Objective:To investigate and distinguish the difference of EEC between elderly and youth by using nonlinear dynamics theory eigenvalues.Methods:The features were extracted from the events of close eyes,open eyes in a quiet situation and N-back letters memory of the high-frequeney EEG for the elderly group and youth group by using the correlation dimension and the lyapunov exponents of nonlinear dynamics.Results:Under close eyes and open eyes in a quiet event,the characteristic values of correlation dimension and lyapunov exponent were significantly different between the elderly group and youth group (P＜0.05).Under the N-back letters memory event,the correlation dimension of the elderly group were significantly higher than that of the youth,but the values of only 14 of the elderly leads lyapunov exponent were greater than those of youth group (P＜0.05).The characteristic value of correlation dimension and lyapunov exponent were all in the peak in five leads including Fz,FCz,Cz,CPz,Pz of the sagittal line no matter whether in the actvities of thinking or not.Conclusions:The elderly brain function is weak and less energy grant compared to the young people.In the case of thinking activities,the elderly people's brain function needs more energy to complete the same thinking activities.The characteristic value of correlation dimension and lyapunov exponent in the three events of close eyes,open eyes in a quiet situation and N-back letters memory can be used to distinguish the difference of EEG between the elderly and the youth.%目的:探讨利用非线性动力学理论特征值来区分老年人和青年人脑电的差异.方法:采用非线性动力学的关联维数和lya-punov指数对老年组和青年组的安静闭眼、安静睁眼和N-back字母记忆事件等的高频脑电进行特征提取,对特征值进行统计分析,分析两组特征值之间的差别.结果:安静闭眼和安静睁眼事件下,老年组多数导联的关联维数和lyapunov指数的特征值与青年组的特征值存在显著差异(P均＜0.05);N-back字母记忆事件下,老人多数导联的关联维数特征值大于青年的特征值,但老年组只有14导联的lyapunov指数特征值大于青年组的特征值(P均＜0.05).不管有无思维活动,人脑在矢状线上的五个导联Fz、FCz、Cz、CPz、Pz的关联维数和lyapunov指数的特征值都处在峰值处.结论:老年人相比青年人脑功能弱、能量发放少;在思维活动情况下,老年需要更多地发放能量来完成相同的思维活动.安静闭眼和睁眼以及N-back字母记忆事件等三个事件的关联维数和lyapunov指数特征值可用来区分老年组和青年组脑电的差异.
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