Objective EEG Quantitative Measurement Method for Amblyopia

Abstract

The invention discloses an objective and quantitative detection method for amblyopia by electroencephalogram (EEG). The method comprises the following steps: firstly, carry out binocular dichoptic viewing display, then design a visual evoked stimulation paradigm, establish a brain-computer interface platform, build a test interaction interface, next determine an amblyopia EEG quantitative index. By using a suppression coefficient (SI) to describe the binocular suppression relationship, quantify the degree of amblyopia, and finally obtain amblyopia detection result feedback, where the computer interaction interface module presents a final amblyopia detection result to realize feedback of a user. The operation is simple and rapid, the applicability is high, and the indexes are objective and quantitative.

Claims

1. An objective and quantitative EEG measurement device for amblyopia, characterized in that, comprising the following module: (1) Visual evoked stimulation paradigm and dichoptic viewing module: visual evoked stimulation paradigm: Using the method based on steady-state motion visual evoked potential (SSMVEP), inducing SSMVEP by stimulating the periodic contraction and expansion of a target object, and selecting an optimal stimulation frequency within a motion visual sensitive frequency range in the human brain, wherein the stimulation frequency is 8 Hz and 12 Hz; using a 3D display and polarized glasses to realize a dichoptic viewing technology to achieve different input information of two eyes; (2) EEG Acquisition Module: placing recording electrodes at an occipital area PO3, PO4, POz, O1, O2 and Oz of a user's head, placing a reference electrode on a position on the earlobe of one side, and placing a ground electrode on a forehead of the user's head, connecting the electrodes to an input of an electroencephalogram (EEG) acquisition module, then processing amplification, filtering, and digital-analog conversion, then connecting to an input of a data processing module, then extracting features of the EEG signal data at the data processing module by using canonical correlation analysis, controlling an output of the results, and connecting to an input of a computer interactive interface module; (the computer interactive interface presenting a pattern of a first step paradigm by, firstly, inputing an 8 Hz flicker paradigm for a left eye and a 12 Hz flicker paradigm for a right eye as a stimulation, and arranging a pause for two seconds after performing the stimulation for a periof of time, and then performing a subsequent stimulation until a total of five stimulation is performed; a second step: changing the temporal frequency of the left eye and the right eye stimulation paradigms by using a 12 Hz flicker paradigm for the left eye and an 8 Hz flicker paradigm for the right eye, and the rest are the same; (3) EEG Signal Processing and Results Feedback: using a suppression coefficient SI to describe the binocular suppression relationship, and then quantifying a degree of amblyopia: $\mathrm{SI}=\frac{R_{RE}-R_{LE}}{R_{RE}+R_{LE}}$ In the formula: SI—Suppression coefficient between two eyes; R.sub.RE-Right-Eye SSMVEP response to stimulus paradigm; R.sub.LE-Left-Eye SSMVEP response to stimulus paradigm; the value of the SI ranges from −1 to 1, 0 represents a balance between the two eyes, that is, the most normal relationship between the two eyes; the closer the absolute value to 1, the stronger the inhibitory relationship between the two eyes; a negative value indicates that the SSMVEP amplitude of the right eye is less than the SSMVEP amplitude of the left eye, that is, the left eye suppresses the right eye; a positive value indicates that the SSMVEP amplitude of the right eye is greater than the SSMVEP amplitude of the left eye, that is, the right eye suppresses the left eye; the computer interactive interface module presenting final results of measurement and realizing a feedback of test result.

2. The objective and quantitative EEG measurement device for amblyopia according to claim 1, characterized in that: in said visual evoked stimulation paradigm and dichoptic viewing module, a corresponding polarization display and polarized 3D glasses are used to realize dichoptic viewing display, so that the left eye and the right eye are presented the stimulation paradigms simultaneously with different temporal frequencies.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG. 1 is a schematic diagram of a brain-computer interface platform according to the present invention.

[0031] FIG. 2 is an illustration showing the correlation between interocular acuity difference and SI index.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0032] The present invention is described in detail regarding the accompanying drawing figures as follows:

[0033] An objective and quantitative EEG measurement method for amblyopia, comprising the following steps of:

[0034] (1) Realization of dichoptic viewing: Use a 3D display and polarized glasses to realize a dichoptic viewing technology, and different input information of two eyes is achieved. The 3D display can realize the 3D presentation in the left and right eye, combined with the polarized glasses, and the visual information presented to the left eye and the right eye can be different.

[0035] (2) Visual evoked stimulation paradigm: Based on steady-state motion visual evoked potential SSMVEP, by using MATLAB Psychophysics Toolbox programming to draw the periodic contraction and expansion movement of the paradigm pattern texture, SSMVEP is induced by stable stimulation. When using this method, the user is not easy to be visually fatigued. The stimulation frequency is 8 Hz and 12 Hz with a high response signal-to-noise ratio.

[0036] (3) EEG data acquisition and processing platform: Before the experiment, the electrodes are arranged according to the 10/20 system method. Place the reference electrode on the subject's left earlobe A1, the ground electrode on the subject's forehead Fpz, and six recording electrodes on the occipital area (PO3, PO4, POz, O1, O2, and Oz). Inject conductive paste into each recording electrode to ensure good contact between the electrode and the scalp. Referring to FIG. 1, the electrodes are connected to the EEG acquisition module. The EEG data is output after amplification, filtering and digital-analog conversion, and is connected to the input of the data processing module. The data processing module uses the canonical correlation analysis method to extract the features of the EEG signal data.

[0037] (4) Testing of the interaction interface: the computer interactive interface presents a pattern, firstly, inputting an 8 Hz flicker paradigm for a left eye and then a 12 Hz flicker paradigm for a right eye as a stimulation. After performing the stimulation for a period of time, arranging a pause for two seconds, and then performing a subsequent stimulation. A total of five stimulation is performed and an SSMVEP response is generated with EEG signal features are obtained by EEG acquisition and data processing. The second step: changing the temporal frequency of the left eye and the right eye stimulation paradigms, by using a 12 Hz flicker paradigm for the left eye and an 8 Hz flicker paradigm for the right eye. After stimulation for a period of time, an SSMVEP response is generated, and EEG signal features are obtained by EEG acquisition and data processing.

[0038] (5) Amblyopic EEG Quantitative Index: Use a suppression coefficient (SI) index to describe the binocular suppression relationship, and then quantify the degree of amblyopia:

[00002]$\mathrm{SI}=\frac{R_{RE}-R_{LE}}{R_{RE}+R_{LE}}$

[0039] In the formula:

[0040] SI—Suppression coefficient between two eyes;

[0041] R.sub.RE-Right-Eye SSMVEP response to stimulus paradigm;

[0042] R.sub.LE-Left-Eye SSMVEP response to stimulus paradigm.

[0043] The value of the SI ranges from −1 to 1, where 0 represents a balance between the two eyes, that is, the normal relationship between the two eyes. The closer the absolute value to 1, the stronger the suppression relationship between the two eyes, and the amblyopia is more severe. A negative value indicates that the SSMVEP amplitude of the right eye is less than that of the left eye, that is, the left eye suppresses the right eye. A positive value indicates that the SSMVEP amplitude of the right eye is greater than that of the left eye, that is, the right eye suppresses the left eye.

[0044] (6) Feedback of test result of amblyopia: the computer interactive interface module presents the final results of amblyopia testing and realizes feedback to users.

[0045] The present invention is described in detail with reference to the embodiments of the present invention as follows:

[0046] The experiment is conducted on 11 amblyopic participants and 12 normal participants by using the method of the present invention. Place electrodes on the subjects according to the above step (3) and build a brain-computer interface platform. The user's head is 150 cm away from the computer screen. Perform experimental paradigm display and data feature extraction according to the above step (4). Obtain the SI index of each subject according to the above step (5). Give feedback of the amblyopia test results for each participant according to the above step (6). The correlation between the EEG amblyopia examination results and the subjective visual acuity difference of the left and right eyes of the subjects is shown in FIG. 2. The linear correlation coefficient r=−0.959, and the linear correlation is significant.

[0047] The present invention can base on the central optic nervous system and apply the brain-computer interface technology to realize objective and quantitative detection of amblyopia, and provide an effective means for rapid quantitative detection and early screening of amblyopia.