Effects Of Unilateral And Bilateral Exercise Intervention On Cortical Activation And Postural Control In Chronic Ankle Instability

Background and objective:Ankle sprain is one of the most common sports injuries in sports activities.About 40%of the patients will suffer repeated sprains and develop into chronic ankle instability(CAI),which shows a series of symptoms such as bilateral periankle muscle strength decline,abnormal proprioceptive,repeated "giving way".Quality of life is severely affected.In recent years,it has been found that there are neuroplasticity changes in the central nervous system in this population,which provides a new possibility to explain the changes of CAI postural control.At the same time,some studies have found that there are postural control disorders in both ankle joints of CAI people,but there is a lack of unified conclusion on the characteristics of cortical activation in CAI people under motion state,especially the activation results of bilateral lower limbs,and the difference of influence of unilateral and bilateral exercise intervention on brain function and postural control of CAI people has not been discussed.Therefore,this study intends to reveal the difference of postural control and cortical activation between CAI and healthy people through horizontal observation of bilateral lower limb,and reveal the influence of unilateral and bilateral exercise intervention on postural control and cortical activation through longitudinal intervention.This paper consists of two studies.This study is divided into two parts:1.Cross-sectional study: Differences in cortical activation and postural control between people with CAI individuals and healthy peopleObjective: To explore the differences of cerebral cortex activation and postural control during postural control task between CAI group and healthy group.Methods: Fifteen subjects without sprain and 15 unilateral CAI subjects were included in the study.The brain function signals were collected under the left and right standing task,and the activation degree(β value)of each brain region of the two groups of subjects was recorded.Then,the single-leg station test,Y-balance test and figure-8single-leg jump test on the force measuring platform were carried out.The total shaking track length of COP,the shaking track length/the maximum shaking diameter/the average shaking speed of X and Y axis,the reaching distance of Y-balance test and the time to complete the figure of 8 hop test were recorded.Results: Compared with the affected leg of the two groups,supplementary motor area(ch28)and Wernicke’s area(ch51)were significantly activated during single-leg standing in CAI(p < 0.05).All indexes of CAI group increased significantly(p < 0.05)during the single leg test of force measuring plate and the one-leg jump test of figure 8.In the Y balance test,the reach distance of CAI group in all three directions was significantly reduced(p < 0.05).Compared with the healthy legs of the two groups,dorsolateral prefrontal area(ch15),primary sensory area(ch33)and middle temporal gyrus(ch40)were significantly activated in CAI group during single-leg standing(p <0.05).The total shaking track length,X-axis tracking length,X-axis average shaking velocity and Y-axis maximum shaking diameter of CAI group increased significantly during single-leg standing(p < 0.05).In the Y balance test,the posterolateral reach distance of CAI group was significantly reduced(p < 0.05).Conclusions:(1)The cortical activation characteristics of CAI group were different from those of healthy people under the one-legged standing task of bilateral lower limbs,suggesting that CAI group may have neuroplasticity changes.(2)The performance of CAI people in bilateral postural stability test was different from that of healthy people without sprain,indicating the existence of bilateral balance defects in CAI people,which needs bilateral rehabilitation intervention.2.Intervention study: The influence of unilateral and bilateral exercise intervention on cortical activation and postural control of CAI populationObjective: To compare the cerebral cortex activation and postural control of CAI population after unilateral and bilateral exercise intervention.Methods: A total of 22 CAI subjects were included and randomly divided into two groups to receive exercise intervention twice a week for 6 weeks.Finally,a total of 18 people completed the training,including 9 people in the unilateral training group and 9people in the bilateral training group.Before and after intervention,f NIRS functional brain imaging device,Y balance test,XPH-B balance evaluator,and figure of "8" hop test were used to evaluate the cerebral cortex activation,static balance,dynamic balance and functional performance of the patients.Results:In terms of postural control,after the unilateral intervention,it was found that the time of figure 8 hop test was significantly reduced(p < 0.05),while the comprehensive value of Y balance test and CAIT questionnaire score were significantly increased(p < 0.05)in the affected leg.The comprehensive value of Y balance test and the score of CAIT questionnaire were significantly increased(p < 0.05)in the healthy leg.In the bilateral training group,the time of figure 8 hop test was significantly reduced(p < 0.05),while the comprehensive value of Y balance test and CAIT questionnaire score were significantly increased(p < 0.05)in the affected leg.The time of figure 8 hop test was significantly decreased(p < 0.05),and the scores of Y balance test and CAIT questionnaire were significantly increased(p < 0.05)in the healthy leg.After unilateral and bilateral intervention,there was no significant difference in all test indexes between the two groups.In terms of cortical activation,it was found that the activation of somatosensory association area(ch44)and superior temporal gyrus(ch52)decreased significantly in the unilateral group during the one-leg standing task after intervention(p < 0.05).In the bilateral group,the activation of dorsolateral prefrontal cortex(ch16)and middle temporal gyrus(ch37)was significantly increased(p < 0.05),while the activation of Wernicke’s area(ch56)was significantly decreased(p < 0.05)during the one-legged standing task after intervention.After unilateral and bilateral intervention,the activation of dorsolateral prefrontal area(ch16)and Wernicke’s area(ch53)were significantly different between the two groups(p < 0.05).The improvement of Y balance test and CAIT score on the affected side after unilateral training were significantly positively correlated with the decrease of cortical activation in the somatosensory association area(p < 0.05),and the improvement of CAIT score on the affected side after bilateral training was significantly positively correlated with the increase of cortical activation in Wernicke’s area(p < 0.05).Conclusions:(1)Both unilateral and bilateral exercise intervention can improve the postural control of CAI patients,and change the degree of cortical activation.(2)After unilateral and bilateral exercise intervention,there is a significant correlation between postural control performance and cortical activation,suggesting the interaction between cortical activation and postural control performance.(3)Bilateral training adopted different cortical activation patterns than unilateral training,but there was no significant advantage in postural control.