Method and device for applying electrical stimulation to the vagus nerve that reflects the degree of symptoms measured by biosignal measurement

Abstract

The present invention is a method for applying electrical stimulation to the vagus nerve via electrodes in contact with the skin of a human body, and includes a reference value setting step for measuring a user's biosignal multiple times at intervals of at least a predetermined time while no electrical stimulation is being applied and setting a reference value for the biosignal; an electrical stimulation guideline input step for inputting an electrical stimulation guideline including a numerical value for the electrical stimulation; a stimulation value adjustment step for measuring the user's biosignal and comparing the calculated value with the reference value before applying the electrical stimulation to adjust the electrical stimulation guideline; and an electrical stimulation step for applying the electrical stimulation with the adjusted value. The present invention has the advantage that the effect of electrical stimulation is further improved by applying electrical stimulation in a manner that reflects the current state of the user.

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for applying electrical stimulation to the vagus nerve, and more particularly to a method and apparatus for applying electrical stimulation to the vagus nerve via electrodes in contact with the skin of a human body. [Background technology]

[0002] The vagus nerve is one of the cranial nerves and is the 10th cranial nerve. It is a mixed nerve containing parasympathetic nerve fibers that emerges from the brain and distributes throughout the face, chest, and abdomen. It is involved in regulating the parasympathetic nervous system, which acts on the heart, lungs, digestive tract, etc. It has the longest and most complex structure of the 12 pairs of cranial nerves, and contains both sensory and motor fibers.

[0003] Vagus nerve stimulators for the treatment of epilepsy and depression have been approved by the U.S. Food and Drug Administration (FDA), and these stimulate the cervical branch located in the neck. However, this type of cervical vagus nerve electrical stimulation requires making an incision directly in the skin to expose the cervical branch of the vagus nerve, wrapping a coil around the outside of the nerve, and attaching a microchip, so it cannot be used for self-treatment by the general public.

[0004] Meanwhile, in traditional Chinese medicine, a method of treating illnesses through acupuncture treatment of the ear is applied. The ear is where the auricular branch of the vagus nerve is distributed, and it is thought to be used for stimulating the vagus nerve.

[0005] For this reason, devices have been developed that electrically stimulate the vagus nerve in the ear in order to alleviate symptoms, but they are not widely used at present because they are not effective enough due to the difficulty of accurately reflecting the user's current condition. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention is intended to solve the problems of the prior art described above, and its purpose is to provide a method and device for applying electrical stimulation to the vagus nerve that reflects the level of the user's current symptoms and has improved effectiveness. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the method of applying electrical stimulation to the vagus nerve according to the present invention is a method of applying electrical stimulation to the vagus nerve via an electrode that contacts the skin of a human body, and includes a reference value setting step of measuring a user's biosignal multiple times at intervals of at least a predetermined time while no electrical stimulation is being applied and setting a reference value for the biosignal; an electrical stimulation guideline input step of inputting an electrical stimulation guideline including a numerical value for the electrical stimulation; a stimulation value adjustment step of measuring the user's biosignal and comparing the calculated value with the reference value before applying the electrical stimulation to adjust the electrical stimulation guideline; and an electrical stimulation step of applying the electrical stimulation with the adjusted value.

[0008] In this case, the measured biological signal may be an electroencephalogram or heart rate variability.

[0009] When the biological signal of the user to be measured is an electroencephalogram, the reference value setting step measures the biological signal a plurality of times at intervals of a predetermined time or more, calculates the FSWR for each biological signal, and sets the FSWR as the FSWR reference value. s In the stimulation value adjustment step, the FSWR calculated by measuring the user's brain waves is set. t and the FSWR s The FSWR is an index that reflects the state of the user's symptoms, and can be characterized by being calculated by dividing the power of a fast wave band, which has a relatively high frequency, by the power of a slow wave band, which has a relatively low frequency, in the measured electroencephalogram.

[0010] Preferably, the fast wave band is brain waves exceeding 13 Hz, and the slow wave band is brain waves below 13 Hz.

[0011] In the reference value setting step, the FSWR s is preferably the sum of the average FSWR value calculated by measuring the electroencephalogram multiple times and the standard deviation of the FSWR value.

[0012] In the stimulus value adjustment step, FSWR t FSWR s It is preferable to adjust the electrical stimulation applied via the electrodes if the electrical stimulation is greater than .

[0013] FSWR t FSWR s It is preferable to increase the duty cycle of the electrical stimulation when the FSWR is larger. t and FSWR s The duty ratio of the electrical stimulation can be increased in proportion to the difference between

[0014] Furthermore, when the measured biosignal of the user is heart rate variability, the reference value setting step measures the biosignal multiple times at intervals of at least a predetermined time, calculates the FSBR for each biosignal, and sets the FSBR as the FSBR reference value. s and in the stimulation value adjustment step, the FSBR calculated by measuring the user's heart rate variability is set. t and the FSBR s The FSBR is an index that reflects the state of the user's symptoms, and can be characterized by being calculated by dividing the power of a high-frequency band, which has a relatively high frequency, by the power of a low-frequency band, which has a relatively low frequency, in the measured heart rate variability.

[0015] It is preferable that the high frequency band is in the range of 0.15 Hz or more and 0.4 Hz or less, and the low frequency band is in the range of 0.04 Hz or more and less than 0.15 Hz.

[0016] In the reference value setting step, the FSBR s is preferably the sum of the average FSBR value calculated by measuring heart rate variability multiple times and the standard deviation of the FSBR value.

[0017] In the stimulation value adjustment step, FSBR t FSBR s It is preferable to adjust the electrical stimulation applied via the electrodes if the electrical stimulation is greater than .

[0018] FSBR t FSBR s When the FSBR is larger, it is preferable to increase the duty ratio of the electrical stimulation. t and FSBR s The duty ratio of the electrical stimulation can be increased in proportion to the difference between

[0019] Before performing the stimulation value adjustment step, an initial stimulation value setting step is performed in which an SPI calculated by applying one or more of demographic indicators and environmental indicators is applied to derive an initial stimulation value by adjusting the numerical value included in the electrical stimulation guideline, and the stimulation value adjustment step adjusts the initial stimulation value, and the SPI is an index that quantifies sensitivity to electrical stimulation, the demographic indicator is an indicator that statistically reflects the degree of sensitivity to electrical stimulation, and the environmental indicator may be an indicator that reflects environmental factors that affect sensitivity to electrical stimulation.

[0020] The demographic indicators preferably include one or more of the following information: age, sex, BMI, medication status, and disease status.

[0021] The environmental indicator preferably includes information on one or more of temperature, humidity, light intensity, and discomfort index.

[0022] According to another aspect of the present invention, a device for applying electrical stimulation to the vagus nerve includes electrodes that contact the skin of a human body to apply electrical stimulation; an input unit that receives input of electrical stimulation guidelines including numerical information for the electrical stimulation; a reference value setting unit that sets a reference value for a biosignal from a user's biosignal measured multiple times at intervals of at least a predetermined time when no electrical stimulation is being applied; and a stimulation value adjustment unit that measures the user's biosignal and compares the calculated value with the reference value before applying the electrical stimulation to adjust the electrical stimulation guidelines.

[0023] In this case, the measured biological signal may be an electroencephalogram or heart rate variability.

[0024] When the measured biological signal is an electroencephalogram, the reference value setting unit calculates an FSWR from each piece of electroencephalogram information of the user measured multiple times at intervals of at least a predetermined time, and sets an FSWR as an FSWR reference value. S and the stimulation value adjusting unit sets an FSWR calculated by measuring the user's brain waves before applying the electrical stimulation. t and the FSWR s The electrical stimulation guideline is adjusted by comparing the FSWR with the measured electroencephalogram (EEG), and the FSWR is an index that reflects the state of the user's symptoms, and can be characterized by being calculated by dividing the power of a fast wave band, which has a relatively high frequency, by the power of a slow wave band, which has a relatively low frequency, in the measured electroencephalogram.

[0025] Preferably, the fast wave band is brain waves exceeding 13 Hz, and the slow wave band is brain waves below 13 Hz.

[0026] FSWR s is preferably the sum of the average FSWR value calculated by measuring the electroencephalogram multiple times and the standard deviation of the FSWR value.

[0027] The stimulus value adjusting unit is FSWR t FSWR sIf it is greater, it is preferable to adjust the electrical stimulation applied via the electrodes.

[0028] FSWR t FSWR s It is preferable to increase the duty cycle of the electrical stimulation when the FSWR is larger. t and FSWR s The duty ratio of the electrical stimulation can be increased in proportion to the difference between

[0029] Furthermore, when the measured biological signal is heart rate variability, the reference value setting unit calculates an FSBR from each piece of heart rate variability information of the user measured multiple times at intervals of at least a predetermined time, and sets an FSBR as an FSBR reference value. s and the stimulation value adjusting unit sets an FSBR calculated by measuring the user's heart rate variability before applying the electrical stimulation. t and the FSBR s The electrical stimulation guideline is adjusted by comparing the FSBR with the FSBR, and the FSBR is an index that reflects the state of the user's symptoms, and can be characterized by being calculated by dividing the power of a high-frequency band, which has a relatively high frequency, by the power of a low-frequency band, which has a relatively low frequency, in the measured heart rate variability.

[0030] It is preferable that the high frequency band is in the range of 0.15 Hz or more and 0.4 Hz or less, and the low frequency band is in the range of 0.04 Hz or more and less than 0.15 Hz.

[0031] FSBR s is preferably the sum of the average FSBR value calculated by measuring heart rate variability multiple times and the standard deviation of the FSBR value.

[0032] The stimulus value adjusting unit is FSBR. t FSBR s If it is greater, it is preferable to adjust the electrical stimulation applied via the electrodes.

[0033] FSBR t FSBR sWhen the FSBR is larger, it is preferable to increase the duty ratio of the electrical stimulation. t and FSBR s The duty ratio of the electrical stimulation can be increased in proportion to the difference between

[0034] The device may further include an initial stimulation value setting unit that derives an initial stimulation value by adjusting a numerical value included in an electrical stimulation guideline by applying an SPI calculated by applying one or more of a demographic indicator and an environmental indicator, wherein the SPI is an index that quantifies sensitivity to electrical stimulation, the demographic indicator is an indicator that statistically reflects the degree of sensitivity to electrical stimulation, and the environmental indicator is an indicator that reflects environmental factors that affect the sensitivity to electrical stimulation, and the stimulation value adjustment unit can adjust the initial stimulation value derived by the initial stimulation value setting unit.

[0035] The demographic indicators preferably include one or more of the following information: age, sex, BMI, medication status, and disease status.

[0036] The environmental indicator preferably includes information on one or more of temperature, humidity, light intensity, and discomfort index. [Effects of the Invention]

[0037] The present invention configured as described above has the advantage that the effect of electrical stimulation is further improved by applying electrical stimulation in a manner that reflects the current state of the user.

[0038] In addition, by applying electrical stimulation in accordance with the user's sensitivity to electrical stimulation, it is possible to prevent the user from feeling pain due to electrical stimulation even when adjusting to the current condition. [Brief explanation of the drawings]

[0039] [Figure 1] 1 is a flowchart illustrating a method for applying electrical stimulation to the vagus nerve that reflects the degree of symptoms based on biosignal measurement according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0040] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0041] However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to only the embodiments described below. The shapes and sizes of elements in the drawings may be exaggerated for clarity, and elements represented by the same reference numerals in the drawings are the same elements.

[0042] Furthermore, throughout the specification, when a part is described as being "coupled" to another part, this includes not only when they are "directly coupled" but also when they are "electrically connected" with another element sandwiched therebetween. Furthermore, when a part is described as "including" or "comprising" a certain component, this does not mean that it excludes other components, but that it can further include or comprise other components, unless otherwise specified.

[0043] Furthermore, terms such as "first" and "second" are used to distinguish one component from another, and should not be used to limit the scope of rights. For example, the first component can be named the second component, and similarly, the second component can be named the first component.

[0044] FIG. 1 is a flowchart illustrating a method for applying electrical stimulation to the vagus nerve that reflects the degree of symptoms measured by biosignal measurement according to the present invention.

[0045] In the first embodiment of the present invention, electrical stimulation is applied to the vagus nerve in accordance with the degree of symptoms detected via electroencephalograms.

[0046] In the method for applying electrical stimulation to the vagus nerve according to this embodiment, a reference value setting step is first performed.

[0047] The reference value is a value that serves as a reference for determining the user's current state. In this embodiment, the FSWR (Fast-to-Slow Wave Ratio) is used as an index that reflects the user's current state with respect to symptoms. The FSWR measurement for setting the reference value is a value calculated by dividing the power of a fast wave band, which has a relatively high frequency, by the power of a slow wave band, which has a relatively low frequency, in electroencephalograms measured without applying electrical stimulation. In this case, the fast wave band is preferably an electroencephalogram exceeding 13 Hz, and the slow wave band is preferably an electroencephalogram below 13 Hz. A change in the FSWR indicates a change in the user's state with respect to symptoms, and the reference value setting step is a step of configuring an FSWR reference for confirming that the state has changed. Since the reference value is used to set a reference for determining the user's state, it is preferable to use multiple pieces of FSWR information. In this case, in order to obtain information about the user's state at normal times rather than information about the state at a specific time, electroencephalograms are repeatedly measured at predetermined time intervals or more, and the FSWR for each is calculated, and the FSWR is set as the FSWR reference value. s For example, it is preferable to use the results of repeatedly measuring the brain waves at the same time throughout the day, particularly at the same time as the time when electrical stimulation is to be applied, and more preferably, to calculate the FSWR for each brain wave using brain wave information measured at the same time over a week, and then set the FSWR. s It is better to set FSWR. s A specific method for setting the FSWR is preferably to set it to a value obtained by adding the standard deviation of the FSWR to the average of the FSWR values ​​calculated by measuring the EEG multiple times. The reference value setting step is a process performed before applying electrical stimulation, and can be repeated to set a new reference value at predetermined intervals, and it is preferable to set a new reference value at weekly intervals. sThe process of setting FSWR is performed by a reference value setting unit, which may include an electroencephalogram (EEG) measuring device for measuring EEG to measure FSWR and derive a reference value, and a storage device and a calculation device for storing EEG data and calculating the average and standard deviation of FSWR.

[0048] FSWR is the reference value s With the above set, the electrical stimulation guideline input step is performed.

[0049] The electrical stimulation guideline includes information about electrical stimulation for vagus nerve stimulation. The electrical stimulation guideline may be determined based on a doctor's diagnosis and prescription at a hospital, or may be derived through a separate program or system. The electrical stimulation guideline for vagus nerve stimulation may include information about the electrical stimulation current, frequency, duty, and stimulation time. While the electrical stimulation guideline is determined based on the user's illness or symptoms, new electrical stimulation guidelines are not received each time the electrical stimulation application device is used. Therefore, electrical stimulation applied according to the electrical stimulation guideline may be ineffective due to a time difference between receiving the electrical stimulation guideline and applying the electrical stimulation. To solve this problem, the present invention is characterized by evaluating the user's current state based on an FSWR reference value obtained in advance through electroencephalogram (EEG) measurement and adjusting the electrical stimulation based on the evaluation.

[0050] In this way, the electrical stimulation guideline including the information about the predetermined electrical stimulation is input through the input unit of the device for applying electrical stimulation to the vagus nerve. The method of inputting the electrical stimulation guideline may be that the information about the electrical stimulation is input directly by the user, or may be automatically input via a code (barcode or QR code) including the information about the electrical stimulation or an information storage device.

[0051] In this embodiment, an initial stimulation value setting step is performed before adjusting the electrical stimulation applied to the user to reflect the current state of the user.

[0052] The initial stimulation value reflects the sensitivity to electrical stimulation and sets the electrical stimulation guideline to a range of electrical stimulation suitable for the user. Sensitivity to electrical stimulation is a concept derived from the fact that pain or discomfort caused by the same electrical stimulation varies from person to person, and refers to the degree to which a person can easily feel pain or discomfort from electrical stimulation. In the present invention, sensitivity to electrical stimulation reflects not only the sensitivity to the strength of physical stimulation and the sensitivity to what a person perceives as pain, but also the sensitivity to what a person feels psychologically or emotionally, even without feeling pain, as the sensitivity to electrical stimulation increases, and in particular, the pain or discomfort increases as the current increases.

[0053] The present invention employs the Stimulation Perception Index (SPI) as an index that quantifies sensitivity to electrical stimulation. The SPI of the present invention is calculated using demographic indicators and / or environmental indicators. The demographic indicators are indicators that statistically represent sensitivity to electrical stimulation based on biological information such as age, gender, BMI (body mass index), medication status, and disease status. For example, young and elderly people are more sensitive to electrical stimulation than young and middle-aged people, women are more sensitive to electrical stimulation than men, and the higher the BMI, the lower the sensitivity to electrical stimulation. The demographic indicators are statistically organized information that can be applied to the SPI index. The environmental indicators are indicators that statistically represent sensitivity to electrical stimulation based on ambient environmental information such as temperature, humidity, illuminance, and discomfort index. For example, when the temperature or humidity is lower than a certain value, sensitivity to electrical stimulation increases, and when the illuminance is lower, sensitivity to electrical stimulation increases. The discomfort index varies in sensitivity to electrical stimulation depending on its range. A high level of sensitivity to electrical stimulation, as indicated by the SPI index, indicates a tendency to feel pain or discomfort from electrical stimulation. Therefore, it is preferable to set an initial stimulation value to reduce the level of stimulation so that the user does not feel pain or discomfort, for example, by reducing the current intensity. However, since the electrical stimulation guideline is provided with a value that can achieve a predetermined effect, simply reducing the current intensity may result in insufficient stimulation and the effect of the electrical stimulation may not be achieved. Therefore, compensation for the reduction in current is necessary, and a method of increasing the duty ratio in proportion to the reduction in current can be applied. It is preferable to not change the frequency of the electrical stimulation guideline, and it is preferable to maintain the electrical stimulation application time because an increase in the duration of electrical stimulation increases the user's discomfort. In this case, the user is evaluated as being sensitive to electrical stimulation only when the SPI index is greater than a predetermined value, and the initial stimulation value can be set to reduce the current and increase the duty ratio in proportion to the excess value. Conversely, if the SPI index is equal to or less than a predetermined value, the current and duty ratio of the input electrical stimulation guideline can be applied as the initial stimulation value.The process of deriving the initial stimulation value from the input electrical stimulation guideline is performed by an initial stimulation value setting unit, which may include a database for deriving the SPI index, an input device for receiving input of age and gender to apply demographic indicators, a BMI meter for directly measuring and applying BMI, an input device for receiving input of information to apply environmental indicators, and a thermometer or hygrometer for directly measuring and reflecting temperature and humidity.

[0054] Next, a stimulus value adjustment step is performed.

[0055] The stimulation value means an electrical stimulation applied to a user through an electrode, and the present invention does not directly apply an electrical stimulation guideline or an initial stimulation value that reflects sensitivity to the electrical stimulation guideline, but adjusts the electrical stimulation guideline or the initial stimulation value to reflect the user's current state and applies it to the user. Specifically, before applying the electrical stimulation, the FSWR calculated by measuring the user's brain waves is used. t is the FSWR set in the previous reference value setting step. s Compare with the above and adjust the electrical stimulation guideline or initial stimulation value. For example, FSWR t FSWR s If the FSWR is greater than 100, the electrical stimulation applied through the electrodes can be adjusted, more specifically, t FSWR s If the FSWR is greater than 1 / 3, it is determined that the user's condition has worsened compared to normal, and the duty ratio of the electrical stimulation included in the electrical stimulation guideline or initial stimulation value is increased to increase the total amount of electrical stimulation applied to the user. t and FSWR sThe duty ratio of the electrical stimulation can be increased in proportion to the difference between the reference value setting unit and the reference value setting unit. The electrical stimulation guideline or initial stimulation value is adjusted by a stimulation value adjusting unit. The stimulation value adjusting unit may include an electroencephalogram measuring device that measures electroencephalograms to calculate FSWR, and a storage device and a calculation device that store electroencephalogram data, calculate FSWR, and compare it with a reference value. Such a stimulation value adjusting unit may use all or some of the elements together with the reference value setting unit.

[0056] In addition, an electrical stimulation step is performed in which electrical stimulation with an adjusted electrical stimulation guideline or initial stimulation value is applied to the electrodes.

[0057] According to the above process, by adjusting the electrical stimulation guideline to reflect the user's sensitivity, not only is the problem of the user feeling pain reduced, but the electrical stimulation is applied to the user with the electrical stimulation guideline or initial stimulation value adjusted to reflect the user's current state, thereby improving the effectiveness of the applied electrical stimulation. The electrical stimulation with the electrical stimulation guideline or initial stimulation value adjusted can be applied to the user via a control device that controls the electrical signals applied to the electrodes.

[0058] In a second embodiment of the present invention, electrical stimulation is applied to the vagus nerve in a manner that reflects the degree of symptoms caused by heart rate variability.

[0059] The method for applying electrical stimulation to the vagus nerve according to this embodiment first performs a reference value setting step. Heart rate variability, which refers to the degree of variation in heart rate, refers to the minute variation from one cardiac cycle to the next. Meanwhile, pulses reflect the characteristics of heart rate, even though the measurement location varies, and therefore can be used as the same as or a substitute for heart rate. Therefore, in the following description, pulse rate variability can be used as a substitute for or approximately the same as heart rate variability, and in this case, the part related to the measurement of heart rate variability can be substituted for the measurement of pulse rate variability.

[0060] The reference value is a value that serves as a reference for determining the user's current condition. In this embodiment, FSBR (Fast-to-Slow Beat Ratio) is used as an index reflecting the user's current condition with respect to symptoms. The FSBR for setting the reference value is a value calculated by dividing the power of a high-frequency band, where the frequency is relatively high, by the power of a low-frequency band, where the frequency is relatively low, in heart rate variability measured without applying electrical stimulation. In this case, the high-frequency band is preferably in the range of 0.15 Hz to 0.4 Hz, and the low-frequency band is preferably in the range of 0.04 Hz to 0.15 Hz. Such a change in FSBR indicates a change in the user's condition with respect to symptoms, and the reference value setting step is a step of configuring an FSBR reference for confirming the change in condition. Since the reference value is used to set a reference for determining the user's condition, it is preferable to use information on multiple FSBRs. In this case, in order to obtain information on the user's condition at normal times rather than information on the condition at a specific time, the heart rate variability is repeatedly measured at intervals of at least a predetermined time, and an FSBR for each measurement is calculated, and the FSBR is set as the FSBR reference value. s For example, it is preferable to use the results of repeatedly measuring heart rate variability at the same time of day, particularly at the same time of day when electrical stimulation is to be applied, and more preferably, to calculate each FSBR using heart rate variability information measured at the same time of day over a week, and set the FSBRs. s A specific method for setting the reference value is preferably to set the reference value by adding the standard deviation of the FSBR to the average of the FSBR values ​​calculated by measuring the heart rate variability multiple times. The reference value setting step is a process performed before applying electrical stimulation, and can be repeated to set a new reference value at predetermined intervals, and it is preferable to set a new reference value at weekly intervals. sThe process of setting FSBR is performed by a reference value setting unit. The reference value setting unit may include an electrocardiogram monitor that measures heart rate variability to measure FSBR and derive a reference value, a storage device and a calculation device that store electrocardiogram data and calculate the average and standard deviation of FSBR.

[0061] FSBR is the reference value s With the above set, the electrical stimulation guideline input step is performed.

[0062] The electrical stimulation guideline includes information about electrical stimulation for vagus nerve stimulation. The electrical stimulation guideline may be determined based on a doctor's diagnosis and prescription at a hospital, or may be derived through a separate program or system. The electrical stimulation guideline for vagus nerve stimulation may include information about the electrical stimulation current, frequency, duty, and stimulation time. While the electrical stimulation guideline is determined based on the user's illness or symptoms, a new electrical stimulation guideline is not received each time the electrical stimulation application device is used. Therefore, electrical stimulation applied according to the electrical stimulation guideline may be ineffective due to a time difference between receiving the electrical stimulation guideline and applying the electrical stimulation. To solve this problem, the present invention is characterized by evaluating the user's current condition based on an FSWR reference value obtained in advance through heart rate variability measurement, and adjusting the electrical stimulation based on the evaluation.

[0063] In this way, the electrical stimulation guideline including the information about the predetermined electrical stimulation is input through the input unit of the device for applying electrical stimulation to the vagus nerve. The method of inputting the electrical stimulation guideline may be that the information about the electrical stimulation is input directly by the user, or may be automatically input via a code (barcode or QR code) including the information about the electrical stimulation or an information storage device.

[0064] In this embodiment, an initial stimulation value setting step is performed before adjusting the electrical stimulation applied to the user to reflect the current state of the user.

[0065] The initial stimulation value reflects the sensitivity to electrical stimulation and sets the electrical stimulation guideline to a range of electrical stimulation suitable for the user. Sensitivity to electrical stimulation is a concept derived from the fact that pain or discomfort caused by the same electrical stimulation varies from person to person, and refers to the degree to which a person can easily feel pain or discomfort from electrical stimulation. In the present invention, sensitivity to electrical stimulation reflects not only the sensitivity to the strength of physical stimulation and the sensitivity to what a person perceives as pain, but also the sensitivity to what a person feels psychologically or emotionally, even without feeling pain, as the sensitivity to electrical stimulation increases, and in particular, the pain or discomfort increases as the current increases.

[0066] The present invention employs the Stimulation Perception Index (SPI) as an index that quantifies sensitivity to electrical stimulation. The SPI of the present invention is calculated using demographic indicators and / or environmental indicators. The demographic indicators are indicators that statistically represent sensitivity to electrical stimulation based on biological information such as age, gender, BMI (body mass index), medication status, and disease status. For example, young and elderly people are more sensitive to electrical stimulation than young and middle-aged people, women are more sensitive to electrical stimulation than men, and the higher the BMI, the lower the sensitivity to electrical stimulation. The demographic indicators are statistically organized information that can be applied to the SPI index. The environmental indicators are indicators that statistically represent sensitivity to electrical stimulation based on ambient environmental information such as temperature, humidity, illuminance, and discomfort index. For example, when the temperature or humidity is lower than a certain value, sensitivity to electrical stimulation increases, and when the illuminance is lower, sensitivity to electrical stimulation increases. The discomfort index varies in sensitivity to electrical stimulation depending on its range. A high level of sensitivity to electrical stimulation, as indicated by the SPI index, indicates a tendency to feel pain or discomfort from electrical stimulation. Therefore, it is preferable to set the initial stimulation value in a direction that reduces the level of stimulation so that the user does not feel pain or discomfort, for example, by reducing the current intensity. However, since the electrical stimulation guideline is provided with a value that can achieve a predetermined effect, simply reducing the current intensity may result in insufficient stimulation and the effect of the electrical stimulation may not be achieved. Therefore, compensation for the reduction in current is necessary, and a method of increasing the duty ratio in proportion to the reduction in current can be applied. It is preferable to not change the frequency of the electrical stimulation guideline, and it is preferable to maintain the electrical stimulation application time because an increase in the duration of electrical stimulation increases the user's discomfort. In this case, the user is evaluated as being sensitive to electrical stimulation only when the SPI index is greater than a predetermined value, and the initial stimulation value can be set in a direction that reduces the current and increases the duty ratio in proportion to the excess value. Conversely, if the SPI index is equal to or less than a predetermined value, the current and duty ratio of the input electrical stimulation guideline can be applied as the initial stimulation value.The process of deriving the initial stimulation value from the input electrical stimulation guideline is performed by an initial stimulation value setting unit, which may include a database for deriving the SPI index, an input device for receiving input of age and gender to apply demographic indicators, a BMI meter for directly measuring and applying BMI, an input device for receiving input of information to apply environmental indicators, and a thermometer or hygrometer for directly measuring and reflecting temperature and humidity.

[0067] Next, a stimulus value adjustment step is performed.

[0068] The stimulation value refers to the electrical stimulation applied to the user through the electrodes, and the present invention does not directly apply the electrical stimulation guideline or the initial stimulation value that reflects the sensitivity to the electrical stimulation guideline, but adjusts the electrical stimulation guideline or the initial stimulation value to reflect the current state of the user and applies it to the user. Specifically, before applying the electrical stimulation, the FSWR calculated by measuring the user's heart rate variability is used. t is the FSWR set in the previous reference value setting step. s Compare with the above and adjust the electrical stimulation guideline or initial stimulation value. For example, FSWR t FSWR s If the FSWR is greater than 100, the electrical stimulation applied through the electrodes can be adjusted, more specifically, t FSWR s If the FSWR is greater than 1 / 3, the user's condition is evaluated as being worse than normal, and the duty ratio of the electrical stimulation included in the electrical stimulation guideline or initial stimulation value is increased to increase the total amount of electrical stimulation applied to the user. t and FSWR sThe duty cycle of the electrical stimulation can be increased in proportion to the difference between the reference value and the electrocardiogram. The electrical stimulation guideline or initial stimulation value is adjusted by a stimulation value adjuster. The stimulation value adjuster may include an electrocardiogram measuring device that measures heart rate variability to calculate FSWR, and a storage device and a calculation device that store electrocardiogram data, calculate FSWR, and compare it with a reference value. Such a stimulation value adjuster may use all or some of the elements together with the reference value setting unit.

[0069] In addition, an electrical stimulation step is performed in which electrical stimulation with an adjusted electrical stimulation guideline or initial stimulation value is applied to the electrodes.

[0070] According to the above process, by adjusting the electrical stimulation guideline to reflect the user's sensitivity, not only is the problem of the user feeling pain reduced, but the electrical stimulation is applied to the user with the electrical stimulation guideline or initial stimulation value adjusted to reflect the user's current state, thereby improving the effectiveness of the applied electrical stimulation. The electrical stimulation with the electrical stimulation guideline or initial stimulation value adjusted can be applied to the user via a control device that controls the electrical signals applied to the electrodes.

[0071] While the present invention has been described above through preferred embodiments, the above-described embodiments are merely illustrative of the technical concept of the present invention, and it will be understood by those skilled in the art that various modifications are possible within the scope of the technical concept of the present invention. Therefore, the scope of protection of the present invention should be interpreted not by specific embodiments but by the matters set forth in the claims, and all technical concepts within the scope equivalent thereto should also be interpreted as being included in the scope of the present invention.

Claims

1. an electrode that contacts the skin of a human body to apply electrical stimulation; an input unit that receives an input of an electrical stimulation guideline including numerical information for the electrical stimulation; a reference value setting unit that sets a reference value for the biosignal from the biosignal of the user measured multiple times at intervals of at least a predetermined time while no electrical stimulation is being applied; a stimulation value adjusting unit that adjusts an electrical stimulation guideline by measuring a biosignal of the user and comparing the calculated value with the reference value before applying the electrical stimulation; The biological signal measured is an electroencephalogram (EEG), the reference value setting unit calculates an FSWR from each of the user's electroencephalogram information measured a plurality of times at intervals of at least a predetermined time, and sets an FSWR reference value FSWR s ; the stimulation value adjusting unit adjusts an electrical stimulation guideline by comparing an FSWR t calculated by measuring an electroencephalogram of the user with the FSWR s before applying the electrical stimulation; The FSWR is an index that reflects the state of the user's symptoms, and is calculated by dividing the power of a fast wave band, which has a relatively high frequency, by the power of a slow wave band, which has a relatively low frequency, in a measured electroencephalogram; The fast wave band is brain waves exceeding 13 Hz, and the slow wave band is brain waves below 13 Hz.

2. The FSWR s 2. The device for applying electrical stimulation to the vagus nerve according to claim 1, wherein the FSWR value is calculated by measuring electroencephalograms multiple times and adding the standard deviation of the FSWR values ​​to the average of the FSWR values.

3. The stimulus value adjusting unit FSWR t FSWR s 2. The device for applying electrical stimulation to the vagus nerve according to claim 1, wherein the electrical stimulation applied via the electrodes is adjusted when the value of the electrical stimulation applied to the vagus nerve is greater than the value of the electrical stimulation applied to the vagus nerve.

4. FSWR t FSWR s 4. The device for applying electrical stimulation to the vagus nerve according to claim 3, wherein the duty ratio of the electrical stimulation is increased when the amplitude of the electrical stimulation is greater than the amplitude of the electrical stimulation.

5. FSWR t and FSWR s 5. The device for applying electrical stimulation to the vagus nerve according to claim 4, wherein the duty ratio of the electrical stimulation is increased in proportion to the difference between the

6. The method further includes an initial stimulation value setting unit that derives an initial stimulation value by adjusting a numerical value included in the electrical stimulation guideline by applying the SPI calculated by applying one or more of the demographic indicators and the environmental indicators, The SPI is an index that quantifies the sensitivity to electrical stimuli, the demographic indicator is an indicator that statistically reflects the degree of sensitivity to electrical stimuli, and the environmental indicator is an indicator that reflects environmental factors that affect the sensitivity to electrical stimuli. The stimulus value adjusting unit adjusts the initial stimulus value derived by the initial stimulus value setting unit; 2. The device for applying electrical stimulation to the vagus nerve according to claim 1, wherein the initial stimulation value setting unit evaluates the subject as sensitive to electrical stimulation only when the SPI is greater than a predetermined value, and sets the initial stimulation value in a direction that reduces the current and increases the duty ratio in proportion to the excess value.

3. The device for applying electrical stimulation to the vagus nerve according to claim 1, wherein the initial stimulation value setting unit applies the current and duty ratio of the input electrical stimulation guideline as the initial stimulation value when the SPI is equal to or less than the predetermined value.

7. The device for applying electrical stimulation to the vagus nerve according to claim 6 , wherein the demographic indicators include one or more of information on age, sex, BMI, whether or not the subject is taking medication, and whether or not the subject has a disease.

8. The device for applying electrical stimulation to the vagus nerve according to claim 6 , wherein the environmental indicator includes information on one or more of temperature, humidity, illuminance, and discomfort index.

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