Paper Accepted (April 2017)

With our work on dynamic balance control during walking in the presence of optical flow perturbations, we often wonder whether the visuomotor control of walking balance adapts to such perturbations over time. Such adaptation may arise from multisensory reweighting, the central process that determines the relative priority placed on somatosensory , visual, and vestibular feedback. Our most recent work investigating the propensity for visuomotor adaptation in human balance control was recently accepted for publication in the journal Human Movement Science.

Thompson JD and Franz JR. Do kinematic metrics of walking balance control adapt to perturbed optical flow? Human Movement Science (In Press).

Abstract. Visual (i.e., optical flow) perturbations can be used to study balance control and balance deficits. However, it remains unclear whether walking balance control adapts to such perturbations over time. Our purpose was to investigate the propensity for visuomotor adaptation in walking balance control using prolonged exposure to optical flow perturbations. Ten subjects (age: 25.4 ± 3.8 years) walked on a treadmill while watching a speed-matched virtual hallway with and without continuous mediolateral optical flow perturbations of three different amplitudes. Each of three perturbation trials consisted of 8 minutes of prolonged exposure followed by 1 min of unperturbed walking. Using 3D motion capture, we analyzed changes in foot placement kinematics and mediolateral sacrum motion. At their onset, perturbations elicited wider and shorter steps, alluding to a more cautious, general anticipatory balance control strategy. As perturbations continued, foot placement tended toward values seen during unperturbed walking while step width variability and mediolateral sacrum motion concurrently increased. Our findings suggest that subjects progressively shifted from a general anticipatory balance control strategy to a reactive, task-specific strategy using step-to-step adjustments. Prolonged exposure to optical flow perturbations may have clinical utility to reinforce reactive, task-specific balance control through training.