Experimental Detection Study on Cerebral Hemorrhage in Rabbits Based on Magnetic Induction Phase Shift Spectroscopy Under the Feature Band / 生物医学工程学杂志

This study was aimed to improve the sensitivity of magnetic induction phase shift detection system for cerebral hemorrhage. In the study, a cerebral hemorrhage model with 13 rabbits was established by injection of autologous blood and the cerebral hemorrhage was detected by utilizing magnetic induction phase shift spectroscopy (MIPSS) detection method under the feature band. Sixty five groups of phase shift spectroscopy data were obtained. According to the characteristics of cerebral hemorrhage phase shift spectroscopy under the feature hand, an effective method, B-F distribution, to diagnose the severity of cerebral hemorrhage was designed. The results showed that using MIPSS detection method under feature band, the phase shift obviously growed with increase of injection volume of autologous blood, and the phase shift induced by a 3-mL injection reached -7.750 3 degrees ± 1.420 4 degrees. B-F distribution could effectively diagnose the severity of cerebral hemorrhage. It can be concluded that the sensitivity of the cerebral hemorrhage magnetic induction detection system is improved by one order of magnitude with the MIPSS detection method under the feature band.

Design of a Brain-computer Interface System Based on Labview and VC / 中国医学物理学杂志

Objective:Labview and VC were used to design software based on the Active One biopotential measurement system to realize the visual evoked potential based brain-computer interface.Methods:The data acquisition software was designed by Labview,the human-interface,real time signal processing and dynamic link library software were designed by VC.Data transmission between Labview and VC was realized through the dynamic link library using shared memory technology.The multimedia timer,DirectDraw technology and parallel port data output were used to design the visual stimulation interface.The 5 points averaging filter combining with averaging method were used to detect the visual evoked potential and the correlation coefficient was computed for signal recognization.Results:The experiments showed that the visual stimulator can produce effective visual stimulation.The data transmission method using the dynamic link library can satisfy the requirement of the system.Conclusions:The real-time signal processing method can improve signal-noise ratio and realize detection and recognization of visual evoked potential.The system can determine which module the subject was fixating and the result was feedback to the subject in real time.

Development of practicality of EEG-based brain-computer interface / 生物医学工程学杂志

Brain-computer interface (BCI) is a system that can create direct connection between brain activity and external devices. In the past 20 years, important' achievements of research on BCI have been made. Now there are lots of research methods based on electroencephalic signals, and researchers are trying to make the BCI system possess the characteristics of real-time and become more natural and practical. This paper presents an overview of real-time and stimulating way to EEG-based BCI research. Through the discussions on the applications of DSP in BCI system, in signal preprocessing and in algorithm optimization, the high lights in real-time research are pointed out. In the discussions about the way to produce EEG signals in BCI, the researchers suggested that the imaging movement be the most ideal way in that it will reduce the discomfort in stimulation by application of the virtual reality technology in BCI system, thus it will be conducive to improvement in the performance of BCI system.

Algorithm of real-time QRS complex detection for the GPRS mobile ECG telemonitoring system / 第三军医大学学报

Objective To develop a real-time QRS complex detection algorithm of dynamic ECG signals for the GPRS mobile telemonitoring system. Methods Before the first and second derivatives of ambulatory ECG signals were processed by moving average method, the signals sampled from CM5 monitoring lead were filtered with the average of continuous four ECG sample signal points. The R waves could be detected precisely by local minima of second derivatives and Q & S waves were located correctly by cross-zero points of first derivatives of ambulatory ECG signals in a short-time searching windows. The QRS recognition thresholds, which could revise themselves according to the detected values and vary with the analyzing signals, were designed in this paper. Results With a polynomial computation complexity, the novel algorithm insensitive to baseline draft and noise caused by mobile communication filtered power-line interference and most of muscle noise and reduced the search time below 0.02 s during detecting each Q wave, R wave and S wave. For the normal and clinical patients, this algorithm correctly detected up to 99.8% of the QRS complex of ambulatory ECG signals. Conclusion The algorithm can meet the need of real-time QRS complex detection and analysis for the GRRS mobile ECG telemonitoring system.