Hemiplegia is a paralysis found only on one side of the body and is typically categorized as right or left side hemiplegia. Paralysis, weakness and spasticity on one side of the body lead to decreased motor control and altered range of motion at the joints.
A stroke occurs when an area of the brain does not receive adequate oxygen and nutrients due to a lack of blood supply, either by obstruction (ischemic stroke, about 80%) or rupture of a vessel (hemorrhagic stroke, about 20%). Almost two-third of hemiplegic patients have sequelae from stroke.
Stroke leads to the damage of motor cortices and their descending corticospinal tracts and subsequent muscle weakness. On the other hand, brainstem descending pathways and the intraspinal motor network are disinhibited and become hyperexcitable, thus leading to poor body support and walking performance. 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 interaction.
Post-stroke hemiplegic gait is proposed its clinical implications for management of hemiplegic gait.
Effect of hemiplegic stroke to gait.
During foot contact, proper heel strike is often lost due to decreased strength of control of the anterior tibialis or spasticity of the calf muscles. The lack of ability to dorsiflex properly is often referred to as foot drop.
Stroke survivors usually have decreased stance phase and prolonged swing phase of the paralytic side. Further, the walking speed is decreased and the stride length is shorter.
Overall hemiplegic stroke commonly leads to difficulties in foot clearance during swing, stability during stance, and maintaining energy efficient gait patterns.
Gait abnormalities along with muscle weakness place stroke survivors at a high risk of fall.
Compensatory pattern of hemiplegic gait.
Compensatory gait patterns are developed to walk with the paralysis, weakness and spasticity caused by a hemiplegic stroke.
A common compensatory pattern to gain foot clearance is circumduction. In circumduction, the hip is abducted as the foot is being progressed forwards, moving the foot laterally to create a semi-circle path of the foot in the medial/lateral plane.
The main compensatory pattern used to minimize the effect of instability during stance is to decrease the unilateral support time on the affected side.
How to quantify hemiplegic gait?
️While changes in hemiplegic gait can be observed, quantifying these changes is important to gain understanding of the gait deviations caused by the stroke.
️Gait mat technology, such as the Zeno Walkway System is commonly used to quantify temporal spatial metrics such as gait speed, step length and stance time
Treatment management to improve gait in hemiplegic stroke.
Patients require treatment in order to improve their gait quality towards pre-stroke quality.
improving walking safety and speed is the major goal for stroke survivors to prevent falls and to improve quality of life.
Bracing and assistive devices are often used to manage the loss of strength and range of motion. An ankle-foot orthotic (AFO) can be used to prevent excessive plantar flexion of the foot and promote improved foot contact.
Walkers and canes can be used, allowing the upper body strength to assist with stance stability. In cases of spasticity, Botulinum toxin injections into the spastic muscles can be considered.
Functional electrical stimulation (FES) can be used in attempt to promote appropriate muscle activation.
Physical therapy is commonly used to improve overall function.
References
· https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6088193/
· https://www.protokinetics.com/common-gait-deviations-post-stroke-hemiplegic-gait/
· https://stanfordmedicine25.stanford.edu/the25/gait.html#hemiplegic-gait
Supun Udara.
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