Home-based FES Training in People With Chronic Stroke

BACKGROUND/SCIENTIFIC RATIONALE: Functional impairment after a stroke often includes slowed gait velocity and increased fall risk attributed to foot drop (the inability to dorsiflex the ankle during the swing phase of gait) and lower limb muscle weakness. Damage in the motor cortex or corticospinal tract often results in significant, persistent distal muscle weakness including the sensorimotor control of the ankle joint, typically because of a combination of weakness of the agonist ankle dorsiflexor muscles and spasticity of the antagonist plantarflexor muscle. This results in slower and abnormal gait which leads to gait compensation strategies such as hip hitching, excess circumduction during gait, reduced foot clearance, and high energy expenditure, all of which are factors which could increase the risk of falls in individuals with stroke.

Electrical stimulation, particularly functional electrical stimulation (FES), has become widely used in the field of rehabilitation. FES is defined as the electrical stimulation of muscles that have impaired motor control to produce a contraction to obtain a functionally useful movement. In the last few years, FES systems have been used as neuroprosthetic devices in rehabilitative interventions such as gait training. Stimulator triggers, implemented to control stimulation delivery, range from open-to closed-loop controllers. Finite-state controllers trigger stimulators when specific conditions are met and utilize preset sequences of stimulation. Thus, wearable sensors provide the necessary input to differentiate gait phases during walking and trigger stimulation to specific muscles. This technology has been largely used to improve gait and balance parameters in people with chronic stroke.

Home-based rehabilitation is a powerful option to increase frequency of exercises, therapy adherence, amount of training per week, and self-confidence. Home-exercise using FES is an option which can help reduce the sequelae of sensorimotor disorders and lends itself as an exciting way for people suffering from various conditions to exercise their muscles. Additionally, it has been well described that extending the use of home-based FES to elderly could increase its impact and beneficiate this population significantly.

One of the most complex issues to wider adoption of FES is its ease of use in the home context. There is a marked difference in the use of a technological and medical device in laboratory or clinical facilities compared to home or other more ecological environments. Software able to include easy training programs based on well-established therapeutic protocols may reduce this gap between laboratory and ecological environments and benefit the use of technological medical devices such as FES. A FES system would allow the participant to easily adjust the type and location of their exercise on a daily basis. On the other hand, any device with currents as low as those used by a FES system should be safe to use in any context, and especially in an unsupervised setting.

Most of the tele rehabilitation platforms lack a medium to provide external physical assistance. Incorporating an actuation modality such as FES or other technological devices at the patient's end, which mimics a therapist in a remote clinic, may be effective for therapeutic purposes until the patient's recovery is maximized. Although a robot-guided rehabilitation intervention or online supervision by the therapist could be a feasible option, it might be more therapeutically beneficial to include FES. This is a treatment where a skeletal muscle can be activated by passing low-level electric currents across the motor neurons. This treatment can be administered by applying transcutaneous electrodes over the surface of the skin. The reason why FES is helpful is because it can strengthen muscle, prevent muscle atrophy, and increase bone density. Moreover, FES has neuroplastic effects as it helps to retrain active motor units and rebuild the weak connections between the brain and the motor neurons. Hence, the inclusion of FES to telerehabilitation programs could increase the efficacy of the therapy and contribute to the recovery process of persons with partial or complete loss of limb function. This project aims to determine whether home-based use of a platform that enables FES exercises is safe and beneficial to individuals with chronic stroke. It also aims to see if 8-weeks of home-based FES and task-specific training can result in improvements in spatio-temporal parameters of gait, mobility, balance and general health.

OBJECTIVE/AIMS: The purpose of this study is to examine the feasibility, safety, efficacy and effect of 12 weeks of home-based combined FES and task-specific training program in people with chronic stroke.

Aim 1: To investigate the feasibility, safety and efficacy of 12-weeks of home-based FES and task-specific training in adults with chronic stroke. H1: 12-weeks of home-based FES training program will be safe, feasible and will not result in any adverse events during the training program.

Aim 2: To examine the effect of 12-weeks of home-based FES and task-specific training on gait, mobility and balance in adults with chronic stroke. H2: Post intervention, adults with chronic stroke will demonstrate improvements in spatial and temporal parameters of gait (gait speed, cadence and gait asymmetry), mobility (physical activity and muscle strength) and balance (anticipatory and reactive balance components).