Abstract
The electromyogram (EMG) activity of external urethral sphincter (EUS) and cystometrogram (CMG) of the urinary bladder can reflect the clinical information and status for the physician about the function of the bladder and urethra. The traditional linear methods cannot well describe complex nature phenomena . There is no exception for our cases. In this thesis, we investigate the time series of EUS EMG signals of normal and SCI Wistar rats with room temperatures from the viewpoint of nonlinear dynamics. The techniques of modern nonlinear dynamical systems are used to analyze the time series of external urethral sphincter electromyogram (EUS EMG) and the cystometrogram (CMG) of the urinary bladder of Wistar rat. They include singular value decomposition (SVD), recurrence plot analysis (RPA), and recurrence quantification analysis (RQA). These methods are good tools to recognize the different phases of micturition and the differences caused by spinal cord injury in Wistar rats. SVD indicates that SCI rats in bursting phase have more principal directions in the embedding space than normal rats. RPA displays the important features in bursting phase for both normal and SCI rats and RQA shows the differences between normal rats, SCI rats bursting with voiding and SCI rats bursting without voiding. Although the dynamics of micturation are complex, they still have some regularity in our study.