Objective To observe the clinical efficacy of closed-loop rehabilitation therapy by brain-computer interface(BCI)combined with exoskeleton robotic hand in patients with hand dysfunction after cerebral infarction and analyze the influence of patients'cognitive function and implicit motor imagery ability on the recognition rate of BCI.Methods A total of 50 patients with cerebral infarction were randomly assigned to the observation group and the control group,25 patients in each group.Both groups received routine rehabilitation programs.In addition to the conventional rehabilitation treatment,the observation group received the closed-loop BCI rehabilitation trainingby brain-computer interface(BCI)combined with exoskeleton robotic hand.The scores of Fugl-Meyer Assessment of the Upper Extremity(FMA-UE),Action Research Arm Test(ARAT),Wolf Motor Function Test(WMFT),and Modified Ashworth scale(MAS)of the wrist flexors were compared between the two groups before and after treatment.Before intervention,the mental rotation test and Montreal Cognitive Assessment(MoCA)were used to assess the baseline implicit motor imagery ability and cognitive level of patients in the observation group.The correlation analysis between these scores and the recognition rate of BCI was conducted to analyze the relevant factors affecting the closed-loop rehabilitation effects of BCI.Results The two groups showed no significant difference in all outcomes before treatment(both P>0.05).After intervention,the observation group exhibited the significantly higher scores of FMA-UE,ARAT,and WMFT(all P<0.05),and significantly lower MAS scores of wrist and finger flexors compared with the control group(all P<0.05).In addition,the recognition rate of BCI was positively correlated with the accuracy of mental rotation test and MoCA score(P<0.05),and negatively corre-lated with the reaction time of mental rotation test(P<0.05).Conclusions Closed-loop rehabilitation training with BCI combined with exoskeleton robot hand can promote the recovery of upper limbs and hand motor function in patients with cerebral infarction.Additionally,the implicit motor imagery ability and cognitive function of patients are suggested to be used for screening the patients suitable for BCI training before the implementation of BCI treatment.