Functional electrostimulation device and functional electrostimulation system

Abstract

A functional electrostimulation device (10) comprises: four or more lead wires (12); four or more electrode parts (13) that are respectively provided to the four or more lead wires (12), and that stimulate four or more upper limb related nerves which constitute the brachial plexus or four or more lower limb related nerves which are positioned in the cauda equine; and a main body part (11) that applies a current to the four or more electrode parts (13) via the four or more lead wires (12).

Description

Functional Electrical Stimulation Apparatus and Functional Electrical Stimulation System

[0001] The present invention relates to a functional electrical stimulation device and a functional electrical stimulation system that are implanted in the human body.

[0002] U.S. Patent No. 6,277,623 discloses a technique for stimulating nerves by transmitting a stimulation signal transcutaneously or subcutaneously for urination control. U.S. Patent No. 6,277,623 discloses a technique for stimulating nerves by transmitting a stimulation signal transcutaneously or subcutaneously for tremor control.

[0003] Patent No. 7013023 Patent No. 6507099

[0004] In order to improve the quality of life of patients suffering from neuromuscular diseases, it is desirable to be able to control paralyzed upper or lower limbs. However, in order to be able to precisely control paralyzed upper or lower limbs using the techniques disclosed in Patent Documents 1 and 2, electrodes for stimulating peripheral nerves must be implanted into each of a plurality of peripheral nerves that are distant from each other, which requires many surgical sites and places a heavy burden on the patient.

[0005] Therefore, the present invention provides a functional electrical stimulation device and a functional electrical stimulation system that can stimulate nerves while reducing the burden on a person due to surgical invasion.

[0006] The functional electrical stimulation device of the present invention is a functional electrical stimulation device implanted in a human body, and comprises four or more lead wires, four or more electrode units provided on each of the four or more lead wires to stimulate four or more upper limb-related nerves that make up the brachial plexus or four or more lower limb-related nerves located in the cauda equina, and a main body unit that passes electric current to the four or more electrode units via the four or more lead wires.

[0007] The functional electrical stimulation system according to the present invention comprises the above-described functional electrical stimulation device, a brain-machine interface implanted in the human body, and an external device capable of wireless communication with the functional electrical stimulation device and the brain-machine interface.

[0008] These comprehensive or specific aspects may be realized as a system, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM, or may be realized as any combination of a system, a method, an integrated circuit, a computer program, and a recording medium.

[0009] According to a functional electrical stimulation device according to one aspect of the present invention, nerves can be stimulated while suppressing the burden on a person due to surgical invasion.

[0010] FIG. 1 is a configuration diagram showing an example of a functional electrical stimulation device according to an embodiment. FIG. 2 is a configuration diagram showing another example of a functional electrical stimulation device according to an embodiment. FIG. 3 is a configuration diagram showing an example of a functional electrical stimulation system according to an embodiment. FIG. 4 is a diagram showing an example of a cuff-type electrode unit according to an embodiment. FIG. 5 is a diagram showing an example of a cuff-type electrode unit according to an embodiment. FIG. 6 is a diagram showing an example of a spiral-type electrode unit according to an embodiment. FIG. 7 is a diagram for explaining that a specific muscle can be selectively contracted by using a functional electrical stimulation device according to an embodiment.

[0011] Hereinafter, the embodiments will be specifically described with reference to the drawings.

[0012] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components shown in the following embodiments are merely examples and are not intended to limit the present invention.

[0013] (Embodiments) Hereinafter, functional electrical stimulation devices and functional electrical stimulation systems according to embodiments will be described.

[0014] FIG. 1A is a diagram illustrating an example of a functional electrical stimulation device 10 according to an embodiment.

[0015] FIG. 1B is a configuration diagram showing another example of the functional electrical stimulation device 10 according to the embodiment.

[0016] As shown in Figures 1A and 1B, a functional electrical stimulation device 10 is a device implanted in a human body. The functional electrical stimulation device 10 is a device for performing functional electrical stimulation (FES). FES is performed with the aim of restoring motor function by electrically stimulating muscles to contract. While FES is mainly performed by directly electrically stimulating muscles, this FES is characterized by electrically stimulating the proximal peripheral nerves to contract muscles and restore motor function with minimal surgical invasiveness.

[0017] For example, when controlling an upper limb, as shown in FIG. 1A, the functional electrical stimulation device 10 is implanted subcutaneously under the armpit of a person, but it may also be implanted subcutaneously in the upper arm. For example, when controlling a lower limb, as shown in FIG. 1B, the functional electrical stimulation device 10 is implanted in the lower back of a person. As shown in FIGS. 1A and 1B, the functional electrical stimulation device 10 includes four or more lead wires 12, four or more electrode units 13 provided on each of the four or more lead wires 12, and a main body 11 that applies current to the four or more electrode units 13 via the four or more lead wires 12. For example, one electrode unit 13 is provided at the tip of each of the four or more lead wires 12. For example, the length of each of the four or more lead wires 12 is 20 cm or less, preferably 15 cm or less. The four or more electrode units 13 stimulate four or more upper limb-related nerves that make up the brachial plexus or four or more lower limb-related nerves located in the cauda equina. For example, a pulse signal of 50 Hz or the like is given to each nerve, and a current of about 1 to 4 mA is passed through the nerve, stimulating the nerve and causing the muscle controlled by that nerve to contract.

[0018] For example, the main body 11 may selectively pass a current to each of the four or more electrode units 13. By selectively passing a current to each of the four or more electrode units 13, it is possible to selectively stimulate four or more upper limb-related nerves or four or more lower limb-related nerves, respectively. This makes it possible to control fine motor movements of the upper limbs or lower limbs.

[0019] For example, the main unit 11 may have a wireless interface and pass current through four or more electrodes 13 based on signals received via the wireless interface. This allows signals for controlling the upper or lower limbs to be received wirelessly from an external device (such as the electroencephalogram (EEG) decoding device 100 described below) outside the body, thereby reducing the risk of infection compared to when the external device is connected to the internal functional electrical stimulation device 10 via a wire. Furthermore, for example, the main unit 11 can selectively pass current through each of the four or more electrodes 13 by receiving an instruction from the external device to pass current through a specific electrode 13 among the four or more electrodes 13.

[0020] For example, main body 11 may have a wireless interface with a wireless charging function. For example, the wireless charging function can be realized by a loop antenna or the like. This allows contactless charging of functional electrical stimulation device 10 implanted in the body.

[0021] For example, when controlling the upper limb, as shown in FIG. 1A , the four or more lead wires 12 may be replaced by five lead wires 12, the four or more electrode units 13 may be replaced by five electrode units 13, and the five electrode units 13 may stimulate five upper limb-related nerves. The upper limb is innervated by five nerves emerging from the brachial plexus, specifically the median nerve, radial nerve, musculocutaneous nerve, axillary nerve, and ulnar nerve (hereinafter referred to as upper limb-related nerves). Therefore, the functional electrical stimulation device 10 may be a device for stimulating these five upper limb-related nerves. For example, the electrode units 13 can be attached to the five upper limb-related nerves by making a single skin incision in the armpit, enabling precise control of the movement of the entire upper limb while reducing the invasiveness and complexity of the surgery.

[0022] For example, when controlling the lower limbs, as shown in FIG. 1B , the four or more lead wires 12 may be four lead wires 12, and the four or more electrode units 13 may be four electrode units 13, and the four electrode units 13 may stimulate four lower limb-related nerves. The locomotion function of the lower limbs is primarily controlled at the L4 and L6 levels. Therefore, the functional electrical stimulation device 10 may be a device for stimulating four lower limb-related nerves located in the cauda equina, specifically, the left L4 ventral root, the left L6 ventral root, the right L4 ventral root, and the right L6 ventral root. For example, the electrodes 13 can be attached to the four lower limb-related nerves through a single incision in the lumbar spine (e.g., around the ilium), thereby reducing the invasiveness and complexity of the surgery while enabling motor control of the lower limbs required for locomotion. Furthermore, because the anterior and dorsal root components of the spinal nerves are not intermingled in the cauda equina, the electrodes 13 can be attached only to the anterior root components of the anterior and dorsal root components. By attaching the electrode portion 13 only to the anterior root component, it is possible to selectively electrically stimulate only the motor nerve, avoiding stimulation of the sensory nerve and enabling motor control without causing unpleasant sensations due to sensory stimulation.

[0023] FIG. 2 is a configuration diagram showing an example of a functional electrical stimulation system 1 according to an embodiment.

[0024] As shown in FIG. 2 , for example, the functional electrical stimulation system 1 includes a functional electrical stimulation device 10 , an electroencephalograph 200 , and an electroencephalogram decoding device 100 .

[0025] The electroencephalograph 200 is an example of a brain-machine interface (BMI) that is implanted inside a human body. The main body of the electroencephalograph 200 is implanted subcutaneously on the head, and electrodes are placed on the surface of the human brain to accurately acquire the human brainwave signals from inside the skull. For example, the electroencephalograph 200 and the electroencephalogram decoding device 100 are wirelessly connected, and the electroencephalograph 200 transmits the acquired brainwave signals to the electroencephalogram decoding device 100.

[0026] EEG decoding device 100 is an example of an external device capable of wireless communication with functional electrical stimulation device 10 and BMI (electroencephalograph 200). EEG decoding device 100 decodes the intention of the person to whom electroencephalograph 200 is attached from the electroencephalogram signal, specifically, the type of movement the person is about to perform, and transmits a signal according to the decoding result to functional electrical stimulation device 10.

[0027] For example, if EEG decoding device 100 decodes from the EEG signal that a person is about to clench their right hand, it generates a signal for stimulating the upper limb-related nerves necessary to cause the person to clench their right hand and transmits it to functional electrical stimulation device 10. The signal for stimulating the upper limb-related nerves is, for example, a signal that indicates how much current should be passed through which of five electrode units 13. As will be described later, the signal for stimulating the upper limb-related nerves may also be a signal that indicates which of multiple electrodes provided on electrode unit 13 should receive the current.

[0028] Because the characteristics of brain waves differ depending on the movement a person is about to perform, a trained model that learns the relationship between the content of the movement and the characteristics of the brain waves can be prepared and stored in a memory or the like of the brain wave decoding device 100. For example, the brain wave decoding device 100 can input acquired brain wave signals into the trained model to decode what movement a person is about to perform. Furthermore, because it is possible to determine in advance what amount of current should be passed through which electrode of which electrode unit 13 in order to cause a person to perform what movement, a table or the like can be prepared that associates the electrode unit 13 (and even multiple electrodes in the electrode unit 13) through which current is passed and the amount of current to be passed with the content of the movement, and this can be stored in a memory or the like of the brain wave decoding device 100. Therefore, the EEG decoding device 100 can determine to which of the four or more electrode units 13 (and further to which of the multiple electrodes provided on the electrode unit 13) and how much current should be passed in order to cause the decoded movement to occur in the human muscles, and can instruct the functional electrical stimulation device 10 to pass the determined amount of current through the determined electrode unit 13.

[0029] In this way, by implanting a BMI device consisting of an electroencephalograph 200 and the like in a person, it is possible to control the paralyzed upper or lower limbs so that they perform a specific movement when the person intends to perform that specific movement.

[0030] Next, the electrode portion 13 will be described in detail.

[0031] For example, each of the four or more electrode units 13 has a structure that allows it to be wrapped around each of four or more upper limb-related nerves or four or more lower limb-related nerves, and has a plurality of electrodes that, when wrapped around each of the four or more upper limb-related nerves or four or more lower limb-related nerves, are aligned in the direction of extension of the wrapped upper limb-related nerves or lower limb-related nerves. For example, the electrode unit 13 includes a cuff-type electrode unit 13 and a spiral-type electrode unit 13. First, the cuff-type electrode unit 13 will be described.

[0032] 3A and 3B are diagrams showing an example of a cuff-type electrode unit 13 according to an embodiment.

[0033] For example, the structure that can be wrapped around nerves may be a wrapped plate-like structure as shown in Fig. 3A. Each of the four or more plate-like electrode units 13 is wrapped around each of the four or more upper limb-related nerves or each of the four or more lower limb-related nerves so as to cover each of the four or more upper limb-related nerves or each of the four or more lower limb-related nerves.

[0034] For example, if a nerve extends in the left-right direction in Fig. 3A, the electrode unit 13 is bent in the up-down direction in Fig. 3A so that the electrode unit 13 is wrapped around the nerve to cover the nerve. Fig. 3B is a diagram showing the electrode unit 13 wrapped around the nerve as viewed from the direction in which the nerve extends.

[0035] For example, as shown in FIG. 3A, the cuff-shaped electrode unit 13 has multiple electrodes 13a-13l. As shown in FIG. 3A, the multiple electrodes 13a-13c are aligned along the direction of the nerve when the electrode unit 13 is wrapped around the nerve. Similarly, the multiple electrodes 13d-13f, the multiple electrodes 13g-13i, and the multiple electrodes 13j-13l are aligned along the direction of the nerve when the electrode unit 13 is wrapped around the nerve. In FIG. 3B, electrodes 13b and 13a are provided behind electrode 13c, electrodes 13e and 13d are provided behind electrode 13f, electrodes 13h and 13g are provided behind electrode 13i, and electrodes 13k and 13j are provided behind electrode 13l.

[0036] For example, when it is necessary to stimulate the area of ​​the nerve around electrodes 13a to 13c in order to cause a specific movement, a voltage can be applied to electrodes 13a to 13c so that electrodes 13a and 13c have a positive potential and electrode 13b has a negative potential, thereby allowing current to flow from electrode 13a to electrode 13b and from electrode 13c to electrode 13b, and the current distribution in the nerve can be localized by so-called three-phase stimulation.

[0037] Next, the spiral electrode portion 13 will be described.

[0038] 4A and 4B are diagrams showing an example of a spiral electrode unit 13 according to an embodiment.

[0039] For example, the structure that can be wrapped around a nerve may be a linear structure as shown in Fig. 4A. Each of the four or more linear electrode units 13 is wound spirally around each of four or more upper limb-related nerves or four or more lower limb-related nerves as shown in Fig. 4A. Fig. 4B is a diagram of the electrode unit 13 wrapped around the nerve as viewed from the direction in which the nerve extends. The spiral shape of the electrode unit 13 makes it difficult for the electrode unit 13 to come off the nerve.

[0040] For example, as shown in Fig. 4A, the spiral-shaped electrode unit 13 has multiple electrodes 13m-13t. As shown in Fig. 4A, the multiple electrodes 13m and 13n are aligned along the direction of extension of the nerve when the electrode unit 13 is wrapped around the nerve. Similarly, the multiple electrodes 13o and 13p, the multiple electrodes 13q and 13r, and the multiple electrodes 13s and 13t are aligned along the direction of extension of the nerve when the electrode unit 13 is wrapped around the nerve. In Fig. 4B, electrode 13m is provided behind electrode 13n, electrode 13o is provided behind electrode 13p, electrode 13q is provided behind electrode 13r, and electrode 13s is provided behind electrode 13t.

[0041] For example, if it is necessary to stimulate the area of ​​the nerve around electrodes 13m and 13n in order to perform a specific movement, a voltage can be applied to electrodes 13m and 13n so that electrode 13m has a positive potential and electrode 13n has a negative potential, thereby allowing a current to flow from electrode 13m to electrode 13n.

[0042] In this way, by arranging multiple electrodes along the direction of the upper limb-related nerves or lower limb-related nerves, it is possible to locally stimulate the upper limb-related nerves or lower limb-related nerves, thereby enabling fine motor control of the upper limbs or lower limbs.

[0043] Next, the ability to selectively contract specific muscles by stimulating nerves will be described with reference to FIG.

[0044] 5 is a diagram illustrating how specific muscles can be selectively contracted using functional electrical stimulation device 10 according to an embodiment. The horizontal axis of each graph represents the amount of current flowing through the nerve, and the vertical axis represents the amount of muscle contraction.

[0045] As shown in the top row of Figure 5, stimulating the radial nerve primarily contracts the triceps brachii muscle. Also, as shown in the middle row of Figure 5, stimulating the axillary nerve primarily contracts the deltoid muscle. Also, as shown in the bottom row of Figure 5, stimulating the musculocutaneous nerve primarily contracts the flexor digitorum superficialis muscle.

[0046] As described above, the functional electrical stimulation device 10 of the present invention can stimulate four or more upper limb-related nerves that make up the brachial plexus or four or more lower limb-related nerves located in the cauda equina. Because the brachial plexus is home to a concentration of upper limb-related nerves that precisely control the upper limbs, a single surgical approach (i.e., a minimally invasive surgical procedure) of implanting the functional electrical stimulation device 10 near the brachial plexus can attach four or more electrode units 13 to four or more upper limb-related nerves, thereby reducing the burden on the patient due to surgical intervention. Furthermore, because the cauda equina is home to a concentration of lower limb-related nerves that control the lower limbs, a single surgical approach (i.e., a minimally invasive surgical procedure) of implanting the functional electrical stimulation device 10 near the cauda equina can attach four or more electrode units 13 to four or more lower limb-related nerves, thereby reducing the burden on the patient due to surgical intervention. Furthermore, since four or more upper limb-related nerves or four or more lower limb-related nerves are concentrated together, the lead wire 12 for passing current to the electrode portion 13 attached to each nerve can be shortened to 15 cm or less, thereby reducing the amount of foreign matter implanted in the body.

[0047] Because peripheral nerves branch into multiple branches at their distal ends, attaching electrodes to all branches requires numerous surgical incisions, placing a significant burden on the patient due to the invasive surgical procedure. However, the functional electrical stimulation device 10 of the present invention can stimulate nerves while minimizing the burden on the patient due to the invasive surgical procedure. Furthermore, a patient implanted with the functional electrical stimulation device 10 can regain control of their paralyzed upper or lower limbs, improving their quality of life.

[0048] (Other Embodiments) As described above, the embodiments have been described as examples of the technology according to the present invention. However, the technology according to the present invention is not limited to these, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate. For example, the following modifications are also included in one embodiment of the present invention.

[0049] For example, in the above embodiment, an example has been described in which the main body 11 of the functional electrical stimulation device 10 has a wireless interface, but the main body 11 of the functional electrical stimulation device 10 does not have to have a wireless interface. For example, communication or charging may be performed via a wired connection.

[0050] For example, in the above embodiment, an example has been described in which the multiple electrodes of the electrode unit 13 are arranged along the direction in which the nerves extend, but the multiple electrodes of the electrode unit 13 do not have to be arranged along the direction in which the nerves extend. Also, the number of multiple electrodes of the electrode unit 13 shown in Figures 3A to 4B is one example, and the number may be more or less than the number shown in Figures 3A to 4B.

[0051] For example, in the above embodiment, the four or more lead wires 12 are four or five lead wires 12, but the four or more lead wires 12 may be six or more lead wires 12. Similarly, the four or more electrode portions 13 may be six or more electrode portions 13.

[0052] In addition, the present invention also includes forms obtained by making various modifications to the embodiments that a person skilled in the art would think of, and forms realized by arbitrarily combining the components and functions in each embodiment within the scope of the present invention.

[0053] (Additional Notes) The above description of the embodiments discloses the following techniques.

[0054] (Technology 1) A functional electrical stimulation device to be implanted in a human body, comprising: four or more lead wires; four or more electrode units provided on each of the four or more lead wires to stimulate four or more upper limb-related nerves that make up the brachial plexus, or four or more lower limb-related nerves located in the cauda equina; and a main body unit that passes electric current to the four or more electrode units via the four or more lead wires.

[0055] Because peripheral nerves branch into multiple branches at their distal ends, attaching electrodes to all branches requires numerous surgical incisions, resulting in significant surgical invasiveness and burden on the patient. In contrast, the functional electrical stimulation device of the present invention can stimulate four or more upper limb-related nerves that make up the brachial plexus or four or more lower limb-related nerves located in the cauda equina. Because the brachial plexus contains a concentration of upper limb-related nerves that provide precise control of the upper limbs, a single surgical approach (i.e., minimally invasive) of implanting a functional electrical stimulation device near the brachial plexus can attach four or more electrodes to four or more upper limb-related nerves, thereby reducing the burden on the patient due to surgical invasiveness. Furthermore, because the cauda equina contains a concentration of lower limb-related nerves that provide control of the lower limbs, a single surgical approach (i.e., minimally invasive) of implanting a functional electrical stimulation device near the cauda equina can attach four or more electrodes to four or more lower limb-related nerves, thereby reducing the burden on the patient due to surgical invasiveness. Furthermore, because four or more upper limb-related nerves or four or more lower limb-related nerves are concentrated in one area, the lead wires used to pass current to the electrodes attached to each nerve can be shortened, thereby reducing the amount of foreign material implanted in the body. Thus, the functional electrical stimulation device of the present invention can stimulate nerves while minimizing the burden on the patient due to surgical invasiveness. Furthermore, a patient implanted with the functional electrical stimulation device can regain control of their paralyzed upper or lower limb, improving their quality of life.

[0056] (Technology 2) A functional electrical stimulation device described in Technology 1, wherein the main body selectively passes current to each of the four or more electrode units.

[0057] According to this, by selectively passing a current through each of the four or more electrodes, it is possible to selectively stimulate four or more upper limb-related nerves or four or more lower limb-related nerves, respectively, thereby enabling fine motor control of the upper or lower limbs.

[0058] (Technology 3) A functional electrical stimulation device described in Technology 1 or 2, wherein the main body has a wireless interface and passes current through the four or more electrode units based on a signal received via the wireless interface.

[0059] This allows signals for controlling the upper or lower limbs to be received via wireless communication with an external device outside the body, thereby reducing the risk of infection compared to when the external device outside the body and the functional electrical stimulation device inside the body are connected by wire.

[0060] (Technology 4) A functional electrical stimulation device described in any one of technologies 1 to 3, wherein the main body has a wireless interface with wireless charging functionality.

[0061] This allows for contactless charging of a functional electrical stimulation device implanted in the body.

[0062] (Technology 5) A functional electrical stimulation device described in any of technologies 1 to 4, wherein each of the four or more electrode units has a structure that allows it to be wrapped around each of the four or more upper limb-related nerves or each of the four or more lower limb-related nerves, and has a plurality of electrodes that, when wrapped around each of the four or more upper limb-related nerves or each of the four or more lower limb-related nerves, are aligned along the extension direction of the wrapped upper limb-related nerve or lower limb-related nerve.

[0063] This allows local stimulation of the upper limb-related nerves or lower limb-related nerves by multiple electrodes aligned along the direction of the upper limb-related nerves or lower limb-related nerves, thereby enabling fine motor control of the upper limbs or lower limbs.

[0064] (Technology 6) A functional electrical stimulation device according to Technology 5, wherein the structure is a plate-like structure, and each of the four or more plate-like electrode portions is wrapped around each of the four or more upper limb-related nerves or each of the four or more lower limb-related nerves to cover the four or more upper limb-related nerves or each of the four or more lower limb-related nerves.

[0065] In this way, the electrode portion may be cuff-shaped.

[0066] (Technology 7) A functional electrical stimulation device described in Technology 5, wherein the structure is a linear structure, and each of the four or more linear electrode portions is spirally wrapped around each of the four or more upper limb-related nerves or each of the four or more lower limb-related nerves.

[0067] In this way, the electrode portion may be of a spiral type. Furthermore, by using a spiral type electrode portion, it is possible to make the electrode portion less likely to come off the nerve.

[0068] (Technology 8) A functional electrical stimulation device described in any one of Techniques 1 to 7, wherein each of the four or more lead wires is 20 cm or less in length.

[0069] In this way, because four or more upper limb-related nerves or four or more lower limb-related nerves are concentrated together, the length of the lead wire for passing current to the electrode portion attached to each nerve can be shortened to 20 cm or less, thereby reducing the amount of foreign matter implanted in the body.

[0070] (Technology 9) A functional electrical stimulation device described in Technology 8, wherein each of the four or more lead wires is 15 cm or less in length.

[0071] In this way, because four or more upper limb-related nerves or four or more lower limb-related nerves are concentrated together, the length of the lead wire for passing current to the electrode portion attached to each nerve can be shortened to 15 cm or less, thereby reducing the amount of foreign matter implanted in the body.

[0072] (Technology 10) The four or more lead wires are five lead wires, the four or more electrode units are five electrode units, and five upper limb-related nerves are stimulated. A functional electrical stimulation device described in any one of technologies 1 to 9.

[0073] In this way, the functional electrical stimulation device may be a device for stimulating the five upper limb-related nerves that make up the brachial plexus, specifically the median nerve, radial nerve, musculocutaneous nerve, axillary nerve, and ulnar nerve. For example, electrodes can be attached to the five upper limb-related nerves through a single incision in the armpit, enabling fine motor control of the upper limb while reducing the invasiveness and complexity of the surgery.

[0074] (Technology 11) A functional electrical stimulation device described in any one of technologies 1 to 9, wherein the four or more lead wires are four lead wires, the four or more electrode units are four electrode units, and four lower limb-related nerves are stimulated.

[0075] In this way, the functional electrical stimulation device may be a device for stimulating four lower limb-related nerves located in the cauda equina, specifically, the left L4 ventral root, the left L6 ventral root, the right L4 ventral root, and the right L6 ventral root. For example, electrodes can be attached to the four lower limb-related nerves through a single incision in the lumbar spine, thereby enabling motor control of the lower limbs while reducing the invasiveness and complexity of the surgery. Furthermore, because the anterior and posterior root components of the spinal nerves are not mixed in the cauda equina, electrodes can be attached only to the anterior root components of the anterior and posterior root components. By attaching electrodes only to the anterior root components, it is possible to selectively electrically stimulate only the motor nerves, avoiding stimulation of sensory nerves and enabling motor control without causing discomfort due to sensory stimulation.

[0076] (Technology 12) A functional electrical stimulation system comprising: a functional electrical stimulation device according to any one of technologies 1 to 11; a brain-machine interface implanted in the human body; and an external device capable of wireless communication with the functional electrical stimulation device and the brain-machine interface.

[0077] This allows for the provision of a functional electrical stimulation system that can stimulate nerves while minimizing the burden on the person due to surgical invasiveness. For example, by attaching a brain-machine interface such as an electroencephalograph to the human brain, it is possible to control the paralyzed upper or lower limbs so that they perform a specific movement when the person intends to perform that movement.

[0078] The present invention can be applied to a device that electrically stimulates nerves.

[0079] REFERENCE SIGNS LIST 1 Functional electrical stimulation system 10 Functional electrical stimulation device 11 Main body 12 Lead wire 13 Electrode unit 13a to 13t Electrodes 100 Electroencephalogram decoding device 200 Electroencephalograph

Claims

1. A functional electrical stimulation device to be implanted in the human body, comprising: four or more lead wires; four or more electrode units provided on each of the four or more lead wires for stimulating four or more upper limb-related nerves that constitute the brachial plexus, or four or more lower limb-related nerves located in the cauda equina; and a main body unit that passes electric current to the four or more electrode units via the four or more lead wires.

2. The functional electrical stimulation device according to claim 1, wherein the main body selectively applies electric current to each of the four or more electrode portions.

3. The functional electrical stimulation device according to claim 1, wherein the main body has a wireless interface and applies current to the four or more electrode units based on a signal received via the wireless interface.

4. The functional electrical stimulation device according to claim 1, wherein the main body has a wireless interface with a wireless charging function.

5. A functional electrical stimulation device as described in claim 1, wherein each of the four or more electrode sections has a structure that allows it to be wrapped around each of the four or more upper limb related nerves or each of the four or more lower limb related nerves, and has a plurality of electrodes that, when wrapped around each of the four or more upper limb related nerves or each of the four or more lower limb related nerves, are aligned in the extension direction of the wrapped upper limb related nerve or lower limb related nerve.

6. A functional electrical stimulation device as described in claim 5, wherein the structure is a plate-like structure, and each of the four or more plate-like electrode portions is wrapped around and covers each of the four or more upper limb-related nerves, or each of the four or more lower limb-related nerves, and is placed on each of the four or more upper limb-related nerves, or each of the four or more lower limb-related nerves.

7. A functional electrical stimulation device as described in claim 5, wherein the structure is a linear structure, and each of the four or more linear electrode portions is spirally wound around each of the four or more upper limb-related nerves, or each of the four or more lower limb-related nerves.

8. The functional electrical stimulation device of claim 1, wherein each of the four or more lead wires is 20 cm or less in length.

9. The functional electrical stimulation device of claim 8, wherein each of the four or more lead wires is 15 cm or less in length.

10. A functional electrical stimulation device according to any one of claims 1 to 9, wherein the four or more lead wires are five lead wires, and the four or more electrode units are five electrode units, stimulating five upper limb-related nerves.

11. A functional electrical stimulation device according to any one of claims 1 to 9, wherein the four or more lead wires are four lead wires, and the four or more electrode units are four electrode units, stimulating four lower limb-related nerves.

12. A functional electrical stimulation system comprising: a functional electrical stimulation device according to any one of claims 1 to 9; a brain-machine interface implanted in the human body; and an external device capable of wireless communication with the functional electrical stimulation device and the brain-machine interface.

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