用小波熵评价人体步态变化

The Assessment of Human Gait Function Based on Wavelet Entropy

目的将小波熵应用于步态数据量化分析,探寻新的评价人体步态功能变化的特征参数。方法运用Bertec三维测力系统,采集10名青年被试者和10名老年被试者的足-地反作用力步态数据,采用离散正交小波变换分解被试组步态数据,定义相对小波能量和小波熵,用t-检验法分别检验基于两个被试组步态数据的相对小波能量及小波熵的差异,来评价人体步态功能变化。结果基于两个被试组步态数据的相对小波能量差异显著;基于老年被试组步态数据的小波熵值明显低于基于青年被试组步态数据的小波熵值,显著性水平值P<0.05,基于两个被试组步态数据的小波熵具有显著差异。结论相对小波能量可提供步态数据中与人体步态功能内在变化相关的细节信息,小波熵能够表征人体步态内在动态变化程度,有望成为临床上可有效评估人体步态功能变化的特征参数。

Objective To seek a useful index for assessing the change of human gait function based on the application of wavelet entropy in the gait data analysis. Methods The ground reaction force （GRF） gait data of 2 groups（ 10 young and 10 elderly subjects） were acquired with Bertec 3 dimensional force measured system （a strain gauge force platform） during normal walking. The orthogonal discrete wavelet transform was used for decomposing the collected gait data. The relative wavelet energy and wavelet entropy were defined and calculated respectively. They were statistically analyzed with t - test technique respectively to evaluate the change of human gait function. Results There was significant difference between the relative wavelet energy from GRF gait data of the two subject groups. The average values of wavelet entropy from the GRF gait data of elderly subject group were obviously less than those from the GRF gait data of young subject group. With the value of significance level of t-test P 〈 0.05, there was significant difference between wavelet entropy of 2 groups. Conclusion The relative wavelet energy can provide the detailed information associated with the change of hu- man gait function in gait data, and the wavelet entropy is able to characterize the degree of the intrinsic change of the human locomotive system. The wavelet entropy can serve as a new index to describe the change of human gait function in future clinical application.