Hemiplegia is one of the most common impairments after stroke and contributes significantly to reduce gait performance.
Although the majority of stroke patients achieve an independent gait, many do not reach a walking level that enable them to perform all their daily activities.
Gait recovery is a major objective in the rehabilitation program for stroke patients.
Restoring functions after stroke is a complex process involving spontaneous recovery and the effects of therapeutic interventions.
The primary goals of people with stroke include being able to walk independently and to manage to perform daily activities. Consistently, rehabilitation programs for stroke patients mainly focus on gait training, at least for sub-acute patients.
Several general principles underpin the process of stroke rehabilitation.
Good rehabilitation outcome seems to be strongly associated with high degree of motivation and engagement of the patient and his/her family.
Setting goals according to specific rehabilitation aims of an individual might improve the outcomes.
In addition, cognitive function is importantly related to successful rehabilitation. Attention is a key factor for rehabilitation in stroke survivors as poorer attention performances are associated with a more negative impact of stroke disability on daily functioning
Introduction to Gait
Walking dysfunction occurs at a very high prevalence in stroke survivors. Human walking is a phenomenon often taken for granted, but it is mediated by complicated neural control mechanisms.
The automatic process includes the brainstem descending pathways and the intraspinal locomotor network. Stroke leads to damage to motor cortices and their descending cortico-spinal tracts and subsequent muscle weakness.
On the other hand, brainstem descending pathways and the intraspinal motor network are disinhibited and become hyper-excitable.
The wide range and hierarchy of post-stroke hemiplegic gait impairments is a reflection of mechanical consequences of muscle weakness, spasticity, abnormal synergistic activation and their interactions.
The below video gives an idea of how gait training with a stroke client may be undertaken and advanced.
The ability to walk independently is a prerequisite for most daily activities. The capacity to walk in a community setting requires the ability to walk at speeds that enable an individual to cross the street in the time allotted by pedestrian lights, to step on and off a moving walkway, in and out of automatic doors, walk around furniture, under and over objects and negotiate kerbs.
A walking velocity of 1.1-1.5 m/s is considered to be fast enough to function as a pedestrian in different environmental and social contexts. It has been reported that only 7% of patients discharged from rehabilitation met the criteria for community walking, which included the ability to walk 500 m continuously at a speed that would enable them to cross a road safely.
The major requirements for successful walking are:
Support of body mass by lower limbs
Propulsion of the body in the intended direction
The production of a basic locomotor rhythm
Dynamic balance control of the moving body
Flexibility, i.e. the ability to adapt the movement to changing
environmental demands and goals.
Gait in Stroke
Post stroke hemiplegic gait is a mixture of deviations and compensatory motion dictated by residual functions, and thus each patient must be examined and his/her unique gait pattern identified and documented.
Walking dysfunction is common in neurologically impaired individuals, arising not only from the impairments associated with the lesion but also from secondary cardiovascular and musculoskeletal consequences of disuse and physical inactivity.
Muscle weakness and paralysis, poor motor control and soft tissue contracture are major contributors to walking dysfunction after stroke.
Typical Kinematic Deviations and Adaptations
Limited ankle dorsiflexion – decreased activation of anterior tibial muscles ; contracture and/or stiffness of calf muscles with premature activation.
Lack of knee flexion (knee hyperextension) – contracture of soleus ; limited control of quadriceps 0-15°
Lack of Knee Extension (knee remains flexed 10-150 with excessive ankle dorsiflexion) – decreased activation of calf muscles to control movement of shank forward at the ankle (ankle dorsiflexion); limited synergic activation of lower limb extensor muscles.
Stiffening of Knee (Hyperextension). This interferes with preparation for push-off – contracture of soleus; an adaptation to fear of limb collapse due to weakness of muscles controlling the knee.
Limited hip extension and ankle dorsiflexion with failure to progress body mass forward over the foot – contracture of soleus.
Excessive Lateral Pelvic Shift – decreased ability to activate stance hip abductors and control hip and knee extensors.
Late Stance (Pre-Swing)
Lack of Knee Flexion and Ankle Plantar-flexion, prerequisites for push-off and preparation for swing – weakness of calf muscles.
Early and Mid-Swing
Limited Knee Flexion normally 35-40° increasing to 60° for swing and toe clearance – increased stiffness in or unopposed activity of two-joint rectus femoris ; decreased activation of hamstrings.
Late Swing (Preparation for Heel Contact and Loading)
Limited Knee Extension and Ankle Dorsiflexion jeopardising heel contact and weight-acceptance – contracted or stiff calf muscles ; decreased dorsiflexor activity.
Decreased walking speed
Short and/or uneven step and stride lengths
Increased stride width
Increased double support phase
Dependence on support through the hands.
Intervention aims to optimize walking performance by:
Preventing adaptive changes in lower limb soft tissues
Eliciting voluntary activation in key muscle groups in lower limbs
Increasing muscle strength and coordination
Increasing walking velocity and endurance
Maximizing skill, eg increasing flexibility
Increasing cardiovascular fitness.
The major emphasis in walking training is on:
Support of the body mass over the lower limbs
Propulsion of the body mass
balance of the body mass as it progresses over one or both lower limbs
Controlling knee and toe paths for toe clearance and foot placement
Optimizing rhythm and coordination.
The study by Ji Young Lim infers that the cut-off values of maximum walking velocity and modified Rivermead Mobility Index (mRMI) are suggested as useful outcome measures for assessing ambulation levels in chronic stroke patients during rehabilitation.
Conventional Gait Training
Conventional gait training has focused on part-practice of components of gait in preparation for walking. It includes
Symmetrical Weight bearing training
Stepping training (swinging/clearance )
Single leg standing
Push off / Calf rise.
Also included are:
Circuit training (reaching in sitting and standing, sit-to-stand, step-ups, heel lifts, isokinetic strengthening, walking over obstacles, up and down slopes).
Neurofacilitation or neurodevelopmental techniques (NDT) to inhibit excessive tone, stimulate muscle activity (if hypotonia is present) and to facilitate normal movement patterns through hands-on techniques.
Practice based on the framework advocated by Berta Bobath remains the predominant physical therapy approach to stroke patients in the UK and is also common in many other parts of the world, including Canada, United States, Europe, Australia, Hong Kong and Taiwan.
It has evolved from its original foundations, however elements still emphasize normal tone and the necessity of normal movement patterns to perform functional tasks
Strength training to improve walking ability Task-specific training to improve walking ability
The OPTIMAL Theory
An online course by Teresa Bisson
Body weight supported treadmill training was one of the first translations of the task-specific repetitive treatment concept in gait rehabilitation after stroke.
Through a systematic review of 6 RCTs of Body Weight Supported Treadmill Training (BWSTT) and 2 RCTs without BWSTT, Teasell et al.
concluded that there was conflicting evidence that treadmill training with or without BWSTT resulted in improvements in gait performance over standard treatments.
Although the evidence supporting treadmill training appears to be conflicting, two recent clinical practice guidelines recommended that BWSTT be included as an intervention for stroke.
Turning-based treadmill training has recently been studied as a treatment for stroke gait training. This treadmill is similar to a regular treadmill except for its circular running motor belt (0.8-m radius), which forces patients to continually turn rather than walk straight. Participants walked on the perimeter of the circular belt as it rotated either clockwise or counterclockwise.
The finding were interesting. Reporting that EEG-EEG connectivity and EEG-EMG connectivity during walking can be enhanced more by a turning-based treadmill instead of a regular treadmill.
Moreover, the improvement in gait symmetry, but not the gait speed, correlated with the modulations in the EEG-EEG and EEG-EMG connectivity over frontal-central-parietal areas of the brain.
A 2018 systematic review designed to assess the effectiveness of two models of gait re-education in post-stroke patients, namely conventional physical therapy and treadmill training, made the concluding remarks that “if advanced gait re-education methods, requiring costly equipment, cannot be used for various reasons, a well-designed conventional gait training is an adequate, affordable and straightforward method to achieve the intended effects of rehabilitation after stroke.” Conventional physical therapy referred to (general exercise program/regular physiotherapy) involved stretching, strengthening, endurance, balance, coordination, range of motion activities, and overground walking practice.
Forms of biofeedback have been in use in physical therapy for more than 50 years, where it is beneficial in the management of neuromuscular disorders. Biofeedback techniques have shown benefit when used as part of a physical therapy program for people with motor weakness or dysfunction after stroke. These methods are getting better at training for complex task-oriented activities like walking and grasping objects as technology continues to advance.
Functional Electrical Stimulation
Functional Electrical Stimulation (FES) is a useful methodology for the rehabilitation after stroke, along or as a part of a Neuro-robot.
FES consists on delivering an electric current through electrodes to the muscles. The current elicits action potentials in the peripheral nerves of axonal branches and thus generates muscle contractions.
FES has been used in rehabilitation of chronic hemiplegia since the 1960s.
Robotic devices provide safe, intensive and task-oriented rehabilitation to people with mild to severe neurologic injury. It does
precisely controllable assistance or resistance during movements
objective and quantifiable measures of subject performance,
increased training motivation through the use of interactive (bio)feedback.
In addition, this approach reduces the amount of physical assistance required to walk reducing health care costs and provides kinematic and kinetic data in order to control and quantify the intensity of practice, measure changes and assess motor impairments with better sensitivity and reliability than standard clinical scales.
After stroke, gait recovery is a major objective in the rehabilitation program, therefore a wide range of strategies and assistive devices have been developed for this purpose. However, estimating rehabilitation effects on motor recovery is complex, due to the interaction of spontaneous recovery, whose mechanisms are still under investigation, and therapy.
The approaches used in gait rehabilitation after stroke include neurophysiological and motor learning techniques, robotic devices, FES, and the new evolving use of Brain Computer Interface. Brain-Computer Interface systems record, decode, and translate some measurable neurophysiological signal into an effector action or behavior. Therefore BCIs are potentially a powerful tool.