Vagus nerve stimulation apparatus and vagus nerve stimulation method

Abstract

The present technology pertains to a vagus nerve stimulation apparatus and a vagus nerve stimulation method capable of easily and appropriately giving electric stimuli to a vagus nerve. A vagus nerve stimulation apparatus according to the present technology is provided with: a first electrode disposed in the vicinity of a stimulation site which is a site at which a vagus nerve of a user is to be stimulated; a second electrode disposed in the vicinity of the stimulation site; and a stimuli control unit for controlling the application of a first electrical signal having a first frequency to the first electrode and the application of a second electrical signal having a second frequency different from the first frequency to the second electrode. The present technology can be applied to, for example, headphones and earphones.

Description

Vagus nerve stimulation device and vagus nerve stimulation method

[0001] The present technology relates to a vagus nerve stimulation device and a vagus nerve stimulation method, and more particularly to a vagus nerve stimulation device and a vagus nerve stimulation method that enable electrical stimulation to be easily and appropriately applied to the vagus nerve.

[0002] Electrical stimulation of the vagus nerve is known to be effective in treating and preventing mental health disorders such as depression. In recent years, it has been claimed that non-invasive vagus nerve stimulation using transcutaneous electrical stimulation activates the parasympathetic nervous system and has the effect of relaxing the body.

[0003] In response to this, for example, a system has been proposed that stimulates the vagus nerve near the ear using electrodes provided in earphones (see, for example, Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2018-535077

[0005] However, when dry electrodes are used as in the invention described in Patent Document 1, the contact impedance between the electrodes and the skin increases, which may prevent sufficient electrical stimulation from being applied. On the other hand, if the electrical stimulation is intensified to provide an appropriate electrical stimulation, problems such as skin inflammation may occur.

[0006] In response to this, it is possible to reduce the contact impedance by using wet electrodes that use physiological saline, etc. However, wet electrodes are difficult to handle, which reduces convenience.

[0007] The present technology has been developed in light of these circumstances, and makes it possible to easily and appropriately apply electrical stimulation to the vagus nerve.

[0008] A vagus nerve stimulation device according to one aspect of the present technology includes a first electrode arranged near a stimulation site that is a site at which a user's vagus nerve is stimulated, a second electrode arranged near the stimulation site, and a stimulation control unit that controls application of a first electrical signal of a first frequency to the first electrode and application of a second electrical signal of a second frequency different from the first frequency to the second electrode.

[0009] A vagus nerve stimulation method according to one aspect of the present technology includes a vagus nerve stimulation device that controls application of a first electrical signal of a first frequency to a first electrode placed near a stimulation site that stimulates a user's vagus nerve, and application of a second electrical signal of a second frequency different from the first frequency to a second electrode placed near the stimulation site.

[0010] In one aspect of the present technology, application of a first electrical signal of a first frequency to a first electrode placed near a stimulation site that stimulates a user's vagus nerve, and application of a second electrical signal of a second frequency different from the first frequency to a second electrode placed near the stimulation site are controlled.

[0011] Fig. 1 is a block diagram showing an embodiment of an information processing system to which the present technology is applied. Fig. 2 is a diagram showing a configuration example of headphones applicable to the present technology. Fig. 3 is a diagram showing an example of electrode arrangement. Fig. 4 is a diagram showing an example of earphones applicable to the present technology. Fig. 4 is a diagram showing an example of electrode arrangement. Fig. 5 is a diagram showing an example of electrode arrangement. Fig. 6 is a flowchart for explaining processing of an information processing system. Fig. 7 is a graph showing an example of waveforms of signals etc. used for electrical stimulation. Fig. 8 is a block diagram showing an example of the configuration of a computer.

[0012] Hereinafter, embodiments of the present technology will be described. The description will be made in the following order: 1. Embodiment 2. Modification 3. Other

[0013] <<1. Embodiment>> <Configuration Example of Information Processing System> FIG. 1 is a block diagram showing an embodiment of an information processing system 1 to which the present technology is applied.

[0014] The information processing system 1 is a system that induces a user to relax by executing a relaxation induction program. The relaxation induction program is a program that induces relaxation by, for example, providing electrical stimulation to the vagus nerve while presenting content that relaxes the user (e.g., music, etc.).

[0015] The information processing system 1 includes a signal processing device 11 and a wearable device 12. The signal processing device 11 and the wearable device 12 perform wired or wireless communication.

[0016] The signal processing device 11 is configured by, for example, a smartphone, a tablet terminal, a personal computer, a music player, etc. The signal processing device 11 plays content to be presented to the user and transmits content data used to output the content to the wearable device 12.

[0017] The wearable device 12 is configured, for example, by a device that is worn by a user and can present content to the user by outputting at least one of an image and a sound. Specifically, the wearable device 12 is configured, for example, by headphones, earphones, a head mounted display (HMD), etc. The wearable device 12 includes a sensing unit 21, a main control unit 22, a stimulus presentation unit 23L, a stimulus presentation unit 23R, and an output unit 24.

[0018] The sensing unit 21 senses a biosignal of the user. The sensing unit 21 includes a biosensor 31 and a signal processing unit 32.

[0019] The biosensor 31 detects a biosignal that can detect a bioindicator used to estimate the user's level of relaxation. For example, the biosensor 31 includes a pulse wave sensor based on the photoplethysmography (PPG) method or the laser-Doppler flowmetry (LDF) method, and detects a pulse wave signal indicating the user's pulse waves as the biosignal. For example, the biosensor 31 includes an electroencephalogram (EEG) sensor, and detects an electroencephalogram signal indicating the user's brain waves as the biosignal. The biosensor 31 supplies the biosignal to the signal processing unit 32.

[0020] The signal processing unit 32 performs predetermined signal processing such as noise removal, amplification, A / D conversion, etc. on the biosignal, and supplies the processed biosignal to the main control unit 22.

[0021] The main control unit 22 is configured by, for example, a microcomputer and controls each unit of the wearable device 12. The main control unit 22 includes a biological index detection unit 41, a stimulation control unit 42, and an output control unit 43.

[0022] The biometric indicator detection unit 41 detects biometric indicators, based on the biometric signals supplied from the sensing unit 21, that are used to estimate the degree of relaxation of the user and measure the effect of the relaxation induction program, for example.

[0023] For example, the bioindex detection unit 41 detects at least one of a sympathetic nervous index and a parasympathetic nervous index (e.g., instantaneous heart rate, heart rate variability index (e.g., RMSSD (Root Mean Square of Successive Difference)) as a bioindex based on the pulse wave signal. For example, the bioindex detection unit 41 detects an electroencephalogram signal index (e.g., alpha wave intensity, theta wave intensity, beta wave intensity) as a bioindex based on the electroencephalogram signal. For example, the bioindex detection unit 41 detects an emotional value (e.g., arousal, valence)) as a bioindex based on at least one of the pulse wave signal or the electroencephalogram signal.

[0024] The stimulation control unit 42 controls the presentation of electrical stimulation by the stimulation presentation units 23L and 23R based on the user's biological indicators and the like.

[0025] The output control unit 43 controls the output of images (moving images or still images) and audio from the output unit 24. For example, the output control unit 43 controls the output of images and audio included in content from the output unit 24 based on content data received from the signal processing device 11. Furthermore, for example, the output control unit 43 controls the presentation of content by the output unit 24 based on a biometric indicator of the user or the like.

[0026] The stimulation presentation unit 23L applies an electrical signal to the user's skin to provide electrical stimulation to the vagus nerve. The stimulation presentation unit 23L includes an oscillator 51aL, an oscillator 51bL, an amplifier 52aL, an amplifier 52bL, an electrode 53aL, an electrode 53bL, an electrode 54aL, and an electrode 54bL.

[0027] The oscillator 51aL oscillates an electric signal of frequency f (hereinafter referred to as electric signal SL1) and supplies it to the amplifier 52aL.

[0028] The amplifier 52aL amplifies the voltage of the electrical signal SL1 and applies the amplified electrical signal SL1 to the electrode 53aL.

[0029] The electrodes 53aL and 54aL are dry electrodes and are placed in contact with the skin near the area where the user's vagus nerve is stimulated (hereinafter referred to as the stimulation area). For example, the electrodes 53aL and 54aL are placed near the user's left ear. The electrode 54aL is connected to ground.

[0030] When the electrical signal SL1 is applied to the electrode 53aL, a voltage due to the electrical signal SL1 is applied between the electrode 53aL and the electrode 54aL. As a result, the electrical signal SL1, which is a current of frequency f, flows from the electrode 53aL to the electrode 54aL via the stimulation site of the user.

[0031] The oscillator 51bL oscillates an electric signal of frequency f+fw (hereinafter referred to as electric signal SL2) and supplies it to the amplifier 52bL.

[0032] The amplifier 52bL amplifies the voltage of the electrical signal SL2 and applies the amplified electrical signal SL2 to the electrode 53bL.

[0033] The electrodes 53bL and 54bL are dry electrodes and are placed in contact with the skin near the same stimulation site as the electrodes 53aL and 54aL. For example, the electrodes 53bL and 54bL are placed near the user's left ear. The electrode 54bL is connected to ground.

[0034] When the electrical signal SL2 is applied to the electrode 53bL, a voltage due to the electrical signal SL2 is applied between the electrode 53bL and the electrode 54bL. As a result, the electrical signal SL2, which is a current having a frequency of f+fw, flows from the electrode 53bL to the electrode 54bL via the stimulation site of the user.

[0035] Then, the electrical signals SL1 and SL2 interfere with each other inside the user's body, and an electrical stimulus of frequency fw due to the interference wave is applied to the vagus nerve at the stimulation site.

[0036] Although not shown in the figure, the stimulation presentation unit 23R has the same configuration as the stimulation presentation unit 23L. That is, the stimulation presentation unit 23R includes an oscillator 51aR, an oscillator 51bR, an amplifier 52aR, an amplifier 52bR, an electrode 53aR, an electrode 53bR, an electrode 54aR, and an electrode 54bR.

[0037] The electrodes 53aR, 53bR, 54aR, and 54bR are dry electrodes and are placed near the user's stimulation site so as to be in contact with the skin. For example, the electrodes 53aR and 54aR are placed near the user's right ear.

[0038] Similar to the stimulation presentation unit 23L, the stimulation presentation unit 23R applies an electrical signal of frequency f (hereinafter referred to as electrical signal SR1) and an electrical signal of frequency f+fw (hereinafter referred to as electrical signal SR2) to the vicinity of the stimulation site. Then, as the electrical signals SL1 and SL2 interfere with each other inside the user's body, an electrical stimulation of frequency fw due to the interference wave is applied to the vagus nerve at the stimulation site.

[0039] The output unit 24 includes various output devices that output at least one of an image and an audio. The output unit 24 outputs at least one of an image and an audio under the control of the output control unit 43. For example, the output unit 24 outputs an image and an audio included in the content received from the signal processing device 11.

[0040] Note that, hereinafter, when there is no need to distinguish between the stimulus presentation units 23L and 23R, they will simply be referred to as the stimulus presentation unit 23. Hereinafter, when there is no need to distinguish between the oscillators 51aL and 51aR, they will simply be referred to as the oscillator 51a. Hereinafter, when there is no need to distinguish between the oscillators 51bL and 51bR, they will simply be referred to as the oscillator 51b. Hereinafter, when there is no need to distinguish between the oscillators 51a and 51b, they will simply be referred to as the oscillator 51. Hereinafter, when there is no need to distinguish between the amplifiers 52aL and 52aR, they will simply be referred to as the amplifier 52a. Hereinafter, when there is no need to distinguish between the amplifiers 52bL and 52bR, they will simply be referred to as the amplifier 52b. Hereinafter, when there is no need to distinguish between the amplifiers 52a and 52b, they will simply be referred to as the amplifier 52.

[0041] Hereinafter, when there is no need to distinguish between electrodes 53aL and 53aR, they will simply be referred to as electrodes 53a. Hereinafter, when there is no need to distinguish between electrodes 53bL and 53bR, they will simply be referred to as electrodes 53b. Hereinafter, when there is no need to distinguish between electrodes 53a and 53b, they will simply be referred to as electrodes 53. Hereinafter, when there is no need to distinguish between electrodes 54aL and 54aR, they will simply be referred to as electrodes 54a. Hereinafter, when there is no need to distinguish between electrodes 54bL and 54bR, they will simply be referred to as electrodes 54b. Hereinafter, when there is no need to distinguish between electrodes 54a and 54b, they will simply be referred to as electrodes 54.

[0042] For example, instead of the electrodes 54aL and 54bL connected to ground, a single electrode 54L may be provided that combines the electrodes 54aL and 54bL. For example, instead of the electrodes 54aR and 54bR connected to ground, a single electrode 54R may be provided that combines the electrodes 54aR and 54bR.

[0043] <Examples of Stimulation Sites> Next, examples of stimulation sites will be described with reference to FIGS.

[0044] FIG. 2 shows a schematic diagram of headphones 101 that can be applied to the wearable device 12.

[0045] The right side of the ear pad 111L for the left ear in the drawing is the front of the ear pad 111L, and the left side of the drawing is the rear of the ear pad 111L. In other words, when a user wears the headphones 101 on their head, the right side of the ear pad 111L in the drawing faces forward, and the left side of the ear pad 111L in the drawing faces rearward.

[0046] Furthermore, the left side of the ear pad 111R for the right ear in the drawing is the front of the ear pad 111R, and the right side of the drawing is the rear of the ear pad 111R. In other words, when the user wears the headphones 101 on their head, the left side of the ear pad 111R in the drawing faces forward, and the right side of the ear pad 111R in the drawing faces rearward.

[0047] Electrodes 53aL to 54bL are arranged below and behind the inner surface of ear pad 111L (the surface that comes into contact with the user's head). Electrodes 53aL and 53bL are arranged side by side in the front-to-back direction. Electrode 53aL is arranged in the front, and electrode 53bL is arranged in the rear. Electrodes 54aL and 54bL are arranged below electrodes 53aL and 53bR side by side in the front-to-back direction. Electrode 54aL is arranged in the rear, and electrode 54bL is arranged in the front.

[0048] Therefore, the path from the electrode 53aL to the electrode 54aL intersects with the path from the electrode 53bL to the electrode 54bL, which makes interference more likely to occur between the electrical signal SL1 flowing from the electrode 53aL to the electrode 54aL and the electrical signal SL2 flowing from the electrode 53bL to the electrode 54bL.

[0049] The electrodes 53aR to 54bR are arranged in the same positions as the electrodes 53aL to 54bL on the inner surface of the ear pad 111R.

[0050] For example, when the user wears the headphones 101, the electrodes 53aR to 54bR come into contact with the vicinity of the mastoid process 122R near the user's right ear 121R, as shown in A and B of Figure 3. This causes the mastoid process 122R to become the stimulation site, and electrical stimulation is applied to it.

[0051] Although not shown in the drawings, electrodes 53aL to 54bL also come into contact with the vicinity of the mastoid process near the user's left ear 121L, similar to electrodes 53aR to 54bR. This causes the mastoid process near the user's left ear 121L to become the stimulation site, and electrical stimulation is applied to it.

[0052] 4 and 5 show examples of the configuration of the earphone 131L and the earphone 131R that can be applied to the wearable device 12. FIG.

[0053] Fig. 4 is a schematic diagram showing the state in which earphone 131L is worn on a user's left ear 121L. Fig. 5A shows an example of the arrangement of electrodes 53 and 54 when earphone 131R is worn on a user's right ear 121R. Fig. 5B is a schematic diagram showing the vicinity of tragus 123R from above when earphone 131R is worn on a user's right ear 121R.

[0054] When the earphone 131R is attached to the user's right ear 121R, the tragus 123R of the right ear 121R is clamped by the earphone 131R, as shown in Fig. 5B. At this time, the electrodes 53aR and 53bR of the earphone 131R contact the outside of the tragus 123R, and the electrode 54R contacts the inside of the tragus 123R.

[0055] As a result, the tragus 123R becomes the stimulation site, and an electrical signal SL1 flows from electrode 53aR to electrode 54R via the tragus 123R, and an electrical signal SL2 flows from electrode 53bR to electrode 54R via the tragus 123R. Then, as the electrical signals SL1 and SL2 interfere with each other at the tragus 123R, an electrical stimulus of frequency fw due to the interference wave is applied to the vagus nerve of the tragus 123R.

[0056] Although not shown, in the user's left ear 121L, as in the right ear 121R, the electrodes 53aL and 53bL of the earphone 131L and the electrode 54L of the earphone 131L come into contact with each other so as to sandwich the tragus of the left ear 121L. This causes the tragus of the left ear 121L to become the stimulation site, causing interference of electrical signals in the tragus of the left ear 121L, and providing electrical stimulation to the vagus nerve in the tragus.

[0057] 5A, the ground electrode 54 may be divided into an electrode 54aR and an electrode 54bR. This also applies to the ground electrode 54 for the left ear.

[0058] For example, the electrodes 53aR and 53bR of the earphone 131R and the electrode 54R of the earphone 131R may sandwich the earlobe 124R (FIG. 6) of the right ear 121R. This causes the earlobe 124R to become the stimulation site, causing interference by electrical signals in the earlobe 124R, and applying electrical stimulation to the vagus nerve near the earlobe 124R.

[0059] Although detailed description will be omitted, the earlobe of the user's left ear 121L may be set as the stimulation site in a similar manner.

[0060] 7A and 7B show an example in which the electrodes 53 and 54 are placed near the auricle 125R of the user's right ear 121R.

[0061] For example, as shown in FIG. 7B, electrodes 53aR and 53bR are placed near the cavity of the concha of the ear 125R, and electrode 54R is placed near the fossa of the concha of the ear 125R.

[0062] As a result, the auricle 125R becomes the stimulation site, and an electrical signal SR1 flows from the electrode 53aR to the electrode 54R via the auricle 125R, and an electrical signal SR2 flows from the electrode 53bR to the electrode 54R via the auricle 125R. Interference between the electrical signals SR1 and SR2 occurs in the auricle 125R, and electrical stimulation is given to the vagus nerve of the auricle 125R.

[0063] Although detailed description will be omitted, the concha of the user's left ear 121L may be set as the stimulation site in a similar manner.

[0064] <Processing of Information Processing System 1> Next, processing of the information processing system 1 will be described with reference to the flowchart of FIG.

[0065] This process is started, for example, when the user operates the signal processing device 11 to instruct the start of a relaxation induction program.

[0066] In step S1, the information processing system 1 starts presenting content.

[0067] Specifically, the signal processing device 11 starts playing the content and transmits the content data to the wearable device 12 .

[0068] In response, the output control unit 43 of the wearable device 12 receives the content data. The output unit 24 starts outputting content based on the content data under the control of the output control unit 43. This starts presenting the content to the user.

[0069] The content to be presented may be automatically selected by the signal processing device 11 or may be selected by the user. The content to be presented may include both images and audio, or may include only one of them.

[0070] In step S2, the wearable device 12 detects a biological indicator. For example, the biological sensor 31 detects a pulse wave signal, which is a biological signal indicating the user's ear pulse wave, using a PPG pulse wave sensor, and supplies the pulse wave signal to the signal processing unit 32.

[0071] The signal processing unit 32 performs predetermined signal processing on the pulse wave signal, such as noise removal, amplification, A / D conversion, etc. The signal processing unit 32 supplies the processed pulse wave signal to the main control unit 22.

[0072] For example, the biometric detector 41 of the main controller 22 detects the user's instantaneous heart rate and heart rate variability index (e.g., RMSSD) based on the pulse wave signal. The biometric detector 41 records the detected instantaneous heart rate and heart rate variability index as the user's biometric index before stimulating the vagus nerve.

[0073] In step S3, the wearable device 12 stimulates the vagus nerve.

[0074] Specifically, under the control of the stimulation control unit 42, the oscillator 51aL oscillates an electrical signal SL1 of frequency f and supplies it to the amplifier 52aL. The amplifier 52aL amplifies the voltage of the electrical signal SL1 and applies the amplified electrical signal SL1 to the electrode 53aL. As a result, a voltage due to the electrical signal SL1 is applied between the electrode 53aL and the electrode 54aL, and the electrical signal SL1, which is a current of frequency f, flows from the electrode 53aL to the electrode 54aL via the stimulation site of the user.

[0075] Under the control of the stimulation control unit 42, the oscillator 51bL oscillates an electrical signal SL2 of frequency f+fw and supplies it to the amplifier 52bL. The amplifier 52bL amplifies the voltage of the electrical signal SL2 and applies the amplified electrical signal SL2 to the electrode 53bL. As a result, a voltage due to the electrical signal SL2 is applied between the electrode 53bL and the electrode 54bL, and the electrical signal SL2, which is a current of frequency f+fw, flows from the electrode 53bL to the electrode 54bL via the stimulation site of the user.

[0076] 9A shows an example of the waveforms of the electric signals SL1 and SL2. The electric signals SL1 (solid line) and SL2 (dotted line) are sine waves with approximately the same amplitude.

[0077] FIG. 9B shows an example of the waveform of an interference signal SL3 generated by interference between the electrical signals SL1 and SL2.

[0078] 9C shows an example of a waveform SL4 of frequency fw indicated by the envelope of the interference signal SL3. The electrical stimulation of the waveform SL4 of frequency fw is applied to the vagus nerve at the stimulation site of the user.

[0079] Under the control of the stimulation control unit 42, the oscillator 51aR oscillates an electrical signal SR1 of frequency f and supplies it to the amplifier 52aR. The amplifier 52aR amplifies the voltage of the electrical signal SR1 and applies the amplified electrical signal SR1 to the electrode 53aR. As a result, a voltage due to the electrical signal SR1 is applied between the electrode 53aR and the electrode 54aR, and the electrical signal SR1 due to a current of frequency f flows from the electrode 53aR to the electrode 54aR via the stimulation site of the user.

[0080] Under the control of the stimulation control unit 42, the oscillator 51bR oscillates an electrical signal SR2 of frequency f+fw and supplies it to the amplifier 52bR. The amplifier 52bR amplifies the voltage of the electrical signal SR2 and applies the amplified electrical signal SR2 to the electrode 53bR. As a result, a voltage due to the electrical signal SR2 is applied between the electrodes 53bR and 54bR, and the electrical signal SR2, which is a current of frequency f+fw, flows from the electrode 53bR to the electrode 54bR via the stimulation site of the user.

[0081] This causes electrical stimulation of frequency fw to be applied to the vagus nerve at the stimulation site of the user.

[0082] By continuing this process for a certain period of time, electrical stimulation is applied to the vagus nerve at the stimulation site of the user for a certain period of time.

[0083] Here, the frequency f is set to, for example, 100 Hz or more. More specifically, the frequency f is set to, for example, around 1 kHz.

[0084] This allows a high-frequency electrical signal to be applied to the stimulation site, reducing the contact impedance between the stimulation site and electrodes 53 and 54. Therefore, electrical stimulation of appropriate intensity can be applied to the user's vagus nerve without increasing the voltage of electrical signals SL1 and SL2. As a result, problems such as skin inflammation are prevented, improving safety.

[0085] The frequency fw is set to, for example, 60 Hz or less. More specifically, the frequency fw is set to, for example, a few Hz to 40 Hz.

[0086] This allows low-frequency electrical stimulation to be applied to the vagus nerve at the stimulation site, enhancing the relaxing effect of the electrical stimulation.

[0087] In step S4, similar to the process in step S2, biomarkers are detected, i.e., the user's biomarkers after vagus nerve stimulation are detected and recorded.

[0088] In step S5, the stimulation control unit 42 determines whether a sufficient relaxation effect is occurring. For example, the stimulation control unit 42 determines whether the bioindicators satisfy a predetermined condition based on at least one of the amount of change in the bioindicators from before stimulation of the vagus nerve and the bioindicators after stimulation of the vagus nerve.

[0089] For example, the stimulation control unit 42 determines whether the instantaneous heart rate has decreased by a certain value or more since before stimulation of the vagus nerve, and whether the RMSSD has increased by a certain value or more since before stimulation of the vagus nerve. For example, if at least one of the conditions is not met, the stimulation control unit 42 determines that a sufficient relaxation effect has not yet occurred, and the process returns to step S3.

[0090] Thereafter, the processes of steps S3 to S5 are repeatedly executed until it is determined in step S5 that a sufficient relaxation effect has been produced.

[0091] On the other hand, in step S5, for example, if the instantaneous heart rate has decreased by more than a certain value since before stimulation of the vagus nerve and the RMSSD has increased by more than a certain value since before stimulation of the vagus nerve, the stimulation control unit 42 determines that a sufficient relaxation effect has occurred, and processing proceeds to step S6.

[0092] In step S6, wearable device 12 stops stimulating the vagus nerve. Specifically, stimulation control unit 42 stops the oscillation of the electrical signal from each oscillator 51. This stops the presentation of electrical stimulation to the vagus nerve.

[0093] In step S7, the information processing system 1 stops presenting the content. Specifically, the output unit 24 stops outputting the content under the control of the output control unit 43. This stops presenting the content to the user. In addition, the output control unit 43 instructs the signal processing device 11 to stop playing the content.

[0094] In response to this, the signal processing device 11 stops the reproduction of the content.

[0095] Thereafter, the processing of the information processing system 1 ends.

[0096] In this way, electrical stimulation can be easily and appropriately applied to the user's vagus nerve. That is, simply by wearing the wearable device 12, the user can percutaneously and non-invasively apply electrical stimulation of an appropriate intensity to the user's vagus nerve. This can relax the user and treat or prevent mental health disorders. Furthermore, problems such as skin inflammation are prevented, improving safety.

[0097] <<2. Modifications>> Modifications of the above-described embodiments of the present technology will now be described.

[0098] <Modifications of the Configuration of Information Processing System 1> The configuration of the information processing system 1 described above is an example, and can be modified as appropriate.

[0099] For example, the signal processing device 11 may be configured to execute part of the processing of the wearable device 12. For example, the signal processing device 11 may be configured to execute part or all of the processing of the main control unit 22 of the wearable device 12.

[0100] For example, the wearable device 12 and the signal processing device 11 may be integrated.

[0101] For example, the wearable device 12 may be configured with multiple devices. For example, the electrodes 53 and 54 may be provided separately from the wearable device 12. In this case, for example, the electrodes 53 and 54 may be connected to the wearable device 12 by a cable or the like. For example, the biosensor 31 may be provided separately from the wearable device 12. In this case, for example, the biosensor 31 may be connected to the wearable device 12 by a cable or the like or wireless communication.

[0102] For example, one or three or more stimulus presentation units 23 may be provided.

[0103] <Modifications Regarding Stimulation Site> For example, the vagus nerve may be stimulated in a site other than the area around the user's ear.

[0104] For example, one or three or more stimulation sites may be set.

[0105] <Other Modifications> The above-described biosignals and bioindicators are merely examples and may be modified as appropriate. For example, two or more types of biosignals may be used.

[0106] The method for determining whether a sufficient relaxation effect is occurring in the process of step S5 in Fig. 8 may be changed as appropriate. Furthermore, the determination conditions may be changed for each user or for each user attribute (e.g., gender, age, height, weight, etc.).

[0107] For example, the stimulation control unit 42 may control the intensity or frequency of the electrical stimulation applied to the vagus nerve by controlling the intensity or frequency of the electrical signal based on the biomarker. For example, if the relaxation effect is low, the electrical stimulation applied to the vagus nerve may be strengthened.

[0108] For example, the output control unit 43 may select content to be presented to the user based on a biological index. For example, if the relaxation effect is low, calmer content may be presented to the user.

[0109] For example, only electrical stimulation may be presented to the user without presenting content.

[0110] The present technology can be applied, for example, to systems and devices that stimulate the vagus nerve in general.

[0111] <<3. Others>> <Example of Computer Configuration> The above-described series of processes can be executed by hardware or software. When the series of processes is executed by software, the programs that make up the software are installed on a computer. Here, the computer includes a computer built into dedicated hardware, and a general-purpose personal computer, for example, that can execute various functions by installing various programs.

[0112] FIG. 10 is a block diagram showing an example of the hardware configuration of a computer that executes the above-described series of processes by a program.

[0113] In the computer 1000 , a CPU (Central Processing Unit) 1001 , a ROM (Read Only Memory) 1002 , and a RAM (Random Access Memory) 1003 are interconnected by a bus 1004 .

[0114] An input / output interface 1005 is further connected to the bus 1004. An input unit 1006, an output unit 1007, a storage unit 1008, a communication unit 1009, and a drive 1010 are connected to the input / output interface 1005.

[0115] The input unit 1006 includes input switches, buttons, a microphone, an image sensor, etc. The output unit 1007 includes a display, a speaker, etc. The storage unit 1008 includes a hard disk, a non-volatile memory, etc. The communication unit 1009 includes a network interface, etc. The drive 1010 drives removable media 1011 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory.

[0116] In the computer 1000 configured as described above, the CPU 1001 performs the above-described series of processes by, for example, loading a program recorded in the memory unit 1008 into the RAM 1003 via the input / output interface 1005 and the bus 1004 and executing it.

[0117] The program executed by the computer 1000 (CPU 1001) can be provided by being recorded on a removable medium 1011 such as a package medium, for example. The program can also be provided via a wired or wireless transmission medium such as a local area network, the Internet, or digital satellite broadcasting.

[0118] In the computer 1000, the program can be installed in the storage unit 1008 via the input / output interface 1005 by inserting the removable medium 1011 into the drive 1010. The program can also be received by the communication unit 1009 via a wired or wireless transmission medium and installed in the storage unit 1008. Alternatively, the program can be installed in the ROM 1002 or the storage unit 1008 in advance.

[0119] The program executed by the computer may be a program that processes in chronological order according to the order described in this specification, or may be a program that processes in parallel or at the required timing, such as when called.

[0120] In this specification, a system refers to a collection of multiple components (devices, modules (components), etc.), regardless of whether all of the components are housed in the same housing. Therefore, multiple devices housed in separate housings and connected via a network, and a single device housed in a single housing with multiple modules, are both systems.

[0121] Furthermore, the embodiments of the present technology are not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present technology.

[0122] For example, the present technology can be configured as a cloud computing system in which a single function is shared and processed collaboratively by a plurality of devices via a network.

[0123] Furthermore, each step described in the above flowchart can be executed by one device, or can be shared and executed by a plurality of devices.

[0124] Furthermore, when one step includes multiple processes, the multiple processes included in that one step can be executed by one device or can be shared and executed by multiple devices.

[0125] <Examples of Combinations of Configurations> The present technology can also have the following configurations.

[0126] (1) A vagus nerve stimulation device including a stimulation control unit that controls application of a first electrical signal of a first frequency to a first electrode placed near a stimulation site that is a site where the user's vagus nerve is stimulated, and application of a second electrical signal of a second frequency different from the first frequency to a second electrode placed near the stimulation site. (2) The vagus nerve stimulation device described in (1), wherein the stimulation control unit controls application of the first electrical signal to the first electrode and application of the second electrical signal to the second electrode based on a biomarker based on a biosignal of the user. (3) The vagus nerve stimulation device described in (2), wherein the biosignal is a pulse wave signal, and the biomarker is a sympathetic nerve index or a parasympathetic nerve index. (4) The vagus nerve stimulation device described in (2), wherein the biosignal is an electroencephalogram signal, and the biomarker is an electroencephalogram signal index. (5) The vagus nerve stimulation device described in (2), wherein the biomarker is an emotional value. (6) The vagus nerve stimulation device according to any one of (2) to (5), further comprising a biosensor that detects the biosignal. (7) The vagus nerve stimulation device according to any one of (2) to (6), further comprising a bioindicator detection unit that detects the bioindicator based on the biosignal. (8) The vagus nerve stimulation device according to any one of (2) to (7), further comprising an output control unit that controls presentation of content to the user based on the bioindicator. (9) The vagus nerve stimulation device according to (8), further comprising an output unit that outputs the content. (10) The vagus nerve stimulation device according to any one of (1) to (9), wherein the first frequency and the second frequency are 100 Hz or more. (11) The vagus nerve stimulation device according to any one of (1) to (10), wherein the difference between the first frequency and the second frequency is 60 Hz or less. (12) The vagus nerve stimulation device according to any one of (1) to (11), wherein the first electrical signal and the second electrical signal are sine waves. (13) The vagus nerve stimulation device according to (12), wherein the stimulation site is stimulated by an interference wave generated by the first electrical signal and the second electrical signal.(14) The vagus nerve stimulation device according to (12) or (13), wherein the first electrical signal and the second electrical signal have approximately the same amplitude. (15) The vagus nerve stimulation device according to any of (1) to (14), wherein the stimulation site is around the ear of the user. (16) The vagus nerve stimulation device according to any of (1) to (15), further comprising the first electrode and the second electrode. (17) The vagus nerve stimulation device according to (16), further comprising a wearable device comprising the first electrode and the second electrode. (18) A vagus nerve stimulation method, comprising: a vagus nerve stimulation device controlling application of a first electrical signal of a first frequency to a first electrode placed in the vicinity of a stimulation site, which is a site at which the vagus nerve of the user is stimulated, and application of a second electrical signal of a second frequency different from the first frequency to a second electrode placed in the vicinity of the stimulation site.

[0127] The effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0128] REFERENCE SIGNS LIST 1 Information processing system, 11 Signal processing device, 12 Wearable device, 21 Sensing unit, 22 Main control unit, 23L, 23R Stimulus presentation unit, 24 Output unit, 31 Biosensor, 32 Signal processing unit, 41 Bioindex detection unit, 42 Stimulus control unit, 43 Output control unit, 51aL to 51bR Oscillator unit, 52aL to 52bR Amplifier unit, 53aL to 53bR, 54aL to 54bR Electrode, 101 Headphones, 131L, 131R Earphones

Claims

1. A vagus nerve stimulation device comprising a stimulation control unit that controls the application of a first electrical signal of a first frequency to a first electrode placed near a stimulation site that stimulates the user's vagus nerve, and the application of a second electrical signal of a second frequency different from the first frequency to a second electrode placed near the stimulation site.

2. The vagus nerve stimulation device of claim 1, wherein the stimulation control unit controls the application of the first electrical signal to the first electrode and the application of the second electrical signal to the second electrode based on a biomarker derived from the user's biosignal.

3. The vagus nerve stimulation device according to claim 2, wherein the biological signal is a pulse wave signal, and the biological index is a sympathetic nerve index or a parasympathetic nerve index.

4. The vagus nerve stimulation device according to claim 2, wherein the biological signal is an electroencephalogram signal, and the biological index is an electroencephalogram signal index.

5. The vagus nerve stimulation device according to claim 2, wherein the biomarker is an emotional value.

6. The vagus nerve stimulation device according to claim 2, further comprising a biosensor for detecting said biosignal.

7. The vagus nerve stimulation device according to claim 2, further comprising a biomarker detection unit that detects the biomarker based on the biosignal.

8. The vagus nerve stimulation device according to claim 2, further comprising an output control unit that controls the presentation of content to the user based on the biometric indicators.

9. The vagus nerve stimulation device according to claim 8, further comprising an output unit for outputting the content.

10. The vagus nerve stimulation device according to claim 1, wherein the first frequency and the second frequency are 100 Hz or higher.

11. The vagus nerve stimulation device according to claim 1, wherein the difference between the first frequency and the second frequency is 60 Hz or less.

12. The vagus nerve stimulation device according to claim 1, wherein the first electrical signal and the second electrical signal are sine waves.

13. The vagus nerve stimulation device according to claim 12, wherein the stimulation site is stimulated by an interference wave generated by the first electrical signal and the second electrical signal.

14. The vagus nerve stimulation device according to claim 12, wherein the first electrical signal and the second electrical signal have substantially the same amplitude.

15. The vagus nerve stimulation device according to claim 1, wherein the stimulation site is around the user's ear.

16. The vagus nerve stimulation device of claim 1, further comprising the first electrode and the second electrode.

17. The vagus nerve stimulation device of claim 16, further comprising a wearable device comprising the first electrode and the second electrode.

18. A vagus nerve stimulation method comprising: a vagus nerve stimulation device controlling application of a first electrical signal of a first frequency to a first electrode placed near a stimulation site that stimulates the user's vagus nerve; and application of a second electrical signal of a second frequency different from the first frequency to a second electrode placed near the stimulation site.

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