Electroencephalograph for determining contact status between electrode and scalp and method for determining same

Abstract

The invention relates to an electroencephalograph for determining the contact status between an electrode and a scalp and a method for determining the contact status between the electrode and the scalp. The electroencephalograph comprises an electroencephalogram signal detecting circuit and a scalp impedance detecting circuit, wherein the electroencephalogram signal detecting circuit is provided with at least one set of interfaces connected with a reference electrode and a plurality of electrodes to be detected, which are contacted with scalp, through lead wires; and the scalp impedance detecting circuit is independent from the electroencephalogram signal detecting circuit to be connected with the interfaces of the electrodes to be detected and the reference electrode. According to the invention, the electroencephalogram signal detecting circuit and the scalp impedance detecting circuit are respectively detected, the contact status is determined by a threshold value determining method, and the method is simple in circuit, high in circuit anti-interference performance and quick in speed; not only can the detection precision of the scalp impedance be improved, but also the acquiring and the process of the electroencephalogram signal can not be influenced; and the large information content electroencephalogram signal can be most accurately processed, and the scalp impedance information can be most timely processed, so that a product is better in performance.

Description

technical field [0001] The invention belongs to the field of medical instruments, in particular to an electroencephalograph for judging the contact state between an electrode and a scalp and a judging method thereof. Background technique [0002] With the advancement and development of science and technology and the continuous improvement of people's living standards, the requirements for medical testing levels are also getting higher and higher. As an important medical device for detecting brain diseases, the EEG system plays an important role in clinical diagnosis. However, the current EEG products have a small storage capacity, a small number of acquisition leads, poor anti-interference ability, and poor stability. Some EEG detection equipment does not have the function of detecting the connection of electrodes. Electricity and the impedance between the electrodes and the scalp. As the study of brain function by biological cybernetics has become an important aspect of b...

AI Technical Summary

Problems solved by technology

The EEG signal is a low-frequency signal of 0-30Hz. The traditional EEG amplifier circuit is designed for low-frequency signals, and the decay of high-frequency signals that modulate impedance information will be serious, so that the obtained impedance information is not accurate enough.

The Chinese patent with the publication number CN101199418 discloses a "Electroelectric Impedance Detection Circuit and EEG Detection Device". In the patent, an EEG impedance detection circuit is proposed. The circuit forms a loop through a constant current source, a scalp, and a grounding resistance. , the circuit separately sets a grounding resistor for measuring the scalp impedance. The excitation circuit and the test circuit share the same ground. In use, the electrode required as the grounding resistor must be in good contact with the scalp, and the response is not between the real measuring electrode and the reference electrode. Impedance of the EEG model increases the complexity and inaccuracy of the test

[0005] Both of the above two public documents use the traditional sinusoidal AC constant current source as the excitation source for human body bioimpedance measurement. Both the EEG signal and the EEG signal will be input into the EEG signal detection circuit at the same time. The sine wave signal is easy to interfere with the measurement of the computer signal, and the processing circuit is more complicated than other circuits.

However, the measured resistance and signal wave phase error of the sinusoidal AC constant current excitation signal lower than 50KHz is large. When the EEG signal is required to be synchronized with the scalp impedance signal within the specified time, an error will occur. In practical applications, only The three states of good, bad and shedding of the electrode and the scalp are judged, rather than precise resistance value, so the circuit of the sinusoidal AC constant current source used as the excitation source of the human body bio-impedance measurement is too complicated

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