Human cortical brain and biomechanical responses to abrupt changes in exoskeleton assistance while walking

Robotic exoskeletons have advanced significantly, yet control systems still face challenges in delivering assistance that seamlessly aligns with the user's musculoskeletal system. To enhance user-device interaction, it is essential to understand the neural mechanisms underlying human adaptation to exoskeleton assistance. Although cortical brain activity plays a critical role in locomotion, how it is modulated by exoskeleton assistance while walking remains poorly understood. This study investigates cortical dynamics during abrupt exoskeleton state changes to clarify the brain's role in gait adaptation. EEG, kinematic, and muscle activity data were collected from 21 healthy adults walking on a treadmill with bilateral ankle exoskeletons. Results reveal that frontal theta-band activity could track exoskeleton state transitions. Adaptations occurred within two strides, reflected in changes in frontal theta, alpha, and beta activity, along with variations in knee and ankle range of motion and muscle activation patterns. These findings demonstrate EEG's sensitivity to neural responses during exoskeleton transitions and highlight its potential application for enabling real-time feedback to optimize personalized assistance.