... implications of nonlinear variability indexes that have been utilized to characterize MFC signals of the elderly subjects during walking Poincaré plot geometry and ApEn analysis of MFC gait data of elderly ... complex and nonlinear [5-7], the application of nonlinear technique seems appropriate In this study, we, therefore, investigate the two types of nonlinear variability indexes (Approximate entropy and ... gait impairment Correlation analysis Correlation analysis was designed to quantify the relationship of mean MFC with Poincaré plot indexes and ApEn values, and the relationships among these measures...