Differences In Executive Function Between Long-term Exercise And Lack Of Exercise In Adolescents With Intellectual Disabilities:A FNIRS Study

Objective: The study used f NIRS as the method to explore the differences in executive function between long-term exercise and non-exercise adolescents with intellectual disabilities（ID）and provide evidence to clarify the brain mechanism of the effect of exercise on the executive function of adolescents with intellectual disabilities.Methods: Forty-four adolescents with intellectual disability aged 12-18 years were recruited in the study.18 adolescents were allocated in the long-term exercise group and 26 participants were allocated in the non-exercise control group.Flanker task,2-Back task,and Dots–Triangles task were used to measure the behavioral outcomes of the subjects’ inhibitory control ability,working memory,and cognitive flexibility,respectively.At the same time,near-infrared brain imaging（f NIRS）was used to monitor and record the changes in Oxy-Hb concentration in the prefrontal cortex region of interest（ROI）during each task,to explore the activation level of the corresponding brain region.Results:（1）In the Dots-Triangles task,the behavioral results showed that there was a significant difference in the accuracy rate between the two groups.Compared with the control group,the long-term exercise group revealed a higher accuracy rate in both behavioral switching conditions（P = 0.046）and switching costs（P=0.020）,but no statistical difference between the two groups was observed in response time in each condition.The results of f NIRS showed that both groups showed decreased Oxy-Hb activation in the right dorsolateral prefrontal region,but the Oxy-Hb concentration in the long-term exercise group in the right dorsolateral prefrontal region was significantly higher than that in the control group（p = 0.038）.The results of Pearson correlation analysis showed that the Oxy-Hb value in the right dorsolateral prefrontal region was negatively correlated with the correct rate of the conversion cost in the Dots-Triangles conversion task（r =-0.427,p = 0.011）.（2）In the 2-Back task,the behavioral results showed a significant higher accuracy rate in the long-term exercise group compared with the control group（p = 0.041）,but there is no significant difference in the response time.The f NIRS results showed that the long-term exercise group’s Oxy-Hb activation was significantly lower than control group in the right frontal polar region（p = 0.003）and right ventral prefrontal region（p = 0.046）.The results of the Pearson correlation analysis showed that the Oxy-Hb value in the right frontal pole region of the 2-Back task had a low negative correlation with the accuracy（r =-0.349,p =0.034）.（3）In the Flanker task,there was no significant difference between the two groups in either behavioral or f NIRS results.Conclusions: This study shows that long-term exercise has different effects on various parts of the executive function of adolescents with intellectual disabilities,as shown below.The results of this study suggest that long-term exercise may have positive effect on the executive function of adolescents with intellectual disabilities,especially in cognitive flexibility and working memory.The results demonstrated that long-term exercise could improve the brain activation patterns of the right dorsolateral prefrontal area,right frontal pole in adolescents with intellectual disabilities,thereby improving the cognitive flexibility and working memory.However,no positive effect of long-term exercise was observed in the inhibitory control ability.