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

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.

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

It consists of 15 daily sessions of voluntary cycling training augmented by functional electrical stimulation (FES) followed by 15 daily sessions of balance training (multimodal biofeedback training). Both cycling and balance training are supported by a visual biofeedback and last about 20 minutes. In addition to cycling or balance training, subjects perform standard physical therapy in order to reach 90 minutes of training per day.

It consists of stretching, muscular conditioning, exercises for trunk control, standing, and walking training, and upper limb rehabilitation.

Subjects are asked to walk three times at self-selected speed over the GaitRite mat using their walking aid (if any) or receiving the needed assistance. Spatial-temporal parameters are evaluated using the GaitRite software.

Subjects are asked to walk three times at self-selected speed over the GaitRite mat using their walking aid (if any) or receiving the needed assistance. Spatial-temporal parameters are evaluated using the GaitRite software.

Subjects are asked to walk along a rectilinear corridor for 6 minutes. The distance covered is measured.

A pedaling test is performed on the motorized cycle-ergometer to measure the force produced by the two sides during voluntary cycling as well as electromyography activations of the main lower limb muscles. Subjects are asked to pedal at four difference target pace (20 RPM, 30 RPM, 40 RPM, and 50 RPM), while the ergometer motor maintains a constant cadence of 10 RPM less than the target. A visual numerical cadence indicator and a metronome help the subjects to keep the constant cadence.

Postural stability is evaluated using the commercial balance board exploited in the experimental intervention program (Balance board basic™, NeuroCom® International, Inc.). Pre-defined assessments are used to evaluate the postural sways during upright stance both with eyes open and closed; the limits of stability in all directions (forward, backward, right, and left); and the capability to shift the weight both left/right and forward/backward.

Inclusion Criteria: post-acute stroke patients experiencing a first stroke (both ischemic or hemorrhagic) less than 6 months before recruitment low level of spasticity of the leg muscles (Modified Ashworth scale <2) no limitations at hip, knee, and ankle joints able to sit up to 30 minutes Exclusion Criteria: neurological impairment (Mini mental scale <24) presence of other neurological diseases spatial hemineglect cardiac pacemakers allergy to electrodes an inability to tolerate electrical stimulation.

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