Evoking Cutaneous Reflexes During Human Walking II. An Open-Source Pseudo-Randomization Approach

This paper, the second in a two-part series, outlines a low-cost, open-source, pseudo-randomization approach for measuring cutaneous reflexes during human walking. The protocol guides users through integrating an Arduino Uno microcontroller, a VICON data acquisition system, and an electrical stimulation device. A custom code was developed in C++, and steps are provided to guide users in downloading and integrating it with an Arduino. This setup provides researchers the ability to define key experimental parameters such as the number of gait cycles to include in quantifying the average time of the subject's walking gait cycle, the number of bins to partition the human walking gait cycle, and the number of stimuli per bin-all while maintaining real-time stimulation capability. During a walking trial, the system is designed to (1) deliver stimuli pseudo-randomly using instances when the foot makes initial contact with the treadmill surface and (2) deliver an even distribution of stimuli across all bins. Real-time feedback mechanisms and data monitoring are enabled via an integrated Arduino and VICON framework, allowing researchers to conduct controlled, repeatable experiments that aim to measure cutaneous reflexes during human walking. This protocol provides a flexible and accessible solution for researchers aiming to investigate phase-dependent modulation of reflexes during normal and perturbed walking conditions. Its modularity and integration with existing motion capture systems make it a powerful tool for both basic and clinical research within the fields of neuroscience, biomechanics, and gait rehabilitation. © 2025 Wiley Periodicals LLC. Basic Protocol 1: Integrating Arduino to VICON data acquisition and stimulator Basic Protocol 2: Downloading and running pseudo-randomized Arduino code.