JP2002529132A - Electrode and electrode arrangement method suitable for functional magnetic resonance imaging apparatus - Google Patents

Abstract

(57) [Summary] In an electroencephalogram acquisition device, an electrode positioning device includes an extensible elastic cap 10, a flexible rubber electrode holder 20A, and a conductive recording electrode (no number). The conductive wire 13 is made of a material such as a metal or a carbon conductive material. No type of ferromagnetic material is used in the structure of the device, so that the device does not cause any undesired impure effects on functional magnetic resonance imaging (MRI) data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Cross-reference of related applications]

This application is a provisional US patent application Ser. No. 60/107, filed Nov. 10, 1998, filed by Don DuRousseau, incorporated herein by reference in its entirety. No. 918 claims priority.

[0002]

FIELD OF THE INVENTION

The present invention relates to medical devices, and more particularly, to being impure from the brain and body without the use of pre-amplification electronics while placed in the harsh operating environment generated by functional magnetic resonance imaging (fMRI) devices. Not related to the technique of acquiring electrical signals.

[0003]

[Background of related application]

Conventional EEG, EOG, ECG, EMG, and other physiological signals are typically recorded using individually placed electrodes attached to the skull and body using an adhesive or cap-type device. Examples of these techniques are described in Sams et al. (
Some have been developed by U.S. Pat. No. 4,085,739) or by Gevins et al. (U.S. Pat. No. 4,967,038 and U.S. Pat. No. 5,038,782). In these mounting methods, electrodes are mounted on an amplifier used to capture and record the relevant electrical and physiological activities. These amplifier devices require very low contact impedance with the skin and are very susceptible to emissions from other electrical devices, such as MRI devices. In such an environment, the input stage of a conventional EEG, ECG, or EMG amplifier will not be affected by the extremely large electric and magnetic fields generated by the magnetic resonance imaging device to the extent that the amplifier can no longer operate properly. Easy to receive. Furthermore, these amplifier devices are almost always operated from an AC voltage source, so that electromagnetic interference (
EMI), this electromagnetic interference contaminates the anatomical and functional data acquired by the fMRI device and compromises the integrity of these data.

[0004] fMR by Ives et al. (US Pat. No. 5,445,162)
Prior attempts to collect EEG signals in an I environment have utilized battery operated analog preamplifier devices that adhere individual electrodes to the skull and amplify electrical activity within the bore of the imaging device. Is what you do. These signals are then converted to light energy by additional analog circuitry located near the patient. Depending on the harsh fMRI environment, these signals are located outside the shielded room along fiber optic cables outside the shielded room that protect the imaging equipment from unwanted interference, and data is collected And transmitted to a secondary amplifying device attached to the PC for processing. However, this optically coupled preamplifier device is expensive, large, and difficult to operate. Further, the AC coupling of the head coil (located in the imaging device) is limited due to dimensional constraints inside the device and due to the design where digital circuitry cannot be used due to broadcast interference from the internal clock circuit. The nature of the type is
It is susceptible to large artifacts due to transitional signals generated during normal operation of the imaging device.

[0005]

Summary of the Invention

In accordance with the present invention, an EEG electrode that uses an elastic head cap (hereinafter referred to as a quick cap) to place electrodes on the head and face and acquire electrical signals and transmit these electrical signals to an external amplifier device. The above-mentioned problems of the prior art are solved by providing the positioning device of the present invention. The quick cap provides a stretchable elastic cap and chin strap that can be easily adapted to a wide variety of head sizes and shapes. The quick cap provides a plurality of electrode holders designed to be filled with a conductive electrolyte. Further, the quick cap provides a wire harness assembly that can be configured with carbon or metal leads and interconnected with any commercially available amplifier device.

[0006] Some specific features and objects of the present invention include the following. The present invention quickly mounts a large number of electrodes on the head and body that can acquire a signal in an fMRI device and transmit that signal out of a shielded environment without any electronic amplification. To provide a low-cost apparatus for the purpose.

Another object of the present invention is to limit the susceptibility of the device to impure effects from the fMRI device and to transmit signals outside the shielded fMRI environment to an amplifier attached to the PC, The use of carbon conductors attached to electrodes located on the head and body to collect and process physiological and other physiologically correlated data.

[0008] Another object of the invention is to make the device susceptible to physiologically and electronically generated impure effects, each held in a flexible rubber electrode mount and connected to a carbon wire. The use of a metal electrode made of tin, gold, silver-silver chloride, or silver chloride powder combinations or amalgam.

It is a further object of the present invention to further limit the susceptibility of the device to physiologically and electronically generated impurity effects, such as carbon, carbonized plastic or The use of a conductive plastic electrode.

It is a further object of the present invention to provide a method for recording signals directly from the brain or spinal cord, while further limiting the susceptibility of the device to physiologically and electronically generated impure effects. The use of a needle electrode, an implantable depth electrode or a cortical surface electrode connected to the

Yet another object of the present invention is to provide a mechanism for placing the electrodes in the proper position on the skull, face, chest or body so that a single signal can be obtained from the eye, heart or muscle. Or the group of electrodes can be used.

[0012] Yet another object of the invention is to provide oxygen uptake, respiration, heart rate, impedance, movement,
Allows the use of a single conductor or group of conductors to connect to and transmit signals from an external transducer device used to measure acceleration, force related signals or other signals It is to be.

[0013] Yet another feature of the invention is that the electrode holder and electrodes are placed on the head, face and body, and while in a magnetic resonance imaging device, EEG, EOG, EMG, ECG and physiological To provide separable elastic caps, chin straps and wire harness parts to obtain other signals correlated to

The above and other features, aspects and advantages of the present invention will become more apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings. Objects and features and advantages of the present invention will become apparent from the following description.

[0015]

[Detailed description of preferred embodiments]

As shown in FIG. 1, the fMRI compatible electrode placement device of the present invention includes an elastic fabric cap portion 10 and a chin strap portion 11, both of which are available from 13441 Liberty Lane, Gordonville, Virginia. Liberty Fabrics (L
Model No. manufactured by J.Iberty Fabrics). 96175 black-0900
Complex Lycra-Spandex such as 0
(Registered trademark) material. A plurality of electrode holders 20a to 2
0n is attached to the elastic cap portion 10. The sign "n" means that the number corresponds to the desired number of electrodes. For example, in typical applications, n can range from 1 to 1024. In FIG. 1, the plurality of conductive wires 13 of the present invention form a harness assembly 14. The conductor can be made of any non-ferrous magnetically conductive material, but is preferably made of carbon. The conductors are wound in groups by a movable wrapping material (not shown) and extend from the electrodes (not shown) held in electrode holders 20a-n away from the head and away from the head.
CHG series 40-pin connector manufactured by Incorporated (not shown)
End with a connector like This flexible wrap (not shown) is used to ensure that the wire cannot be coiled while in the MRI machine environment and prevents heating of the lead wire material. Is done.

As shown in FIGS. 2A-2D, the electrode holder 20 is preferably made of a single piece of molded medical grade EPDM rubber, such as Compound L-5099. The electrode holder 20 provides a central bore portion 21 that allows access to the central well portion 22 and is pressed against the skull surface. To fill the central well portion 22 and form a bridging portion that transmits electrical signals from the outer skin surface to electrodes (not shown) resting on ridge portions 23 located within the central well portion 22 of the electrode holder 20. The electrolyte is injected through the central hole 21. On the side of the electrode holder 20 near the top,
Holes 24 are present at the locations where the conductor attachment portions of the electrodes (not shown) extend from the electrode holder. On the outer part of the electrode holder 20 there is a recess 25, which, when the electrode holder is pushed through the elastic cap fabric 10, uses two O-rings 25 in this recess to resilient the cap 10. Hold the fabric from above and below.

As shown in FIGS. 3A to 3C, the electrode 30 of the present invention has a disk portion 31 having a central hole 32. The electrode 30 also includes a wire attachment 33. Conductor mounting part 33
Extends outwardly from the disk portion 31 to provide a passage 34. Such a passage 34
Can be made by drilling or other mechanisms. The drilled passage 34 provides an opening through which the conductor 13 passes, and the conductor is attached to the electrode 30 by swaging the mounting 33 onto the conductor 13.

In a typical assembly sequence, an O-ring is fitted over conductor 13. The electrode 30 is inserted into the central well portion 22 of the electrode holder 20 and rests on the raised portion 23 to ensure the correct position. The electrode holder is inserted through a buttonhole or other opening in the elastic fabric cap and secured by positioning one or more O-rings on the fabric. The conductor 13 is placed in the passage 34 and the mounting portion 33 is swaged onto the conductor.

Another embodiment of a preferred electrode of the present invention is shown in FIGS. 4A-4F, wherein a typical bowl-shaped electrode 40 is made of a metal (eg, Specialized Labratory Equivalent).
pment, 232 Selsdon Rd. Metals manufactured by South Croydon Surrey, UK, PN: BO196 / 02) or conductive plastics 41 (eg, Plastics One, 6591 Merriman
Rd., SW, Roanoke, VA, PN: 36562). In a typical metal electrode, a central hole 43 is present to allow the injection of electrolyte into the skin surface. In addition, a well 44 is provided to hold the electrolyte in contact with the electrode surface. In a typical conductive plastic electrode 41, a central hole 45 is present to allow injection of the electrolyte into the skin surface. The vertical hole portion 46 is provided again,
The electrolyte is held in contact with the electrode surface. Both types of electrodes 40 and 41 can be easily carried within the electrode holder 20 of the present invention.

Another embodiment of a preferred electrode of the present invention is shown in FIGS. 5A-5D, in which a conductive plastic electrode 50 (eg, Select Engineering Inc., 260 L
unenburg St., Fitchburg, MA, PN: Manufactured by SRT-3001 / LP / 0.06) and carbon electrode 51 (for example, Select Engineering Inc., 260 Lunenburg St., Fitc.
hburg, MA, PN: manufactured by SRT-3001 / CF / 40). In both cases, the non-metallic nature of the electrode material renders the electrode insensitive to induced currents present in an MRI (Magnetic Resonance Imaging) environment, as well as other physiological artifacts caused by movement of the human body within the MRI device. To On the conductive plastic electrode 50, there is a wire attaching means 52. The wire attachment means 52 provides a surface on which a conductive epoxy (eg, EPO-TEK E2101) is used to attach the carbon wire 13 to the conductive plastic electrode 50. There is a vertical hole portion 53 on the carbon electrode 51. The vertical portion 53 holds the electrolyte in contact with the electrode surface. Conductor 13 is attached to carbon electrode 51 at the electrode attachment point 54 by using conductive epoxy. Both the conductive plastic electrode 50 and the carbon electrode 51 are carried in the electrode holder 20 of the present invention.

Another embodiment of a preferred electrode of the present invention is shown in FIG. In FIG. 6, an implantable depth electrode assembly 60 (for example, AD-Technical Instrument Corp., 1901 Will)
iam St., Racine, WI, PN: SP-10P). The implantable depth electrode assembly 60 of this embodiment includes ten separate electrodes 61a-j. Each of the electrodes 61a-j obtains signals from different regions of the brain. The depth electrode assembly 60 may be placed on the patient's cortex to collect electrical signals from multiple depth regions of the brain simultaneously. Although the depth electrode assembly 60 is not carried in the electrode holder 20 of the present invention, the wire harness assembly 14 is directly connected to the depth electrode assembly connection mechanism 62.

Another embodiment of the preferred electrode of the present invention is shown in FIG. There, an aggregate of subdural cortical surface electrodes, or aggregate 70 (1901 William St., R
acine, WI, PN: T-WS-20 manufactured by AD-Tech Medical Equipment Company, etc.). In the example given, the subdural cortical surface electrode assembly 70 of this example has twenty separate electrodes 71a-t arranged in a grid pattern. Each grid pattern captures signals from different regions of the brain. However, there are other subdural cortical surface electrode assemblies that provide different numbers of electrodes. Gratings with up to 128 separate electrodes (not shown) are readily available on the market, but other numbers of electrodes can be used. The subdural cortical surface electrode assembly 70 is placed in the patient's cortex to collect signals from multiple regions of the brain underlying the grid-like pattern formed by the electrodes of the assembly. Subdural cortical surface electrode assembly 7
0 indicates that the conductive wire harness assembly 14 is directly connected to the subdural cortical surface electrode assembly connecting device 72 without being supported by the electrode holder 13 of the present invention.

Another embodiment of the preferred electrode of the present invention is shown in FIG. There, a subdural cortical surface electrode assembly 80 (1901 William St., Racine, Wis.).
, PN: T-WS-8 manufactured by AD-Tech Medical Equipment Company). In the subdural cortical surface electrode assembly 80 of this embodiment, eight separate electrodes 81a-h are arranged in a strip pattern. Each strip-like pattern captures signals from different regions of the brain. However, other subdural cortical surface electrode assemblies providing from 1 to 128 separate electrodes (not shown) are readily available on the market. The subdural cortical surface electrode assembly 80 is placed in the patient's cortex to collect signals from multiple regions of the brain underlying the strip-like pattern formed by the electrodes of the assembly. The subdural cortical surface electrode assembly 80 is not supported by the electrode holder 13 of the present invention, but is directly connected to the conductor wire harness assembly 14 via an assembly connection device 82.

In operation, the assembled Quick-Cap is placed on the patient's head and then, in a suitable embodiment, each electrode holder is filled with a conductive solution. Some abrasion of the skin during wear may be required to reduce the impedance at the skin electrolyte interface to an acceptable level determined by the input characteristics of the amplifier device to which the Quick-Cap is attached. .

As mentioned above, problems associated with collecting patient data in an MRI environment may be solved. In this description, only the preferred embodiment of the invention has been shown and described, but as noted above, the invention may be used in various other combinations and environments, and Changes or modifications are possible within the spirit of the invention.

[Brief description of the drawings]

FIG. 1 shows a separate conductor attached to an electrode (not shown) held in an electrode holder.
FIG. 2 is a side view of the elastic cap and chin strap portion of the exemplary embodiment of the present invention, showing the electrode holder and the wire harness assembly.

FIG. 2A is a sectional side view of the electrode holder of FIG. 1; FIG. 2B is a plan view of the embodiment of FIG. 2A. 2C is a side view of the embodiment of FIG. 2A. 2D is a plan view of a rubber O-ring used to attach the electrode holder to the elastic cap portion of FIG.

FIG. 3A is a cross-sectional side view of an example electrode held along the line AA in FIG. 3B, held in the electrode holder of FIG. 2A. FIG. 3B is a plan view of the embodiment of FIG. 3A. 3C is a side view of the embodiment of FIG. 3A.

FIG. 4A shows one of the cup-shaped electrodes held in an electrode holder as an example of FIG. 2A.
FIG. 9 is a perspective plan view of one alternative embodiment. 4B is one of the cup-shaped electrodes held in the electrode holder as an example of FIG. 2A.
FIG. 9 is a perspective bottom view of one alternative embodiment. 4C is a plan view of the embodiment of the electrode of FIG. 4A. 4D is a side view of the embodiment of the electrode of FIG. 4A. 4E is a cross-sectional view of an alternative embodiment of the conductive plastic electrode embodiment held in the electrode holder of FIG. 2A. 4F is a plan view of the embodiment of the electrode of FIG. 4E.

FIG. 5A is a plan view of an alternative embodiment of the embodiment of the conductive plastic electrode held in the electrode holder of FIG. 2A. 5B is a cross-sectional view along the line BB of the embodiment of the conductive plastic electrode of FIG. 5A. 5C is a plan view of an alternative embodiment of the carbon electrode embodiment held in the electrode holder of FIG. 2A. 5D is a cross-sectional side view taken along line CC of the embodiment of the carbon electrode of FIG. 5C.

FIG. 6 is a plan view of an alternative embodiment of the embodiment of the cortical depth electrode used with the carbon wire harness of the present invention.

FIG. 7 is a plan view of an alternative embodiment of the embodiment of the cortical grid electrode used with the carbon wire harness of the present invention.

FIG. 8 is a plan view of an alternative embodiment of the embodiment of the cortical strip electrode used with the carbon wire harness of the present invention.

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Claims (26)

[Claims] 1. An electrode assembly coupled to an electrode conductor to carry an electrical signal within a functional magnetic resonance imaging device during normal operation without interfering with the integrity of the magnetic resonance imaging data. An electrode assembly comprising one or more electrodes. 2. The electrode assembly according to claim 1, wherein the electrode is silver, tin, gold, carbon, platinum, iridium, tinsel, stainless steel, amalgam of Ag / AgCl, or an electrically conductive plastic or carbonized plastic. Alternatively, an electrode assembly made of a material selected from a group consisting of a combination of carbon fibers. 3. The electrode assembly according to claim 1, wherein the electrode is a hypodermic needle,
An electrode assembly that is an electrode of the subdural cortex or a subdural depth electrode. 4. The electrode assembly according to claim 1, wherein the electrode conductor is silver,
Tin, gold, carbon, platinum, iridium, tinsel, stainless steel, Ag / AgC
An electrode assembly made of a material selected from the group consisting of amalgam or a combination of electrically conductive plastic, carbonized plastic or carbon fiber. 5. The electrode assembly according to claim 4, wherein said electrode conductor is made of carbon. 6. The electrode assembly according to claim 4, wherein said at least two electrode conductors are coated with a flexible material. 7. The electrode assembly according to claim 6, wherein the flexible material is formed so as to prevent the electrode conductor from being wound in a coil shape. 8. The electrode assembly according to claim 1, wherein the electrode conductor transmits a signal over a distance of 304.8 cm or more without amplification. 9. The electrode assembly according to claim 1, wherein each of said one or more electrodes is disposed in an electrode holder. 10. The electrode assembly according to claim 9, wherein the electrode holder houses an opening for applying an electrode to a patient. 11. The electrode assembly according to claim 9, wherein the electrode holder has one or more O-rings. 12. The electrode assembly according to claim 9, wherein said electrode holder is made of a flexible material. 13. The electrode assembly according to claim 10, wherein said electrode holder is made of rubber. 14. The electrode assembly according to claim 9, wherein the plurality of electrode holders are mounted on an elastic cap disposed on a patient's head. 15. With one or more electrodes coupled to the electrode conductors to carry electrical signals within the MEG imaging device during normal operation without interfering with the integrity of the acquired data. Electrode assembly. 16. An electrode conductor for carrying electrical signals in an environment in which a functional magnetic resonance imaging device and at least one MEG imaging device are operating without interfering with the integrity of the acquired data. An electrode assembly comprising one or more connected electrodes. 17. A transducer conductor assembly adapted to carry an electrical signal within a functional magnetic resonance imaging device during normal operation without interfering with the integrity of the magnetic resonance imaging data. A transducer wire assembly comprising or more connecting wires. 18. The converter conductor assembly of claim 17, wherein said at least one connection conductor is configured to carry a signal from a signal source, said signal comprising an EOG signal, an EMG signal, an ECG signal. And a signal conductor to or from a transducer for measuring impedance, skin conductance, acceleration, motion or respiration. 19. An electrode conductor for carrying electrical signals in an environment in which a functional magnetic resonance imaging device and at least one MEG imaging device are operating without interfering with the integrity of the acquired data. Comprising one or more connected electrodes;
An electrode assembly, wherein said one or more electrodes and electrode leads are held in place with a flexible coating material. 20. A method for collecting electrical data during normal operation of a functional magnetic resonance imaging apparatus without interfering with the integrity of the magnetic resonance imaging data, the method comprising the steps of: The method comprising using a ferromagnetic material. 21. The method of claim 20, wherein the non-ferromagnetic material comprises:
Silver, tin, gold, carbon, platinum, iridium, tinsel, stainless steel, Ag / A
The method is a material selected from the group consisting of amalgam of gCl, or a combination of electrically conductive plastic, carbonized plastic or carbon fiber. 22. The method of claim 20, further comprising attaching the electrode holder to a flexible cap. 23. The method of claim 22, comprising wrapping the conductor with a flexible material. 24. The method of claim 22, comprising securing the flexible cap to the head using a string. 25. The method of claim 24, comprising adjusting the length of the string using at least one Velcro ™ between the string and the flexible cap. Is the way. 26. The method according to claim 20, comprising attaching the at least one electrode and the conductive wire to a patient using a flexible covering.