Augmented Feedback to Influence Gait Symmetry: A Feasibility Study to Quantify Effects on the Global Gait Pattern

Recovering gait is a major priority after a neurological injury. It involves motor learning and motor control processes that are usually driven by the feedback provided by therapists. Since strong evidence show that augmented feedback can boost such processes in healthy subjects, its use for personalizing post-stroke gait therapy is raising interest. Specifically, gait asymmetry, a common characteristic in pathological post-stroke gait, could be targeted by augmented feedback. However, asymmetry results from a change in several dependent gait parameters while augmented feedback is commonly given on a single one only. In that case, it remains unclear how the different components of gait symmetry are affected by augmented feedback. In this pilot study involving twelve healthy participants, we investigated how gait parameters, measured during treadmill walking, are impacted by real-time augmented visual feedback targeting stance time, with the objective of manipulating gait symmetry (i.e., increasing asymmetry in the case of healthy subjects). We showed that augmented feedback on temporal symmetry also affects kinetic symmetry with a correlation coefficient of 0.65 for ground reaction force. It also impacts the kinematic pattern of gait, as measured by the Gait Deviation Index, with an average decrease of 21.7 points when walking with augmented feedback. This work is a first step towards a more comprehensive understanding of the impact of augmented visual feedback on gait symmetry. It highlights that, based on a deeper knowledge of the underlying mechanisms, augmented feedback on a single parameter could be used to intentionally tackle several gait disorders. It yet also outlines the risks of compensatory behaviors, that have to be carefully considered.