Comparison of the passive dynamics of walking on ground, tied-belt and split-belt treadmills, and via the Gait Enhancing Mobile Shoe (GEMS)

One-year retention of gait speed improvement in stroke survivors after treatment with a wearable home-use gait device

Background

Gait impairments after stroke are associated with numerous physical and psychological consequences. Treatment with the iStride® gait device has been shown to facilitate improvements to gait function, including gait speed, for chronic stroke survivors with hemiparesis. This study examines the long-term gait speed changes up to 12 months after treatment with the gait device.

Methods

Eighteen individuals at least one-year post-stroke completed a target of 12, 30-minute treatment sessions with the gait device in their home environment. Gait speed was measured at baseline and five follow-up sessions after the treatment period: one  week, one  month, three months, six months, and 12 months. Gait speed changes were analyzed using repeated-measures ANOVA from baseline to each follow-up time frame. Additional analysis included comparison to the minimal clinically important difference (MCID), evaluation of gait speed classification changes, and review of subjective questionnaires.

Results

Participants retained an average gait speed improvement >0.21 m/s compared to baseline at all post-treatment time frames. Additionally, 94% of participants improved their gait speed beyond the MCID during one or more post-treatment measurements, and 88% subjectively reported a gait speed improvement.

Conclusion

Treatment with the gait device may result in meaningful, long-term gait speed improvement for chronic stroke survivors with hemiparetic gait impairments.

Clinical trial registration

https://clinicaltrials.gov/ct2/show/NCT03649217, identifier NCT03649217.

Motorized Shoes Induce Robust Sensorimotor Adaptation in Walking

The motor system has the flexibility to update motor plans according to systematic changes in the environment or the body. This capacity is studied in the laboratory through sensorimotor adaptation paradigms imposing sustained and predictable motor demands specific to the task at hand. However, these studies are tied to the laboratory setting. Thus, we asked if a portable device could be used to elicit locomotor adaptation outside the laboratory. To this end, we tested the extent to which a pair of motorized shoes could induce similar locomotor adaptation to split-belt walking, which is a well-established sensorimotor adaptation paradigm in locomotion. We specifically compared the adaptation effects (i.e. after-effects) between two groups of young, healthy participants walking with the legs moving at different speeds by either a split-belt treadmill or a pair of motorized shoes. The speeds at which the legs moved in the split-belt group was set by the belt speed under each foot, whereas in the motorized shoes group were set by the combined effect of the actuated shoes and the belts' moving at the same speed. We found that the adaptation of joint motions and measures of spatial and temporal asymmetry, which are commonly used to quantify sensorimotor adaptation in locomotion, were indistinguishable between groups. We only found small differences in the joint angle kinematics during baseline walking between the groups - potentially due to the weight and height of the motorized shoes. Our results indicate that robust sensorimotor adaptation in walking can be induced with a paired of motorized shoes, opening the exciting possibility to study sensorimotor adaptation during more realistic situations outside the laboratory.

Relearning functional and symmetric walking after stroke using a wearable device: a feasibility study

BACKGROUND

Gait impairment is a common consequence of stroke and typically involves a hemiparetic or asymmetric walking pattern. Asymmetric gait patterns are correlated with decreased gait velocity and efficiency as well as increased susceptibility to serious falls and injuries.

RESEARCH QUESTION

This paper presents an innovative device worn on a foot for gait rehabilitation post stroke. The device generates a backward motion to the foot, which is designed to exaggerate the existing step length asymmetry while walking over ground. We hypothesize this motion will decrease gait asymmetry and improve functional walking in individuals with chronic stroke.

METHODS

Six participants with chronic stroke, more than one year post stroke, received four weeks of gait training with three sessions per week. Each session included 30 min of walking over ground using the wearable device. Gait symmetry and functional walking were assessed before and after training.

RESULTS

All participants improved step length symmetry, and four participants improved double limb support symmetry. All participants improved on all three functional outcomes (gait velocity, Timed Up and Go Test, and 6-Minute Walk Test), and five participants improved beyond the minimal detectable change or meaningful change in at least one functional outcome.

CONCLUSION

The results indicate that the presented device may help improve stroke patients' walking ability and warrant further study. A gait training approach using this new device may enable and expand long-term continuous gait rehabilitation outside the clinic following stroke.

TRIAL REGISTRATION

NCT02185404. Registered July 9, 2014, https://clinicaltrials.gov/ct2/show/NCT02185404.

Knee orthosis with variable stiffness and damping that simulates hemiparetic gait

Individuals with unilateral stroke have neuromuscular weakness or paralysis on one side of the body caused by some muscles disengaging and others overexciting. Hyperextension of the knee joint and complete lack of plantar flexion of the ankle joint are common symptoms of stroke. This paper focuses on the creation and implementation of a small, lightweight, and adjustable orthotic device to be positioned around the knee of an able-bodied person to simulate hemiparetic gait. Force and range of motion data from able-bodied subjects fitted with the orthosis, inducing hemiparetic gait, was collected using the Computer Assisted Rehabilitation ENvironment (CAREN) system. The four parameters that the design focused on are damping, catch, hysteresis, and stiffness. The main goal of the project was to discern whether this device could be utilized as a viable research instrument to simulate hemiparetic gait. It was hypothesized that the device has the potential to be utilized in the future as a rehabilitation device for people with stroke since it has been designed to induce larger knee flexion as an after effect. A comparison between how the dominant leg was affected by the orthosis and how the non-dominant leg was affected was investigated as well. The results show that the device affected the velocities, knee angles, and force profiles of the subject's gait.

Perception of gait patterns that deviate from normal and symmetric biped locomotion

This study examines the range of gait patterns that are perceived as healthy and human-like with the goal of understanding how much asymmetry is allowable in a gait pattern before other people start to notice a gait impairment. Specifically, this study explores if certain abnormal walking patterns can be dismissed as unimpaired or not uncanny. Altering gait biomechanics is generally done in the fields of prosthetics and rehabilitation, however the perception of gait is often neglected. Although a certain gait can be functional, it may not be considered as normal by observers. On the other hand, an abnormally perceived gait may be more practical or necessary in some situations, such as limping after an injury or stroke and when wearing a prosthesis. This research will help to find the balance between the form and function of gait. Gait patterns are synthetically created using a passive dynamic walker (PDW) model that allows gait patterns to be systematically changed without the confounding influence from human sensorimotor feedback during walking. This standardized method allows the perception of specific changes in gait to be studied. The PDW model was used to produce walking patterns that showed a degree of abnormality in gait cadence, knee height, step length, and swing time created by changing the foot roll-over-shape, knee damping, knee location, and leg masses. The gait patterns were shown to participants who rated them according to separate scales of impairment and uncanniness. The results indicate that some pathological and asymmetric gait patterns are perceived as unimpaired and normal. Step time and step length asymmetries less than 5%, small knee location differences, and gait cadence changes of 25% do not result in a change in perception. The results also show that the parameters of a pathologically or uncanny perceived gait can be beneficially altered by increasing other independent parameters, in some sense masking the initial pathology.