Devices used to detect or stimulate activity of nervous tissue

Abstract

To provide a device which is used for detection or stimulation of nervous tissue activities, excellent in delivery performance to the cerebral blood vessel, and has reduced contact with the blood vessel wall.SOLUTION: A device 1 is provided with at least either a first intravascular device 10 or a second intravascular device 20 which is provided with at least one of a first intravascular electrode 11, a first intravascular spare electrode 12, a second intravascular electrode 21 and a second intravascular spare electrode 22 arranged in the blood vessel of an organism and for detection or stimulation of activities of nervous tissues positioned outside the blood vessel nearby. The intravascular electrode and the intravascular spare electrode are provided for a wire member.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to devices used to sense or stimulate activity in nervous tissue. [Background technology]

[0002] Conventionally, when measuring the brainwaves of animals, humans, and other living organisms, transcranial measurements have been performed by attaching electrodes to the scalp to measure brainwaves. This method allows easy measurement of brainwaves, but has the following drawbacks. That is, since only information from the surface of the brain can be obtained, only brainwaves near the surface of the brain can be measured, and brainwaves generated deep within the brain cannot be measured. In addition, accurate measurement is difficult because brainwaves are attenuated when passing through the skull.

[0003] To overcome these drawbacks, subdural electrodes and stereotactic deep brain electrodes (SEEG) have come into use. In these methods, the skull is opened or a hole is drilled in the skull, and electrodes are inserted directly into the brain to measure EEG. Although this is highly invasive, it is possible to measure the necessary EEG with high accuracy. SEEG also makes it possible to measure EEG deep in the brain, making it possible to identify areas of brain tissue that cause epilepsy, for example.

[0004] However, as mentioned above, subdural electrodes and SEEG require the skull to be opened or a hole to be drilled, which is highly invasive. In addition, because the skull must be opened or a hole must be drilled, measurements cannot be taken easily and it is difficult to take measurements over long periods of time, such as several days. Furthermore, SEEG is very expensive.

[0005] Patent Document 1 discloses a technique for sensing or stimulating electrical activity of nerve tissue within a blood vessel. Specifically, in Patent Document 1, a stent provided with electrodes is expanded in a cerebral blood vessel and anchored to the blood vessel wall, thereby sensing or stimulating electrical activity of nearby neural tissue. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2017-159079 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the technology of Patent Document 1 uses a stent with expansive force, so operability is likely to decrease due to friction with the catheter during delivery to the cerebral blood vessels. This phenomenon can be further exacerbated by the bulkiness of the electrodes. Furthermore, since the metal struts of a stent remain in contact with the cerebral blood vessel wall over a wide area, prolonged use of the stent can increase the risk of developing a blood clot.

[0008] An object of the present invention is to provide a device which is used for detecting or stimulating the activity of nerve tissue, has excellent deliverability to cerebral blood vessels, and can reduce contact with blood vessel walls. [Means for solving the problem]

[0009] The present invention solves the above problems by the following solving means. Note that, for ease of understanding, the following description will be given with reference numerals corresponding to the embodiments of the present invention, but the present invention is not limited thereto.

[0010] The first invention is an apparatus (1) comprising at least one intravascular device (10, 20) for placement within a blood vessel of a living organism and comprising at least one electrode (11, 12, 21, 22) for sensing or stimulating activity of neural tissue located outside the vessel in the vicinity, the electrode (11, 12, 21, 22) being provided on a wire member.

[0011] A second invention is an apparatus (1) according to the first invention, wherein at least one of the intravascular devices (10, 20) has a plurality of the electrodes (11, 12, 21, 22), the electrodes (11, 12, 21, 22) being spaced apart by less than 1 cm from each other and attached to the same wire member.

[0012] The third invention is an apparatus (1) according to the first or second invention, which comprises a plurality of the intravascular devices (10, 20), and the electrodes (11, 12, 21, 22) of the different intravascular devices (10, 20) are arranged at least 1 cm apart from each other within the blood vessel.

[0013] A fourth invention is a device (1) according to any one of the first to third inventions, wherein the wire member has a spiral portion (13) that is expandable and contractable in the circumferential direction and that is engaged with the wall of the blood vessel in the expanded state.

[0014] A fifth aspect of the present invention is an apparatus (1) according to any one of the first to fourth aspects of the present invention, wherein the intravascular device (1) is placed in a blood vessel for one day or more.

[0015] A sixth invention is an apparatus (1) according to any one of the first to fifth inventions, wherein the blood vessel in which the intravascular device is placed is the cerebral venous sinus. Effect of the Invention

[0016] According to the present invention, it is possible to provide a device which is used for detecting or stimulating the activity of nerve tissue, has excellent deliverability to cerebral blood vessels, and reduces contact with blood vessel walls. [Brief description of the drawings]

[0017] [Figure 1] 1 is a block diagram showing a configuration of an embodiment of an apparatus according to the present invention; [Diagram 2] FIG. 2 is a diagram illustrating an example of the configuration of the vicinity of the tip of the first intravascular device 10 on the side that is inserted into a cerebral blood vessel. [Diagram 3] FIG. 13 is a diagram for explaining another example of the configuration of the vicinity of the tip of the first intravascular device 10 on the side that is inserted into a cerebral blood vessel. [Figure 4] FIG. 4 is a diagram showing a modification of the first intravascular device 10 shown in FIG. [Diagram 5] 1 is a flowchart illustrating an embodiment of an electroencephalogram measuring method. [Figure 6] FIG. 1 is a diagram showing measurement points in a verification experiment. [Figure 7] FIG. 13 is a diagram showing a portion of the electroencephalogram measurement results obtained in a verification experiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

[0019] (Embodiment) FIG. 1 is a block diagram showing the configuration of an embodiment of an electroencephalogram measuring device used in a method of measuring an electroencephalogram according to the present invention. Note that the figures shown below, including FIG. 1, are schematic diagrams, and the size and shape of each part are exaggerated or omitted as appropriate to facilitate understanding. In the following description, specific numerical values, shapes, materials, etc. are given, but these can be changed as appropriate.

[0020] The device 1 of this embodiment is a device used for detecting or stimulating neural activity of a living organism such as an animal or a human being. The apparatus 1 includes a first intravascular device 10, a second intravascular device 20, a first reference electrode 30, a second reference electrode 40, and a calculation unit 50. However, the present invention is not limited to this, and the number of intravascular devices and reference electrodes may be one, or three or more. Furthermore, the apparatus does not need to include a reference electrode and a calculation unit (particularly in the case of stimulation applications).

[0021] The first intravascular device 10 is placed within a blood vessel (typically a cerebral vessel) of an organism during measurement and comprises at least one electrode for sensing or stimulating activity of neural tissue located outside the vessel nearby. The electrodes are provided on a wire member. The wire member in the present invention refers to a member that is rod-shaped in an extended state and does not have an internal cavity, unlike a cylindrical body.

[0022] FIG. 2 is a diagram illustrating the configuration of the vicinity of the tip of the first intravascular device 10 on the side that is inserted into a cerebral blood vessel. The first intravascular device 10 is inserted into the cerebral blood vessels through a catheter used in conventional cerebral intravascular surgery. At this time, since the electrodes are provided on the wire member, the expansion force is smaller than that of a stent, and the slidability against the catheter is excellent, so that the deliverability to the cerebral blood vessels is excellent. In addition, since the wire member is prevented from contacting the blood vessels (particularly, as in this embodiment, the rod-shaped wire member in its natural state hardly comes into contact with the blood vessel wall), adverse events are unlikely to occur even if the device is left in the blood vessels for a long period of time. For this reason, it is preferable that the device is left in the blood vessels for one day or more (specifically, two days or more, five days or more, seven days or more, two weeks or more, or one month or more). The first intravascular device 10 includes a core material 13 and an insulator 14. More specifically, for example, the core material 13 may be a stainless steel ultra-fine wire, and the outer periphery of the core material 13 may be coated with an insulator 14. An example of the stainless steel ultra-fine wire of the core material 13 is SUS304 with a diameter of about 0.34 mm. An example of the insulator 14 is a polyimide tube or a PTFE tube. Although the insulator 14 itself is a cylindrical body, the inside of the insulator is filled with a core material, and therefore the insulator 14 is regarded as a wire member in the first intravascular device.

[0023] The first intravascular device 10 includes a first intravascular electrode 11 and a first spare intravascular electrode 12, which are spaced apart from each other by less than 1 cm and are attached to the same wire member. However, this is not limited to this, and one intravascular device may be provided with one electrode or a plurality of electrodes, three or more.

[0024] In this embodiment, the first intravascular electrode 11 is provided in a ring shape with a width of 1 mm all around without being covered with the insulator 14. The first intravascular electrode 11 is electrically connected to a calculation unit 50 (described later) by a wiring 15 passing through the insulator 14. The first intravascular reserve electrode 12 is disposed at a position 5 mm away from the first intravascular electrode 11. The first intravascular reserve electrode 12 is provided in a ring shape with a width of 1 mm all around without being covered with the insulator 14. The first intravascular reserve electrode 12 is electrically connected to a calculation unit 50 (described later) by wiring 16 passing through the insulator 14. In this way, the first intravascular reserve electrode 12 has a similar configuration to the first intravascular electrode 11, and is spaced apart from each other by less than 1 cm, and the nerve tissues that can be detected or stimulated can be considered to be equivalent, so that the first intravascular reserve electrode 12 serves as a backup for the first intravascular electrode 11.

[0025] FIG. 3 is a diagram for explaining another example of the configuration of the vicinity of the tip of the first intravascular device 10 on the side to be inserted into a cerebral blood vessel. The wire member has a spiral portion 13 that can expand and contract in the circumferential direction and is engaged with the wall of the blood vessel in the expanded state. By engaging the spiral portion 13 with the wall of the blood vessel, the positions of the electrodes 11 and 12 in the blood vessel are substantially fixed, so that the activity of the nerve tissue can be detected or stimulated more accurately. Here, unlike normal blood vessels that have a nearly perfect circle in cross section, cerebral blood vessels (particularly cerebral venous sinuses) are irregular, so a spiral body with excellent conformal deformation is more likely to achieve both a small expansion force and a high position fixing effect than a rigid stent. This can provide a synergistic effect that it is easier to design the contact area with the blood vessel to be smaller than a stent, and it is easier to improve the delivery performance because of its excellent sliding properties with the catheter.

[0026] The second intravascular device 20 includes a second intravascular electrode 21, a second spare intravascular electrode 22, a core material 23, an insulator 24, a wire 25, and a wire 26. The second intravascular device 20 has a similar configuration to the first intravascular device 10, and therefore a detailed description thereof will be omitted. However, the present invention is not limited to this, and only one of the first intravascular device and the second intravascular device may have the above-mentioned configuration.

[0027] In FIG. 3, the electrodes are provided at locations other than the spiral portion 13 (for example, a straight portion proximal to the spiral portion 13). However, this is not limited thereto, and for example, the electrode 17 may be provided at the spiral portion 13 as shown in FIG. 4, or the electrodes may be provided at both the spiral portion 13 and other locations. Electrodes 11, 12 provided at locations other than the spiral portion are preferable in that the distance between the electrodes does not change, making it easy to detect or stimulate the activity of nervous tissue as expected. Electrode 17 provided at the spiral portion is preferable in that it is placed in contact with or near the blood vessel wall, making it easy to improve the sensitivity of detecting or stimulating the activity of nervous tissue.

[0028] The first reference electrode 30 is an electrode that obtains a reference potential of the brain waves measured by the first intravascular electrode 11 and the first spare intravascular electrode 12. The first reference electrode 30 is not inserted into the body but is attached outside the body, for example, to the earlobe.

[0029] The second reference electrode 40 is an electrode that obtains a reference potential of the brain waves measured by the second intravascular electrode 21 and the second spare intravascular electrode 22. The second reference electrode 40 is not inserted into the body but is attached outside the body, for example, to the earlobe.

[0030] The calculation unit 50 obtains the potential information obtained from each of the electrodes and calculates the measurement result of the electroencephalogram. The simplest form of the calculation performed by the calculation unit 50 is, for example, to set the measurement result of the first intravascular electrode 11 as the measurement result of the electroencephalogram with the reference potential obtained by the first reference electrode 30 as the reference (zero). In addition to the above, the calculation unit 50 can perform various calculation filter processes such as noise removal.

[0031] Next, a method for measuring electroencephalograms (detecting activity of nervous tissue) using the device 1 of this embodiment will be described. FIG. 5 is a flowchart illustrating the electroencephalogram measuring method. In the electroencephalogram measuring method using the apparatus 1 of this embodiment, first, in step (hereinafter simply referred to as S) 11, the first intravascular device 10 is placed in a cerebral blood vessel.

[0032] In S12, the second intravascular device 20 is placed in a cerebral blood vessel at a predetermined distance from the first intravascular device 10. The cerebral blood vessel may be a cerebral vein such as a venous sinus (e.g., superior sagittal sinus, sigmoid sinus, transverse sinus, straight sinus, inferior sagittal sinus), internal jugular vein, cortical vein, internal cerebral vein, or a cerebral artery such as anterior cerebral artery, middle cerebral artery, or posterior cerebral artery. For example, when the first intravascular device 10 is placed on the left brain side, the second intravascular device 20 is placed on the right brain side. Here, the above-mentioned predetermined distance is preferably 1 cm or more, and more preferably 2 cm or more. If the first intravascular device 10 and the second intravascular device 20 are too close, it is difficult to determine which position is being detected or stimulated.

[0033] The first intravascular device 10 and the second intravascular device 20 can be inserted into the cerebral blood vessels in the same manner as in conventionally known cerebral intravascular treatments using catheters.

[0034] In S13, the first reference electrode 30 is attached to the earlobe. In S14, the second reference electrode 40 is attached to the earlobe. In S15, measurement of brain waves is started. In S16, after the necessary electroencephalogram measurements are performed, the measurement is terminated.

[0035] Next, an experiment was carried out to verify that electroencephalograms can be appropriately measured by the electroencephalogram measuring method using the device 1 of this embodiment, and will be described. In addition to the electroencephalogram measuring method of this embodiment, a conventional electroencephalogram measuring method in which electrodes are attached to the scalp surface (hereinafter also referred to as a comparative example) was performed for verification. For the electroencephalogram measuring method of this embodiment, a first intravascular electrode 11 was placed at a position near the front of the head in the superior sagittal sinus (a blood vessel extending back and forth through the center of the brain) and measurement was performed. For comparison, an electrode of the comparative example was also attached at a position away from the position where the first intravascular electrode 11 was placed and measurement was performed.

[0036] FIG. 6 is a diagram showing measurement points in the verification experiment. More specifically, in the verification experiment, the measurement target was a pig's electroencephalogram, and the electrodes of the comparative example were attached to four locations: the frontal region F3 of the left brain, the occipital region P3 of the left brain, the frontal region F4 of the right brain, and the occipital region P4 of the right brain. In addition, a reference electrode for the left brain was attached to the left earlobe A1, and a reference electrode for the right brain was attached to the right earlobe A2. Meanwhile, the tip of the first intravascular device 10 of this embodiment (the first intravascular electrode 11 and the first spare intravascular electrode 12) was placed in the superior sagittal sinus near the frontal region F3.

[0037] FIG. 7 is a diagram showing a portion of the electroencephalogram measurement results obtained in the verification experiment. F3 is an electroencephalogram obtained from an electrode attached to the frontal region F3 of the left brain in the comparative example. F4 is an electroencephalogram obtained from an electrode attached to the frontal region F4 of the right brain in the comparative example. P3 is an electroencephalogram obtained from an electrode attached to P3 at the back of the left brain in the comparative example. P4 is an electroencephalogram obtained from an electrode attached to the occipital region P4 of the right brain in the comparative example. 11 denotes an electroencephalogram obtained from the first intravascular electrode 11 of this embodiment. 12 denotes an electroencephalogram obtained from the first auxiliary intravascular electrode 12 of this embodiment. It should be noted that the waveforms of 11 and 12 are shown at a scale that is reduced in the vertical direction to 1 / 4 of the waveforms of the other comparative examples. 7, the electroencephalograms (11, 12) obtained by the electroencephalogram measuring method of this embodiment both contain peaks unique to the electroencephalograms (F3, F4) obtained by the measurement at the front of the head in the comparative example, but do not contain peaks unique to the electroencephalograms (P3, P4) obtained by the measurement at the back of the head in the comparative example. Conversely, peaks unique to each of the left brain (F3) and the right brain (F4) are both included in the electroencephalograms (11, 12). From these facts the following can be deduced: The electrodes attached to the wire members can detect the activity of nearby nerve tissue outside the blood vessels with high sensitivity. Furthermore, the ability to detect means that the nerve tissue and the electrodes are electrically connected, so it is possible to stimulate nerve activity with high efficiency by supplying electricity from a power source to the electrodes. Similar EEG patterns are observed when the electrodes are less than 1 cm apart from the neural tissue, so backup electrodes should be spaced less than 1 cm apart. When the distance from the neural tissue to the electrode differed by 1 cm or more, it was possible to distinguish and detect the activity of the neural tissue that was closer to the electrode. Therefore, when distinguishing and detecting and stimulating the activity of multiple neural tissues, the electrodes should be placed at a distance of 1 cm or more.

[0038] Considering the above, the present invention can be used for various purposes. For example, if the intravascular device of the present invention is appropriately positioned in a cerebral blood vessel near the left and right brain and electroencephalograms are detected, it can be used to identify epilepsy foci and detect epileptic seizures. In addition, for diseases whose causative site is deep in the brain (epilepsy, depression, involuntary movements due to Parkinson's disease, persistent vegetative state, etc.), if the intravascular device of the present invention is appropriately positioned at the causative site and electrical stimulation is supplied, it can be used to treat these diseases.

[0039] (Variations) The present invention is not limited to the above-described embodiment, and various modifications and variations are possible, and these are also within the scope of the present invention.

[0040] (1) In the embodiment, an example in which electrodes are placed at two locations in a cerebral blood vessel has been described, but the present invention is not limited to this, and electrodes may be placed at three or more locations.

[0041] (2) In the embodiment, a specific example of pigs has been described as an example, but the present invention is not limited thereto, and the device of the present invention may be used for other mammals such as mice, rats, monkeys, and humans.

[0042] The embodiments and modifications may be used in appropriate combination, but detailed description thereof will be omitted. The present invention is not limited to the embodiments described above. [Explanation of symbols]

[0043] 1 device 10. First intravascular device 11 First intravascular electrode 12 First spare intravascular electrode 13 Core material 14 Insulators 15, 16 Wiring 20 Second intravascular device 21 Second intravascular electrode 22 Second spare intravascular electrode 23 Core material 24 Insulators 25, 26 Wiring 30 1st reference electrode 40 Second reference electrode 50 Arithmetic section

Claims

1. At least one intravascular device is disposed within a brain vasculature of an organism, the intravascular device comprising at least one electrode for sensing or stimulating activity of nearby extravascularly located neural tissue; The electrode is provided on a wire member, The wire member has a core material and an insulator covering the core material, The electrode is provided in a ring shape around the entire circumference without being covered with the insulator, A device comprising a wire connected to the electrode, passing through the insulator, and extending linearly.

2. 2. The device of claim 1, wherein the electrodes are provided on straight portions of the wire members.

3. At least one of the intravascular devices has a plurality of the electrodes; 3. A device as claimed in claim 1 or 2, wherein the electrodes are spaced less than 1 cm apart and are provided on the same wire member.

4. A plurality of the intravascular devices are provided, 4. Apparatus according to any one of claims 1 to 3, wherein the electrodes of the separate intravascular devices are positioned within the blood vessel at least 1 cm apart from each other.

5. The device according to claim 1 , wherein the wire member is expandable and contractable in the circumferential direction and has a spiral portion that is anchored to the wall of the blood vessel in an expanded state.

6. 6. The apparatus of claim 1, wherein the intravascular device is adapted to be left in the blood vessel for one or more days.

7. 7. The apparatus of claim 1, wherein the blood vessel in which the intravascular device is placed is a cerebral venous sinus.

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