Fall Prevention and Locomotion Recovery in Post-stroke Patients: A Multimodal Training

Stroke

post-acute stroke, functional electrical stimulation, biofeedback, balance, cycling, rehabilitation, gait

The study proposes a novel rehabilitative program for the recovery of locomotor abilities in post-acute stroke patients. The hypothesis is that a rehabilitative program which involves a biofeedback cycling training combining voluntary effort and Functional Electrical Stimulation (FES) of the leg muscles, and a biofeedback balance training is superior to usual care in improving walking abilities, disability, motor performance, and independence of post-acute stroke patients. The innovative approach is to investigate whether interventions which do not directly involve locomotor functions but movements similar in terms of kinematic patterns and neural commands (e.g. pedaling), or aimed at recovering an essential prerequisite for walking, such as postural control during upright stance, may improve and/or accelerate the recovery of walking abilities. A single-blind randomized controlled study is carried out. Participants are post-acute stroke patients experiencing a first stroke less than 6 months before recruitment, with an adult age, a low level of spasticity of the leg muscles (Modified Ashworth scale \<2), no limitations at hip, knee, and ankle joints, and able to sit up to 30 minutes. Subjects are randomized to one of two groups, one performing the novel rehabilitative program in addition to usual care (experimental group), and one performing usual care alone (control group). The experimental program consists of 15 sessions of FES-supported voluntary cycling training followed by 15 sessions of balance training. Both cycling and balance training are supported by a visual biofeedback in order to maximize patients' involvement in the exercise and are performed in addition to usual care. The control group is involved in standard physical therapy which includes stretching, muscular conditioning, exercises for trunk control, standing, and walking training, and upper limb rehabilitation. Both training programs last 6 weeks and patients are trained daily for about 90 minutes. Cycling and balance training last about 20 minutes; thus, patients in the experimental group perform only about 70 minutes of usual care. Participants are evaluated at baseline (T1), after the end of the cycling training or after 3 weeks of usual care (post-treatment, T2), after the end of the whole intervention (post-treatment, T3), and about 6 months after the end of the intervention (follow-up, T4).

More details on the experimental training program are here provided. The cycling training is performed on a motorized cycle-ergometer (MOTOmed, Reck GmbH) equipped with force sensors mounted at the base of the cranks (PowerForce system, Radlabor GmbH). The acquired force signals are displayed to the subjects who are asked to achieve a symmetrical involvement of the two legs. To deliver FES, a current-controlled 8-channel stimulator (RehaStim; Hasomed GmbH) is used and surface electrodes are applied in a bipolar configuration on the quadriceps, hamstrings, gastrocnemius lateralis, and tibialis anterior of both legs. Rectangular biphasic pulses with a pulse width of 400 μs and a stimulation frequency of 20 Hz are adopted. The stimulus intensity is set on each muscle the first day of training: for the paretic muscles values well tolerated by the subject and able to produce visibly good muscle contractions are identified, whereas for the healthy side lower values just above the sensory threshold are used. The stimulation timing is synchronized to the cycling movement according to physiological stereotyped activation patterns. The balance training is performed during upright stance using a balance board (Balance board basic™, NeuroCom® International, Inc.). Subjects are asked to keep still or move their center of pressure following a target displayed on a screen in front of them.

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