Objective:To measure the cerebral cortical activity by the functional near-infrared spectroscopy,fNIRS during the bilateral single-leg standing in population with chronic ankle instability(CAI)and healthy controls.Method:Sixteen healthy participants without any sprains and 16 participants with unilateral CAI were recruit-ed.The fNIRS was used to collect the brain function signals during the bilateral single-leg standing task.Based on the concentration of oxyhemoglobin(HbO2),the functional activation(β value)of each brain region of the two groups was calculated,and the differences between the groups during the tasks were compared in nine brain regions,including the dorsolateral prefrontal cortex(DLPFC),primary sensory area(S1),supplemen-tary motor area(SMA),and middle temporal gyrus(MTG).Result:Compared to healthy participants,CAI participants exhibited significantly increased cortical activity based on the β value in right SMA(ch28)and left Wernicke's area(ch51)during the single-leg standing on the injured side.During the single-leg standing on the uninjured side,CAI participants exhibited significantly increased cortical activity in the right side of DLPFC(ch15),S1(ch33)and MTG(ch40).Conclusion:The cerebral cortex activation in patients with CAI is different from that in healthy people,ac-cording to the neural mechanism of posture control.There is a higher activation of DLPFC,S1,MTG,SMA,and Wernicke's area in CAI patients during the state of postural control.

Objective:To measure the cerebral cortical activity by the functional near-infrared spectroscopy,fNIRS during the bilateral single-leg standing in population with chronic ankle instability(CAI)and healthy controls.Method:Sixteen healthy participants without any sprains and 16 participants with unilateral CAI were recruit-ed.The fNIRS was used to collect the brain function signals during the bilateral single-leg standing task.Based on the concentration of oxyhemoglobin(HbO2),the functional activation(β value)of each brain region of the two groups was calculated,and the differences between the groups during the tasks were compared in nine brain regions,including the dorsolateral prefrontal cortex(DLPFC),primary sensory area(S1),supplemen-tary motor area(SMA),and middle temporal gyrus(MTG).Result:Compared to healthy participants,CAI participants exhibited significantly increased cortical activity based on the β value in right SMA(ch28)and left Wernicke's area(ch51)during the single-leg standing on the injured side.During the single-leg standing on the uninjured side,CAI participants exhibited significantly increased cortical activity in the right side of DLPFC(ch15),S1(ch33)and MTG(ch40).Conclusion:The cerebral cortex activation in patients with CAI is different from that in healthy people,ac-cording to the neural mechanism of posture control.There is a higher activation of DLPFC,S1,MTG,SMA,and Wernicke's area in CAI patients during the state of postural control.