The Impact of Stimulation Parameters on Reaction Times Following Transcutaneous Electrical Stimulation in the Lower Leg

The growing need for human-machine interfaces (HMIs) underscores the importance of sensory feedback, with electrical stimulation offering efficient interaction in various applications. While its sensory effects are extensively studied, investigations into the reaction time (RT) following transcutaneous electrical stimulation (TES) remain limited. This study aimed to evaluate how stimulation parameters influence RT. We examined RT and RT variability among twenty healthy participants aged 21 to 61 years. Participants underwent 16 stimulation patterns (10 repetitions per pattern) with combinations of four pulse frequencies (4, 26, 48, 70 Hz) and four pulse amplitudes (1.5, 2.0, 2.5, 3.0 times of sensory threshold) on four skin locations in the lower leg above peroneal nerve, tibial nerve, tibialis anterior muscle, and a lateral shank control site. RT was assessed as participants dorsiflexed their foot in response to electrical stimulation. Results revealed that both RT and its variability decreased as pulse frequency and amplitude increased, and there was an interaction effect between pulse frequency and amplitude. However, no significant difference was found in RT across stimulation locations. These findings demonstrate how stimulation parameters affect the speed and efficiency of communication between the user and the stimulator, showing promises for augmenting real-time feedback HMIs.