Different Types of Visual Perturbation Induced Different Demands and Patterns in Active Control: Implication for Future Sensorimotor Training.

Background: Sensorimotor training using visual perturbations has been widely applied to astronauts for rapidly handling and adapting to unpredictable environments. However, these visual perturbations might not be strong enough to trigger long-term effects. Therefore, this study aimed to develop a novel sensorimotor training paradigm using pseudo-random visual perturbations and to determine the demands and patterns of active control under different types of visual perturbations. Method: Thirty healthy young adults participated in this study. Four walking conditions were randomly assigned to these participants: 1) walking without optic flow (NoOptic), 2) walking with the optic flow (Optic), 3) walking under reduced visual capability (Vre), and 4) walking under perturbed optic flow (Vpe). The dependent variables were the step length variability, the step width variability, the 95% confidence interval ellipse area, the long axis of the ellipse, and the short axis of the ellipse. Results: The results indicated that 1) the step length variability and the ellipse area were greater in Vre compared to Optic (p < 0.001, p < 0.001). Moreover, the step width variability and ellipse area were greater in Vpe than Optic (p < 0.001, p = 0.002). Conclusion: The abovementioned results demonstrated that 1) walking in both Vre and Vpe conditions required greater demands and different patterns in active controls compared to the Optic condition, suggesting both Vre and Vpe conditions could be applied for sensorimotor training; 2) the Vre condition would be the first choice if there were no concerns in potential trips on the treadmill.

Using a Portable Pressure-Sensing Walkway to Detect Age-Related Alternations in Foot Integrated Pressure During Multiple Obstacle Negotiation.

Multiple obstacle avoidance induces a higher potential of falls among older adults. This study attempted to add other important measurements by investigating the pressure-related gait parameters when stepping over multiple obstacles on a portable pressure-sensing walkway. Twenty-six young and 26 older participants were recruited in this study. A portable pressure-sensing Zeno walkway and cyclogram intersection point analysis method was introduced to collect both spatial-temporal and pressure-related gait parameters. Older adults significantly reduced foot integrated pressure of the leading leg when stepping over the second obstacle compared with young adults (p = .0078). A significantly larger cyclogram intersection point shift in medial-lateral direction was found in older adults than in young adults (p = .024) when stepping over the second obstacle, especially in the lateral direction. The results of this study showed that a pressure-sensing walking combined with cyclogram intersection point method could detect foot pressure distribution differences caused by aging.