JP2004254893A - Brain waves measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brain waves measuring method with which brain waves can be measured from the outside of a scalp in accordance with a region of activity of brain waves to be measured. <P>SOLUTION: A structural picture of the brain is taken with MRI 4 in a MRI photographing step 1, and a three-dimensional rendering indication of the brain and the scalp is performed by segmentation of the photographed structural image of the brain in a rendering indication step 2. Then, the brain waves measuring electrodes are disposed on the surface of the scalp in accordance with the region of activity of the brain waves to be measured based on the above rendering indication in an electrode disposing step 3. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electroencephalogram measurement technique, and more particularly to a method for measuring an electroencephalogram by arranging an electroencephalogram measurement electrode on a scalp in accordance with an active area of an electroencephalogram to be measured.
[0002]
[Prior art]
EEG is said to indicate the accumulation and summation of electrical activity of many neurons and synapses in the cerebral cortex under the electrode, and electroencephalography directly and dynamically changes the brain function that changes every moment. It can be said that it is an inspection method that can be caught.
[0003]
The conditions targeted for electroencephalography include consciousness disorders, general intellectual disorders, syncope, convulsions, behavioral abnormalities, central motor sensation disorders, language disorders, and other disease names.Eligible disease names include epilepsy, brain tumor, Head trauma, cerebrovascular disorder, encephalitis, cerebral palsy, migraine, paroxysmal autonomic imbalance, endocrine or metabolic disorders with neurological symptoms.
[0004]
In many diseases, general EEG abnormalities that are not specific to the disease are often seen, but EEG obtained from epilepsy or the like is almost disease-specific and useful for disease diagnosis. In clinical EEG diagnosis, the frequency, appearance, continuity, and temporal transition of individual waves in terms of their wave patterns, and how they are connected, as well as regional differences and phase relationships, are observed from multiple angles. The extent, extent and progress of the process, and the improvement are interpreted comprehensively.
[0005]
Here, each part of the brain to be subjected to the electroencephalogram measurement and the brain function will be briefly described. FIG. 6 is a diagram showing the cerebral cortex of the human brain. For convenience, the brain is divided into four parts: frontal lobe 11, parietal lobe 12, occipital lobe 13, and temporal lobe 14. The Sylvian groove 17 separates the temporal lobe 14 from other areas. A central groove 18 protrudes from the most parietal portion of the brain, and separates the frontal lobe 11 from the parietal lobe 12. The parietal lobe 12 and the occipital lobe 13 are separated by a portion called a gyrus not shown.
[0006]
When viewed from the left side of the cerebral cortex, the central groove 18 runs from the middle to the bottom. In front of the central groove 18, there is a motor area 15 that transmits a motion command to each part of the body so as to occupy a part of the frontal lobe 11. Behind the central groove 18, there is a somatosensory area 16 occupying a part of the parietal lobe 12 so as to line up with the motor area 15 and recognizing somatosensory such as tactile sensation, pain, and pressure. In addition, there is a visual cortex 20 at the back of the occipital lobe 13 of the posterior tail of the cerebral cortex, and an auditory cortex at a part of the temporal lobe 14 below the somatosensory cortex 16. In the figure, 21 surrounded by a circle is a motor language center.
[0007]
The most widely used method of measuring electroencephalograms today is the ten-twenty electrode-system proposed by Jasper et al. In Canada and standardized by the International Electroencephalographic Society of 1958.
[0008]
In the 10-20 electrode arrangement method shown in FIG. 7, first, a sagittal center line connecting the root of the nose (NASION) and the occipital pole (INION) is drawn, and the midpoint is divided into ten equal parts as the vertex (vetex). Consider the circumference of the skull passing through the root of the nose, the left and right preauricular points, and the occipital pole, and divide the circumference on both sides into 10 equal parts. Next, draw four concentric circles whose radius is smaller by 1/10 of the sagittal center line, centered on the crown, and draw a line segment connecting the center with each point obtained by equally dividing each individual skull circumference line into ten. The coordinates shown in Fig. 7 are completed.
[0009]
On this ^{_{coordinate, Fp 1, Fp 2, F}} 7, F 8, T 3, T 4, T 5, T 6, O 1, O 2, F z, C z, take _{P z.} Further, _{F z} and _F 7, the midpoint of the _{F 8, C z} and _T 3, the midpoint of _{T 4,} and _{P z} and _T 5, respectively to the midpoint of _{T 6 F 3} and _F 4, _{C 3} and C ₄ and P ₃ and P ₄ . One electrode A ₁ , A ₂ is attached to each earlobe. This is a method called the 10-20 electrode arrangement method.
[0010]
Such a conventional electroencephalogram measurement method, ie, a 10-20 electrode arrangement method, is described in Non-Patent Document 1 below, for example.
[0011]
[Non-patent document 1]
Basics of Physiological Psychology, May 1998, Kiyoshi Fujisawa and 2 others, Kitaoji Shobo, p. 93
[0012]
[Problems to be solved by the invention]
The 10-20 electrode arrangement method of the prior art described above arranges electrodes evenly on a human scalp. However, the brain below the human scalp is actually distorted and is often asymmetric, as shown in FIG. FIG. 8 shows the state of the human brain in which the longitudinal cerebral fissure 22, which is the groove separating the left and right hemispheres, is tilted to the left.
[0013]
In this way, despite the fact that the human brain is left-right non-contrast, using the prior art 10-20 electrode placement method, the EEG is measured by arranging the electroencephalogram measurement electrodes at equal positions with respect to the scalp. However, there arises a problem that the brain wave is not measured in a form corresponding to the active area of the brain wave to be measured.
[0014]
In addition, there are individual differences in the shape of the brain, and the position of the active area of the brain wave is often quite different, so the brain wave of the brain part just below the electrode attached based on the 10-20 electrode placement method is used. There is a possibility that the meaning of the comparison may be lost even if the comparison is performed by a plurality of persons.
[0015]
For example, in FIG. 9 showing the electrode arrangement on the scalp, when the active region of the electroencephalogram to be measured is the position A on the left side of the longitudinal cerebral fissure 22, using the conventional technique, The electrodes may be arranged at the shifted position B, and there is a possibility that the electroencephalogram in the active region of the electroencephalogram to be measured is not actually measured.
[0016]
An object of the present invention is to solve the above-mentioned problems of the prior art and to provide an electroencephalogram measurement method capable of measuring an electroencephalogram from above the scalp in accordance with an active area of an electroencephalogram to be measured.
[0017]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention relates to a method for measuring an electroencephalogram, comprising the steps of taking a structural image of a brain using MRI, and segmenting the taken structural image of the brain to form a tertiary brain and scalp. It is configured to include the step of rendering and displaying the original, and the step of arranging the electroencephalogram measurement electrode on the scalp in accordance with the active area of the electroencephalogram to be measured based on the rendering and display.
[0018]
By using the present invention, it becomes possible to measure an electroencephalogram from above the scalp according to the active area of the electroencephalogram.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an outline of an electroencephalogram measurement method of the present invention. 1 is an MRI imaging step of imaging a structural image of the brain using MRI (nuclear magnetic resonance imaging), and 2 is a three-dimensional rendering display of the brain and the scalp by segmenting the captured structural image of the brain. The rendering display step 3 is an electrode arrangement step of arranging an electroencephalogram measurement electrode on the scalp in accordance with the active area of the electroencephalogram to be measured based on the rendering display. 4 is an MRI and 5 is a rendering system. The rendering display step 2 is performed using a general-purpose rendering system 5.
[0020]
Next, an electroencephalogram measurement method according to an embodiment of the present invention will be described based on FIG. 2 with reference to FIGS. 3 to 5. FIG. 2 is a diagram showing a brain wave measurement processing flow according to the embodiment of the present invention. First, a structural image of the brain is captured using the MRI 4 (step S1). By performing imaging using the MRI 4, for example, a brain structural image as shown in FIGS. 3A and 3B is obtained.
[0021]
Next, the obtained brain structural image is segmented, and the brain and the scalp are three-dimensionally rendered and displayed (step S2). An example of such a rendering display is shown in FIG.
[0022]
By performing such a rendering display, the position of the main groove of the brain inside the head can be known from the outside of the head, so that the position of the active area of the electroencephalogram to be measured can be grasped. For example, when it is desired to measure the electroencephalogram of the motor language center 21, since the position of the Sylvian groove 17 in FIG. 5 showing the cerebral cortex of the human brain can be grasped by the processing of step S2, the activity of the electroencephalogram of the motor language center 21 is obtained. It can be seen that the region is, for example, around the position a in FIG.
[0023]
Finally, an electroencephalogram measurement electrode is arranged on the scalp according to the active area of the electroencephalogram to be measured based on the rendering display (step S3). For example, as shown in FIG. 5, the electrode is shifted from a position b, which is an electrode arrangement position by the 10-20 electrode arrangement method, to a position a, which is an area where brain waves of the motor language center 21 to be measured are active. In this manner, the brain waves of the motor language center 21 can be measured by shifting the electrodes.
[0024]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to arrange an electroencephalogram measurement electrode on a scalp according to the active area of an electroencephalogram, and to measure an electroencephalogram.
[Brief description of the drawings]
FIG. 1 is a diagram showing an outline of an electroencephalogram measurement method.
FIG. 2 is a diagram showing a brain wave measurement processing flow.
FIG. 3 is a diagram showing an example of a brain structure image.
FIG. 4 is a diagram in which a brain and a scalp are three-dimensionally rendered and displayed.
FIG. 5 is a diagram showing an electrode arrangement.
FIG. 6 is a diagram showing the cerebral cortex of the human brain. FIG. 7 is a diagram showing a 10-20 electrode arrangement method.
FIG. 8 is a diagram showing a human brain.
FIG. 9 is a diagram showing an electrode arrangement.
[Explanation of symbols]
1 MRI imaging step 2 Rendering display step 3 Electrode placement step 4 MRI
Reference Signs List 5 rendering system 11 frontal lobe 12 parietal lobe 13 occipital lobe 14 temporal lobe 15 motor cortex 16 somatosensory cortex 17 Sylvian groove 18 central groove 19 auditory cortex 20 visual cortex 21 motor language center 22 cerebral longitudinal fissure

Claims (1)

An electroencephalogram measurement method,
Taking a structural image of the brain using MRI;
Segmenting the captured brain structural image, rendering the brain and scalp three-dimensionally rendered,
Placing an electroencephalogram measurement electrode on the scalp in accordance with the active area of the electroencephalogram to be measured based on the rendering display.

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