the deficit in the gait when compared to healthy subjects; hence, the most appropriate treatment can be applied in the rehabilitation.

The basic mechanics of bipedal walking lead to asymmetric behavior

This paper computationally investigates whether gait asymmetries can be attributed in part to basic bipedal mechanics independent of motor control. Using a symmetrical rigid-body model known as the compass-gait biped, we show that changes in environmental or physiological parameters can facilitate asymmetry in gait kinetics at fast walking speeds. In the environmental case, the asymmetric family of high-speed gaits is in fact more stable than the symmetric family of low-speed gaits. These simulations suggest that lower extremity mechanics might play a direct role in functional and pathological asymmetries reported in human walking, where velocity may be a common variable in the emergence and growth of asymmetry.

An advanced rehabilitation robotic system for augmenting healthcare

Emerging technologies such as rehabilitation robots (RehaBot) for retraining upper and lower limb functions have shown to carry tremendous potential to improve rehabilitation outcomes. Hstar Technologies is developing a revolutionary rehabilitation robot system enhancing healthcare quality for patients with neurological and muscular injuries or functional impairments. The design of RehaBot is a safe and robust system that can be run at a rehabilitation hospital under the direct monitoring and interactive supervision control and at a remote site via telepresence operation control. RehaBot has a wearable robotic structure design like exoskeleton, which employs a unique robotic actuation--Series Elastic Actuator. These electric actuators provide robotic structural compliance, safety, flexibility, and required strength for upper extremity dexterous manipulation rehabilitation training. RehaBot also features a novel non-treadmill paddle platform capable of haptics feedback locomotion rehabilitation training. In this paper, we concern mainly about the motor incomplete patient and rehabilitation applications.

Biomechanics of human movement and its clinical applications

All life forms on earth, including humans, are constantly subjected to the universal force of gravitation, and thus to forces from within and surrounding the body. Through the study of the interaction of these forces and their effects, the form, function and motion of our bodies can be examined and the resulting knowledge applied to promote quality of life. Under gravity and other loads, and controlled by the nervous system, human movement is achieved through a complex and highly coordinated mechanical interaction between bones, muscles, ligaments and joints within the musculoskeletal system. Any injury to, or lesion in, any of the individual elements of the musculoskeletal system will change the mechanical interaction and cause degradation, instability or disability of movement. On the other hand, proper modification, manipulation and control of the mechanical environment can help prevent injury, correct abnormality, and speed healing and rehabilitation. Therefore, understanding the biomechanics and loading of each element during movement using motion analysis is helpful for studying disease etiology, making decisions about treatment, and evaluating treatment effects. In this article, the history and methodology of human movement biomechanics, and the theoretical and experimental methods developed for the study of human movement, are reviewed. Examples of motion analysis of various patient groups, prostheses and orthoses, and sports and exercises, are used to demonstrate the use of biomechanical and stereophotogrammetry-based human motion analysis studies to address clinical issues. It is suggested that further study of the biomechanics of human movement and its clinical applications will benefit from the integration of existing engineering techniques and the continuing development of new technology.

Influence of systematic increases in treadmill walking speed on gait kinematics after stroke

BACKGROUND

Fast treadmill training improves walking speed to a greater extent than training at a self-selected speed after stroke. It is unclear whether fast treadmill walking facilitates a more normal gait pattern after stroke, as has been suggested for treadmill training at self-selected speeds. Given the massed stepping practice that occurs during treadmill training, it is important for therapists to understand how the treadmill speed selected influences the gait pattern that is practiced on the treadmill.

OBJECTIVE

The purpose of this study was to characterize the effect of systematic increases in treadmill speed on common gait deviations observed after stroke.

DESIGN

A repeated-measures design was used.

METHODS

Twenty patients with stroke walked on a treadmill at their self-selected walking speed, their fastest speed, and 2 speeds in between. Using a motion capture system, spatiotemporal gait parameters and kinematic gait compensations were measured.

RESULTS

Significant improvements in paretic- and nonparetic-limb step length and in single- and double-limb support were found. Asymmetry of these measures improved only for step length. Significant improvements in paretic hip extension, trailing limb position, and knee flexion during swing also were found as speed increased. No increases in circumduction or hip hiking were found with increasing speed. Limitations Caution should be used when generalizing these results to survivors of a stroke with a self-selected walking speed of less than 0.4 m/s. This study did not address changes with speed during overground walking.

CONCLUSIONS

Faster treadmill walking facilitates a more normal walking pattern after stroke, without concomitant increases in common gait compensations, such as circumduction. The improvements in gait deviations were observed with small increases in walking speed.

Translating research into clinical practice: integrating robotics into neurorehabilitation for stroke survivors

Technological advances continue to infuse the field of neurorehabilitation with both excitement and apprehension. A challenge for clinicians is to determine which of the growing number of devices or interventions available should be incorporated into their clinical practice, and when and with whom they should be offered, in order to best assist their patients in attaining the highest level of function and quality of life. Robotics is one area of technology that has seen robust growth in rehabilitation applications, so much so that the presence of robotic devices in rehabilitation centers has become an expectation among patients, their caregivers, and therapists. Although rehabilitation robotic devices afford the opportunity to provide high doses of repetitive movement in a reliable and controllable manner, the role they play in the continuum of clinical care remains uncertain. The focus of this article is on translating the empirical evidence related to the application of rehabilitation robotics for improving lower limb and walking function in a manner that the clinician, or any stakeholder, will be able to incorporate relevant findings into clinical practice. A process is outlined and applied to a recent review of the literature related to the use of robotics for the treatment of lower limb and walking function in persons with stroke. This process provides the reader with a tool that can be applied to the translation and implementation of evidence related to any intervention for any client with neurological injury or disease.

Role of Robotics in Neurorehabilitation

Over the past decade, rehabilitation hospitals have begun to incorporate robotics technologies into the daily treatment schedule of many patients. These interventions hold greater promise than simply replicating traditional therapy, because they allow therapists an unprecedented ability to specify and monitor movement features such as speed, direction, amplitude, and joint coordination patterns and to introduce controlled perturbations into therapy. We argue that to fully realize the potential of robotic devices in neurorehabilitation, it is necessary to better understand the specific aspects of movement that should be facilitated in rehabilitation. In this article, we first discuss neurorecovery in the context of motor control and learning principles that can provide guidelines to rehabilitation professionals for enhancing recovery of motor function. We then discuss how robotic devices can be used to support such activities.

Abnormal volitional hip torque phasing and hip impairments in gait post stroke

The purpose of this study was to quantify how volitional control of hip torque relates to walking function poststroke. Volitional phasing of hip flexion and extension torques was assessed using a load-cell-instrumented servomotor drive system in 11 chronic stroke subjects and 5 age-matched controls. Hips were oscillated from approximately 40 degrees of hip flexion to 10 degrees of hip extension at a frequency of 0.50 Hz during three movement conditions [hips in phase (IP), 180 degrees out of phase (OP), and unilateral hip movement (UN)] while the knees and ankles were held stationary. The magnitude and phasing of hip, knee, and ankle torques were measured during each movement condition. Surface electromyography was measured throughout the legs. Over ground gait analysis was done for all stroke subjects. During robotic-assisted movement conditions, the paretic limb produced peak hip torques when agonist hip musculature was stretched instead of midway through the movement as seen in the nonparetic and control limbs (P < 0.012). However, mean torque magnitudes of the paretic and nonparetic limbs were not significantly different. Abnormalities of paretic hip torque phasing were more pronounced during bilateral movement conditions and were associated with quadriceps overactivity. The magnitude of flexion torque produced during maximal hip extension was correlated with the Fugl Meyer Score, self-selected walking speed, and maximal hip extension during over ground walking. These results suggest that hyperexcitable stretch reflexes in the paretic limb impair coordinated hip torque phasing and likely interfere with walking function post stroke.