Electrical stimulation device, electrical stimulation system, and kit

Abstract

To provide an electrical stimulation device capable of reliably applying stimulation to the arrector pili muscle.SOLUTION: An electrical stimulation device for applying electrical stimulation to the arrector pili muscle comprises an electrode pair arranged on a skin surface, where a current density at a cathode of the electrode pair is in the range from 0.1 mA / cm2 to 100 mA / cm2 inclusive in terms of effective value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to electrical stimulation devices, electrical stimulation systems, and kits. [Background technology]

[0002] Patent Document 1 describes a method for improving aging by activating arrector pili muscle cells through physical stimulation such as stretching of the skin or stimulation by drug treatment. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2021 / 167097 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 does not disclose anything about using electrical stimulation to activate arrector pili muscle cells. Furthermore, even if electrical stimulation is used, setting the conditions for effectively stimulating the arrector pili muscles is more difficult than setting the conditions for physical stimulation such as stretch stimulation, and has not been fully studied until now.

[0005] An object of one aspect of the present disclosure is to provide an electrical stimulation device that can reliably stimulate the arrector pili muscles. [Means for solving the problem]

[0006] One aspect of the present disclosure is an electrical stimulation device that applies electrical stimulation to the arrector pili muscles, the electrical stimulation device comprising an electrode pair that is placed on the skin surface, and a current density at the cathode of the electrode pair that is 0.1 mA / cm in effective value. 2 More than 100mA / cm 2 The following is the result. [Effects of the Invention]

[0007] According to one aspect of the present disclosure, an electrical stimulation device capable of reliably stimulating the arrector pili muscles can be provided. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of an electrical stimulation device according to one embodiment of the present disclosure. [Figure 2] FIG. 1 is a schematic diagram of an electrical stimulation system according to one embodiment of the present disclosure. [Figure 3] 10 is a graph showing the effect of pain reduction by transcutaneous electrical stimulation in Experiment 2. [Figure 4] 10 is a graph showing the NRS grades (original standard) felt by subjects in Experiment 2 in response to electrical stimulation. [Figure 5] 1 is a graph showing the relationship between the conductance of the stratum corneum and the minimum amount of current required to induce goosebumps, obtained in Experiment 3. [Figure 6] 1 is a graph showing the relationship between the capacitance of the stratum corneum and the minimum amount of current required to induce goosebumps, obtained in Experiment 3. [Figure 7] 10 is a graph showing the relationship between the DC resistance of the skin application agent and the minimum amount of current required to induce goosebumps, obtained in Experiment 4. [Figure 8] 1 is a graph showing the goosebump-inducing effect of applying a skin application agent in Experiment 4. [Figure 9] Photograph of the electrical stimulation system used in Experiment 6. [Figure 10] 10 is a graph showing the relationship between the duration of continuous use and the height of goosebumps, obtained in Experiment 6. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described. In the accompanying drawings, unless otherwise specified, the same or corresponding components will be denoted by the same reference numerals and the description thereof will be omitted.

[0010] The arrector pili muscles are involuntary muscles whose main function is to make hair stand on the surface of the skin. It is known that weakening of these muscles is related to skin sagging, elasticity, etc. The inventors adopted electrical stimulation, which had not been thoroughly studied until now, as a means of training the arrector pili muscles, and further conducted various studies on the conditions for stimulating the arrector pili muscles. As a result, they found a means that can reliably apply electrical stimulation to the arrector pili muscles, and further found a means that can reliably apply stimulation to the arrector pili muscles with reduced or no pain.

[0011] First Embodiment One embodiment of the present disclosure is an electrical stimulation device that applies electrical stimulation to the arrector pili muscles, the electrical stimulation device including an electrode pair that is placed on the skin surface, and a current density at the cathode of the electrode pair that is 0.1 mA / cm in effective value. 2 More than 100mA / cm 2 The following is the result.

[0012] Fig. 1 shows a schematic diagram of an electrical stimulation device according to a first embodiment. As shown in Fig. 1, the electrical stimulation device 1 includes an electrical stimulation generator 10 and an anode 11 and a cathode 12 (hereinafter, collectively referred to as an electrode pair or a first electrode pair) that are placed in contact with the skin. The electrical stimulation generator 10 may be either a constant-current electrical stimulation device or a constant-voltage electrical stimulation device, but a constant-current electrical stimulation device capable of outputting a constant current is preferred from the standpoints of ease of output adjustment and safety. An example of the electrical stimulation generator 10 is the DS7R manufactured by Digitimer Ltd.

[0013] Both the anode 11 and the cathode 12 may be any electrode that can be placed in contact with the skin, and are preferably adhesive gel-type electrodes that can be attached in close contact with the skin. However, in order to adjust the current density (described in detail later), the cathode 12 may be a rod-shaped electrode that can reduce the electrode area. In the case of non-adhesive electrodes, it is preferable to provide an attachment means such as tape for attaching the electrode.

[0014] The device of this embodiment applies electrical stimulation from the skin surface. The electrical stimulation can be applied to any part of the body where stimulation of the arrector pili muscles is desired. The part to which electrical stimulation is applied may be, for example, the face, scalp, neck, décolleté, arms, legs, hands, etc. Since the face is an area where many people are concerned about sagging and loss of elasticity, the satisfaction of the patient is high when facial sagging and other issues are improved by electrical stimulation. Therefore, the device of this embodiment is particularly suitable as a device for applying electrical stimulation to the face.

[0015] The determination of whether the device of this embodiment has stimulated the arrector pili muscles is made by visually observing the induction of goosebumps on the skin surface (the formation of goosebumps) or the standing of hair on the skin surface. However, since there are areas on the skin of the body that are hairless or have no noticeable hair, it is preferable to determine that the induction of goosebumps has been reliably stimulated, that is, that sufficient stimulation has been applied to target the arrector pili muscles. When an electrode pair is placed on the skin and electrical stimulation is applied, the area that stimulates the arrector pili muscles is mainly around the cathode, so the above visual observation is made around the cathode.

[0016] The electrical stimulation applied by the device of this embodiment is preferably a pulse wave from the viewpoint of safety. The pulse wave may be a monophasic pulse wave or a biphasic pulse wave. However, a monophasic pulse wave is preferred because it can stimulate the arrector pili muscles over a wide area of ​​the skin and can apply a large amount of direct current. A biphasic pulse wave is preferred because it is perceived as a milder stimulation, reduces pain, and reduces the amount of direct current applied. The waveform of the electrical stimulation is preferably a rectangular wave, but may also be a triangular wave, a sine wave, or the like.

[0017] In the device of this embodiment, the effective value is 0.1 mA / cm 2 More than 100mA / cm 2 Electrical stimulation was applied at the following current density: the effective current density was 0.1 mA / cm 2 This ensures that electrical stimulation can be applied to the arrector pili muscles reliably, and the current density is 100mA / cm 2The safety of the treatment is ensured by keeping the effective current density below 50 mA / cm. 2 Less than 20 mA / cm, preferably 2 Less than or equal to 10 mA / cm, more preferably 10 mA / cm 2 Less than 7mA / cm, more preferably 2 Less than 2.5 mA / cm, more preferably 2 By setting the effective current density at the upper limit, pain during treatment can be reduced. Note that the effective current density is 2.5 mA / cm or less. 2 If the voltage is less than this, it is highly safe and preferable for electrical stimulation of body parts above the neck.

[0018] The current density is the value obtained by dividing the amount of current by the electrode area, and the effective value of the current density is the value obtained by dividing the effective value of the amount of current by the electrode area. As described above, the area in which the arrector pili muscles are stimulated by the application of electrical stimulation is mainly around the cathode, so the electrode area is the electrode area of ​​the cathode. The electrode area is also the area in which the electrode comes into contact with the skin.

[0019] The effective value of the current (pulse DC current value) can be calculated using the following formula: I RMS =√{T ON / (T ON +T OFF )}*I PULSE I RMS : Effective value of current (mA) I PULSE : Peak current (mA) T ON : Time during which current flows per pulse (s) T OFF : Time without current per pulse (s) T ON is equal to the pulse width, and T OFF is the reciprocal of the frequency. Therefore, for example, if the frequency is 20 Hz and the pulse width is 8 ms, the peak current (I PULSE ) is 0.25mA, the effective value of the current I RMS becomes 0.1mA.

[0020] The effective value of the current may be preferably 0.01 mA or more and 50 mA or less, more preferably 0.05 mA or more and 25 mA or less, even more preferably 0.1 mA or more and 20 mA or less, and even more preferably 0.7 mA or more and 10 mA or less. By setting the effective value of the current to 0.01 mA or more, sufficient electrical stimulation can be applied to the arrector pili muscles. Furthermore, by setting the effective value of the current to 50 mA or less, pain during treatment can be reduced. Note that an effective value of the current to 25 mA or less is highly safe for electrical stimulation of body parts above the neck, and is therefore preferable.

[0021] The area of ​​the cathode is preferably 1 mm 2 More than 100mm 2 The area of ​​the cathode may be 1 mm or less. 2 By setting the cathode area to 100mm or more, an excessive increase in current density can be avoided and safety can be ensured. 2 By setting the area of ​​the cathode to 10 mm or less, sufficient electrical stimulation can be given to the arrector pili muscles. 2 More preferably, 30 mm 2 More preferably, 50 mm 2 By setting the upper limit of the area of ​​the cathode as described above, pain during treatment can be reduced.

[0022] The frequency of the electrical stimulation applied to the skin may be preferably 1 Hz or more and 200 Hz or less, more preferably 5 Hz or more and 150 Hz or less, even more preferably 10 Hz or more and 100 Hz or less, and even more preferably 25 Hz or more and 90 Hz or less. By setting the frequency to 1 Hz or more, sufficient electrical stimulation can be applied to the arrector pili muscles. Furthermore, by setting the frequency to 200 Hz or less, electrical stimulation can be reliably applied to the arrector pili muscles in the skin, and pain during treatment can be reduced. Note that a frequency of less than 100 Hz, more preferably 90 Hz or less, is preferable because high reproducibility can be obtained (goosebumps can be stably induced).

[0023] The distance between the electrodes, i.e., the shortest distance between the anode 11 and the cathode 12, may be preferably 1 mm or more and 45 mm or less, more preferably 3 mm or more and 40 mm or less, and even more preferably 5 mm or more and 30 mm or less. By making the distance between the electrodes 1 mm or more, contact between the electrodes can be prevented even if the skin on which the electrodes are placed moves. Furthermore, by making the distance between the electrodes 45 mm or less, and particularly 30 mm or less, electricity flows to a more appropriate depth below the skin surface, allowing for more sufficient electrical stimulation to be applied to the arrector pili muscles rather than the muscles below the skin. From the perspective of reducing pain during treatment, a distance between the electrodes of 28 mm or more is preferred.

[0024] The pulse width of the applied pulse wave may be preferably 10 μs or more and 10,000 μs or less. A pulse width in this range enables more reliable electrical stimulation of the arrector pili muscles.

[0025] Furthermore, the pulse wave has an On time (time during which current flows) and an Off time (time during which current does not flow). In this embodiment, the On time may be approximately 0.05 seconds or more and 2 seconds or less, and the Off time may be approximately 0.5 seconds or more and 3 seconds or less. It is preferable that the On time is shorter than the Off time. In this specification, the On time and Off time are referred to as On-Off time, and may be expressed together as "(On time) / (Off time)". For example, if the On time is 1 second and the Off time is 2 seconds, it is expressed as "1 / 2".

[0026] The electrical stimulation used in this embodiment does not have to have a wave with an On time and an Off time as described above, but may have a form in which the On time continues throughout the treatment time on the skin.

[0027] In this embodiment, the voltage that generates the electrical stimulation applied to the skin may be 1V or more and 100V or less.

[0028] When the first embodiment is provided as a device for applying electrical stimulation to the face, it is preferable to make electrical stimulation device 1 small and portable. Furthermore, electrical stimulation device 1 (including electrical stimulation generator 10, electrodes 11 and 12, and wires connecting the two) may be housed in a single housing, with the surfaces of electrodes 11 and 12 that are attached to the skin exposed from the housing. In this case, electrical stimulation system 100 can be provided as a product that a user can press against their face to apply electrical stimulation to the skin of their face.

[0029] Second Embodiment Although the first embodiment described above is a form in which an electrostimulation device is used alone, it is also possible to construct an electrostimulation system that includes an additional electrostimulation device in addition to the electrostimulation device.

[0030] Therefore, the second embodiment may be an electrical stimulation system that includes an electrical stimulation device having a first electrode pair that applies electrical stimulation to the arrector pili muscles, and an additional electrical stimulation device having a second electrode pair that applies electrical stimulation for pain relief, wherein the first electrode pair is arranged side by side on the skin surface, and the second electrode pair is arranged on the skin surface so as to sandwich the first electrode pair.

[0031] Fig. 2 schematically illustrates an electrical stimulation system 100 according to a second embodiment. The electrical stimulation system 100 shown in Fig. 2 includes an additional electrical stimulation device 2 that applies an electrical stimulation different from that of the electrical stimulation device 1 and that acts to reduce the electrical stimulation provided by the electrical stimulation device 1, in addition to the electrical stimulation device 1 of the first embodiment described with reference to Fig. 1. The configuration and operating conditions of the electrical stimulation device 1 may be the same as those described in the first embodiment.

[0032] As shown in Figure 2, additional electrical stimulation device 2 includes additional electrical stimulation generator 20, and anode 21 and cathode 22 (hereinafter collectively referred to as an electrode pair or second electrode pair) that are placed in contact with the skin. Additional electrical stimulation generator 20 is not particularly limited as long as it is a device that can apply transcutaneous electrical nerve stimulation (TENS) used in physical therapy. Examples of common EMS (Electrical Muscle Stimulation) devices include the iStim series manufactured by Medical Instruments Co., Ltd.

[0033] Both the anode 21 and the cathode 22 may be any electrode that can be placed in contact with the skin, and are preferably adhesive gel-type electrodes that can be attached in close contact with the skin. The anode 21 and the cathode 22 of the additional electrical stimulation device 2 may be identical to each other. As shown in FIG. 2, the second electrode pair (anode 21 and cathode 22) of the additional electrical stimulation device 2 is preferably placed spaced apart from the first electrode pair (anode 11 and cathode 12) of the electrical stimulation device 1, sandwiching the first electrode pair. In this case, the electrode of the second electrode pair adjacent to the cathode 12 of the first electrode pair is preferably placed at a distance of 1 mm or more from the cathode 12. Furthermore, the second electrode pairs are preferably placed at a distance of 5 mm or more and 300 mm or less.

[0034] The additional electrical stimulation device 2 may be operated so as to overlap with the operation of the electrical stimulation device 1, but it is preferable to start operation simultaneously with the operation of the electrical stimulation device 1 and end operation simultaneously with the end of the operation of the electrical stimulation device 1. The pain-relieving effect of applying transcutaneous electrical stimulation (TENS) is known in the field of physical therapy, but until now, there has been insufficient knowledge about the use of transcutaneous electrical stimulation (TENS), which is the same electrical stimulation, to relieve pain caused by electrical stimulation of the arrector pili muscles. This disclosure has shown that applying transcutaneous electrical stimulation (TENS) using the additional electrical stimulation device 2 can effectively reduce pain caused by electrical stimulation applied by the electrical stimulation device 1. For example, compared to 100% pain when using the electrical stimulation device 1 alone, pain can be reduced to 60% or less, preferably 30% or less. Note that pain can be assessed using, for example, a numeric rating scale (NRS).

[0035] The transcutaneous electrical stimulation (TENS) applied by the additional electrical stimulation device 2 in this embodiment is preferably a stimulation applied to induce muscle contraction. Stimulation that induces muscle contraction is more effective in reducing pain caused by stimulation by the electrical stimulation device 1 than stimulation that induces muscle contraction. The transcutaneous electrical stimulation (TENS) may be a constant voltage stimulation. The additional electrical stimulation device 2 can apply stimulation under conditions of, for example, 1 V to 100 V and a current of 0.1 mA to 100 mA. The frequency of the transcutaneous electrical stimulation (TENS) may be preferably 2 Hz to 200 Hz, more preferably 10 Hz to 150 Hz, and even more preferably 20 Hz to 100 Hz. Applying additional transcutaneous electrical stimulation at a frequency within the above range more effectively reduces pain caused by electrical stimulation of the arrector pili muscles by the electrical stimulation device 1.

[0036] When the second embodiment is provided as a system for applying electrical stimulation to the face, it is preferable that electrical stimulation device 1 and additional electrical stimulation device 2 are integrated into one unit, and furthermore, made compact and portable. Electrical stimulation device 1 (including electrical stimulation generator 10, electrodes 11, 12, and wires connecting them) and additional electrical stimulation device 2 (including additional electrical stimulation generator 20, electrodes 21, 22, and wires connecting them) may be housed in a single housing, with the skin-attaching surfaces of electrodes 11, 12, 21, 22 exposed from the housing. In this case, electrical stimulation system 100 can be provided as a product that a user can press against their face to apply electrical stimulation to their facial skin.

[0037] Third Embodiment

[0038] The electrical stimulation system 100 according to the second embodiment described above reduces pain caused by electrical stimulation by using the additional electrical stimulation device 2, even with the same amount of current. However, if electricity can be made to flow more easily to the arrector pili muscles, the arrector pili muscles can be sufficiently stimulated with a small amount of current, making it possible to perform treatment with little or no pain. To achieve this, the inventors have investigated a means for making it easier for electricity to flow to the arrector pili muscles.

[0039] It has been empirically known that goosebumps are more likely to be induced in the summer when the skin is sweaty. Therefore, it is generally believed that the presence of a liquid such as sweat on the skin surface, which increases the conductivity of the skin surface (reduces electrical resistance), makes it easier for electricity to flow to the arrector pili muscles. Based on this knowledge, it was predicted that applying a highly conductive skin liniment to the skin surface would promote electrical stimulation of the arrector pili muscles, and even a small amount of current would effectively stimulate the arrector pili muscles (effectively induce goosebumps). However, contrary to this prediction, the inventors have found that the lower the conductivity of the skin liniment applied to the skin surface, i.e., the higher the insulating property, the smaller the minimum current required to induce goosebumps.

[0040] Therefore, a third embodiment of the present disclosure is a kit including an electrical stimulation device that applies electrical stimulation to the arrector pili muscles and has an electrode pair that is placed on the skin surface, and a highly insulating skin application agent that is applied to the skin surface.

[0041] The configuration and operating conditions of the electrical stimulation device may be the same as those described in the first embodiment. In the third embodiment, an electrical stimulation device 1 (FIG. 1) is combined with a highly insulating skin liniment to be applied to the skin surface. When the highly insulating skin liniment is applied to the skin surface using the kit according to the third embodiment and an electrode pair is placed so as to overlap the applied area, electrical stimulation can be applied to the arrector pili muscles with a small amount of current, thereby reducing pain caused by the electrical stimulation.

[0042] In this specification, "high insulation" refers to insulation that can reduce pain compared to when the skin application agent is not applied to the skin surface, and may refer to insulation with a DC resistance of 500 Ω or more. The DC resistance of the skin application agent may be preferably 800 Ω or more, more preferably 1,000 Ω or more, and even more preferably 2,000 Ω or more. When the DC resistance of the skin application agent is above this value, pain during application of electrical stimulation can be further reduced. Furthermore, the upper limit of the DC resistance of the skin application agent is not particularly limited, but may be 30,000 Ω or less.

[0043] The skin application agent is not particularly limited as long as it has the above-mentioned high insulating properties, is applicable to human skin, and is in a form that can be spread over the skin surface. Furthermore, the skin application agent may be an oil-based agent mainly composed of oily components, a water-based agent mainly composed of aqueous components, or an emulsion-based agent composed of a blend of oily and aqueous components. The emulsion-based agent may be emulsified by the addition of an emulsifier or may not contain an emulsifier, and may be either a water-in-oil type or an oil-in-water type. Furthermore, the skin application agent may contain a solid component such as a powder. The skin application agent may be, for example, a cosmetic such as a lotion, emulsion, or serum, a personal care product (daily hygiene product), or a base used for a cosmetic or personal care product (hereinafter also referred to as a cosmetic base). As cosmetic bases, oily bases such as hydrocarbon oils, silicone oils, ester oils, etc. are preferred from the viewpoint of high insulating properties. Specific examples include petrolatum, isododecane, squalane, squalene, dimethicone, olive fruit oil, coconut oil, and horse oil. The above skin application agents can be used alone or in combination of two or more. Skin application agents that are less likely to penetrate the skin are more effective at lowering the minimum current required to induce goosebumps, i.e., at reducing pain during electrical stimulation of the arrector pili muscles.

[0044] The skin application agent is preferably applied to an area including the position where the electrode pair (anode 11 and cathode 12) of electrical stimulation device 1 will be placed, overlapping the area. The highly insulating skin application agent is in contact with both anode 11 and cathode 12, which is thought to prevent electricity from flowing to the very surface of the skin and allow electricity to flow more easily to the dermis where the arrector pili muscles are located, making it easier for electrical stimulation to reach the arrector pili muscles.

[0045] While preferred embodiments of the present disclosure have been described above as the first to third embodiments, these embodiments or the features included in these embodiments can be combined in any manner. For example, as the second embodiment, an electrical stimulation system 100 including an electrical stimulation device 1 and an additional electrical stimulation device 2 has been described. When using such an electrical stimulation system 100, the highly insulating skin application agent described in the third embodiment may be used in combination.

[0046] <Electrical stimulation method> Furthermore, one embodiment of the present disclosure is a method for applying electrical stimulation to the arrector pili muscles using an electrical stimulation device including a pair of electrodes, the pair of electrodes being placed on a skin surface, and a current density of 0.1 mA / cm at the cathode of the electrode pair. 2 More than 100mA / cm 2 and applying electrical stimulation to the subject, the electrical stimulation being:

[0047] Another embodiment of the present disclosure is a method for applying electrical stimulation to the arrector pili muscles using an electrical stimulation system including an electrical stimulation device having a first electrode pair that applies electrical stimulation to the arrector pili muscles, and an additional electrical stimulation device having a second electrode pair that applies electrical stimulation for pain relief, the electrical stimulation method including placing the first electrode pair side by side on the skin surface and placing the second electrode pair on the skin surface so as to sandwich the first electrode pair.

[0048] Yet another embodiment of the present disclosure is a method for applying electrical stimulation to the arrector pili muscles using an electrical stimulation device equipped with a pair of electrodes, the electrical stimulation method including applying a highly insulating skin application agent to the skin surface and positioning the pair of electrodes so as to overlap the applied area. [Example]

[0049] [Experiment 1: Examination of electrical stimulation conditions I] (Example 1-1 to Example 1-3) In Experiment 1, a square-wave constant current was applied to the subject's skin to evaluate whether goosebumps were induced and the pain felt by the subject. This experiment used a device with a configuration similar to that of the electrical stimulation device 1 shown in Figure 1. The electrical stimulation generator 10 was a constant-current electrical stimulation generator (DS7R, manufactured by Digitimer Ltd.), the anode 11 was an adhesive gel-type electrode (Vitrode F, 25 cm x 45 cm, manufactured by Nihon Kohden Corporation), and the cathode 12 was a rod-shaped electrode (cylindrical, 1 mm diameter x 10 mm length, manufactured by Unique Medical Co., Ltd.). The experiment was conducted using this electrical stimulation device in a constant temperature and humidity environment of 24 ± 1°C and 45 ± 2% humidity. Two subjects (Nos. 1 and 2) were tested, and the test site was the outer forearm of subject S. The cathode was soaked in lotion and then applied to the skin, secured in place with surgical tape.

[0050] The frequency, pulse width, on-off time, inter-electrode distance, electrode area (cathode area), waveform, etc. were set to the conditions shown in Table 1, and electrical stimulation was applied to the subject's skin. As shown in Table 1, experiments were conducted at different frequencies for each example. In each of the tables below, unless otherwise specified, "current amount" refers to the peak current amount indicated by the electrical stimulation device, and "current density" refers to the current density calculated from the peak current amount.

[0051] The evaluation was carried out as follows: <Goosebump induction evaluation> The area around the cathode was visually observed to confirm whether goosebumps were induced during electrical stimulation. During observation, the room lights were turned off and an LED light (double-arm LED lighting device PF-D (XR9457), manufactured by Carton Optical Co., Ltd.) was used to illuminate the area where electrical stimulation was being administered from an oblique angle. Evaluation was based on the following criteria. ○: I was able to definitely confirm that I was getting goosebumps. △: It was confirmed that goosebumps were generated, but the goosebumps were only slightly raised. ×: No goosebumps were observed.

[0052] <Pain assessment> Subjects were asked about pain during electrical stimulation and were asked to respond to which of the following statements applied to them: ◎: It doesn't hurt. 〇: The pain is not too severe and is tolerable. △: I feel a strong pain, but it's tolerable. △ - The pain is quite strong, but manageable. ×: The pain is unbearable. Of the above ratings, ◎~△ - Therefore, even if the experiment did not employ a means to reduce pain, it is highly likely that a pain-free or almost pain-free use form can be realized by, for example, using additional electrical stimulation (TENS; transcutaneous electrical stimulation) and / or applying a skin application agent.

[0053] [Table 1]

[0054] From Table 1, it was found that goosebumps were induced in all of Examples 1-1 to 1-3, that is, the arrector pili muscles were reliably stimulated. When only the frequency was changed, the amount of current decreased as the frequency increased, but as shown in Table 1, it was found that goosebumps could be induced with a small amount of current if the frequency was high.

[0055] (Example 2-1 to Example 2-12) The experiment was carried out in the same manner as in Example 1-1 above, except that the conditions were changed as shown in Table 2. As shown in Table 2, in each example, electrical stimulation was applied at a different inter-electrode distance.

[0056] [Table 2]

[0057] From Table 2, it was found that goosebumps were induced in all of Examples 2-1 to 2-12, but goosebumps were more reliably induced in Examples 2-1 to 2-8, where the inter-electrode distance was 25 mm or less. Furthermore, pain was reduced in Examples 2-1 to 2-8. This is thought to be because the increased inter-electrode distance allows electricity to flow more easily to deeper layers, reducing the density of the current flowing through the Aδ fibers present in the superficial layers.

[0058] (Example 3-1 to Example 3-7) The experiment was conducted in the same manner as in Example 1-1 above, except that the conditions were changed as shown in Table 3. As shown in Table 3, electrical stimulation was applied using a biphasic pulse wave with a different current amount in each example.

[0059] [Table 3]

[0060] From Table 3, it was found that goosebumps were induced in all of Examples 3-1 to 3-7. In other words, it was confirmed that goosebumps can be induced even with biphasic pulse waves. However, the area where goosebumps were induced (skin area) was smaller than in another experimental example using monophasic pulse waves under the same conditions except for the waveform. Furthermore, although pain occurred in all cases, it was tolerable.

[0061] (Example 4-1 to Example 4-2) The experiment was carried out in the same manner as in Example 1-1 above, except that the conditions were changed as shown in Table 4. As shown in Table 4, electrical stimulation was applied with different pulse widths in each example.

[0062] [Table 4]

[0063] From Table 4, it was found that goosebumps were induced in both Examples 4-1 and 4-2. However, the pain was strong under all conditions, and changing the pulse width did not have much effect on the pain. For example, the pulse width in Example 4-1 was one-tenth of the pulse width in Example 4-2, but in that case the amount of current was ten times greater, so it is thought that reducing the pulse width would not contribute to pain reduction.

[0064] (Example 5-1 to Example 5-4) An experiment was conducted in the same manner as in Example 1-1 above, except that the conditions were changed as shown in Table 5. As shown in Table 5, the on time (time during which the current flows) of the on / off current was changed in each example. Note that in Examples 5-1 to 5-4, a biphasic pulse wave stimulation was used.

[0065] [Table 5]

[0066] Table 5 shows that goosebumps were induced in all of Examples 5-1 to 5-4. However, in Examples 5-2 to 5-4, where the On time was less than 1 second, the area (skin area) where goosebumps were induced was smaller than in Example 5-1. In addition, the pain was rated as being tolerable in all cases, and no reduction in pain was observed by changing the On time under the conditions in Table 5.

[0067] (Example 6-1 to Example 6-4) An experiment was carried out in the same manner as in Example 1-1 above, except that the conditions were changed as shown in Table 6. As shown in Table 6, the electrode area was changed in each example.

[0068] [Table 6]

[0069] From Table 6, it was found that goosebumps were induced under all conditions of Examples 6-1 to 6-3. It was also found that pain was reduced in Examples 6-1 and 6-2, which had smaller electrode areas and therefore smaller current densities.

[0070] [Experiment 2: Examination of pain relief by additional electrical stimulation] In Experiment 2, we investigated the extent to which additional electrical stimulation could reduce pain caused by electrical stimulation of the arrector pili muscles. Six subjects (No. 1 to No. 6) were recruited, consisting of three men and three women aged 25 to 60. In this experiment, an electrical stimulation system similar to the electrical stimulation system 100 shown in Figure 2 was used. Specifically, the electrical stimulation device 1 used in Experiment 1 was installed, and an additional electrical stimulation device 2 was also installed. The additional electrical stimulation device included an EMS (Electrical Muscle Stimulation) device (iStim EV-804, manufactured by Ikukawa Instruments Co., Ltd.) as the additional electrical stimulation generator 20, and adhesive gel-type electrodes (Vitrode F150M, 25 cm x 45 cm, manufactured by Nihon Kohden Corporation) as the anode 21 and cathode 22. As shown in FIG. 2, anode 21 and cathode 22 of additional electrical stimulation device 2 were attached so as to sandwich anode 11 and cathode 12 of electrical stimulation device 1, but spaced apart from anode 11 and cathode 12, respectively.

[0071] First, using only the electrical stimulation device used in "Experiment 1," a constant current was passed through the subject's skin under the same conditions as in Example 1-1 above (waveform: square wave, stimulation waveform: monophasic pulse wave, pulse width: 500 μs, on time: 1 s / off time: 2 s, frequency: 20 Hz, inter-electrode distance: 20 mm). The current was gradually increased, and the current at which goosebumps were induced was recorded for each subject.

[0072] Next, transcutaneous electrical nerve stimulation (TENS) was applied by additional electrical stimulator 2 at the current level required to induce goosebumps, for the duration of the constant current applied by electrical stimulator 1. The applied transcutaneous electrical stimulation current level varied slightly depending on the subject, but was sufficient to induce mild muscle contraction. More specifically, the peak current was approximately 35 mA and the voltage was approximately 20 V (a level of strength that induces muscle contraction). The transcutaneous electrical stimulation was administered at two frequencies: 20 Hz and 100 Hz, and the pain-reducing effect was evaluated for each case.

[0073] <Evaluation of pain relief> In this experiment, a numeric rating scale (NRS) was used to evaluate pain relief. Specifically, the amount of current was gradually increased using only the electrical stimulation device 1, and the pain when goosebumps were induced was graded on an 11-point NRS scale from 0 to 10, with "10" representing pain and "0" representing no pain. The amount of current when goosebumps were induced varied between subjects, ranging from 2.0 to 6.5 mA.

[0074] Next, subjects were asked to rate the pain they felt when transcutaneous electrical stimulation (TENS) was administered using the additional electrical stimulator 2. The subjects were asked to rate both their left and right forearms, and the NRS ratings were averaged to determine the subject's pain grade. R was used as the statistical language, and analysis was performed using the nonparametric Steel-Dwass algorithm. Significant differences were p<0.05. Figure 3 shows the results of the pain reduction evaluation.

[0075] As shown in Figure 3, transcutaneous electrical stimulation (TENS) was found to significantly reduce goosebump-induced pain. In particular, 100 Hz TENS stimulation significantly reduced pain compared with 20 Hz TENS stimulation.

[0076] While the above evaluation was based on a comparison between the presence and absence of TENS, we also examined the pain level (according to the original standard) when the subjects' NRS grade was set to "10" as the worst pain they had ever experienced in their lives. To do so, we asked the subjects to evaluate the pain when goosebumps were induced using only the electrical stimulation device 1, i.e., by increasing the current without TENS. The results are shown in Figure 4. As shown in Figure 4, the NRS grade for pain when goosebumps were induced without TENS varied among subjects, but ranged from 3 to 5. Furthermore, Figure 3 indicates that pain was reduced by approximately 70% when 100 Hz TENS was administered. Therefore, based on Figures 3 and 4, it can be inferred that pain when 100 Hz TENS was administered would be approximately NRS grade "1" according to the original standard (where "10" represents the worst pain experienced in one's life).

[0077] [Experiment 3: Investigation of goosebump induction by application of skin lining I] In Experiment 3, we investigated the relationship between the electrical properties (conductance and capacitance) of the stratum corneum after application of the skin ointment and the amount of current required to induce goosebumps. The following skin ointment samples were used: Skin application agent A1: Lotion Skin application agent A2: Lotion Skin application agent A3: emulsion Skin application agent A4: Cream Skin application agent A5: Cream Skin application agent A6: Base (cosmetic petrolatum; Vaseline P, manufactured by Nikko Rica Corporation) Skin application agent A7: Cream Skin application agent A8: Cream ·Skin liniment A9: Emulsion The outer side of the subject's forearm was washed with soap and allowed to dry for approximately 10 minutes in a constant temperature and humidity environment (24°C, 45%). A thin layer of skin liniment was then applied evenly to the area where the cathode and anode would be attached, overlapping the area. Specifically, approximately 20 μL of the skin liniment was applied if it was a lotion or emulsion, and approximately one micro-spatulaful was applied if it was a cream or base. Ten minutes after application of the skin liniment, immediately before the application of the electrical stimulation described below, the conductance of the stratum corneum was measured using a stratum corneum moisture content measuring device (Skicon-200EX, Yayoi Co., Ltd.) and the capacitance was measured using a skin measuring device (Corneometer, Courage+Khazaka electronic GmbH).

[0078] Ten minutes after application of the skin application agent, electrical stimulation was applied to the skin using the electrical stimulation device used in "Experiment 1" under the same conditions as in Example 1-1 above (waveform: square wave, stimulation waveform: monophasic pulse wave, pulse width: 500 μs, on time: 1 s / off time: 2 s, frequency: 20 Hz, electrode distance: 20 mm). However, the cathode of the electrical stimulation device was placed on the skin without applying lotion. The current was gradually increased, and the current when goosebumps were induced was recorded. The experiment was conducted on the outer sides of both the left and right forearms of two subjects, and the measured values ​​were averaged.

[0079] Figure 5 shows a graph in which the horizontal axis represents stratum corneum conductance and the vertical axis represents the amount of current required to induce goosebumps. As shown in Figure 5, there was a significant (p<0.01) strong positive correlation between stratum corneum conductance and the amount of current. This indicates that applying a skin ointment with the property of reducing stratum corneum conductance can reduce the amount of current required to induce goosebumps, thereby enhancing goosebump induction.

[0080] Figure 6 shows a graph plotting the capacitance of the stratum corneum on the horizontal axis and the amount of current required to induce goosebumps on the vertical axis. As shown in Figure 6, there was a significant (p<0.05) moderately positive correlation between the capacitance of the stratum corneum and the amount of current. This indicates that applying a skin ointment that reduces the capacitance of the stratum corneum can reduce the amount of current required to induce goosebumps, thereby enhancing goosebump induction.

[0081] [Experiment 4: Investigation of goosebump induction by application of skin lining II] In Experiment 4, the relationship between the application of skin lining agents and the amount of current required to induce goosebumps was examined. The following skin lining agents were used as skin lining agent samples. Skin application agent B1: Lotion, RDC: 679Ω Skin application agent B2: Lotion, RDC: 2650Ω Skin application agent B3: emulsion, RDC: 3970Ω Skin application agent B4: Lotion, RDC: 4188Ω Skin application agent B5: Base (cosmetic petrolatum; Vaseline P, manufactured by Nikko Rica Corporation) The DC resistance (RDC) of each of the skin application preparations B1 to B4 was measured using a measuring device that combined an LCR meter (IM3536, manufactured by Hioki E.E. Corporation) and a holder (SH2 Z, manufactured by Toyo Corporation). Specifically, each skin application preparation was filled into the holder and measurements were taken. Note that because it was difficult to accurately measure the DC resistance using the above device when the skin application preparation was in cream form, the DC resistance of skin application preparation B5 (cosmetic petrolatum) was not measured.

[0082] As in "Experiment 3" above, a skin ointment was applied to the area where the cathode was to be attached, and electrical stimulation was given using an electrical stimulation device. The amount of current was gradually increased, and the amount of current when goosebumps were induced was recorded.

[0083] Figure 7 shows a graph plotting the DC resistance of skin linings B1 to B4 on the horizontal axis and the amount of current at which goosebumps were induced on the vertical axis. As shown in Figure 7, there was a significant (p<0.05) strong negative correlation between the DC resistance of the skin linings and the amount of current. This suggests that applying a skin lining with high DC resistance (high insulation) to the skin before electrical stimulation can induce goosebumps even with a small amount of current, i.e., stimulate the arrector pili muscles.

[0084] Furthermore, for two cosmetics, Skin Coating B1, which had the lowest DC resistance among the above skin coating samples, and Skin Coating B5 (cosmetic petrolatum), which was not measured in this experiment but is generally known to have high DC resistance, the amount of current at which goosebumps were induced was measured by starting the application of electrical stimulation 10 minutes after application of the cosmetic, as described above. The amount of current at which goosebumps were induced was also measured when the application of electrical stimulation was started immediately after application of the skin coating. The results are shown in Figure 8.

[0085] As shown in Figure 8, for both skin linings B1 and B5, the amount of current required to induce goosebumps was smaller when stimulation began 10 minutes after application. Furthermore, skin lining B5 (cosmetic petrolatum) was found to be able to induce goosebumps with a small amount of current, regardless of the time between application and the start of stimulation. This suggests that a highly insulating skin lining, such as petrolatum, can stimulate the arrector pili muscles with a small amount of electricity, i.e., without causing significant pain, regardless of the timing of application of the skin lining.

[0086] [Experiment 5: Examination of Electrical Stimulation Conditions II] In "Experiment 4," we investigated the electrical stimulation conditions when using skin application agent B5 (cosmetic petrolatum).

[0087] (Example 7-1 to Example 7-3) In Examples 7-1 to 7-3, the experiments were conducted in the same manner as in "Experiment 4," except that a constant current stimulator (manufactured by the inventor) capable of applying electrical stimulation with a larger pulse width was used as the electrical stimulation generator, and the conditions were changed as shown in Table 7. Electrical stimulation was initiated 10 minutes after application of the skin application agent. Electrical stimulation was applied with a different pulse width in each example. Note that monophasic pulse wave stimulation was used in Example 7-1, and biphasic pulse wave stimulation was used in Example 7-3.

[0088] [Table 7]

[0089] From Table 7, it was found that goosebumps were induced in all of Examples 7-1 to 7-3. In addition, since doubling the pulse width reduces the amount of current to almost half, it was also found that increasing the pulse width is effective in reducing the amount of current.

[0090] (Example 8-1 to Example 8-4) An experiment was carried out in the same manner as in Example 7-1, except that the conditions were changed to those shown in Table 8. As shown in Table 8, electrical stimulation was applied to different electrode areas in each example.

[0091] [Table 8]

[0092] From Table 8, it was found that goosebumps were induced in all of Examples 8-1 to 8-4. It was also found that goosebumps could be induced sufficiently even when the measured current amount was small, below 1 mA, as in Examples 8-1 to 8-4. The current amount and current density conditions in Examples 8-1 to 8-4 are relatively low, and can be said to be highly safe for electrical stimulation of body parts above the neck.

[0093] [Experiment 6: Examination of the effects of repeated electrical stimulation] In Experiment 6, we investigated the effect of repeated use of electrical stimulation on improving the contractile force of the arrector pili muscles. For this experiment, we created an integrated electrical stimulation device 1 and an additional electrical stimulation device 2, a transcutaneous electrical stimulation (TENS) application device. Figure 9 shows a photograph of the electrical stimulation system 100 used. The electrical stimulation system 100 includes a frame F that can be worn on the arm, and the anode 11 and cathode 12 of the electrical stimulation device 1 and the anode 21 and cathode 22 of the additional electrical stimulation device 2 are fixed to this frame F. Since the relative positions of the electrodes can be fixed, the same conditions can be reproduced each time a trial is performed.

[0094] Three subjects used the electrical stimulation system, five days a week for eight weeks. Trials were conducted once per day. For each trial, a thin layer of Vaseline was applied to the intended electrode placement site on the subject's outer forearm, and the frame F with the attached electrodes was placed. Electrical stimulation was administered for approximately three minutes. Each trial was administered to both arms. To ensure consistent placement of the electrodes throughout the continuous use period, the skin was marked with the electrode placement locations. The electrical stimulation conditions using the electrical stimulation device 1 were the same as those in Experiment 1-1 (waveform: square wave, stimulation waveform: monophasic pulse wave, pulse width: 500 μs, on-time: 1 s / off-time: 2 s, frequency: 20 Hz, inter-electrode distance: 20 mm). The electrical stimulation conditions using the additional electrical stimulation device 2 were the same as those for transcutaneous electrical stimulation (TENS) in Experiment 2 (except for a frequency of 100 Hz).

[0095] <Evaluation of contractile force of arrector pili muscles> The condition of the induced goosebumps was observed before the start of continuous use of electrical stimulation, 4 weeks after the start, and 8 weeks after the start. Specifically, the current of the electrical stimulation was gradually increased during the trial, and as soon as goosebumps were induced, a replica of the skin in the state where goosebumps were induced was collected. Specifically, when the electrodes of the electrical stimulation device 1 were placed, a drug for collecting replicas (a mixture of SILFLO and CATALIST, manufactured by Amic Group Co., Ltd.) was applied to the area where the cathode 12 was attached and the surrounding area (approximately 16 cm 2 ) and then peeled off after the agent had hardened to obtain a replica.

[0096] The three most prominent holes, i.e., the deepest and largest visually, were selected from the collected replicas. The depth of each hole was measured using a white light interferometer (Newview 8300, Zygo Corporation) and image analysis. The average depth was calculated and used as the goosebump height. A comparison of the heights before (0 w) and 8 weeks after (8 w) of continuous electrical stimulation revealed a significant increase in goosebump height (p<0.05). Using R as the statistical language, a repeated measures ANOVA was used to test for significance, with Bonferoni multiple comparisons used. The results are shown in Figure 10.

[0097] As shown in Figure 10, the experiment revealed that continuous application of electrical stimulation increased the height of goosebumps when goosebumps were induced. In other words, it was suggested that continuous daily application of electrical stimulation to the skin improved the contractile force of the arrector pili muscles. In light of the known reports that the arrector pili muscles become thinner with age, it was found that the use of the electrical stimulation device or electrical stimulation system according to this embodiment can improve the contractile force of the arrector pili muscles, that is, by training the arrector pili muscles, it is possible to suppress the deterioration of the arrector pili muscles due to age.

[0098] Although the present invention has been described above based on the embodiments, the present invention is not limited to these embodiments. Furthermore, the above embodiments can be variously changed, modified, substituted, added, deleted, and combined within the scope of the claims, and these also fall within the technical scope of the present invention. [Explanation of symbols]

[0099] 1. Electrical stimulation device 2. Additional electrical stimulation device (transcutaneous electrical stimulation device) 10 Electrical stimulation generating unit (electrical stimulation device main body) 11 Anode of electrical stimulation device 1 12 Cathode of electrical stimulation device 1 20 Additional electrical stimulation generating unit (additional electrical stimulation device main body) 21 Anode of additional electrical stimulator 2 22 Cathode of additional electrical stimulator 2 100 Electrical Stimulation System

Claims

1. An electrical stimulation device that applies electrical stimulation to the arrector pili muscles, a pair of electrodes to be placed on the skin surface; The effective current density at the cathode of the electrode pair is 0.1 mA / cm 2 100mA / cm or more 2 The following is an electrical stimulation device.

2. The area of ​​the cathode is 1 mm ２ More than 100 mm ２ 2. The electrical stimulation device of claim 1, wherein:

3. The electrical stimulation device according to claim 1 or 2, wherein the distance between the electrodes is 1 mm or more and 40 mm or less.

4. 3. The electrical stimulation device according to claim 1, wherein the pulse width of the electrical stimulation is 10 μs or more and 10,000 μs or less.

5. The electrical stimulation device according to claim 1 or 2, wherein the frequency of the electrical stimulation is 1 Hz or more and 200 Hz or less.

6. The electrical stimulation device according to claim 1 or 2, wherein the electrical stimulation is constant current stimulation.

7. an electrical stimulation device that applies electrical stimulation to the arrector pili muscles and that is equipped with a first electrode pair; an additional electrical stimulation device for applying pain-relieving electrical stimulation, the additional electrical stimulation device including a second electrode pair; The first electrode pair is arranged side by side on the skin surface, The electrical stimulation system, wherein the second electrode pair is positioned on the skin surface to sandwich the first electrode pair.

8. The electrical stimulation system of claim 7 , wherein the frequency of the electrical stimulation applied by the additional electrical stimulation device is equal to or greater than 2 Hz and equal to or less than 100 Hz.

9. an electrical stimulation device that applies electrical stimulation to the arrector pili muscles and that has an electrode pair that is placed on the skin surface; and a highly insulating skin application agent to be applied to the skin surface.

10. 10. The kit of claim 9, wherein the skin application agent has a DC resistance of 500 Ω or more.

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