The Effect Of High-definition Transcranial Direct Current Stimulation On Posture Control Performance In The Y-balance Task

Purpose: Posture control refers to the skeletal muscle response of the human body to maintain body balance or to external disturbances.It is a complex interaction process between the human sensory and motor system and the external environment.The ability of posture control will affect the athlete’s performance and the risk of injury.Transcranial direct current stimulation(t DCS)is used to enhance the human posture control ability due to the property of modulating cortical excitability.However,current studies mainly focused on the participants with postural control disorders,and there is no exploration of the effect of t DCS of the primary motor cortex on the postural control ability of healthy adults.Therefore,this study took the Y-balance task as the target action,measured the center of gravity,the center of pressure sway and velocity,and the kinematics and kinetics property,and explored the effects of t DCS of the primary motor cortex on healthy participants.Methods: In this double-blinded sham-controlled study,twelve healthy young participants were recruited.A trained researcher was arranged to operate the t DCS.Participants were asked to receive a single-session anodal-t DCS(2m A stimulation for20 minutes)and sham stimulation(30 seconds of active stimulation only at the beginning)at 3-7 days intervals.The center of gravity,the center of pressure sway and velocity,and the kinematics and kinetics property were assessed before and immediately after a 20-minute session of stimulation.Two-way repeated-measures ANOVA was used to examine the effects of t DCS on posture control.Results: After transcranial direct current stimulation of the primary motor cortex: 1)there were no significant changes in Y-balance task performance(reach direction and duration time);2)the center of gravity sway was significantly decreased in the posteromedial direction;3)the center of pressure sway and velocity was significantly decreased in the posteromedial direction;4)it was observed that the increase in knee extension moment after the a-t DCS was significantly greater than that of s-t DCS.Conclusion: This study found that the anode transcranial direct current stimulation of the primary motor cortex did not improve the task performance of healthy adults.But reduced the center of gravity and the center of pressure sway,and significantly increased knee extension moment.Thus t DCS of the primary motor cortex may increase the posture control performance of healthy adults.It may help adults to spend less energy on posture control and reduce the risk of imbalance.