Lower Limb Voluntary Movement Improvement Following a Robot-Assisted Locomotor Training in Spinal Cord Injury

Individuals with spinal cord injury (SCI) suffer from severe impairments in voluntary movements. Literature reports a reduction in major kinematic and kinetic parameters of lower limbs’ joints. A body weight support treadmill training with robotic assistance has been widely used to improve lower-extremity function and locomotion in persons with SCI. Our objective was to explore the effects of 4-weeks robot-assisted locomotor training on voluntary movement of the ankle musculature in patients with incomplete SCI. In particular, we aimed to characterize the therapeutic effects of Lokomat training on kinematic measures (range of motion, velocity, smoothness) during a dorsiflexion movement. We hypothesized that training would improve these measures. Preliminary results show an improvement of kinematic parameters during ankle dorsiflexion voluntary movement after a 4-weeks training in the major part of our participants. Complementary investigations are in progress to confirm these results and understand underlying mechanisms associated with the recovery

A flexible and accurate method to estimate the mode and stability of spontaneous coordinated behaviors : the index-of-stability (IS) analysis

Patterns of coordination result from the interaction between (at least) two oscillatory components. This interaction is typically understood by means of two variables: the mode that expresses the shape of the interaction, and the stability that is the robustness of the interaction in this mode. A potent method of investigating coordinated behaviors is to examine the extent to which patterns of coordination arise spontaneously. However, a prominent issue faced by researchers is that, to date, no standard methods exist to fairly assess the stability of spontaneous coordination. In the present study, we introduce a new method called the index-of-stability (IS) analysis. We developed this method from the phase-coupling (PC) analysis that has been traditionally used for examining locomotion–respiration coordinated systems. We compared the extents to which both methods estimate the stability of simulated coordinated behaviors. Computer-generated time series were used to simulate the coordination of two rhythmic components according to a selected mode m:n and a selected degree of stability. The IS analysis was superior to the PC analysis in estimating the stability of spontaneous coordinated behaviors, in three ways: First, the estimation of stability itself was found to be more accurate and more reliable with the IS analysis. Second, the IS analysis is not constrained by the limitations of the PC analysis. Third and last, the IS analysis offers more flexibility, and so can be adapted according to the user’s needs