ABSTRACT
Objective To propose a method for analyzing the hip joint signals during human walking based on Hilbert-Huang transform (HHT) method and verify its feasibility. Methods First, the hip joint angles of one healthy subject were measured by using the hip joint measuring platform composed of acceleration sensors and gyroscopes. Second, all intrinsic mode functions (IMFs) at different scales, which could be further analyzed and combined, were obtained by applying the ensemble empirical mode decomposition (EEMD) to original signals. Finally, the Hilbert spectrum of original signals were plotted and analyzed. Results The signals representing different motion modes as well as gait characteristics indicated by rotating track of the hip joint were obtained. The Hilbert spectrum could show the intra-wave frequency modulation in the main motion mode and the characteristics of walking frequencies. Conclusions This method can be used in rehabilitation and treatment of patients with gait diseases. By using this method, the characteristic signals of the hip joints at different frequency scales can be effectively decomposed, and the post-processing signals can be filtered and centrally corrected, so as to adaptively analyze gait signals of the patients.
ABSTRACT
Objective To accurately measure the motion angels of hand-related joints during manipulations of acupuncture needle thrusting-pulling and twirling, so as to provide quantitative references for acupuncture manipulation. Methods Six acupuncturists with over 3-year acupuncture experience and one volunteer were enrolled in this study. The angles of the forearm, wrist, metacarpophalangeal & interphalangeal joints of the thumb and index finger in each acupuncturist when performing thrusting-pulling and twirling manipulation were measured by the video motion capture (VMC) system, and the different ranges of above-mentioned angles among the 6 acupuncturists when performing 10 trails of thrusting-pulling and twirling manipulations on the volunteer’s thigh were compared. Results There was no significant difference in the ranges of relevant hand-related angles in the acupuncturist (P>0.05). The manipulation of thrusting-pulling was mainly managed by the wrist joint, with the range of (7.23±1.87)°, while the manipulation of twirling was mainly managed by the interphalangeal joints of the index finger, and the range of the first and second interphalangeal joints of the index finger was (28.33±2.18)°and (10.43±1.69)°, respectively. Conclusions The VMC can be a reliable method to quantify the parameters of acupuncture manipulation. Different acupuncture manipulation shows particular variation of the joint angles, which can be used as a reference to quantify the acupuncture manipulation.
ABSTRACT
Objective To establish a neural probe-brain tissue numerical model and investigate tissue injuries induced by probe during its insertion into brain tissues. Methods The material of brain tissue was described by a hyper-viscoelastic constitutive equation. Tissue failure and separation were simulated by the element deletion method based on a maximum principle strain failure criteria, and tissue injuries were quantified by the mean effective strain. Then effects of probe wedge angle, inserting speed and probe stiffness on the acute injury were investigated. Results Tissue strain generated by probe with wedge angle of 150° was increased by 37.1% compared with the strain induced with wedge angle of 90°. Along the insertion path, probe with a slow speed of 100 μm/s induced much higher strain value (>57%) compared to that with relatively faster speed of 500 μm/s, which generated the strain value below 25%. The probe stiffness, however, had a negligible effect on tissue injury. The strain within the tissue was only increased by 1%-2% while the stiffness decreased from 165 GPa to 5 kPa. Conclusions The established numerical model can provide references for the design of neural probe and probe inserting parameters, which will be helpful to reduce tissue injuries induced by probe insertion and thus improve the working life of neural probe to meet the long-term clinical application.