Effects of cerebellar transcranial alternating current stimulation on balance and gait in healthy subjects

Background: Transcranial Alternating Current Stimulation (tACS) is a non-invasive brain stimulation technique that modulates cortical oscillations and influences behavior. Objectives: This study aimed to explore the effects of cerebellar theta (5 Hz) and gamma (50 Hz) tACS on human balance and gait through kinematic analysis. Materials and methods: Nineteen right-handed healthy subjects participated in three randomized motor tasks: postural standing (PS), gait initiation (GI), and gait cycle (GC). Participants underwent theta-, gamma-, or sham-tACS over the cerebellum while kinematic data were collected using a force platform and an 8-camera optoelectronic system. Results: Theta-tACS significantly influenced motor behavior during PS and GC, but not GI. Specifically, it reduced the Maximum Radius, Total Trace Length, Longitudinal Range, and Area during PS, and decreased Stride Width during GC. In contrast, cerebellar gamma-tACS had no significant effect on any kinematic parameters across the tasks. Conclusions: Cerebellar theta-tACS may enhance postural stability and gait control in healthy individuals. We hypothesize that theta-tACS may entrain theta-resonant neurons in the cerebellar cortex, affecting motor control networks involved in balance and gait. Significance: This study highlights tACS's potential as a non-invasive treatment for balance and gait disorders associated with cerebellar dysfunction.