Study On New Type Of Automatic EEG Monitoring System

The electroencephalogram(EEG) is one of the most important bio-electric signals of the human. Now many people pay much attention to the therapy effects through monitoring the EEG. But existing electroencephalogram has many shortcomings, such as expensiveness, weak anti- disturbance ability, single detecting function. So the new type of monitoring system is needed.On the other hand, the research international has testified that the spreading depressions (SD) in the brain have relationship with cerebral infarction. The evolution of cerebral infarction and medical effect can be observed through the spreading depressions. So SD has very important clinical research value. The research also indicates that SD is millivolt voltage signal with slow variation. Through practical research, a set of apparatus to monitor EEG and SD at the same time was designed according to the actual require of hospital. This thesis also gave the monitoring soft having graphical user interface and function of power spectrum analyzing.Because of the disturbance of environment and apparatus, the detected signal is very faint and the detection is very difficult. Based on existing device, the disturbance was decreased by adopting the new type of trap filter circuit and differential amplifier circuit, the measuring signal met the requirement in the end.First, this thesis calculated and designed the signal gained circuit based on the character of the SD and EEG, then chose the new generation microprocessor, AT89C52 to design the data collection system. Through programming the COM port of microprocessor realized the communication with PC. The practical using has proved the good traits of the circuit ,simple,reliable and has strong anti-disturbance. Last this thesis used the VB6.0 language to program the monitoring soft. It realized the function of serial communication, displaying the SD and EEG, recording and saving the data.In addition, this soft also can get data filter and automatic function of identifying the SD wave. Then the power spectrum was programmed to satisfy the researcher' needs. And the actual use proved that the power spectrum of cerebral infarction patient was different than the normal people.