| ?Background?The cerebral cortex has the advanced function of language,learning,memory and thinking,and it is the most advanced part of the nervous system.These activities activate the related functions through the discharge of neurons in the cerebral cortex.Ischemic stroke is one of the common diseases of cerebral cortex injury.Clinically from the anatomical level through the position,size and the changes of lesions before and after to assessment the severity?prognosis and rehabilitation of patients,but the evaluation on the function of the brain is less.The current clinical examination of brain function mainly include the functional magnetic resonance imaging,single photon emission computed tomography/computed tomography,positron emission magnetoencephalography and electroencephalography.But these are expensive and need to check for a long time,contact with radioactive material,low time resolution.Modern science indicate that EEG is a large number of nerve cells in the nonlinear coupling,dynamics of nonlinear analysis method is more suitable for the study of the functional activities of the brain,the nonlinear parameter of approximate entropy can quantitative estimation the complexity of the signal is the new development of nonlinear method.This study uses EEG approximate entropy,analysis the EEG signal of young people in different cognitive process,and EEG signal changes in patients with ischemic stroke of acute stage and recovery stage,trying to seek a simple,safe and realtime,dynamic observation of brain function new method.?Objective?In this study,we investigated the changes of the EEG approximate entropy in healthy young people under different cognitive states like keep eyes closed to be quiet and keep eyes closed to mental arithmetic.Objective to investigate the changes of the EEG approximate entropy in patients with ischemic stroke during acute stage to functional recovery stage.To analyze the correlation between EEG approximate entropy and stroke score in patients with ischemic stroke.Objective to find a simple and objective method to monitor the change of brain function.?Materials and Methods?EEG examination was carried out on 28 healthy young people with different states like keep eyes closed to be quiet and keep eyes closed to mental arithmetic.As well as 12 patients with acute ischemic stroke(72h)and functional recovery period(after six months)of EEG examination and Stroke Scale score,while the control group underwent EEG in 20 healthy elderly people,using EEG approximate entropy analysis the EEG signal data.?Results?1?Normal young people regardless any states like eyes closed mental arithmetic and keep eyes closed to be quiet,the EEG approximate entropy fluctuations in 0~1.2?The EEG approximate entropy of normal young people with eyes closed and mental arithmetic was significantly higher than that of eyes closed to be quiet,and the difference was statistically significant.3?Under normal circumstances,no matter what kind of thinking condition,the left superior hemisphere of the EEG approximate entropy is higher than the right hemisphere,and the temporal(F7,F8,T3,T4,T5,T6)EEG approximate entropy is higher than that of other leads.Be quiet and eyes closed state change into eye closed and mental arithmetic,the whole brain EEG approximate entropy increases,and the prefrontal,frontal,central and parietal regions(Fp1,Fp2,F3,F4,C3,C4,P3,P4)increased more greatly.4?Patients with acute ischemic stroke compared with normal control group at the same time the EEG approximate entropy can be seen throughout the brain of the lead ApEn decreased significantly,the difference was statistically significant(P<0.05),and the ischemia area decreased significantly.Under normal circumstances,the left dominant hemisphere higer than the right side trend does not exist,and become similar or lower than the right side,such as the left prefrontal,frontal,central,parietal,temporal region(Fp1,F3,C3,P3,T5)decreased more significantly than the right side.5?Compared with the normal control group,the patients with ischemic stroke in recovery stage were significantly same from the normal control group at the same time.The results showed that all the brain lead had different degrees of recovery.Non responsible lesions lead were restored to normal control group at the same level,and the EEG approximate entropy of artery defect in the left side of the brain is still low,mainly for the temporal region(F7,T5)the recovery is not complete,the difference was statistically significant(P<0.05).6?Compared with patients with ischemic stroke in the recovery phase and acute phase of EEG approximate entropy,as stroke score improved,better recovery,EEG approximate entropy in addition to ischemic area such as the left temporal region,parietal region(T3,T5,C3)had little difference with the acute stage,the other EEG approximate entropy significantly improved.7?Patients with ischemic stroke that most of the EEG approximate entropy were negatively correlated with the age,NIHSS score and MRS score,and were positively correlated with BI score.?Conclusions?1?Through the observation of the EEG approximate entropy of the normal young people with diferent mental state,we can see that the valve of approximate entropy is 0~1.2?The more complex of the thinking,the more active the brain,the higher of the EEG approximate entropy,and the different thinking operations,the active parts of the brain and the degrees of activity is different.3?The changes of brain function in different state of mind can be monitored dynamically and in real time with the approximate entropy.4?In the acute stage of ischemic stroke,the approximate entropy of EEG in the whole brain was significantly decreased,and the approximate entropy of the EEG in the ischemic area decreased more obviously,which could be used as an auxiliary diagnostic value.5?During the recovery period of ischemic stroke,the approximate entropy of each lead is higher than that of the former,mean the function of the brain cells can be recovered.It can be used as the evaluation index of clinical therapeutic effect.6?The approximate entropy of EEG was negatively correlated with the NHISS score,the more severe the disease,the lower of approximate entropy,the better the condition,the higher of approximate entropy,the approximate entropy is related to the patient's condition. |
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