Nerve stimulation device, nerve stimulation system, and nerve stimulation method

Abstract

An object of the present technology is to provide a nerve stimulation device, a nerve stimulation system, and a nerve stimulation method capable of applying abundant variations of electrical stimulation to a nerve with high accuracy without having wiring between the nerve stimulation device and an external power supply.SOLUTION: The nerve stimulation device includes a power receiving unit 130, a stimulation electrode 150, and a stimulation current generating unit 140 that generates a stimulation current to be applied to the stimulation electrode 150. The power receiving unit 130, the stimulation electrode 150, and the stimulation current generating unit 140 can be implanted in a living body. The stimulation electrode 150 is electrically connected to a nerve in a living body. The stimulation current generating unit 140 has a stimulation current pattern selecting part 143 for selecting a stimulation current pattern based on the change of the frequency when the power receiving unit 130 receives the power, and a stimulation current generating part 144 for generating the stimulation current based on the stimulation current pattern.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The technical field of the present specification relates to neurostimulation devices, systems and methods. [Background technology]

[0002] A technique called functional electrical stimulation (FES) is known, which stimulates muscles or nerves to contract paralyzed muscles, thereby compensating for the lost function of those muscles. Techniques using FES to improve recovery after neurological disorders and support rehabilitation have also become known (see, for example, Patent Document 1).

[0003] In addition to compensating for motor function, functional electrical stimulation has been shown to have a wide range of applications, such as improving bladder-related dysfunction by sacral nerve stimulation (see, for example, Patent Document 2) and treating epilepsy by vagus nerve stimulation (see, for example, Patent Document 3). Furthermore, Non-Patent Document 1 discloses treatment methods using functional electrical stimulation for traumatic brain injury, Parkinson's disease, dysphagia, heart failure, epilepsy, gastrointestinal inflammatory disease, upper motor neuron lesions, changes in memory and cognition, and neuromodulation of disorders of consciousness. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Application No. 2018-040038 [Patent Document 2] Patent Application No. 2018-500525 [Patent Document 3] Patent Application No. 2012-160152 [Non-patent literature]

[0005] [Non-Patent Document 1] A. Majid et al., Electroceuticals, Springer International Publishing AG 2017. Summary of the Invention [Problem to be solved by the invention]

[0006] Functional electrical stimulation systems used in clinical practice to date include those that use surface electrodes and those that place electrodes inside the body. When using surface electrodes, stimulation is applied to muscles using surface electrodes placed on the surface of the body. This can be painful, and it is difficult to control the precise and precise stimulation of multiple muscles. When electrodes are placed inside the body, wiring is required to connect the internal electrodes to an external power source. These wirings increase the risk of infection.

[0007] Therefore, it is desirable to apply electrical stimulation to muscles with high precision without using wiring between the device and an external power source. Currently, devices that exercise muscles by applying electrical stimulation can induce repetitive movements similar to convulsions, but are almost unable to induce complex movements such as walking.

[0008] Furthermore, research results have been published showing that electrical stimulation can be used not only to exercise muscles but also to treat depression, etc. As mentioned above, Non-Patent Document 1 describes treatment methods using functional electrical stimulation for traumatic brain injury, Parkinson's disease, dysphagia, heart failure, epilepsy, gastrointestinal inflammatory diseases, upper motor neuron lesions, changes in memory and cognition, and neuromodulation of disorders of consciousness, etc.

[0009] The problem that the technology of this specification aims to solve is to provide a nerve stimulation device, nerve stimulation system, and nerve stimulation method that can apply a wide variety of electrical stimuli to nerves with high precision in a nerve stimulation system in which part of the nerve stimulation system is implanted in the body, without requiring wiring between the system and an external power source. [Means for solving the problem]

[0010] A nerve stimulation device according to a first aspect includes a power receiving unit, a nerve stimulation electrode, and a stimulation current generating unit that generates a stimulation current to be applied to the nerve stimulation electrode. The power receiving unit, the nerve stimulation electrode, and the stimulation current generating unit are implantable in a living body. The nerve stimulation electrode is electrically connected to a nerve in the living body. The stimulation current generating unit includes a stimulation current pattern selecting unit that associates a frequency before a change and a frequency after a change with a stimulation current pattern, and that, when the frequency received by the power receiving unit changes, selects a stimulation current pattern that corresponds to the frequency before the change and the frequency after the change in the frequency. and a stimulation current generating section that generates a stimulation current based on the stimulation current pattern selected by the stimulation current pattern selecting section.

[0011] This nerve stimulator operates the stimulation current generating unit via wireless power supply. The nerve stimulator also applies a stimulation current to the nerve based on changes in frequency when the power receiving unit receives power. This frequency change acts as a control signal that specifies the stimulation current. Therefore, simply by supplying power from outside the living body to the power receiving unit inside the living body, the stimulation current generating unit inside the living body can apply an accurate stimulation current to the nerve. [Effects of the Invention]

[0012] This specification provides a nerve stimulation device, a nerve stimulation system, and a nerve stimulation method that can provide a wide variety of electrical stimulation to nerves with high precision in a nerve stimulation system in which part of the nerve stimulation system is implanted inside the body, without requiring wiring between the system and an external power source. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic configuration diagram of a nerve stimulation system 100 according to a first embodiment. [Figure 2] 1 is a block diagram showing a control system of a nerve stimulation system 100 according to a first embodiment. [Figure 3]1A to 1C are diagrams illustrating leg movements of a rat R1 caused by stimulation provided by the nerve stimulation system 100 of the first embodiment. [Figure 4] 1 is a diagram illustrating the relationship between the nerve stimulation provided by the nerve stimulation system 100 of the first embodiment and the movement of the rat R1. FIG. [Figure 5] 10 is a diagram illustrating an example of the relationship between the power transmission frequency of the nerve stimulation system 100 according to the first embodiment and the movement of a rat R1. FIG. [Figure 6] FIG. 10 is a diagram showing a transmission voltage and a stimulation current in a nerve stimulation system according to a modified example of the first embodiment. [Figure 7] FIG. 10 is a schematic configuration diagram of a nerve stimulation system 200 according to a second embodiment. [Figure 8] FIG. 10 is a diagram showing an electrode arrangement in a modified example of the nerve stimulation system 200 of the second embodiment. [Figure 9] 10 is a graph illustrating the waveform of a stimulation current applied by the nerve stimulation system of the fifth embodiment. [Figure 10] 10 is an image showing rat R1 used in Experiment 2. [Figure 11] 10 is a graph showing the experimental results of Experiment 2. DETAILED DESCRIPTION OF THE INVENTION

[0014] Specific embodiments will be described below with reference to the drawings, taking a nerve stimulation device, a nerve stimulation system, and a nerve stimulation method as examples. The nerve stimulation system described below is installed in a rat. However, the following embodiments are not limited to rats and can also be applied to humans and other animals.

[0015] (First embodiment) 1. Neurostimulation System 1 is a schematic diagram of a nerve stimulation system 100 according to a first embodiment. The nerve stimulation system 100 is provided in a rat R1. The nerve stimulation system 100 includes a control unit 110, a power transmitting unit 120, a power receiving unit 130, a stimulation current generating unit 140, a stimulation electrode 150, and wiring 160.

[0016] The control unit 110 and the power transmitting unit 120 are located outside the rat R1.

[0017] The power receiving unit 130, the stimulation current generating unit 140, the stimulation electrode 150, and the wiring 160 can be implanted in a living body. In practice, the power receiving unit 130, the stimulation current generating unit 140, the stimulation electrode 150, and the wiring 160 are implanted inside the rat R1. The nerve stimulation device A1 includes the power receiving unit 130, the stimulation current generating unit 140, the stimulation electrode 150, and the wiring 160.

[0018] The control unit 110 controls the power transmitting unit 120. The control unit 110 controls the power and frequency at which the power transmitting unit 120 transmits power. The control unit 110 is, for example, a PC.

[0019] The power transmitting unit 120 transmits power to the power receiving unit 130. The power transmitting unit 120 has a power transmitting coil. The power transmitting unit 120 performs, for example, wireless power transmission using magnetic resonance. The power transmitting unit 120 can supply power to the power receiving unit 130 inside the body of the rat R1.

[0020] The power receiving unit 130 is supplied with power from the power transmitting unit 120. The power receiving unit 130 has a power receiving coil. The power receiving unit 130 is supplied with power from the power transmitting unit 120 outside the body of the rat R1.

[0021] The stimulation current generating unit 140 generates a stimulation current to be applied to the stimulation electrode 150. The stimulation current generating unit 140 selects a stimulation current pattern to be applied to the stimulation electrode 150 in accordance with changes in the frequency at which the power receiving unit 130 receives power. The power transmitting frequency of the power transmitting unit 120 and the power receiving frequency of the power receiving unit 130 are basically the same. Therefore, the stimulation current generating unit 140 selects a stimulation current pattern to be applied to the stimulation electrode 150 in accordance with changes in the frequency at which the power transmitting unit 120 transmits power.

[0022] The stimulation electrodes 150 are nerve stimulation electrodes for applying electrical stimulation to the nerves of rat R1. The stimulation electrodes 150 are placed in contact with the nerves of rat R1. Therefore, the stimulation electrodes 150 are electrically connected to the nerves of rat R1. Each stimulation electrode 150 is connected to a motor nerve of rat R1. The stimulation electrodes 150 apply a stimulation current generated by the stimulation current generating unit 140. The stimulation electrodes 150 are connected to the nerves that move the hind limbs of rat R1.

[0023] The wiring 160 electrically connects the stimulation current generating unit 140 and the stimulation electrode 150 .

[0024] 2. Control System 2 is a block diagram showing a control system of the nerve stimulation system 100 of the first embodiment. The control unit 110 inputs, to the power transmitting unit 120, the magnitude and frequency of the current when the power transmitting unit 120 transmits power, as input signals.

[0025] The power transmitting unit 120 includes a power transmitting coil 121, a power transmitting signal generating unit 122, and a power transmitting signal transmitting unit 123. The power transmitting coil 121 transmits power to the power receiving coil 131. The power transmitting signal generating unit 122 generates a frequency of a current to be passed through the power transmitting coil 121. The frequency is determined by an input signal from the control unit 110. The power transmitting signal transmitting unit 123 generates a current to be actually passed through the power transmitting coil 121.

[0026] The power receiving unit 130 includes a power receiving coil 131 and a power transmission signal receiving unit 132. The power receiving coil 131 generates a current due to the magnetic field formed by the power transmitting coil 121. The power transmission signal receiving unit 132 receives a frequency from the current flowing through the power receiving coil 131. The power receiving unit 130 receives power using at least a first frequency and a second frequency. In this way, the power transmission signal receiving unit 132 detects the frequency at which the power receiving unit 130 receives power.

[0027] The stimulation current generating unit 140 includes a power supply unit 141, a stimulation current pattern storage unit 142, a stimulation current pattern selection unit 143, a stimulation current generation unit 144, and an electrode selection unit 145. The power supply unit 141 supplies the power supplied to the power receiving coil 131 to each unit.

[0028] The stimulation current pattern storage unit 142 stores a set of a frequency change pattern, a stimulation current pattern, and an electrode. The stimulation current pattern storage unit 142 stores a correspondence relationship that associates a combination of a frequency change from a first frequency to a second frequency with a stimulation current pattern when the power receiving unit 130 receives power.

[0029] The stimulation current pattern selection unit 143 selects a stimulation current pattern based on a change in frequency when the power receiving unit 130 receives power. The stimulation current pattern selection unit 143 selects a stimulation current pattern from a combination of changes in frequency from a first frequency to a second frequency. Specifically, the stimulation current pattern selection unit 143 selects a stimulation current pattern by referring to the correspondence relationship in the stimulation current pattern storage unit 142.

[0030] The stimulation current generating unit 144 generates a stimulation current to be applied to the stimulation electrode 150. Specifically, the stimulation current generating unit 144 generates a stimulation current based on the stimulation current pattern selected by the stimulation current pattern selecting unit 143.

[0031] The electrode selection unit 145 selects the stimulation electrode 150 through which the stimulation current generated by the stimulation current generation unit 144 flows.

[0032] 3. Leg Movement Patterns in Rats FIG. 3 is a diagram illustrating leg movements of rat R1 due to stimulation provided by the nerve stimulation system 100 of the first embodiment. As shown in FIG. 3, rat R1 performs four movements. The nerve stimulation system 100 controls flexion and extension movements of the ankle joint and knee joint of rat R1. The movements related to the ankle joint are dorsiflexion and plantar flexion. The movements related to the knee joint are extension and flexion. By combining these movements, the nerve stimulation system 100 can cause rat R1 to walk.

[0033] 4. The relationship between nerves and leg movements 4 is a diagram illustrating the relationship between the nerve stimulation provided by the nerve stimulation system 100 of the first embodiment and the movement of rat R1. As shown in FIG. 4, when the ankle joint is dorsiflexed, stimulation is applied to the peroneal nerve. When the ankle joint is plantarflexed, stimulation is applied to the tibial nerve. When the knee joint is extended, stimulation is applied to the femoral nerve. When the knee joint is flexed, stimulation is applied to the biceps femoris branch of the sciatic nerve.

[0034] 5. Stimulation current Table 1 illustrates the relationship between the stimulation pattern, the change in frequency (kHz), the nerve to be stimulated, and the movement of rat R1. The stimulation current pattern storage unit 142 stores a table corresponding to Table 1.

[0035] [Table 1] Pattern Frequency Changes Neurological Movement (kHz) Pattern 1 95→90 Peroneal nerve dorsiflexion Pattern 2 95→110 Tibial nerve plantar flexion Pattern 3 100→90 Femoral nerve extension Pattern 4 100→110 Sciatic nerve flexion

[0036] Here, the change in frequency refers to a change in the frequency of the change in the magnetic field when power is supplied from the power transmitting unit 120 to the power receiving unit 130. When the stimulation patterns and the frequencies are in one-to-one correspondence, the number of patterns is the same as the number of frequencies. In the first embodiment, the frequency changes and the stimulation patterns are in one-to-one correspondence. When there is a limit to the frequencies that can be used for power supply, many stimulation patterns can be adopted by using frequency changes.

[0037] FIG. 5 is a diagram illustrating the relationship between the power transmission frequency of the nerve stimulation system 100 according to the first embodiment and the movement of the rat R1.

[0038] The case where the power transmission frequency is changed from 95 kHz to 90 kHz will be described. In this case, the stimulation current pattern selection unit 143 refers to Table 1 stored in the stimulation current pattern storage unit 142 and selects Pattern 1. The stimulation current generation unit 144 generates a stimulation current to be applied to the peroneal nerve. The electrode selection unit 145 applies the current generated by the stimulation current generation unit 144 to the electrode in contact with the peroneal nerve. This causes rat R1 to perform dorsiflexion movement.

[0039] The case where the power transmission frequency is changed from 95 kHz to 110 kHz will be described. In this case, the stimulation current pattern selection unit 143 refers to Table 1 stored in the stimulation current pattern storage unit 142 and selects Pattern 2. The stimulation current generation unit 144 generates a stimulation current to be applied to the tibial nerve. The electrode selection unit 145 applies the current generated by the stimulation current generation unit 144 to the electrode in contact with the tibial nerve. This causes rat R1 to perform plantar flexion.

[0040] The case where the power transmission frequency is changed from 100 kHz to 90 kHz will be described. In this case, the stimulation current pattern selection unit 143 refers to Table 1 stored in the stimulation current pattern storage unit 142 and selects pattern 3. The stimulation current generation unit 144 generates a stimulation current to be applied to the femoral nerve. The electrode selection unit 145 applies the current generated by the stimulation current generation unit 144 to the electrode in contact with the femoral nerve. This causes rat R1 to perform an extension movement.

[0041] The case where the power transmission frequency is changed from 100 kHz to 110 kHz will be described. In this case, the stimulation current pattern selection unit 143 refers to Table 1 stored in the stimulation current pattern storage unit 142 and selects pattern 4. The stimulation current generation unit 144 generates a stimulation current to be applied to the biceps femoris branch of the sciatic nerve. The electrode selection unit 145 applies the current generated by the stimulation current generation unit 144 to the electrode in contact with the biceps femoris branch of the sciatic nerve. This causes rat R1 to perform a flexion movement.

[0042] 5 shows that the frequency of power supplied from power transmitting unit 120 to power receiving unit 130 changes over time. In accordance with this change in frequency, stimulation current generating unit 144 and electrode selecting unit 145 stimulate the respective nerves.

[0043] In Figure 5, the time interval between stimulation currents is 0.2 ms. The peroneal nerve is stimulated for 0.2 ms, followed by no stimulation for 4.8 ms. The tibial nerve is stimulated for 0.2 ms, followed by no stimulation for 4.8 ms. The femoral nerve is stimulated for 0.2 ms, followed by no stimulation for 4.8 ms. The biceps femoris branch of the sciatic nerve is stimulated for 0.2 ms, followed by no stimulation for 4.8 ms.

[0044] In this way, the nerve stimulation system 100 can pass a stimulation current to each nerve at regular intervals. In Fig. 5, the stimulation system 100 passes a stimulation current to a different nerve every 5 ms. Fig. 5 is an example, and the nerve stimulation system 100 can provide a different current stimulation pattern.

[0045] The stimulation current is not actually a constant current but a 50 Hz alternating current, and the application time of this alternating current is 0.2 ms.

[0046] As shown in Table 1, 95 kHz and 100 kHz are the frequencies before the change, and 90 kHz and 110 kHz are the frequencies after the change.

[0047] In this way, the nerve stimulation system 100 can control the stimulation given to the nerves of rat R1 by temporally changing the frequency when transmitting power. Furthermore, the control unit 110 on the power transmission side can freely change the frequency, so the nerve stimulation system 100 can generate a variety of nerve stimulation patterns.

[0048] In this way, the instruction contents that are meant by the change in power transmission frequency are determined in advance, and the stimulation current generating unit 140 generates the stimulation current according to the instruction contents.

[0049] 6. Nerve stimulation methods The stimulation current generating unit 144 of the nerve stimulation system 100 applies nerve stimulation to the motor nerves of the rat R1 by passing a stimulation current through the motor nerves, thereby controlling the movement of multiple muscles.

[0050] 7. Effects of the First Embodiment In the nerve stimulation system 100 of the first embodiment, the stimulation current generating unit 140 is operated by wireless power supply. Furthermore, the frequency change pattern when the power transmitting unit 120 supplies power to the power receiving unit 130 is linked to the stimulation current pattern generated by the stimulation current generating unit 140. In other words, the frequency change pattern from the power transmitting unit 120 to the power receiving unit 130 serves as a control signal for the stimulation current generating unit 140.

[0051] Therefore, it is possible to miniaturize the part of the nerve stimulation system 100 that is implanted in the living body. Furthermore, by using the frequency change pattern from the power transmitting unit 120 to the power receiving unit 130, the nerve stimulation system 100 can specify the stimulation current pattern to be generated by the stimulation current generating unit 140.

[0052] Furthermore, the frequency change pattern is input to the power receiving unit 130 in a very short time. Therefore, the stimulation current generating unit 140 can stimulate each nerve of the rat R1 in a complex manner. Therefore, the nerve stimulation system 100 can exercise multiple muscles in a complex and continuous manner. In other words, the rat R1 can perform complex movements.

[0053] 8. Variations 8-1.Neurostimulator The nerve stimulation device in the modified example of the first embodiment is a device obtained by removing external devices from the nerve stimulation system 100. That is, the nerve stimulation device includes a power receiving unit 130, a stimulation current generating unit 140, a stimulation electrode 150, and wiring 160. The power receiving unit 130 may be supplied with power from a power transmitting unit different from that in the first embodiment.

[0054] 8-2. Control of front legs Other stimulation electrodes 150 can be placed in contact with nerves in the front legs of rat R1 to control the movement of the front legs of rat R1.

[0055] 8-3. Transmission frequency In the first embodiment, 95 kHz and 100 kHz are the frequencies before the change, and 90 kHz and 110 kHz are the frequencies after the change. This may be reversed. In this case, 90 kHz and 110 kHz are the frequencies before the change, and 95 kHz and 100 kHz are the frequencies after the change. Also, frequencies other than 90 kHz, 95 kHz, 100 kHz, and 110 kHz may be used.

[0056] 8-4. Number of transmission frequencies The number of frequencies employed may be increased.

[0057] 8-5. Stimulation current application time In the first embodiment, the stimulation current application time may be set to a time other than 0.2 ms, and the time interval between stimulation currents may be set to a time other than 4.8 ms.

[0058] 8-6. Stimulation current magnitude Two types of stimulation current may be provided: current value I1 and current value I2. For example, current value I2 is greater than current value I1. Alternatively, three or more types of current values ​​may be provided.

[0059] 6 is a diagram showing the transmission voltage and stimulation current in the nerve stimulation system according to the modified example of the first embodiment. As shown in FIG. 6, the higher the transmission voltage, the higher the stimulation current. In this way, the magnitude of the stimulation current may correspond to the magnitude of the current flowing through the receiving coil 131. The larger the current flowing through the receiving coil 131, the larger the magnitude of the stimulation current.

[0060] 8-7.Stimulation current frequency The frequency of the stimulation current may be changed to a frequency other than 50 Hz. The reaction speed of the muscle depends on the stimulation current. The frequency of the stimulation current is preferably about 50 Hz. When the frequency of the stimulation current is 50 Hz, the movement of rat R1 is completed in about 1 second. When the frequency of the stimulation current is 30 Hz, the movement of rat R1 is completed in about 6 seconds. The frequency of the stimulation current is preferably, for example, 40 Hz or more and 70 Hz or less.

[0061] 8-8. Power transmission signal receiver The power transmission signal receiving unit 132 is located inside the power receiving unit 130. The power transmission signal receiving unit 132 may be located inside the stimulation current generating unit 140.

[0062] 8-9.High frequency current 5 and 6, the stimulation current is depicted as a square wave. A stimulation current that is close to a square wave may be generated by continuously applying a high-frequency current.

[0063] 8-10. Feedback Control and Feedforward Control The control unit 110 of the nerve stimulation system 100 of the first embodiment preferably performs feedback control. For example, PID control is available. For the feedback control, it is preferable to have an information collection unit such as a camera that observes the hind limbs of the rat R1. The information collection unit transmits information to the control unit 110. In addition to the feedback control, it is also preferable to perform feedforward control.

[0064] 8-11.Wireless power supply method The technique of the first embodiment can be applied regardless of the wireless power feeding method, such as a magnetic field resonance method or an electric field coupling method.

[0065] 8-12. Power transmission unit The power transmitting unit 120 may include a microcomputer, a DC power supply, an oscillator, and a regulator.

[0066] 8-13. Stimulation current generation unit The stimulation current generating unit 140 may include a low-pass filter and a comparator.

[0067] 8-14. Application to other animals The nerve stimulation system 100 of the first embodiment may be applied to humans and other animals.

[0068] 8-15. Combination The above modifications may be freely combined.

[0069] (Second embodiment) A second embodiment will be described.

[0070] 1. Neurostimulation System 7 is a schematic configuration diagram of a nerve stimulation system 200 according to the second embodiment. As shown in FIG. 7, the nerve stimulation system 200 includes a control unit 210, a power transmitting unit 220, a power receiving unit 230, a stimulation current generating unit 240, a blocking electrode 250, and a stimulation electrode 260.

[0071] The control unit 210, the power transmitting unit 220, the power receiving unit 230, and the stimulation current generating unit 240 are similar to the control unit 110, the power transmitting unit 120, the power receiving unit 130, and the stimulation current generating unit 140 of the first embodiment, respectively. The control unit 210 has a fixing portion for attachment to a person's leg. The fixing portion is configured so that a belt-shaped member can be wrapped around the person's leg.

[0072] The block electrode 250 can be implanted in a living body. In practice, the block electrode 250 is implanted in a human body and electrically connected to a human nerve. The block electrode 250 is an electrode for blocking the transmission of nerve signals from the central nervous system. The block electrode 250 applies a high-frequency alternating current of approximately 1 kHz or more and 50 kHz or less to the nerve. In this way, the block electrode 250 at least temporarily blocks the transmission of nerve signals from the central nervous system.

[0073] The stimulation electrode 260 is an electrode for stimulating the motor nerve to move the muscle. The stimulation electrode 260 is located closer to the peripheral side of the nerve than the block electrode 250. The stimulation electrode 260 applies a low-frequency alternating current of approximately 1 Hz or more and 100 Hz or less to the nerve. This enables the stimulation electrode 260 to move the peripheral side of the motor nerve.

[0074] 2. Effects of the Second Embodiment The nerve stimulation system 200 of the second embodiment includes a block electrode 250 and a stimulation electrode 260. The block electrode 250 blocks nerve signals transmitted from the central to the peripheral side, and the stimulation electrode 260 transmits the nerve signals to the peripheral side. Therefore, for patients whose brains are unable to transmit appropriate nerve signals, the nerve stimulation system 200 transmits appropriate nerve signals, thereby enabling the patient to move appropriately. For example, the nerve stimulation system 200 overcomes a patient's walking disorder.

[0075] 3. Variations 3-1. Electrode 8 is a diagram showing an electrode arrangement in a modified example of the nerve stimulation system 200 of the second embodiment. The nerve stimulation system 200 may have a block electrode 250, a stimulation electrode 260, and a stimulation electrode 270. The stimulation electrode 270, the block electrode 250, and the stimulation electrode 260 are arranged in this order from the central nerve side. The block electrode 250 is sandwiched between the stimulation electrode 270 and the stimulation electrode 260. The stimulation electrode 260 is arranged on the peripheral nerve side from the block electrode 250. The stimulation electrode 270 is arranged on the central nerve side from the block electrode 250.

[0076] In this case, the block electrode 250 blocks nerve signals from the central nerve side, and the stimulation electrode 260 can pass a stimulation current to the peripheral nerve side. Furthermore, the block electrode 250 blocks nerve signals from the peripheral nerve side, and the stimulation electrode 270 can pass a stimulation current to the central nerve side. In other words, the block electrode 250 blocks nerve signals from either the central nerve side or the peripheral nerve side.

[0077] (Third embodiment) A third embodiment will be described.

[0078] 1. Neurostimulation System The mechanical configuration of the nerve stimulation system of the third embodiment is similar to that of the nerve stimulation system 200 of the second embodiment. The block electrode 250 of the nerve stimulation system of the third embodiment is electrically connected to a human sensory nerve. The block electrode 250 blocks nerve signals returning from the peripheral side to the central side.

[0079] 2. Effects of the Third Embodiment The nerve stimulation system of the third embodiment applies nerve stimulation to the patient's sensory nerves using a block electrode 250. The block electrode 250 blocks nerve signals from the patient's sensory nerves, thereby inhibiting the transmission of nerve signals responsible for pain to the central nervous system. The nerve stimulation system can prevent the patient from perceiving pain. In other words, the nerve stimulation system can treat chronic pain.

[0080] (Fourth embodiment) A fourth embodiment will be described.

[0081] 1. Neurostimulation System The mechanical configuration of the nerve stimulation system of the fourth embodiment is similar to that of the nerve stimulation system 100 of the first embodiment or the nerve stimulation system 200 of the second embodiment. The stimulation electrodes of the nerve stimulation system of the fourth embodiment are implanted in the brain.

[0082] 2. Effects of the Fourth Embodiment The stimulation electrodes of the nerve stimulation system of the fourth embodiment are electrically connected to the desired nerve. This is expected to enable the treatment of various diseases. For example, it is conceivable to treat diseases caused by abnormalities in the stimulation current pattern that stimulates nerve fibers. It is also conceivable that the stimulation current pattern can be used to promote or suppress the secretion of hormones in the brain, thereby regulating the amount of hormone secretion in the brain and thereby treating diseases. Specific examples include depression, epilepsy, cardiovascular disease, sepsis, obesity, diabetes, lung injury, stroke, and traumatic brain injury.

[0083] (Fifth embodiment) A fifth embodiment will be described.

[0084] 1. Neurostimulation System The mechanical configuration of the nerve stimulation system of the fifth embodiment is similar to that of the nerve stimulation system 100 of the first embodiment.

[0085] 2. Stimulation current waveform 9 is a graph illustrating the waveform of the stimulation current applied by the nerve stimulation system of the fifth embodiment. The horizontal axis of FIG. 9 represents time, and the vertical axis of FIG. 9 represents the magnitude of the stimulation current.

[0086] 9, the stimulation current pattern has a first interval T1, a second interval T2, a third interval T3, a fourth interval T4, a fifth interval T5, and a sixth interval T6. The length of each interval is, for example, 0.2 ms. Of course, the length of each interval may be other than the above.

[0087] 2-1. Section 1 (Increasing section) In the first section T1, the stimulation current increases over time. The rate of increase in the current is not constant. The absolute value of the slope, which indicates the rate of change in the current, gradually increases over time.

[0088] 2-2.Second Section (fixed section) In the second section T2, the stimulation current is constant. In the second section T2, a constant large current flows.

[0089] 2-3. Section 3 (Decreasing section) In the third section T3, the stimulation current decreases over time. The rate of decrease is not constant. The absolute value of the slope, which indicates the rate of change in current, gradually decreases over time.

[0090] 2-4. Section 4 (linear increase section) In the fourth interval T4, the stimulation current increases over time. The rate of increase in current is constant, i.e., the current increases linearly.

[0091] 2-5. Section 5 (fixed section) In the fifth section T5, the stimulation current has a constant value. The current value in the fifth section T5 is smaller than the current value in the second section T2. ​​In other words, a constant small current flows in the fifth section T5.

[0092] 2-6. Section 6 (linear decrease section) In the sixth interval T6, the stimulation current decreases over time. The rate of decrease is constant, i.e., the current decreases linearly.

[0093] In this way, in the fifth embodiment, a first stimulation current pattern is applied in a first period (first interval T1), and a second stimulation current pattern is applied in a second period (second interval T2) following the first period. Of course, stimulation current patterns can be applied sequentially from the third period onwards.

[0094] The stimulation current pattern storage unit 142 stores a first stimulation current pattern to be applied during a first period and a second stimulation current pattern to be applied during a second period. The stimulation current pattern selection unit 143 selects the first stimulation current pattern to be applied during the first period and the second stimulation current pattern to be applied during the second period. The stimulation current generation unit 144 generates a stimulation current of the first stimulation current pattern during the first period and generates a stimulation current of the second stimulation current pattern during the second period. Here, the second period is the period following the first period.

[0095] 3. Relationship between the waveform of the stimulation current and the biological response A case will be described in which a square wave is used as the waveform of the stimulation current as in the first embodiment. In this case, thick axons such as Aα fibers that control skeletal muscles, tendons, etc. are excited first. Thick axons have a fast average conduction velocity and a low threshold for excitation. In other words, when a square wave is used, thick axons such as Aα fibers are easily excited, making it difficult to selectively excite thin axons.

[0096] For this reason, stimulating nerve fibers with square waves can cause the following side effects: For example, when stimulating the vagus nerve, nerves in the pharynx and larynx can be stimulated, resulting in side effects such as hoarseness, respiratory depression or apnea, bradycardia, nausea, and headache.

[0097] In order to stimulate the targeted nerve fibers, it is conceivable to change the amplitude, frequency, etc. of the stimulation current pattern.

[0098] In the fifth embodiment, various stimulation current patterns can be generated. Therefore, by selecting an appropriate stimulation current pattern, it is possible to excite targeted nerve fibers. For example, this nerve stimulation system has the potential to selectively stimulate Aδ fibers, which control relatively clear cutaneous thermal and pain sensations, B fibers, which are preganglionic fibers of the sympathetic nerve, and C fibers, which are postganglionic fibers of the sympathetic nerve.

[0099] 4. Effects of the Fifth Embodiment The nerve stimulation system of the fifth embodiment sequentially applies different currents as stimulation current patterns, which allows for the generation of more complex stimulation current patterns, potentially enabling selective stimulation of targeted nerve fibers.

[0100] 5. Variations FIG. 9 illustrates a complex stimulation current pattern, and stimulation current patterns other than those illustrated in FIG. 9 can be generated. The stimulation current generating unit 144 can generate various current increase / decrease patterns. Therefore, the sections in FIG. 9 may be freely combined. The stimulation current generating unit 144 can generate more detailed patterns regarding the rate of current increase and decrease.

[0101] (Combination of embodiments) The first to fifth embodiments may be combined, including modified examples.

[0102] (experiment) 1. Experiment 1 The hind limbs of rat R1 were exercised using the nerve stimulation system 100 of the first embodiment, which enabled the rat R1 to move its hind limbs as if walking.

[0103] 2. Experiment 2 The nerve stimulation system 200 of the second embodiment was used to exercise the ankle of rat R1.

[0104] FIG. 10 is an image showing rat R1 used in Experiment 2.

[0105] Figure 11 is a graph showing the experimental results of Experiment 2. The horizontal axis of Figure 11 is time. The vertical axis of Figure 11 is the ankle angle or the magnitude of the stimulation current. Rising from the bottom of Figure 11 are the proximal stimulation current and the distal stimulation current. The proximal stimulation current is the current measured by the central stimulation electrode 270. The distal stimulation current is the current measured by the peripheral stimulation electrode 260. The regular proximal stimulation current is blocked by the block electrode 250, resulting in a somewhat irregular distal stimulation current.

[0106] The target angle is the angle of the ankle of rat R1 targeted by nerve stimulation system 200. The ankle angle is a measurement of the angle of the ankle of rat R1.

[0107] In this way, rat R1 was able to move by nerve signals from the nerve stimulation system 200 while blocking nerve signals from the central side.

[0108] (Addendum) A nerve stimulation device according to a first aspect includes a power receiving unit, a nerve stimulation electrode, and a stimulation current generating unit that generates a stimulation current to be applied to the nerve stimulation electrode. The power receiving unit, the nerve stimulation electrode, and the stimulation current generating unit are implantable in a living body. The nerve stimulation electrode is electrically connected to a nerve in the living body. The stimulation current generating unit includes a stimulation current pattern selecting unit that selects a stimulation current pattern based on a change in frequency when the power receiving unit receives power, and a stimulation current generating unit that generates a stimulation current based on the stimulation current pattern selected by the stimulation current pattern selecting unit.

[0109] In a nerve stimulation device according to a second aspect, the power receiving unit receives power using at least a first frequency and a second frequency, and the stimulation current pattern selector selects a stimulation current pattern from a combination of frequency changes from the first frequency to the second frequency.

[0110] In the nerve stimulation device according to the third aspect, the stimulation current generating unit has a stimulation current pattern storage unit that stores a correspondence relationship between a combination of frequency changes from a first frequency to a second frequency and a stimulation current pattern, and the stimulation current pattern selection unit selects a stimulation current pattern by referring to the correspondence relationship in the stimulation current pattern storage unit.

[0111] In the nerve stimulation device according to the fourth aspect, the stimulation current generating unit has an electrode selecting section that selects to which nerve stimulation electrode the stimulation current generated by the stimulation current generating section is to be applied.

[0112] In the nerve stimulation device according to the fifth aspect, the power receiving unit or the stimulation current generating unit has a transmission signal receiving section that detects the frequency at which the power receiving unit receives power.

[0113] A sixth aspect of the nerve stimulation device includes a block electrode that can be implanted in a living body. The block electrode is electrically connected to a nerve in the living body and blocks nerve signals from the central nerve side or the peripheral nerve side.

[0114] In the nerve stimulation device of the seventh aspect, the stimulation current pattern selection unit selects a first stimulation current pattern to be applied in a first period and selects a second stimulation current pattern to be applied in a second period following the first period. The stimulation current generation unit generates a stimulation current of the first stimulation current pattern in the first period and generates a stimulation current of the second stimulation current pattern in the second period.

[0115] A nerve stimulation system according to an eighth aspect includes the above nerve stimulation device, a power transmitting unit that transmits power to the power receiving unit, and a control unit that controls the frequency at which the power transmitting unit transmits power.

[0116] A nerve stimulation method according to a ninth aspect uses the above nerve stimulation system to control the movement of a plurality of muscles by applying a plurality of nerve stimuli to motor nerves in a living body.

[0117] A nerve stimulation method according to a tenth aspect uses the above nerve stimulation system to apply nerve stimulation to sensory nerves in a living body, thereby suppressing transmission of pain to the central nervous system. [Explanation of symbols]

[0118] 100...Neurostimulation system 110...Control unit 120...Power transmission unit 130...Power receiving unit 140...Stimulation current generating unit 150…Stimulation electrode 160...Wiring

Claims

1. A power receiving unit; a nerve stimulation electrode; a stimulation current generating unit that generates a stimulation current to be applied to the nerve stimulation electrode; and The power receiving unit, the nerve stimulation electrode, and the stimulation current generating unit are It can be implanted in the body, The nerve stimulation electrode It is electrically connected to nerves in the body, The stimulation current generating unit comprises: a stimulation current pattern selection unit that associates a stimulation current pattern with a frequency before and a frequency after the change, and selects the stimulation current pattern corresponding to the frequency before and the frequency after the change when the frequency at which the power receiving unit receives power changes; a stimulation current generating unit that generates a stimulation current based on the stimulation current pattern selected by the stimulation current pattern selecting unit; 1. A neurostimulation device comprising:

2. The nerve stimulation device according to claim 1, The power receiving unit is receiving power using at least a first frequency and a second frequency; The stimulation current pattern selection unit selecting the stimulation current pattern from a combination of changes in frequency that change from the first frequency to the second frequency; 1. A neurostimulation device comprising:

3. The nerve stimulation device according to claim 2, The stimulation current generating unit comprises: a stimulation current pattern storage unit that stores a correspondence relationship between a combination of frequency changes from the first frequency to the second frequency and the stimulation current pattern; The stimulation current pattern selection unit selecting the stimulation current pattern by referring to the correspondence relationship in the stimulation current pattern storage unit; 1. A neurostimulation device comprising:

4. The nerve stimulation device according to any one of claims 1 to 3, The stimulation current generating unit comprises: an electrode selection unit that selects to which of the nerve stimulation electrodes the stimulation current generated by the stimulation current generation unit is to be applied; 1. A neurostimulation device comprising:

5. The nerve stimulation device according to any one of claims 1 to 4, The power receiving unit or the stimulation current generating unit is A transmission signal receiving unit that detects the frequency at which the power receiving unit receives power.

1. A neurostimulation device comprising:

6. The nerve stimulation device according to any one of claims 1 to 5, A block electrode that can be implanted in a living body is provided. The block electrode is It is electrically connected to nerves in the body and Blocking nerve signals from the central or peripheral nervous system 1. A neurostimulation device comprising:

7. The nerve stimulation device according to any one of claims 1 to 3, The stimulation current pattern selection unit selecting a first stimulation current pattern to apply during a first time period; selecting a second stimulation current pattern to be applied during a second time period following the first time period; The stimulation current generating unit generating a stimulation current of the first stimulation current pattern during the first time period; generating a stimulation current of the second stimulation current pattern during the second time period; 1. A neurostimulation device comprising:

8. A nerve stimulation device according to any one of claims 1 to 7; a power transmitting unit that transmits power to the power receiving unit; a control unit for controlling a frequency at which the power transmitting unit transmits power; A neurostimulation system comprising:

9. A nerve stimulation method for controlling the movement of a plurality of muscles by applying a plurality of nerve stimuli to motor nerves in a living body (excluding humans), using the nerve stimulation system according to claim 8.

10. A nerve stimulation method for suppressing transmission of pain to the central nervous system by applying nerve stimulation to sensory nerves in a living body (excluding humans) using the nerve stimulation system according to claim 8.

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