KR101607893B1 - Apparatus for generating sssep and operating method thereof - Google Patents

Abstract

According to the present invention, a device operating method for generating steady-state somatosensory evoked potential (SSSEP) of a brainwave comprises: a step of transmitting a first control signal which generates at least one electric stimulus having a different current, a frequency or a pulse width; a step of receiving a brainwave signal sensed as a response to the generated electric stimulus; a step of eliminating noise from the received brainwave signal; a step of extracting a feature point from the brainwave where noise is eliminated; a step of classifying each of the brainwaves by a command based on the feature point of the brainwave signal; and a step of receiving/transmitting a second control signal whose at least one among a current, a frequency, or a pulse width is changed. The purpose of the present invention is to provide an apparatus and a method for generating somatosensory evoked potential capable of providing different commands of the SSSEP.

Description

[0001] APPARATUS FOR GENERATING SSSEP AND OPERATING METHOD THEREOF [0002]

The present invention relates to an apparatus and method for generating SSSEP using an electric stimulus, and more particularly, to a method for generating a steady state sensory evoked potential to control interfaces of various devices.

Brain-Computer Interface technology allows the activity of the neurons in the user's brain to be connected to the computer, making it possible to communicate with the computer without the need for an input device such as a mouse or a keyboard.

In particular, brain-computer interface technology has been used mainly in prosthetic control to assist movement of patients with motor neurons due to accidents or diseases, and spellers to enable communication.

In order to reflect the user's intention in real time on the application device, the induced potential may be used. Trigger potential refers to the potential generated by the human body due to the stimulus when the human body is subjected to a constant direct or indirect stimulus. Evoked potentials can be observed with EEG recordings. Especially, since the evoked potential has a high information transfer rate, it can reflect the intention of the user in real time and has shorter learning and training time than other systems using EEG, There is an advantage in that various commands can be created.

In addition, the evoked potentials are divided according to the types of stimuli. Among them, steady-state visual evoked potential (SSVEP) by visual stimulation and steady-state somatosensory potential by tactile stimulation Evoked Potential, SSSEP).

In this regard, Korean Patent Laid-Open No. 10-2013-0108778 (entitled: SSVEP-based vehicle safety driving control system and method) discloses a technology for grasping the driving state of the front vehicle and the state of the driver's attention.

However, since the steady-state visual evoked potential utilizes the physiological mechanism of the EEG response, when the gazing of the flashing light at regular intervals uses the principle that the signal synchronized with the period of flashing of the light in the cerebral cortex is detected, May cause noise due to noise. In addition, it is caused by visual stimulation, which has a limitation of eye gaze and can cause eye fatigue.

On the other hand, in general, there is an advantage that the tactile stimulation-induced steady state sensory evoked potential has no limitation of eyes, but there is a problem of compliance with repetitive stimulation. In addition, since the apparatus for inducing the stimulation using mechanical vibration requires hardware for causing vibration, the volume is necessarily increased.

In addition, the types of stimuli using mechanical vibration are not as diverse as those of visual stimuli, so the commands do not vary. There is a problem that it is difficult to precisely grasp the intention of the user or precisely control the device in accordance with the intention of the user.

It is an object of the present invention to provide an apparatus and a method for generating a somatosensory evoked potential capable of providing various commands of a bodily sensory evoked potential in a steady state.

According to an aspect of the present invention, there is provided a method of operating an apparatus for generating a steady state sensory evoked potential in an EEG according to an aspect of the present invention, Receiving a sensed EEG signal as a response to each generated electrical stimulus, removing noise from the received EEG signal, extracting feature points from the EEG signal from which the noise has been removed, Classifying the EEG signals according to commands based on the feature points of the EEG signals, and transmitting a second control signal in which one of the current, the frequency, and the pulse width is changed.

According to a second aspect of the present invention, there is provided an apparatus for generating a steady state sensory evoked potential, comprising: a memory for storing a data transmitting and receiving unit, a steady state sensory evoked potential generating application; And a processor executing the application. At this time, the processor transmits a first control signal for generating one or more electrical stimuli that differ in current, frequency, or pulse width depending on the execution of the application, receives the sensed EEG signal as a response to each generated electrical stimulus, A method of extracting feature points from a noise-canceled EEG signal, classifying each EEG signal by commands based on the feature points of the EEG signal, and changing the current, frequency, or pulse width 2 control signal.

According to the present invention, since the tactile sense is induced through the electric stimulation, the operation method of the steady state sensory evoked potential generating device can ensure high performance as compared with that caused by spontaneous imagination.

Further, according to an embodiment of the present invention, various currents, frequencies, or pulse widths can be used to prevent complications and generate a large number of commands.

In addition, according to the embodiment of the present invention, interfaces for using electric tactile stimulation such as a mobile phone, a steering wheel of a vehicle, and a haptic device are increasingly used in various fields.

FIG. 1 is a block diagram for explaining an apparatus for generating a sensed-state potential according to an embodiment of the present invention. Referring to FIG.
2 is a block diagram illustrating a central processing unit according to an embodiment of the present invention.
3 is a block diagram illustrating the function of the steady state sensory evoked potential generation application according to one embodiment of the present invention.
4 is a flowchart illustrating a method of operating the apparatus for generating a sensory evoked potential according to an embodiment of the present invention.
FIG. 5 is a diagram illustrating a method of stimulating agent according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "electrically connected" with another part in between . Also, when an element is referred to as "comprising ", it means that it can include other elements as well, without departing from the other elements unless specifically stated otherwise.

Throughout this specification, when an element is referred to as "including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise. The word " step (or step) "or" step "used to the extent that it is used throughout the specification does not mean" step for.

Hereinafter, a method and an apparatus for operating the apparatus for generating a sensed-state-of-steady-state potential according to an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram for explaining an apparatus for generating a sensed-state potential according to an embodiment of the present invention. Referring to FIG.

Referring to FIG. 1, the steady state sensory evoked potential generating apparatus 10 includes a stimulating unit 100, a central processing unit 200, and a sensing unit 300. The stimulation unit 100 and the sensing unit 300 can transmit and receive signals to and from the central processing unit 200 according to the execution of the central processing unit 200. In this case, the stimulating unit 100 and the sensing unit 300 may be separately provided from the central processing unit 200, or may be implemented in a form coupled to the central processing unit 200.

The functional blocks shown in FIG. 1 and described below are merely examples of possible implementations. In other implementations, other functional blocks may be used without departing from the spirit and scope of the following detailed description. Also, while one or more functional blocks of the steady state sensory evoked potential device 10 are represented as discrete blocks, one or more of the functional blocks of the steady state sensory evoked potential device 10 may be implemented with various hardware And a combination of software configurations.

Further, a display may be further included. The display can display the necessary information for each step on the screen. For example, depending on the execution of the central processing unit 200, the degree of electrical stimulation such as current, frequency or pulse width may be displayed.

The stimulating unit 100 may receive the first and second control signals from the central processing unit 200 to generate electrical stimulation. That is, the stimulating portion 100 generates one or more electric stimuli that differ in current, frequency, or pulse width. At this time, the first and second control signals provided from the central processing unit 200 may be provided by arranging the order of the electric stimulation differently, or may change the duration of the electric stimulation. In addition, a tool that can be input in the form of a switch is provided on the steady state sensory evoked potential generating device 10, and the first and second control signals are transmitted to the stimulating unit by receiving a desired step, order, You may. In addition, the central processing unit 200 may include software capable of providing various electrical stimuli.

In addition, the stimulation unit 100 may provide an electrical stimulus to cause tactile stimulation in the body's sensory area of the user. The stimulation at this time is preferably a current, frequency, or pulse width that is tactile stimulus, harmless to the body, and does not shrink the user's muscles.

Particularly, in order to prevent the complication due to the tactile stimulation caused by the electric stimulation, it is possible to control the pulse width so that the vibration intensity of the same frequency is different from the vibration stimulus of the same frequency. At this time, the frequency corresponding to the specific command can be controlled through the modification of the frequency. The steady state sensory evoked potential generating apparatus 10 may first transmit a second control signal to the stimulating unit 100 in which the current, frequency, or pulse width is changed before the adaptation phenomenon occurs.

In general, evoked potentials include auditory evoked potentials, visual evoked potentials, somatic evoked potentials (SSEPs), motor evoked potentials (MEPs), motor evoked potentials ) Are used variously. The stimulation signals that induce the respective excitation potentials include auditory stimulation signals, visual stimulation signals, stimulus signals of the upper limbs or lower limbs, stimulation signals of the scalp area scalp, and electric stimulation signals of the cervical vertebrae do. Here, the somatosensory evoked potential can be used as a stimulus signal.

Here, the stimulation signal is not particularly limited, and the stimulation potential sensed through the sensing unit 300 may be all that is generated from an electrode which is in contact with the muscle of the subject to which the stimulation signal is applied.

The sensing unit 300 senses an EEG generated as a response to each generated electrical stimulus, and transmits the generated EEG to the transceiver of the central processing unit 200. In addition, EEG equipment can be used to detect EEG signals for stimulation. At this time, EEG measurement can extract brain waves from at least 4 channels according to the international electrode system. The extraction method attaches the microchip to the scalp in a noninvasive manner, attaching the channel to the sensory motor cortex region because it acquires brain waves induced from the somatosensory area.

First, downsampling the EEG signals measured in terms of system operation speed and optimal memory management. The EEG extracted from EEG (Electroenceplography) contains various noise components. Types of noise components include electromyogram (EMG), eye blinking, and eye movement (EOG) components. These noises are larger than the EEG signal several times, so it is desirable to remove them to obtain the EEG signal.

Next, the central processing unit 200 will be described in more detail with reference to FIG. 2 to FIG.

2 is a block diagram illustrating a central processing unit according to an embodiment of the present invention.

Referring to FIG. 2, the central processing unit 200 may include a memory 210, a processor 220, and a data transmitting / receiving unit 230.

The memory 210 may include a steady state sensory evoked potential generation application 211. The function of the application 211 will be described with reference to FIG. 3 as an example.

3 is a block diagram illustrating the function of the steady state sensory evoked potential generation application according to one embodiment of the present invention.

3, the application 211 may include a control signal generating unit 2111, a noise removing unit 2112, a feature point extracting unit 2113, and an EEG signal classifying unit 2114.

The processor 220 first generates a first control signal for generating at least one electric stimulus having a different current, frequency or pulse width in the control signal generator 2111 and outputs the first control signal to the stimulation unit 100 ). ≪ / RTI > The transmission and reception of data at this time can be performed through the transmission / reception unit 230.

Next, the processor 220 receives the detected EEG signal as a response to each generated electrical stimulus, and the noise remover 2112 can remove noise from the received EEG signal.

For example, the noise removing unit 2112 can perform a linear separation by grasping time-frequency components of an electromyogram (EMG) signal and a safety degree (EOG) signal from a received EEG signal. In addition, the noise can be removed by using Independent Component Analysis.

Noise can be removed using a filter, which can be removed using a notch filter. In addition, a band-pass filter may be used to filter the remaining frequency regions other than the frequency region desired by the user.

Next, the feature point extracting unit 2113 can extract the feature points from the noise-canceled EEG signals. In this case, the feature point extracting unit 2113 can extract a feature point by converting a noise-removed EEG signal into a frequency domain and extracting a frequency having a power value equal to or higher than a set threshold value.

Especially, the noise-canceled EEG can be analyzed in the spatial frequency domain. And converts it into a frequency domain using a technique of converting a signal to a frequency domain such as Fast Fourier Transform (FFT). A specific threshold value can be set and a frequency having a power value of a frequency band equal to or higher than a threshold value can be extracted as a feature point.

In addition, the common spatial pattern filtering technique is used to maximize spatial characteristics of a signal. This technique is used to maximize the spatial boundary of the sensory motor cortex area. It can be used to maximize spatial features, extract the band power, and then extract the characteristics of frequency components.

The band power can be extracted as the effect of obtaining the power spectral density in the time domain by obtaining the variance of the signal to which the spatial filtering is applied and applying the log. It is possible to finally extract the joint feature points by dimensionally combining the features of the extracted frequency components and the band power feature points to which the spatial filter is applied.

Next, the EEG signal classifier 2114 classifies the EEG signals according to commands based on the feature points of the EEG signals.

That is, the EEG signal classifying unit 2114 classifies the EEG signals according to commands based on the feature points of the EEG signals. For example, extracted minutiae are classified through CCA (Canonical Correlation Analysis) method. In particular, it can be classified according to the degree of association between the extracted feature point and a specific frequency corresponding to a specific command.

Next, the central processing unit 200 can transmit a second control signal that changes either the current, the frequency, or the pulse width. That is, the control signal generating unit 2111 generates and transmits a second control signal that changes either the current, the frequency, or the pulse width before the adaptive reaction of the body sensation occurs due to the electric stimulation, . Also, when the adaptive reaction occurs, the second control signal that changes the current, the frequency, or the pulse width may be transmitted to change the electric stimulus in the stimulation unit 110 receiving the second control signal.

In addition, the central processing unit 200 may further include a stimulation unit 100 that generates electrical stimulation based on the first and second control signals. The stimulation unit 100 may be coupled to the inside of the steady state sensory evoked potential generator 10, or may be disposed outside and separate from the stimulation unit 100. In the separated form, the stimulation unit 100 may be connected to the transceiver unit 230 of the steady state sensory evoked potential generator 10 to transmit and receive information through the network.

The sensing unit 300 may further include a sensing unit 300 sensing the EEG signal before transmitting the EEG signal generated by the central processing unit 200 and transmitting the signal to the transceiving unit 230. Likewise, the sensing unit 300 may be coupled to the inside of the steady state sensory evoked potential generating device 10, or may be disposed outside and separate from the sensing unit 300. In the separated form, the sensing unit 300 may be connected to the transceiver 230 of the steady state sensory evoked potential generator 10 to transmit and receive information through the network.

In addition, the central processing unit 200 may detect the aforementioned compliance phenomenon. For example, the EEG signal obtained from the sensing unit 300 may be outputted in a frequency range of a predetermined interval through Fast Fourier Transform (FFT) in the central processing unit 200. In addition, the central processing unit 200 can calculate a threshold value during a training time for each user and an average peak value (peak) of each frequency. If an adaptive response occurs, the frequency magnitude in a certain section may gradually decrease and become smaller than the average peak value, and this point may be set as a time point at which the adaptive reaction occurs.

Next, FIG. 4 is a flowchart for explaining a method of operating the apparatus for generating a normal-sensed sensory evoked potential according to an embodiment of the present invention.

Referring to FIG. 4, the method for operating the steady state sensory evoked potential generator includes transmitting a first control signal for generating at least one electrical stimulus having a different current, frequency, or pulse width (S400) A step S430 of removing the noise from the received EEG signal, a step S430 of extracting a feature point from the EEG signal from which noise has been removed, (S440) classifying each EEG signal by command based on the EEG signal, and transmitting a second control signal in which any one of current, frequency, and pulse width is changed (S450).

First, the central processing unit 200 transmits a first control signal for generating at least one electric stimulus having a different current, frequency, or pulse width (S400).

At this time, due to the first control signal transmitted by the central processing unit 200, the stimulation unit 100 may generate one or more electric stimuli having different current, frequency or pulse width.

In addition, electrical stimulation may be induced in the stimulation unit 100 to generate a tactile sense of the user. At this time, the current, frequency, or pulse width generated in the stimulation unit 100 can be controlled so that the electric stimulation is harmless to the body and is maintained to the extent that the user's muscle is not contracted. Frequency, or pulse width before it is turned on.

For example, the electrode used in the stimulation unit 100 may form one channel in the form of a cathode and an anode. That is, an electric stimulus is given to one electrode, and this electric stimulus permeates through the skin to stimulate the sensory nerve, and can escape through the other electrode. At this time, the electrode used is thin in a patch form and can be adhered to the skin. Further, in order to use the electrode, distilled water or the like may be applied to the skin to lower the resistance.

Next, the central processing unit 200 receives the sensed EEG signal as a response to each electrical stimulus generated in the previous step S400 (S410). At this time, the sensing unit 300 can detect an EEG signal for stimulation through the EEG equipment.

Next, the central processing unit 200 removes noise from the EEG signal received in the preceding step S410 (S420). At this time, the time-frequency component of the EMG signal and the safety (EOG) signal can be grasped and linearly separated from the received EEG signal. In addition, it is possible to remove noise using an Independent Component Analysis (ANOVA) method. By using a notch filter and a band-pass filter, May be filtered.

Next, in step S420, the central processing unit 200 extracts feature points from the noise-canceled EEG signal (S430). More specifically, it is possible to extract a feature point by converting a signal having a noise-removed EEG signal into a frequency domain and extracting a frequency having a power value equal to or higher than a set threshold value.

Next, the central processing unit 200 classifies the EEG signals according to commands based on the feature points of the EEG signals extracted in the preceding step S430 (S440).

At this time, the extracted minutiae can be classified by the CCA (Canonical Correlation Analysis) method, and classified according to the degree of association between the minutiae extracted and the specific frequency corresponding to the specific command.

For example, a specific threshold value is set and the power of the frequency band exceeding the threshold value is extracted as a feature point. In addition, the common spatial pattern filtering technique is used to maximize spatial characteristics of a signal. This is a technique used to maximize the spatial boundary of the sensory cortex in the cortical area. It is used to extract the characteristics of the frequency component by maximizing spatial characteristics and extracting the band power. The band power can be extracted with the same effect of obtaining the power spectral density in the time domain by obtaining the variance of the signal to which the spatial filtering is applied and applying the log.

It is possible to finally extract the joint feature points by dimensionally combining the features of the extracted frequency components and the band power feature points to which the spatial filter is applied. If the extracted feature points are input to the classification algorithm of Multiclass Linear Discriminant Analysis (LDA), the Linear Classifier (LDA) minimizes the variance within the class using covariance and eigenvectors, and classifies the covariance between classes as the maximum have. Therefore, the time difference can be reduced when detecting and classifying EEG signals that change in real time because they can be classified quickly.

Next, the central processing unit 200 classifies the EEG signals from the preceding step S440 and then changes either the current, the frequency, or the pulse width before the adaptation reaction of the body senses to each of the provided electric stimuli is generated (S450).

Alternatively, if an adaptive reaction occurs, a second control signal that changes either the current, the frequency, or the pulse width may be transmitted. At this time, the second control signal is transmitted to the stimulation unit 100, whereby the electrical stimulation can be controlled. At this time, the adaptation reaction of the somatosensory to each electric stimulus may be detected by monitoring the EEG signal.

FIG. 5 is a diagram illustrating a method of stimulating agent according to an embodiment of the present invention.

Referring to FIG. 5, the magnetic stimulation unit 100 is classified into two electrodes. The stimulation unit 100 is located in both arms of the user and can stimulate the median nerve, one of the peripheral nerves of the arm. Median nerves are generally known to be involved in motor functions such as palm sensation, movement of some fingers, and wrist flipping.

In addition, the sensing unit 300 is located in the head of the user due to the International 10-20 method of positioning the electrodes on the scalp when recording brain waves. In this way, 19 electrodes can be placed at approximately equal intervals in the cerebral cortex.

As shown in FIG. 5, the central processing unit 200 may be connected to the stimulation unit 100 and the sensing unit 300, or may be independently provided externally.

In some cases, the visual stimulation may be induced together as shown in Fig. That is, it is also possible to display direction information such as an arrow according to the frequency or to present time information indicating a specific command on the screen, and to detect a signal corresponding to the time stimulus. Through this, it is possible to classify a specific command or to recognize a specific command to the user.

At this time, the processor 220 may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable recording medium. At this time, the computer readable recording medium may include a program command, a data file, a data structure, or the like, alone or in combination. On the other hand, the program commands to be recorded on the recording medium may be those specially designed and configured for the present invention or may be available to those skilled in the computer software.

The computer-readable recording medium includes a magnetic recording medium such as a magnetic medium such as a hard disk, a floppy disk and a magnetic tape, an optical medium such as a CD-ROM and a DVD, a magnetic disk such as a floppy disk, And a hardware device specifically configured to store and execute program commands such as a magneto-optical media and a ROM, a RAM, a flash memory, and the like.

On the other hand, such a recording medium may be a transmission medium such as a light or a metal wire, a wave guide, or the like including a carrier wave for transmitting a signal designating a program command, a data structure and the like. The program commands also include high level language code that can be executed by a computer using an interpreter or the like, as well as machine language code such as that produced by a compiler. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

The operation method of the apparatus for generating a normal state sensory evoked potential according to an embodiment of the present invention causes electrical stimulation in which current, frequency, or pulse width is different, and brain waves are measured in the scalp, (SSSEP) so as to control the instrument interface by generating various commands as well as to identify the sensory triggering potential (SSSEP). The apparatus for generating a normal state sensory evoked potential according to an embodiment of the present invention requires four or more commands and can be utilized to configure an interface for autonomously controlling the apparatus without restriction of sight line. Therefore, it can be a great help for the convenience of the device interface control of the general public as well as the limb paralysis patients due to the spinal injury.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

10: Normal state sensory evoked potential generator
100:
200: central processing unit
210: memory
211: Application
2111: Control signal generator
2112: Noise canceling
2113: Feature point extraction unit
2114: EEG signal classifier
220: Processor
230: Transmitting /
300:

Claims (15)

A method of operating a device for generating a steady state sensory evoked potential,
Transmitting a first control signal for generating at least one electrical stimulus different in current, frequency or pulse width;
Receiving a sensed EEG signal as a response to each of the generated electrical stimuli;
Removing noise from the received EEG signal;
Extracting feature points from the noise-canceled EEG signal;
Classifying the EEG signals according to commands based on feature points of the EEG signals; And
And transmitting a second control signal that changes either the current, the frequency, or the pulse width when the adaptive response of the body sensation is generated by the electrical stimulation or when the adaptive response occurs, A method of operating an evoked potential generator. The method according to claim 1,
The generated electrical stimulation
Wherein the tactile sense stimulus is generated and has a current, frequency, or pulse width that is harmless to the body and does not shrink the user's muscles. The method according to claim 1,
The EEG signal
A method of operating a device for generating a steady state sensory evoked potential that is sensed by an EEG instrument. The method according to claim 1,
The step of removing noise
(EMG) signal and an EOG signal from the received EEG signal and linearly separating the EMG signal and the EOG signal. The method according to claim 1,
The step of removing noise
A method of operating a steady state sensory evoked potential generator comprising removing noise using an Independent Component Analysis and using a Notch filter and a bandpass filter. The method according to claim 1,
The step of extracting the feature points
And converting the noise-canceled EEG signal into a frequency domain and extracting a frequency having a power value equal to or higher than a preset threshold value. The method according to claim 1,
The step of classifying by the command
And classifying the extracted feature points by a degree of association between the extracted feature points and a specific frequency corresponding to a specific command. delete delete A computer-readable recording medium recording a program for performing the method according to any one of claims 1 to 7 on a computer. A device for generating a steady state sensory evoked potential,
A data transmission / reception unit;
A memory for storing a steady state sensory evoked potential generating application; And
And a processor executing the application,
The processor comprising:
A first control signal for generating at least one electric stimulus different in current, frequency or pulse width depending on the execution of the application,
Receiving a sensed EEG signal as a response to each of the generated electrical stimuli,
Removing noise from the received EEG signal,
Extracting feature points from the noise-canceled EEG signal,
Classifying the EEG signals by commands based on the feature points of the EEG signals,
Wherein the second control signal is a signal that changes the current, frequency, or pulse width when an adaptive response of the somatic sensation is generated by the electrical stimulation or when an adaptive response occurs, Generating device. 12. The method of claim 11,
And a magnetic pole portion for generating electrical stimulation based on the first and second control signals. 12. The method of claim 11,
And a sensing unit for sensing the EEG signal and transmitting the sensed EEG signal to the transceiver unit. delete delete

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