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Hou W.-S.,Chongqing University | Hou W.-S.,Chongqing Engineering Research Center for Quality and Safety Control of Medical Device | An Y.,Chongqing University | Yang D.-D.,Chongqing University | And 3 more authors.
Yiyong Shengwu Lixue/Journal of Medical Biomechanics | Year: 2012

Objective: To detect the recruitment pattern of motor unit in human flexor digitorum superficialis (FDS) at different force levels produced by the index finger. Methods: Eight subjects were recruited to produce a certain force level with the index finger to match the ordered force level (20%, 40%, 60% maximum voluntary contraction). During the force tracking task, the multi-channel surface electromyography (sEMG) signals were recorded on FDS using 8×1 (row×column) electrode-array. The motor unit action potential (MUAP) information was extracted by Fast Independent Component Analysis (FastICA), and then the correlation between MUAP pattern and force level was analyzed. Results: Four different types of MUAP were extracted successfully by FastICA from original sEMG signals and the total number of MUAP showed an increasing trend with the force level increasing. At different force levels, the proportion of different types of MUAP was different, showing different trends with change of the force level. Conclusions: At different levels of the finger force, the recruitment pattern of motor unit in FDS will be changed so as to produce the force accordingly. Source


Guo B.-B.,Chongqing University | Guo B.-B.,Chongqing Engineering Research Center for Quality and Safety Control of Medical Device | Zheng X.-L.,Chongqing University | Zheng X.-L.,Chongqing Engineering Research Center for Quality and Safety Control of Medical Device | And 5 more authors.
Dianzi Keji Daxue Xuebao/Journal of the University of Electronic Science and Technology of China | Year: 2012

The activity pattern in human visual cortex is studied and the common feature of volunteers is extracted based on analysis of regions of interest (ROI). By combining physiological structure and Talairach coordinates system, the same ROIs are obtained from the three-dimensional cortical model of each volunteer, these ROIs is then projected into the two-dimensional cortical model with the same topology, and the maximum activation intensity of each ROI is extracted. The common activation feature of volunteers is drawn and described via statistical analysis of ROIs. Experiment results show that the proposed method overcomes the limitation of traditional voxel-based analysis in extracting the common activation feature of volunteers. Source


Mou Z.-X.,Chongqing University | Hou W.-S.,Chongqing University | Hou W.-S.,Chongqing Engineering Research Center for Quality and Safety Control of Medical Device | Zheng X.-L.,Chongqing University | And 7 more authors.
Chongqing Daxue Xuebao/Journal of Chongqing University | Year: 2011

Micro-coil array and matching capacitors together can realize the parallel transmission of multichannel signal. In order to improve the accuracy and reliability of receiving information from each channel and to reduce the size of implant systems, two kinds of micro-coil arrays fabricated by using PCB (printed circuit board) and FPC (flexible printed circuit) technology respectively are presented. Then the two micro-coil arrays are used in multi-channel transmission device with a 2 * 2 array. The coupling efficiency of two kinds of process coils under ideal coupling, spatial mismatch as well as different load conditions are tested. The results show that two kinds of coils are affected by spatial mismatch. However, if the transverse mismatch is restricted less than 3 mm and the angular mismatch is less than 30°, the two kinds of coils can be used for signal transcutaneous transmission for implantable electrical stimulation devices at the laboratory stage, and the channel output signal can meet the requirements of electrical nerve stimulation. As for the reliability of the system, FPC coil shows more advantages, and it is more adapted to implantable system. Source


Hou W.,Chongqing University | Hou W.,Chongqing Engineering Research Center for Quality and Safety Control of Medical Device | Wan S.,Chongqing University | Wu X.,Chongqing University | And 7 more authors.
Chongqing Daxue Xuebao/Journal of Chongqing University | Year: 2013

A DSP-based experimental system with real-time finger joint angle detection and prosthetic finger control is designed here. The prototype system is mainly composed of four parts: real-time finger posture detection, joint angle analysis, control pulse encode, and underactuated prosthetic hand with three individually active fingers, i.e. thumb, index finger and middle finger. The real-time finger joint movement is detected by acceleration sensor ADXL330, and the microprocessor DSPTMS320F2812 is used to collect the output of acceleration sensor and calculate angle changes of the finger joint instantaneously. Then, the angle changes are encoded to PWM pulse sequence to control the stepper motor, which drove the rotation of prosthetic finger joint. Preliminary tests are given to multi-finger motion detection and real-time prosthetic finger control, respectively. The experimental results show that the acceleration sensor ADXL330 can be used to reliably detect the gesture of finger movements, it can effectively drive flexion movement and extension movement of prosthetic finger, and the grip action can be completed with the coordination of thumb, index finger, and middle finger. Source

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