CN1120694C - Multi-channel electroencephalo signal measuring method and apparatus without hardware lead permutator - Google Patents

Abstract

The present invention relates to a multi-channel electroencephalogram signal measuring method and an apparatus without a hardware lead permutator. A human brain electrode is used for measuring electroencephalogram signals of a human body; the signals measured by the human brain electrode are inputted into N channels of unipolar electroencephalogram magnifiers; the input signals of the N channels of unipolar lead electroencephalogram magnifiers are inputted into an A/D converter; N channels of collecting systems are used for collecting the signals outputted by the A/D converter into a computer; simultaneously, more than N channels of unipolar lead electroencephalogram signals and bipolar lead electroencephalogram signals are obtained. By using the method and the apparatus of the present invention, a hardware lead permutator is not needed for obtaining more than N channels of electroencephalogram signals by the N channels of magnifiers.

Description

The no hardware method and apparatus that the multiple tracks EEG signals of permutator is measured that leads

Technical field

The present invention relates to the method and apparatus of a kind of acquiring biological electric signals, processing, particularly a kind of hardware permutator that leads that need not just can access the method and apparatus of the EEG signals that the single, double utmost point of a plurality of passages leads.

Background technology

The problem that exists in traditional electroencephalograph is: can only obtain a simple N signal with a plurality of passages (N) amplifier, can not obtain the single, double utmost point EEG signals of leading simultaneously.And EEG measuring is led and can't be broken away from the permutator that leads fully when switching, no matter be machinery or electrical switch.The use hardware quantity is big, the cost height.

The present invention is just in order to solve above-mentioned deficiency, and providing a kind of can provide more brain electric informations and need not hardware the lead method and apparatus of multiple tracks electroencephalogram electric signal measurement of permutator of the no hardware of permutator that leads.

In order to finish the present invention, in the present invention the EEG amplifier of N passage is designed to be suitable for the EEG measuring of unipolar lead, these EEG signals are changed the back by computer sampling through A/D, and utilize corresponding algorithm, can obtain simultaneously in computer $\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}(N-n)$ The EEG signals that the individual single, double utmost point leads.And the noise of one pole eeg amplifier and touch rejection ratio altogether and can reach the desired index of EEG measuring fully.

For finishing the present invention, in leading the device of multiple tracks electroencephalogram electric signal measurement of permutator, no hardware of the present invention comprises: N road one pole eeg amplifier, A/D converter, computer.N road one pole brain electricity by input computer after, machine can obtain simultaneously as calculated $\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}(N-n)$ The individual one pole that leads, bipolar and average benchmark EEG signals, these signals can print by outut device.

Description of drawings

Fig. 1 represents the electroencephalograph structure of prior art;

Fig. 2 is the EEG measuring ideograph of electroencephalograph of the present invention;

EEG measuring ideograph when Fig. 3 is the port number N=16 of electroencephalograph of the present invention;

Fig. 4 is the layout sketch map of the amplifier in the EEG measuring pattern of the present invention;

Fig. 5 is the measuring method of the traditional equal benchmark unipolar lead of brain level of expression;

Fig. 6 represents electroencephalograph structure of the present invention.

The specific embodiment

Below in conjunction with description of drawings the present invention.By among Fig. 1 as can be known, in the prior art in order to measure people's EEG signals that difference is led, between human body electroencephalogram's electrode and N passage eeg amplifier, must be added with the permutator that leads, and in the present invention shown in Figure 2, between human body electroencephalogram's electrode and N passage unipolar lead eeg amplifier used in the present invention, not re-use the permutator that leads.In EEG measuring ideograph shown in Figure 4, selected for use and be suitable for the amplifier of a measuring N passage unipolar lead electroencephalogram simultaneously, such architectural feature is to have increased N+1 buffer in the front of traditional N passage brain electricity difference amplifier, the impedance that has guaranteed each road difference amplifier differential input terminal is comparatively close, and prevents owing to the do not match amplifier that causes of input impedance is touched the mould rejection ratio altogether and descended; The N+1 of an input channel buffer is designed to have good symmetry and very low noise level, makes the common mode rejection ratio of whole eeg amplifier be not less than 80db, and noise level can reach the clinical requirement index; The eeg amplifier of this novel measurement pattern not only is suitable for the unipolar lead EEG measuring, but also following two kinds of EEG measuring forms can be arranged:

(1) all anodes (or negative terminal) of N channel amplifier are connected all that the other end then is connected with each electrode for encephalograms respectively on some shared brain electrodes, in this measurement form, when shared electrode for encephalograms is positioned at ear-lobe or other and is similar to the zero-potential point position, what the N channel amplifier measured is N passage unipolar lead EEG signals, and when common electrode was positioned at other position, brain position, what measure was N passage bipolar lead EEG signals.

(2) each input of N channel amplifier can be on demand links with compound mode and electrode for encephalograms arbitrarily, with the signal of the single, double utmost point electrode for encephalograms of measuring N passage.

The computational methods of one pole and bipolar lead electroencephalogram are as follows: (1) unipolar lead EEG signals

If U ₀, U ₁, U ₂... U _N-1, U _NBe the signal on the electrode for encephalograms, wherein U ₀For from ear-lobe or other than the signal on the distal part potential electrode, as the common reference point of unipolar lead, U ₁, U ₂U _N-1, U _NBe the EEG signals on other each electrode on the scalp.

As pressing the coupling method among the present invention, the signal of being exported from the N channel amplifier is U ₁-U ₀, U ₂-U ₀..., U _N-1-U ₀, U _N-U ₀This N channel signal is the unipolar lead EEG signals.(2) bipolar lead EEG signals

The bipolar lead EEG signals can be chosen two subtraction wantonly and obtain from N passage unipolar lead EEG signals, shown in the following formula:

(U _m-U ₀)-(U _L-U ₀)=U _m-U _LHere, m, L are respectively by any two the different numbers 1 to N.According to this formula, N passage bipolar lead electroencephalogram is total at most $\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}(N-n)$ Plant compound mode, therefore can obtain so many bipolar lead EEG signals.

Can obtain the single, double utmost point EEG signals of leading at synchronization with said method, can only be timesharing and obtain the EEG signals that difference leads in traditional use hardware switch conversion, can not obtain so many EEG signals at synchronization.

And the accuracy of the EEG signals of the average benchmark unipolar lead of being measured by measurement pattern of the present invention is higher.In the measuring method of traditional equal benchmark unipolar lead of brain level that Fig. 5 began, establish U among the figure ₁, U ₂... U _N-1, U _NBe the current potential of each measurement electrode for absolute zero, if total N measurement electrode, so i (i=1,2 ..., N) the average benchmark unipolar lead in road brain electricity U _0iFor

U _0i＝U _i×(1-1/N)≈U _i

The resulting U of traditional measurement method as can be seen from the above equation _0iWith U _iBetween certain error is arranged, cause that the error of measurement result is bigger.And in the traditional measurement method another the place defective be that resistor network causes the input impedance of eeg amplifier asymmetric, can cause common mode disturbances.

And utilize measurement pattern among the present invention, can obtain the method for the average benchmark one pole of a kind of better acquisition EEG signals.Utilize N passage one pole eeg amplifier, can measure the EEG signals of N road unipolar lead: U ₁-U ₀, U ₂-U ₀..., U _N-1-U ₀, U _N-U ₀U wherein ₀Be the current potential of reference electrode, existing order $U_R=\left[\underset{n-1}{\overset{N}{\mathrm{\Σ}}}(U_n-U_0)\right]/N=[\left(\underset{n=1}{\overset{N}{\mathrm{\Σ}}}{U}_n\right)/N]-U_0$ At this, with U _RBe called " with reference to the power station ".With each road one pole EEG signals with subtract each other with reference to the power station: U _0i=(U _i-U ₀)-U _R $=(U_i-U_0)-\left[\underset{n-1}{\overset{N}{\mathrm{\Σ}}}(U_n-U_0)\right]/N$ $=$ $U_i-[\underset{n-1}{\overset{N}{\mathrm{\Σ}}}\left(U_n\right)/N]$ By the theory of bio electricity volume conductor, in the following formula Be approximately zero, so just can obtain U _0i=U _i

Like this, just can obtain N passage unipolar lead EEG signals, and utilize them to obtain than the traditional measurement method one pole EEG signals of the average benchmark of N passage more accurately.And when measuring without resistor network, prevented the generation of common mode disturbances.

Listed the single, double utmost point that when N is 8,16,24, the obtains number that leads in the table below:

Therefore, use method and apparatus of the present invention, can obtain at the same time manying a lot of EEG measuring signals, saved the hardware switch that leads, both reduced cost, improved the accuracy of measuring again than prior art.Not only be suitable for measuring the one pole EEG signals, also be suitable for obtaining simultaneously $\underset{n-1}{\overset{N-1}{\mathrm{\Σ}}}(N-n)$ The EEG signals of individual bipolar lead, noise level and common mode rejection ratio can satisfy in the EEG measuring regulation requirement to noise fully.And can obtain the EEG signals of the unipolar lead of the average benchmark in N road exactly.

Claims (5)

1. one kind is not had the hardware method that the multiple tracks EEG signals of permutator measures of leading, and it is characterized in that:

A. by N human body electrode for encephalograms and a shared electrode for encephalograms, produce and measure human body electroencephalogram's signal;

B. with in the described human body electroencephalogram's signal input N road unipolar lead eeg amplifier that records, one of all two inputs of described N road amplifier are connected to shared electrode for encephalograms, each other end of amplifier two inputs links to each other with a described N electrode for encephalograms respectively, and shared electrode for encephalograms is located on the approximate zero potential point;

C. will be by in the N road unipolar lead eeg amplifier amplifying signal input a/d converter;

D. will be selected respectively by computer from the digital signal of A/D converter input by N track data harvester, be the unipolar lead EEG signals when selecting the one pole EEG signals to the signal between shared electrode for encephalograms; Be the bipolar lead EEG signals of this two electrode when selecting wantonly two unipolar lead EEG signals to subtract each other; The single, double utmost point EEG signals sum that leads amounts to $N+\underset{n=1}{\overset{N-1}{\mathrm{\Σ}}}(N-n)$

2. method according to claim 1 is characterized in that described shared electrode for encephalograms is positioned at the ear-lobe position.

3. method according to claim 1 and 2 is characterized in that the unipolar lead EEG signals U of the average benchmark in i road in described any N road one pole EEG signals _0iBe i road one pole EEG signals U _i, i.e. U _0i=U _i

4. one kind is not had the lead measuring device of multiple tracks EEG signals of permutator of hardware, it is characterized in that:

This device is linked in sequence successively by following each several part and forms, N road human body electrode for encephalograms and a shared electrode for encephalograms, connect N+1 road buffer respectively, corresponding connection N road brain electricity difference amplifier, one of all inputs of wherein said N road amplifier connect the output of the buffer of shared electrode for encephalograms connection, the outfan of the buffer that each other end of amplifier in is corresponding with a described N electrode for encephalograms respectively links to each other, shared electrode for encephalograms is located on the approximate zero potential point, the outfan of described each amplifier connects N road A/D converter according to this, connect computer again, then output.

5. according to claim 4, it is characterized in that described output signal receives display and/or printer; Described computer is a microprocessor based computer.

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