Neuromotor Strategy of Gait Rehabilitation for Lower-Limb Spasticity

Abstract

Assisting users and restoring human locomotion for patients with lower limb spasticity is a challenging task. Studies focusing on patients with abnormal walking behavior are scarce because there is an important variability from one patient to another. Those patients could benefit the most from rehabilitation and assistive mechatronic devices, there is no generic controlling scheme or any dynamical gain indicator. This contribution introduces a bio-kinematic index which is called Neuro-motor index (NMI), based on electromyographic (EMG) and joint angles measurements. NMI is derived from the nonlinear regression with a combination of two co-contraction indices (CCI), which allows addressing the variability of walking situations. This new index is evaluated on patients with cerebral palsy and a stroke. Then, the estimation error was calculated in comparison with the other co-contraction indices. This estimation shows that this index has the highest signification of joint angles prediction. Thus it can be suitable in adaptive rehabilitation control for spasticity cases.

Upper Limbs Muscle Co-Contraction Changes Correlate With The Physical Motor Impairments in CMT

“…A movement was considered to begin when the marker velocity first became greater than 5% of the peak velocity and was considered to end after the speed dropped and remained below the 5% threshold again. Raw EMG signals were band-pass filtered (10-400 Hz, 2nd order), full wave rectified and then low-pass filtered (4 Hz, 4th order) in order to obtain the EMG linear envelopes [33]. Finally, all data were timenormalized to 100% of the movement duration and then, in order to not alter the variability in EMG, the EMG linear envelopes of each muscle was amplitudenormalized to their maximum value obtained across recorded different tasks [34,35], thus also taking into…”

Surface-Electromyography-Based Co-Contraction Index for Monitoring Upper Limb Improvements in Post-Stroke Rehabilitation: A Pilot Randomized Controlled Trial Secondary Analysis

“…The instants of initiation and termination of each repetition of the object pacing task were computed as the times at which the velocity of the hand marker exceeded or fell below a threshold of 5% of the maximum value [1,2]. Raw sEMG signals (examples reported in Figure 1C,D) were band-pass filtered (10-400 Hz, 2nd order Butterworth), full-wave rectified and then low-pass filtered (4 Hz, 4th order Butterworth) in order to obtain the sEMG linear envelopes [24]. The sEMG linear envelopes were time-normalized to 100% of the movement duration, and then, to preserve the variability in sEMG, the signal of each muscle was amplitude-normalized to their maximum peak value obtained on all the recorded tasks [30].…”

“…In this expression (Equation ( 1)), proposed by Frost in 1997, A ij (t) represents the overlapping activity of the muscles i and j in the sEMG envelopes, while T represents the task duration of the signal (Figure 1E,F) [4,13,[24][25][26]. The CCI ranges from 0 to 1 (dimensionless value (um)), where 0 indicates that the activities of the two muscles did not overlap at all during the task, while 1 indicates that the activities of the two muscles were fully overlapping, and the level of sEMG activity was maintained at 1 during the task [4,25].…”

“…The sEMG-based co-contraction index (CCI), which is commonly used for the quantification of muscle co-contraction [4,8,9], can be an easy-to-use method for assessing motor control, having a quick implementation and easy interpretation even by non-technical experts, such as clinicians [9]. Previous studies have proposed Frost's CCI as a quantitative, robust, and accurate outcome measure in pathological subjects, capable of providing a rapid indication of the simultaneous activation of antagonist muscles with respect to healthy subjects [4,13,[24][25][26]. The use of such an instrumented index overcomes the limitations related to clinical scales as outcome measures, which may suffer from poor sensitivity to changes and floor/ceiling effects.…”