EEG Technology

As one of the most important means to study brain science, EEG is the overall reflection of excitatory and inhibitory postsynaptic potentials of a large number of neurons in the brain on the scalp. The electrode affixed to the forehead surface is used to collect the potential difference of the human cortex on the body surface, and then the EEG signal is obtained through subsequent voltage amplification, filtering, digitization, feature recognition and algorithm processing, and then the EEG power.

the frequency band ratio of the EEG wave and other parameters are calculated, and the waveform and parameter display are applied through the processing of the host computer. The evaluation and research of brain diseases and action awareness is one of the key technologies for high-end monitoring applications.

EEG measurement principle

EEG signals are much weaker than electrocardiogram signals, usually only a few tens of microvolts, and are more susceptible to external interference. The frequency distribution of the EEG signal is between 0.5-30Hz, and the EEG amplitude is between 5-200uV, making it a typical non-stationary random signal. The application research of EEG signals in clinical practice divides EEG into several different signal segments according to frequency bands, which are sequentially referred to as δ Wave θ Wave α Wave β Wave. This also presents some difficulties for the clinical application of EEG.

Therefore, extracting high-quality EEG signals is the foundation of the application of this anesthesia depth monitoring system. The EEG monitoring system mainly consists of sensors, cables, hardware systems, and monitor monitoring systems.

EEG Technology一Advantage

High performance EEG signal extraction

EEG signal acquisition needs the characteristics of high common-mode rejection ratio, high input impedance and low noise.The EEG acquisition system design of this system mainly includes the sensor electrode part, the pre-protection and anti-defibrillation circuit part, the pre-follow circuit part, the EEG myoelectric pre-amplification circuit part, the EEG myoelectric filter circuit part, the baseline fast recovery circuit part, the EEG post-amplification circuit part, the power supply part, the electrode impedance detection part, and the high-precision AD data acquisition part.

To ensure EEG signal extraction, the system noise is less than 5uV, and the common mode rejection ratio is greater than 120dB.

Multifunctional parameter calculation

EEG measurement technology has a powerful function of characteristic parameter calculation, and the algorithm mainly includes signal preprocessing and parameter calculation. Signal pre-processing mainly uses high-pass filtering, low-pass filtering and 50HZ depower notch to denoise the signal, and calculates the signal quality index and noise level through signal quality judgment.

The parameter calculation includes the calculation of α,β,γ,δ wave power specific gravity by EEG power spectrum, in addition to the calculation of β ratio, SEF (edge spectrum), EMG power, TP total power spectrum isofrequency domain parameters. The inhibitory level index (BSI) was calculated by time domain evaluation of EEG signals.

Comprehensive sensor support

EEG measurement technology supports a variety of sensor matching systems, with forehead electrodes, head-mounted electrodes, and cap electrodes for different applications.