Devices and methods for transcranial magnetic stimulation

Abstract

A TMS coil assembly for magnetically stimulating a brain region of a subject, the TMS coil assembly comprising one or more coil assemblies each including adjacently or spaced apart flexible wing-like coil structures configured to adjustably deform along a tilt axis passing between the wing-like coil structures to conform to a curved surface of the subject's head and apply a desired tilt angle between the wing-like coil structures while bringing a substantial loop portion of the wing-like coil structures into direct contact with the curved surface of the head, thereby maximizing the loop portion tangential to the curved surface of the head and minimizing the loop portion non-tangential to the curved surface. A fixation device can be used to maintain the desired tilt angle between the wing-like coil structures when positioned on the subject's head during a TMS procedure, thereby maximizing the strength of the electric field induced at the head.

Description

[Technical field]

[0001] The present disclosure relates generally to brain stimulation devices and methods, and more particularly to transcranial magnetic stimulation (TMS) devices for stimulating selected brain regions. [Background technology]

[0002] This section is intended to provide background information related to the present application, which is not necessarily prior art.

[0003] Transcranial magnetic stimulation (TMS) is a non-invasive technique used to apply short electromagnetic pulses to the brain to activate its neuronal structures. The pulses are administered by a stimulator configured to pass high electrical currents through an electromagnetic coil placed externally over / near the patient's head region (e.g., placed on the scalp for brain therapy), which induces electrical currents in the underlying tissue, resulting in localized axonal depolarization. The technique has become a major tool in research into the central nervous system, as well as an established treatment option for various psychiatric disorders and a potentially promising treatment option for various neurobehavioral and neurological disorders.

[0004] Most known TMS coils stimulate superficial brain regions of the cerebral cortex, but the decay rates of the magnetic and electric fields induced by such TMS coils are high as a function of distance from the coil. This makes conventional TMS coils generally less effective at influencing deeper neuronal structures. It may be possible to stimulate deeper neuronal structures by increasing the strength of the induced field significantly. However, operating at such high strengths may increase the risk of seizures and physiological damage to brain tissue.

[0005] No. 7,407,478, the disclosure of which is incorporated herein by reference, discloses a method of deep brain TMS with minimal stimulation of superficial regions, allowing stimulation of deep brain regions while minimizing side effects. The device described therein includes a base and an extension, the base having individual windings for individual paths of current, and the extension designed to minimize unwanted stimulation of other regions of the brain.

[0006] The most widely used TMS coil is the flat figure-of-eight coil (also referred to herein as the butterfly coil), e.g., having two helical coil wings arranged in a common plane. The flat butterfly coil is placed over the cerebral cortex, with only the central segment in contact with the subject's head / scalp. At this point, a maximum electric field is induced beneath the central segment of the butterfly coil, responsively stimulating neural structures in this region. However, studies using volume conductors with flat geometries (Branston NM et al, "Magnetic stimulation of a volume conductor produces a negligible component of induced current perpendicular to the surface", J. Physiol. (Lond) 1990;423:67; Roth BJ et al, "A model of the stimulation of a nerve fiber by electromagnetic radiation", IEEE Trans. Biomed Eng. 1990;37:588-597; Tofts PS "The distribution of induced currents in magnetic stimulation of the nervous system", Phys. Med. Biol. 1990;35:1119-28; Tofts PS et al, "The measurement of electric field, and the influence of surface charge, in magnetic stimulation", Electroencephalogr. Clin. Neurophysiol. 1991;81:238-9) and spherical geometries (Branston NM et al, "Analysis of the distribution of currents induced by a changing magnetic field in a volume conductor”,Phys.Med.Biol.1991;36:161-8;Cohen D.et al, "Developing a more focal magnetic stimulator. Part I: some basic principles", J. Clin. Neurophysiol. 1991;8:102-11; Eaton H. "Electric field induced in a spherical volume conductor from arbitrary coils: application to magnetic stimulation and MEG", Med. Biol. Eng. Comput. 1992;30:433-40) demonstrate that coil elements perpendicular to the brain surface induce a build-up of surface charge, which completely cancels the perpendicular component of the induced field at all points in the tissue. In addition, the electric field in other directions is greatly reduced.

[0007] For this reason, a TMS coil design is needed that has a minimum number of coil elements perpendicular to the surface of the treated subject's skull to reduce static charge buildup and increase the effectiveness of magnetic coupling between the coil and the brain tissue. The coil should induce a desired electric field strength in the relevant brain tissue that is viable for neuronal stimulation by available TMS stimulators for most of the population. Stimulation strength is routinely tailored individually for each subject based on the subject's motor threshold. For this reason, coil efficiency must ensure that the motor threshold and stimulation strength of the majority of the relevant population are within an acceptable range for the available stimulator output.

[0008] Therefore, the coil design needs to be efficient in terms of energy consumption, coil heating rate, compact size, and ease of operation.

[0009] US Patent No. 9,067,052 discloses a method of applying a rotating field with a TMS coil, where two coils are placed perpendicular to each other and an alternating current pulse is passed through each coil. Because the alternating current pulses in the two coils are not simultaneous, but there is a time delay between the operation of one coil and the operation of the second coil, there is a phase between the currents in the two coils and therefore between the pulses of the electric field induced in the brain tissue by the coils. When the phase is 90 degrees, a rotating field is induced in the brain. Typically, neurons with axons parallel to the induced electric field are stimulated. This setup allows stimulation of neurons in brain regions aligned in various directions. Summary of the Invention

[0010] There is a need in the art for a TMS device that is configured to efficiently stimulate deep neural structures in a subject's brain and that is adjustable to fit the size and shape of the subject's skull / head. The present application provides an electromagnetic coil designed to induce a magnetic field in the brain tissue of a subject.

[0011] To optimize the effectiveness of stimulation of neural tissue in a desired brain region / portion, it is desirable to minimize the magnitude of the non-tangential components of the induced electric field. To effectively and efficiently stimulate deep neural tissue, the coil configurations disclosed herein are designed to provide high electric field magnitudes tangential to the head / skull while minimizing all non-tangential electric fields.

[0012] Typically, the ability to generate an action potential response in a neuron depends primarily on two properties: the size and orientation of the neuron. The dependence on orientation arises because the magnetic stimulation of a neuron occurs at its axon, whose projection along the induced electric field is the relevant parameter for achieving excitation. Typically, the orientation of neurons in deep brain tissue is random, i.e., neurons are aligned in various directions. Thus, by inducing a rotating electric field whose orientation affects a wide range of angles during a single pulse, many axons can be excited at once, stimulating many neurons. The rotating field can be induced using any of the techniques disclosed in U.S. Pat. No. 9,067,052, the disclosure of which is incorporated herein by reference.

[0013] According to possible embodiments herein, a TMS coil configuration for transcranial magnetic stimulation is provided. The TMS coils disclosed herein generally include one or more butterfly coils, each having two or more coupled wing coil structures designed to enhance flexibility.

[0014] The term wing-like coil structure as used herein generally refers to a coil structure that includes an arrangement of one or more EM coil loops that are adjacent (proximate) to or spaced apart from another arrangement of one or more EM coil loops (i.e., another wing-like coil structure). It is noted that the butterfly coils disclosed herein need not be symmetrical, i.e., the EM coil loops may be arranged differently from the adjacent or spaced apart wing-like coil structures, e.g., the EM coil loops in each wing-like coil structure may have different geometries, different numbers of loops, and / or wires with different cross-sectional areas and / or geometries. Furthermore, in possible embodiments, the EM coil loops of the wing-like coil structures need not necessarily be electrically coupled or connected to each other.

[0015] That is, in some embodiments, the butterfly coil has a figure-of-eight shape with two adjacently located wing-like coil structures. In other possible embodiments, the wing-like coil structures of the butterfly coil have a defined distance (e.g., 10-70 mm) separating them. The two wing-like coil structures of the butterfly coil are in some embodiments made to be bendable and hinged one to the other so that one can move / deform relative to the other to conform to the shape of the subject's head. In this way, the geometry of the TMS coil can be adjusted to the curvature of the subject's head, for example by establishing a grip thereon such that many, all or most of the loop elements of the wing-like coil structures are in contact with the subject's head, i.e., the coil elements are in contact with the subject's hair and / or scalp.

[0016] In the embodiments disclosed herein, the individual loop segments / portions of the wing coil structure located at the center of the butterfly coil or coils carry current in the main direction of the respective wing coil structure, and are referred to herein as main loop segments or portions. The embodiments disclosed herein are configured such that the orientation of the main loop segments is all or mostly tangential to the underlying head curvature (such as a portion of the skull) for all or most of its path. To optimize the effect of neural activation in the target brain structure located under the central segment of the butterfly coil or coils, it is desirable to minimize the non-tangential components of the induced electric field. Since the orientation of the electric field induced by any coil element is parallel to the orientation of the element of the coil carrying the alternating current, it is desirable to minimize the portion of the coil element that is non-tangential to the head (skull) of the subject.

[0017] The butterfly coil segments / portions carrying current in a direction opposite to the main direction are located to the sides / outside of the two wing-like coil structures and are referred to herein as return loop segments or portions. In possible embodiments, the return loop segments are also made to bendable to fit the curvature of the head or head portion of the subject. Optionally, in some embodiments, only the return loop segments of the wing-like coil structure are preferably configured to deform to fit the geometry of the portion of the subject's head, while the geometry of the main loop segments remains substantially unchanged.

[0018] In some embodiments, the wing coil structure of one or more butterfly coils can be fixed in a flat position / shape such that all of the elements of the loops of the wing coil structure lie substantially in a common plane. In this flat configuration, the coil functions similarly to a conventional / standard figure-of-eight TMS coil.

[0019] In some embodiments, the wing coil configurations of the one or more butterfly coils can be changed between a locked state and a released state, in which one can be moved relative to the other to accommodate the curvature of the subject's head or a portion thereof. The angle between the wing coil configurations can be held at a desired angle in the locked state of the one or more butterfly coils using one or more releasable connectors and / or elastic / adjustable straps. The TMS coil can include one or more head straps (also referred to herein as fixation means) and / or other attachment means configured to secure the TMS coil to the subject's head and / or allow all or most of the elements of the coil loop to be securely attached at a desired position and / or tilt / angle during a TMS treatment session performed therewith.

[0020] In some embodiments, the TMS coil device comprises an array of cross coil structures, each cross coil structure having an expansion axis that intersects with an expansion axis of at least another coil structure of the TMS coil device. For example, in some embodiments, the cross coil structures form an equiangular TMS coil structure, where the angle between the expansion axes of each pair of adjacently located cross coils is substantially 180° / n, where n≧2 is an (integer) number of cross coils in the TMS coil structure.

[0021] Optionally, in some embodiments, the array of cross coils preferably comprises a lower flexible butterfly coil and an upper butterfly coil, where the orientation of the wing-like coil structure of the upper butterfly coil has a desired angle with respect to the orientation of the wing-like coil structure of the lower butterfly coil, e.g., the angle between the deployment axes of the butterfly coils is 90° or less. In some embodiments, the lower flexible butterfly coil carries an upper flexible butterfly coil, where the angle between the deployment axes of the wing-like coil structures of the lower and upper butterfly coils is about 90°.

[0022] Each of the cross coils (e.g., lower and upper flexible butterfly coils) can be electrically connected to a respective channel of a multi-channel TMS stimulator, or alternatively, can be electrically connected to different stimulator units. The timing of the operation of the cross coils can be controlled to implement a desired TMS stimulation protocol. For example, actuating the coils of two cross coil TMS coil structures with a time delay that results in a 90 degree phase shift can induce a rotational field in the underlying brain tissue, stimulating neurons in different orientations.

[0023] In some possible embodiments, the cross coil (e.g., a flexible butterfly coil) is made from conductive wire (e.g., copper wire). In some embodiments, the conductive wire is about 7-10 mm long. 2and wound to form a coil including a plurality of loop windings electrically connected in series. The conductive wire is preferably electrically insulated. In some embodiments, the windings are multiple wires twisted or bundled together.

[0024] In some embodiments, there are multiple layers of electrical insulation covering the conductive wires of the coil. For example, the conductive wires can be electrically insulated with at least one insulating layer, such as sintered PTFE. Additionally, all of the conductive wires may be surrounded by one or more layers of shielding that provide electrical insulation. Such shielding may include, for example, sintered CR PTFE wrapped in tape and / or a double SPC braided shield.

[0025] In some embodiments, the loop winding configuration of the coil (e.g., one or more winged coils) is held by a support structure that, on the one hand, maintains a generally fixed shape of the elongated coil configuration, while on the other hand allows some freedom of movement and flexibility.

[0026] In some embodiments, there is one degree of freedom to adjust the angle between the coil segments / portions (e.g., at least one wing of a flexible wing-like coil structure) that extend along or relative to the deployment axis of the coil. In other possible embodiments, additional degrees of freedom are provided, such as flexibility of the coil segments / portions (e.g., wings of a butterfly coil element), which allows them to conform to the curved shape of a human head, or at least a portion of the head.

[0027] The number, length, configuration and filling parameters of the windings of the one or more flexible coils are configured to obtain a desired range of coil inductance. Typically, the desired inductance range for each cross coil (e.g., flexible butterfly coil) is 15-30 microhenries. Too high an inductance will reduce coil efficacy and increase pulse width, often accompanied by increased coil resistance, energy consumption and coil heating. Too small an inductance will cause a faster rate of change of current, which may damage stimulator components.

[0028] In some embodiments, neuronal navigation tools are integrated into the TMS device. Neuronal navigation is important to allow accurate placement of the coil at the desired location on the head and to provide reproducible and accurate stimulation of the desired brain target. There are several types of neuronal navigation techniques that can be used. One neuronal navigation technique is based on an optical neuronal navigation approach, where sensors are placed on at least one of the TMS coils and on the head of the recipient.

[0029] For example, in a possible embodiment, a camera, typically with a transmitter and receiver in the infrared (IR) range, is positioned to constantly track the position and orientation of the sensor. The position of the sensor can be registered in association with a brain mapping, e.g., obtained based on either a standard MRI or a personal MRI of the individual subject being treated. A processor can be used to integrate all the information, the position of the sensor, together with an MRI-based image of the brain, which is displayed on a display / screen, and the system can provide instructions to manually navigate one or more TMS coils for placement at target locations on the head of the treated subject based on the registered sensor positions and the brain mapping. Furthermore, the system can constantly track the position of the TMS coil on the head and provide warnings if it deviates from a tolerance range, ensuring accurate placement of the coil throughout the treatment session.

[0030] Another neuronal navigation approach is based on electromagnetic (EM) tracking. In this approach, one or more TMS coils and EM sensors are placed on the subject's head, which act as localization points for the device in 3D space. A field generator or transmitter is used to emit a low-intensity, varying EM field and establish a measurement volume. When the EM sensors enter the EM field, tiny currents are induced inside them. Those induced currents are relayed to a sensor interface unit (SIU), where they are amplified and digitized to generate measurement data / signals. The measurement data / signals are sent to the system's control unit (SCU), which calculates the position and orientation of each EM sensor on the treated subject's head, e.g., as changes occur.

[0031] In another embodiment, the functions of the SIU and SCU are performed by an electronic unit, which calculates the tracking data of the sensor as position and rotation matrices. This tracking data is communicated to an application interface for real-time manual navigation of the instrument relative to the patient image set, based on either a standard MRI or a personal MRI of the individual subject being treated. The advantage of the EM-based tracking method is that it does not require line of sight, in contrast to optical methods, which require line of sight between the camera and the sensor.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention belongs. Methods and materials similar or equivalent to those described herein can be used to carry out or test the present invention, but suitable methods and materials are described below. In case of conflict, the present specification, including definitions, will prevail. In addition, the materials, methods and examples are merely illustrative and are not intended to be limiting.

[0033] In one aspect, a TMS coil assembly for magnetically stimulating a brain region of a subject is provided. The TMS coil assembly includes one or more coil assemblies, each of which includes adjacently or spaced apart flexible wing-like coil structures, configured to adjustably deform along a tilt axis passing between the wing-like coil structures to conform to a curved surface of the subject's head, applying a desired tilt angle between the wing-like coil structures and bringing a substantial loop portion of the wing-like coil structures into direct contact with the curved surface of the head, thereby maximizing the loop portion tangential to the curved surface of the head and minimizing the loop portion non-tangential to the curved surface. A fixation device having a coil retention structure attached to each butterfly coil can maintain a desired tilt angle between the butterfly coils of the wing-like coil structures when placed on the subject's head during a TMS procedure, thereby maximizing the strength of the electric field induced in the head. Optionally, the desired tilt angle is a straight angle.

[0034] The TMS coil assembly, in some embodiments, is configured to define a field application axis passing between the wing-like coil structures. The tilt axis and the field application axis can be substantially parallel or coincident. Optionally, the TMS coil assembly is configured to define a central interaction zone relative to the field application axis, where the additive electric and magnetic fields generated by the wing-like coil structures are at a maximum strength. In a possible application, the TMS coil assembly includes a locking mechanism configured to lock the wing-like coil structures at a desired tilt angle applied by the fixation device.

[0035] In some embodiments, the fixing device comprises one or more coil holding structures attached to the wing-like coil structures and configured to facilitate adjustment of the tilt angle. Optionally, and preferably in some embodiments, the one or more coil holding structures are hinged at one or more pivots. To facilitate setting the desired tilt angle between the wing-like coil structures, one or more lever members coupled to at least one of the coil holder device and the coil holding structures, respectively, may be used. In this configuration, a locking mechanism may be used to maintain the lever members locked relative to the coil holder device to prevent further tilting of the wing-like coil structures.

[0036] The TMS coil assembly can include one or more releasable connectors, each configured to couple one of the lever members to the coil holder device, Each releasable connector can be coupled to a respective lever member by a respective elastic and / or adjustable strap.

[0037] In some embodiments, a fastening means is provided for attaching the TMS coil assembly to the subject's head. The fastening means can include a head strap configured to fasten the TMS coil assembly to the head and with a majority of its loops in direct contact with the head.

[0038] The TMS coil assembly may be configured with multiple degrees of curvature of the winged coil structure / lobes to allow the loops of the coil to conform to the subject's head and have the majority of the loops in direct contact with the head. Optionally, the loops of the winged coil structure are configured to flexibly conform and contact the head in all of the coil portions facing the head.

[0039] In possible embodiments, the wing-like coil structure has a generally circular shape, or a generally elliptical shape, or a generally rectangular shape.

[0040] In another aspect, a TMS coil array for magnetically stimulating a brain region of a subject is provided. The TMS coil array includes two or more of the TMS coil assemblies according to any of the embodiments disclosed herein, each of the TMS coil assemblies having a deployment axis substantially perpendicular to its tilt axis, and the deployment axis of each of the two or more TMS coil assemblies intersects with the deployment axis of at least one other of the TMS coil assemblies. In some embodiments, the TMS coil array includes two TMS coil assemblies connected to two different sides of a single fixation device. Optionally, the angle between the tilt axes of the TMS coil assemblies is about 90 degrees.

[0041] In some embodiments, the TMS coil array is configured such that each of the two or more TMS coil assemblies has a central interaction zone, and the interaction zones of the two or more TMS coil assemblies substantially coincide.

[0042] Optionally, each of the TMS coil assemblies is electrically connected to a respective independent channel of a stimulation device configured to control timing of operation of the TMS coil assemblies. In a possible embodiment, the TMS coil array is configured to induce a rotational field in brain tissue by manipulating a phase difference between at least two currents in the TMS coil assemblies.

[0043] In a possible embodiment, each wire or a portion of the wires of the TMS coil assembly are separately electrically insulated. Optionally, one or more layers of electrically insulating shielding may be used to surround all of the wires of the TMS coil assembly.

[0044] The TMS coil array, in some embodiments, is configured for neuronal navigation of the position of the coil assembly on the head. Neuronal navigation can be based on optical tracking and / or electromagnetic tracking.

[0045] In yet another aspect, a method for treating a neurophysiological disorder is provided, comprising the steps of: positioning at least one TMS coil assembly having a wing-like coil structure on a head portion of a subject; setting a tilt angle between the wing-like coil structures such that the wing-like coil structures conform to a curvature of the head and a majority of its loops directly contact the head; and passing a current through the at least one TMS coil assembly to stimulate a region of the subject's brain. The method may include changing the TMS coil assembly to a released state before setting the tilt angle, and then changing the TMS coil assembly to a locked state to prevent further tilt between the wing-like coil structures.

[0046] In yet another aspect, a method for treating a neurophysiological disease is provided, comprising: placing a TMS coil assembly or a TMS coil array of any one of the embodiments disclosed herein on a head of a subject to be treated and setting a tilt angle between at least two wing-like coil structures thereof to conform to a curved region of the head; and passing a current through the TMS coil assembly of the TMS coil array to stimulate a region of the brain of the subject. The neurophysiological disease may be overcome at least one of depression, bipolar disorder, schizophrenia, PTSD, Parkinson's disease, dystonia, movement disorder, Alzheimer's disease, mild cognitive impairment, autism, Asperger's syndrome, multiple sclerosis, ALS, Tourette's syndrome, blepharospasm, stroke, chronic pain, eating disorder, obesity, anorexia nervosa, bulimia, any addiction including smoking addiction, drug addiction, alcoholism or gambling addiction, ADHD, OCD, epilepsy, migraine, tinnitus. [Brief description of the drawings]

[0047] In order to better understand the subject matter disclosed herein and to illustrate how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which the features shown are intended to illustrate only some embodiments of the invention, unless otherwise expressly stated. In the following drawings, like reference numerals are used to indicate corresponding parts.

[0048] [Figure 1] 1A-1G are schematic diagrams illustrating a TMS coil device including a flexible circular butterfly coil according to some possible embodiments, where FIG. 1A is a perspective view of a circular butterfly coil having an angle between the two wings of the coil, FIG. 1B is a top view of the circular butterfly coil configured to form a flat / planar wing arrangement similar to a standard figure-of-eight coil, FIG. 1C shows the flexible circular butterfly coil attached to a subject's head in a position close to the midline, showing how the wing coil structure conforms to the shape of the head / skull, and FIG. 1D shows the flexible circular butterfly coil attached to a subject's head in a lateral position. FIG. 1C shows a flexible circular butterfly coil with the center of the butterfly coil approximately above the right hand motor cortical representation in the left hemisphere and the coil elements / wings conforming to the shape of the head; FIG. 1E shows the circular butterfly coil and the means and mechanisms that allow it to be locked in a flat / planar wing arrangement; FIG. 1F shows the coil in a case and the means and mechanisms that allow it to be locked in a flat / planar wing arrangement; and FIG. 1G shows a flexible circular butterfly coil over a human head and the means and mechanisms that allow its wings to conform to the curvature of the head and to be attached to the head with the appropriate angle between the wings. [Diagram 2]2A-2D are schematic diagrams illustrating a TMS coil device including an elliptical butterfly coil according to some possible embodiments, in which FIG. 2A is a top view of an elliptical butterfly coil configured to form a flat wing arrangement similar to a standard figure-of-eight coil according to some embodiments, FIG. 2B is a side view of an elliptical butterfly coil having an angle between the two wings, FIG. 2C shows a flexible elliptical butterfly coil attached to a subject's head in a position close to the midline with the coil / wing elements conforming to the shape of the head, and FIG. 2D shows a flexible elliptical butterfly coil attached to a subject's head in a lateral position with the coil center approximately above the right hand motor cortical representation in the left hemisphere and the coil elements conforming to the shape of the head. [Diagram 3] 3A-3E are schematic diagrams of a TMS device including an array of flexible cross coils according to some possible embodiments, where FIG. 3A and FIG. 3B are top and bottom perspective views of a flexible cross coil array including a lower butterfly coil and an upper butterfly coil oriented orthogonally to each other, FIG. 3C shows a flexible cross coil array with an electromagnetic neuronal navigation sensor coupled to two wings of the lower flexible cross coil, FIG. 3D shows a cross coil array with a lower flexible elliptical butterfly coil and an upper flexible circular butterfly coil, one oriented perpendicular to the other, attached to a subject's head in a position close to the midline with the coil elements conforming to the shape of the head, and FIG. 3E shows a cross coil array attached to a subject's head in a lateral position with the center of the cross coil approximately above the right hand motor cortical representation in the left hemisphere and the coil elements / wings conforming to the shape of the head. [Figure 4] 4A-4C show schematic coil stimulation schemes according to some possible embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] One or more specific embodiments of the present disclosure are described below with reference to the drawings, which are to be considered in all respects as illustrative only and not restrictive in any respect. In order to provide a concise description of the embodiments, not all features of the actual implementation are described in the specification. The elements illustrated in the drawings are not necessarily to scale or in correct proportion, which is not essential. Instead, emphasis is placed on clearly illustrating the principles of the present invention so that those skilled in the art will be able to manufacture and use the disclosed coil assemblies upon understanding the principles disclosed herein. The present invention may be provided in other specific forms and embodiments without departing from the essential characteristics described herein.

[0050] In a broad aspect, the present disclosure aims to combine techniques for inducing a rotating electromagnetic field inside a subject's head with a flexible coil design configured to minimize or completely eliminate coil elements / portions that are perpendicular to the surface of the subject's head.

[0051] 1A and 1B, top perspective and bottom views, respectively, of a butterfly-shaped electromagnetic coil assembly 10 according to some possible embodiments are shown. The butterfly-shaped electromagnetic coil assembly 10 includes two spaced apart wing-like coil structures / lobes 10a, 10b including a plurality of loops, each wing-like coil structure / lobe 10a, 10b forming a substantially planar circular coil structure coupled to a support unit including an adjustable / flexible fixation device 12 that mechanically couples between the lobes 10a, 10b of the two spaced apart wing-like coil structures / loops. The fixation device 12 is configured in some embodiments to vary the angle between the planes of the two spaced apart wing-like coil structures / loops 10a, 10b to fit / adapt the coil assembly 10 to the size / shape of the head / skull of the subject.

[0052] In some possible embodiments, the fixation device 12 includes a pair of "Y" shaped coil retaining structures 12a, 12b. Each of the "Y" shaped coil retaining structures 12a, 12b has a respective leg portion 12g and two arm portions 12r extending therefrom. The arm portions 12r can extend diagonally laterally from the leg portion 12g of each "Y" shaped coil retaining structure 12a, 12b to form a three-pointed star structure. In this specific and non-limiting example, the arm portions 12r extend on either side from the respective leg portions 12g along the diameter of the respective wing-like coil structure / lobe 10a, 10b and extend axially therefrom to engage with the arm portions 12r of the other wing-like coil structure / lobe of the coil structure 10.

[0053] The wing-like coil structures / lobes 10a, 10b of the coil structure 10 are secured to the legs 12g and arms 12r via fasteners 15, such as cable ties / zip ties. Each of the arm portions 12r includes a respective shoulder portion 12s pivotally connected to the wing / lobe arm portion 12r, such as via a hinge 12i, configured to allow angular movement of one of the "Y"-shaped coil retaining structures 12a, 12b relative to the other. Thus, the angle between the "Y"-shaped coil retaining structures 12a, 12b (and thus the angle between the planes of the two spaced apart wing-like coil structures / lobes 10a, 10b) can be manipulated, i.e., increased or decreased, to change the angular orientation of the (planes of) the two spaced apart wing-like coil structures / lobes 10a, 10b relative to each other. In this manner, the coil assembly 10 can be adjusted to closely fit / adjust to the size of the subject's head / skull, thereby allowing a majority of the lower windings of each of its wings / lobes 10a, 10b to contact the subject's head.

[0054] 1A illustrates a coil assembly 10 in a tilted configuration in which the wing-like coil structures / lobes 10a, 10b of the coil assembly 10 are angularly tilted about their tilt axis 12x defined by hinges 12i such that an obtuse angle is formed between the wing-like coil structures / lobes. As shown, each shoulder portion 12s can extend vertically downwardly or upwardly from a free end of a respective arm portion 12r to define an engagement surface 12e for a respective hinge 12i that pivotally connects with arm portion 12r of another "Y" shaped coil retaining structure.

[0055] Optionally, in some embodiments, each of the substantially planar wing-like coil structures / lobes 10a, 10b of the coil structure 10 is preferably made from a single continuous conductive wire wound to form multiple loops. The two laterally wound wing-like coil structures / lobes 10a, 10b are electrically connected in series by an intermediate wire segment 10c.

[0056] 1B shows the coil assembly 10 in a planar state with the wing-shaped coil structure / lobes 10a, 10b aligned in the same geometric plane as their winding loops along the extension axis (also referred to herein as the deployment axis) 12y of the coil assembly 10. In some embodiments, each loop of the wing-shaped coil structure / lobe 10a, 10b of the coil assembly includes two layers of loop windings. In particular, each of the winding lobes 10a, 10b includes multiple circular loops, and in this particular embodiment, four loops are shown spirally wound outward from one or more innermost loops to one or more outermost loops. The loops are spirally wound such that each loop has an upper winding and a lower winding that form two layers of coils in each of the wing-shaped coil structure / lobes 10a, 10b.

[0057] As shown in Figure 1A, in some embodiments, an intermediate wire segment 10c connects the innermost loop of one winged coil structure / lobe 10a to the outermost loop of the other winged coil structure / lobe 10b, such that the two wings / lobes generate additive magnetic fields toward the subject's TMS brain target. In some possible embodiments, the winged coil structure / lobe of the coil assembly 10 is configured to have a degree of flexibility, thereby providing an adjustable, wearable coil structure that can closely conform to the shape of various curved portions / regions of the subject's skull, as further described and exemplified herein with reference to Figures 1C-1E.

[0058] As shown in FIG. 1B, the adjacently arranged portions / elements of the two spaced apart wing-like coil structures / lobes 10a, 10b define a central interaction zone ii where the additive electric and magnetic fields generated by the wing-like coil structure / lobe elements are at a maximum strength. In this configuration, the electric field generated by the wing-like coil structures / lobes 10a, 10b of the coil assembly 10 is substantially tangential to the head of the subject (e.g., a selected portion of the skull) along the field application axis 10x, which in some embodiments is substantially perpendicular to the extension / deployment axis 12y of the coil assembly 10 and substantially parallel to or coincident with the tilt axis 12x of the wing-like coil structures / lobes 10a, 10b of the coil 10. Such an arrangement of the wing-like coil structures / lobes 10a, 10b results in the tangential electric field being maximized along the field application axis 10x, while all non-tangential components of the electric field are substantially attenuated and / or negligibly eliminated. In this manner, the strength of the induction field in the target brain region beneath the central segment of the coil assembly 10, i.e., the interaction zone ii, is increased, improving stimulation of desired neural structures in the brain.

[0059] In operation, the angle between the winged coil structures / lobes 10a, 10b is adjusted according to the dimensions of the subject's skull, so that the winged coil structures / lobes 10a, 10b are positioned over the upper portion of the subject's head such that each wound winged coil structure / lobe is positioned over the upper side of the parietal bone. Electric current is generated by a signal source (not shown) connected to the coil assembly 10 via coil current terminals 11a, 11b. The electric current passed through the winged coil structures / lobes 10a, 10b generates an electromagnetic field directed to a specific target brain region of the subject, affecting the electrical stimulation responsiveness of that region.

[0060] 1C and 1D, a treatment session that can be applied using the coil assembly 10 according to several possible embodiments is shown. For simplicity, in these examples, the coil assembly 10 is shown without fixation devices (12 in Figs. 1A and 1B) and is positioned in different regions and orientations on the patient's skull 17. As shown, the configuration of the coil assembly 10 is flexible enough to provide an adjustable, wearable coil structure that can conform to the shape of various curved portions / regions of the subject's skull, so that most or all of the lower windings of the wings / lobes can be in direct contact with the subject's head 17 to maximize the strength of the electromagnetic field induced by the coil at the TMS target.

[0061] In particular, in Fig. 1C, the wing-like coil structure / lobes 10a, 10b of the coil 10 are positioned in the central parietal portion of the skull 17 such that the axis of elongation (12y in Fig. 1B) is substantially parallel to or aligned with the coronal plane (i.e., horizontal) of the skull 17. As shown, an electric field is generated by the coil assembly 10 along a field application axis 10x that is substantially parallel to or aligned with the sagittal plane of the skull 17. The wing-like coil structure / lobes of the coil assembly 10 can be secured to the subject's head 17 by one or more straps 10k, as shown in Fig. 1D.

[0062] In Figure 1D, the elongation axes (12y in Figure 1B) of the wing-like coil structures / lobes 10a, 10b of the coil assembly 10 are approximately parallel to or aligned with the coronal plane (i.e., horizontal) of the skull 17, such that, for example, one of the wing-like coil structures / lobes 10a is located in the central parietal portion of the skull 17 while the other wing-like coil structure / lobe 10b is located to the side of the parietal portion of the skull 17, to position the interaction zone ii of the coil assembly 10 approximately above the right hand motor cortical representation in the left hemisphere. In this arrangement, an electric field is generated by the coil assembly 10 along a field application axis 10x in a plane that is slightly tilted relative to the sagittal plane of the skull 17.

[0063] FIG. 1E shows the circular butterfly coil 10 in a planar state and secured by a coil securing mechanism 29. The coil securing mechanism 29 allows the wings 10a, 10b to be secured at a desired angle to fit snugly on the subject's head. In this particular non-limiting example, the coil securing mechanism 29 includes respective levers 13a, 13b coupled to respective coil securing structures 12a, 12b. As shown, the levers 13a, 13b can be coupled to a coil holder device 41 via respective straps 19a, 19b. The straps 19a, 19b are connected to the coil holder device 41 via respective releasable connectors (e.g., buckles) 23, 24 that are rotatably coupled to the coil holder device 41 in some embodiments.

[0064] Each of the levers 13a, 13b in some embodiments comprises a mounting portion 13t configured to connect directly to the coil fixing structures 12a, 12b, and a tilt lever portion 13r extending upwardly from the mounting portion 13t to facilitate manual adjustment of the tilt angle between the wing-like coil structures 10a, 10b. Optionally, in some embodiments, the straps 19a, 19b are elastic straps, preferably configured to maintain a certain level of tension. Alternatively or additionally, the straps 19a, 19b are adjustable straps configured to adjust the loop size of the straps.

[0065] Each releasable connector (e.g., buckle) 23, 24 may have a male side 23m, 24m snap-connectable to a respective female side 23f, 24f. In some embodiments, the male side 23m, 24m is connected to a respective strap 19a, 19b, and the respective female side 23f, 24f is rotatably connected to a coil holder device 41, as shown in FIG. 1E. In other embodiments, the male side 23m, 24m of each buckle 23, 24 is coupled to the coil holder device 41, and the female side 23f, 24f is coupled to a fixing means 12a, 12b attached to the coil assembly, such as via a strap 19a, 19b and / or a lever 13a, 13b. When the releasable connector 23, 24 is closed (i.e., when the male side 23m, 24m and the female side 23f, 24f are coupled), the wing-like coil structure 10a, 10b is locked in a flat planar state. When the releasable connectors 23, 24 are opened (i.e. when the male sides 23m, 24m and the female sides 23f, 24f are separated), the wing-like coil structures 10a, 10b can be bent and they can be tilted to form various angles between them.

[0066] During the TMS procedure, the coil is placed on the subject's head. A typical procedure is the determination of the location of the hotspot and the motor threshold (MT), which is the minimum stimulation output required to elicit a motor response in the muscles of the hand or foot. The hotspot is the location and orientation of the coil on the motor cortex where MT is minimal. Another procedure is moving the coil from the hotspot on the motor cortex to a treatment location, wearing the coil at the treatment location, and performing a TMS treatment session. In one embodiment, all or part of the above procedure is performed with the releasable connectors 23, 24 closed, so that the wing-like coil structures 10a, 10b are fixed in a flat planar state. In another embodiment, all or part of the above procedure is performed with the releasable connectors 23, 24 open, so that the wing-like coil structures 10a, 10b can be bent and tilted to form various angles between them. In some embodiments, the wing-like coil structures 10a, 10b are made to fit a portion of the subject's head.

[0067] That is, the releasable connectors 23, 24 are configured to define a locked state of the coil fixing mechanism 29 and a released state thereof. In the released state, the releasable connectors 23, 24 are opened to facilitate adjustment of a suitable tilt angle between the wing-like coil structures 10a, 10b to closely fit the head of a patient to be treated. In the locked state, the releasable connectors 23, 24 are closed to maintain the tilt angle between the wing-like coil structures 10a, 10b during a TMS treatment session and prevent further tilt between the wing-like coil structures 10a, 10b.

[0068] FIG. 1F shows the butterfly coil housed within the case element 10s, along with a buckle 23 that allows the wing-like coil structure to be secured in a flat position, and a head strap 32 that allows the wing-like coil structure to be fitted snugly to the subject's head when the buckle 23 is opened, with the wing-like coil structure conforming to the head and taking a particular angle between the wing-like coil structures.

[0069] FIGURE 1G shows the circular butterfly coil 10 attached to a human head 50. Here the buckles (23, 24 in FIGURE 1E) are shown in an open position so that the wing coil structure can assume various angles. As shown, head straps 32 attach the wing coil structure to the head 50.

[0070] 2A and 2B, top and side views of a butterfly-shaped electromagnetic coil assembly 20 according to some possible embodiments are shown, respectively. The butterfly-shaped electromagnetic coil assembly 20 includes two spaced apart elliptical wing-like coil structures / lobes 20a, 20b arranged along an extension / deployment axis 26y, each wing-like coil structure / lobe forming a planar coil structure, and an adjustable / flexible fixation device 26 connecting between the two elliptical wing-like coil structures / lobes 20a, 20b. The fixation device 26 is configured to easily change the angle between the planes of the two elliptical wing-like coil structures / lobes 20a, 20b, thereby allowing the coil assembly 20 to fit / adjust to the size / shape of the head / skull of the subject, while allowing elastic deformation of other parts of the wing-like coil structures / lobes of the coil 20.

[0071] In some possible embodiments, the fixation device 26 is formed by a pair of fixation plates 26a, 26b to which the main parts / elements of the loops of the wing-like coil structures / lobes 20a, 20b are attached, for example, by a plurality / array of fasteners 15 (e.g., cable ties / zip ties), respectively. Optionally, in some embodiments, the fixation plates 26a, 26b are pivotally connected between them, preferably via a hinge 26i configured to allow angular movement of one of the fixation plates 26a, 26b relative to the other about their tilt axis 26x. Optionally, in some embodiments, the tilt axis 26x is preferably substantially perpendicular to the deployment axis 26y.

[0072] Thus, the angle between the fixation plates 26a, 26b can be manipulated, i.e., increased or decreased, to change the angular orientation of the (planes of) the elliptical wings / lobes 20a, 20b relative to one another. In this manner, the coil assembly 20 can be easily adjusted to closely fit / adjust to the size of the subject's curved head / skull, such that most or all of the lower windings of the wings / lobes 20a, 20b are in direct contact with the subject's head (17).

[0073] The return portions / elements of the loops of the coil assembly 20 are attached, for example, by a plurality / array of fasteners 15 (e.g. cable / zip ties) to a fixing plate 25 distributed along the segments of the loops of the coil 20 outside the interaction area ii. The flexibility of the winged coil structure / lobes 20a, 20b of the coil assembly 20 is thus improved by connecting the main portions / elements of the coil loops inside the interaction zone ii to a single fixing plate 26a, 26b and connecting the return portions / elements of the coil loops relatively distant (with loop paths) by a plurality of fixing plates 25 (three in this non-limiting example). In this way, more than one-quarter of the length of the loops is free on both sides of the fixing plates 26a, 26b in the interaction area ii, which allows the return portions / elements of the loops outside the interaction area ii to flexibly deform relative to the main portions / elements of the loops.

[0074] FIG. 2A shows the coil assembly 20 in a planar state, with its wing-like coil structures / lobes generally aligned along a deployment axis 26y. FIG. 2B shows the coil assembly 20 in a tilted configuration, in which the coil's wing-like coil structures / lobes 20a, 20b are angularly tilted about a tilt axis 26x defined by hinges 26i to form an obtuse angle therebetween. Optionally, in some embodiments, the wing-like coil structures / lobes of the coil assembly 20 are preferably made from a single continuous conductive wire that is wound to form two laterally wound wing-like coil structures / lobes 20a, 20b electrically connected in series by an intermediate wire segment 20c that electrically connects the innermost loop of the wing-like coil structure / lobe 20b to the outermost loop of the wing-like coil structure / lobe 20a. The coil assembly 20 can be electrically coupled to a signal power source (not shown) via the coil current terminals 21a, 21b to generate additive magnetic fields through the wing-like coil structures / lobes.

[0075] The coil assembly 20 also includes a number of auxiliary fixation plates 25 (in this particular configuration, three for each wing / lobe 20a, 20b). The wires of the wing / lobe are connected to each of the fixation plates 25 by a number / array of fasteners 15 (e.g., cable ties / zip ties) configured, for example, to hold the loops of the wing-like coil structure / lobe together and maintain the planar shape of the wing-like coil structure / lobe 20a, 20b.

[0076] As shown in FIG. 2A, adjacently positioned portions / elements of the two spaced apart wing-like coil structures / lobes 20a, 20b define an interaction zone ii where the additive magnetic field generated by the wing-like coil structures / lobes is maximized. The electric field generated by the coil assembly 20 is tangential to the subject's head (e.g., a selected portion of the skull) along a field application axis 20x that is approximately parallel to or coincident with the tilt axis 26x of the wing-like coil structures / lobes 20a, 20b of the coil assembly 20. Such an arrangement of the wing-like coil structures / lobes 20a, 20b maximizes the tangential component of the induced electric field in the interaction zone ii, while all non-tangential components of the induced electric field are significantly attenuated or negligibly eliminated. In this manner, stimulation of the desired target neural structure of the subject's brain can be improved.

[0077] FIG. 2C shows the electromagnetic coil assembly 20 in operation, positioned on the head / skull 17 of a subject. As shown, the wing-shaped coil structure / lobes 20a, 20b are positioned in the central parietal portion of the skull 17, and are positioned such that the tilt axis 26x of the coil assembly 20 is approximately parallel to or aligned (i.e., perpendicular to) the coronal plane of the skull 17. FIG. 2D shows the application of the coil assembly 20 such that the elliptical wing-shaped coil structure / lobes 20a, 20b are lateral to the sagittal plane of the subject's head 17, and their deployment axis (26y in FIG. 2A) is approximately parallel thereto, for example, placing the interaction area ii of the coil 20 approximately above the right hand motor cortical representation of the left hemisphere.

[0078] 3A and 3B, top and bottom views, respectively, are shown of a compound electromagnetic coil array (also referred to herein as a crossed coil structure) 30 according to several possible embodiments. The compound electromagnetic coil array 30 includes a butterfly coil assembly 10, shown in FIGS. 1A and 1B, with the loops of its circular wing-like coil structure / lobes 10a, 10b coupled to the underside of a fixation device 12, and a coil assembly 20, shown in FIGS. 2A and 2B, with the loops of its elliptical wing-like coil structure / lobes 20a, 20b coupled to the opposite upper side of the fixation device 12.

[0079] The coils 10, 20 are arranged in a composite coil array 30 to form a defined angle (e.g., 90°) between the tilt axis of coil 10 (12x in FIG. 1B) and the tilt axis of coil 20 (26x in FIG. 2A). Such a crossed coil structure 35 can be obtained similarly by forming a defined angle between the deployment axis of coil 10 (12y in FIG. 1B) and the deployment axis of coil assembly 20 (26y in FIG. 2A).

[0080] This crossed coil structure 30 makes it possible to set a desired tilt angle between the wing-like coil structures 10a, 10b and / or 20a, 20b of the coil assemblies 10, 20 while ensuring that the central interaction zones ii of the coil assemblies 10, 20 are substantially coincident. In particular, a desired tilt angle between the wing-like coil structures 10a, 10b of the coil assembly 10 can be obtained by deforming the crossed coil structure 30 along the tilt axis 12x of the coil assembly 10, thereby also at least partially deforming the wing-like coil structures 20a, 20b of the coil assembly 20 along their deployment axis 26y.

[0081] In some possible embodiments, the elliptical wing-like coil structure / lobes 20a, 20b are accommodated on the upper surface of the fixation device 12 in a plane substantially parallel to the plane of the circular wing-like coil structure / lobes 10a, 10b of the loop. Note that terms such as upper and lower are used herein to indicate the orientation of the coil assembly disclosed herein in its operating state. In this embodiment, the lower surface of the fixation device 12 faces the skull / head of the subject, and the circular wing-like coil structure / lobes 10a, 10b are positioned above / on the skull / head of the subject, while the elliptical wing-like coil structure / lobes 20a, 20b are positioned slightly above the skull / head of the subject.

[0082] As can be better seen in Fig. 3B, this configuration of the combined coil 30 maintains flexibility of the return elements / portions of the loops of the coil assemblies 10, 20, while allowing flexible deformation for the main portions / elements of the loops located within the interaction zone ii of the combined / crossed coil structure 30. In this way, the geometry of the combined / crossed coil structure 30 can be adjusted to accommodate the portion placed on the head of a treated subject, while ensuring that the central interaction zone ii of the coil assemblies 10, 20 are substantially coincident, with the majority of the loops directly contacting the subject's head.

[0083] In some embodiments, the elliptical wing-like coil structure / lobes 20a, 20b of the coil assembly 20 and the circular wing-like coil structure / lobes 10a, 10b of the coil assembly 10 are electrically actuated by a multi-channel TMS stimulator 46, as shown in FIG. 4A. Optionally, in some embodiments, the composite electromagnetic coil array 30 is preferably controllably manipulated to induce a desired stimulation pattern. More specifically, the circular wing-like coil structure / lobes 10a, 10b of the coil assembly 10 can be actuated by a first alternating current supply, e.g., a series of current pulses, and the elliptical wing-like coil structure / lobes 20a, 20b of the coil assembly 20 can be actuated by a second alternating current supply, e.g., a series of current pulses, the first and second current supplies being configured to have a preset phase shift between them, e.g., a phase shift of π / 2. In this way, a rotating electromagnetic field can be generated that is maximized in the coincident interaction zones ii of the coil assemblies 10, 20.

[0084] Alternatively, as shown in FIG. 4B, two different stimulators 46a, 46b can be used to generate the first and second current supplies for the coil assemblies 10, 20 separately. Optionally, a controller 44 can be used to adjust the first and second current supplies driving the coil assemblies 10, 20 to ensure that a desired phase difference is maintained therebetween. Alternatively, as shown in FIG. 4C, a single channel stimulator 47 can be used to generate a supply current for one of the coil assemblies 10 (or 20), and a phase shift unit 45 can be used to receive a current supply from the stimulator 47 and generate another supply current for the other coil 20 (or 10) having a desired phase difference therefrom. Optionally, a controller 44 can be used to control the phase shift unit 45 and / or the stimulator 47 to ensure that a desired phase difference is maintained between the two supply currents.

[0085] In some embodiments, only the circular wing-like coil assemblies / lobes 10a, 10b of the coil assembly 10 or only the elliptical wing-like coil structures / lobes 20a, 20b of the coil assembly 10 are activated by the supplied current, as desired.

[0086] When the coil assemblies 10, 20 of the combined / crossed coil array 30 are operated with two different alternating currents having a phase shift of about 90°, the magnetic field generated thereby in the corresponding interaction zone ii is at its maximum strength and the electric field generated thereby rotates tangentially with respect to the head of the treated subject (e.g., a selected portion of the skull). This configuration of the combined / crossed coil assembly 30 maximizes the magnetic field generated by the combined / crossed coil array 30 in the corresponding interaction zone ii of the coil assemblies 10, 20 and significantly attenuates all non-tangential components of the magnetic field generated thereby. Thus, it is expected that the use of the combined / crossed coil array 30 will result in a significantly lower motor threshold compared to a conventional flat figure-of-eight coil.

[0087] In a possible embodiment, a combined / cross coil structure as shown in Figures 3A-3C is prepared using multiple (three or more) butterfly coils to obtain a desired angle between the deployment angle of each butterfly coil and the deployment angle of at least one other of the multiple butterfly coils. For example, in a possible embodiment, the combined / cross coil structure can be configured to form an equiangular TMS coil structure, where the angle between the deployment axes of each pair of adjacently disposed butterfly coils is substantially 180° / n, where n > 2 is the (integer) number of cross coils in the TMS coil structure.

[0088] In some embodiments, the combined / crossed coil array 30 is coupled to a fixed frame structure 31 that encircles the elliptical wings / lobes 20a, 20b. Gripping loops 31p may be provided on the fixed frame structure 31 to facilitate positioning and adjustment of the coil array 30 on the subject's (17) head. One or more strap fasteners 33 may be attached to the fixed frame structure 31 for securing the coil array 30 to the subject's head, for example by a head strap.

[0089] 3C shows the coil array 30 engaged with a holder device 41 configured to facilitate placement of the coil array 30 on the subject's head. In this non-limiting example, the coil array 30 includes sensor elements 42, 43 (e.g., EM sensors) coupled to opposite sides of the fixation device 12 for electromagnetic neuronal navigation. The sensor elements 42, 43 can be coupled to the combined / crossed coil array 30 by attachment to levers 13a and / or 13b.

[0090] The sensor elements 42, 43 are used in conjunction with other sensor elements (not shown) placed on the subject's head, so that the combined / crossed coil array 30 can be precisely positioned over the target TMS region of the subject's head. The holder device 41 can include an electromagnetic (EM) field generator or transmitter (not shown) configured to emit a low intensity variable EM field that establishes a measurement volume sensed by the sensor elements. In operation, when the sensor elements 42, 43 enter the generated EM field, a small current is induced in the sensor elements. The induced current is relayed via wires 42w, 43w to a sensor interface unit (SIU) 41u, which is configured to amplify and digitize the received signal and transmit it to a system control unit (SCU) 44.

[0091] The control unit 44 is configured to calculate the position and orientation (e.g., as a change) of each sensor element 42, 43 based on the received signal and the geometrical position of the sensors 42, 43 relative to the coil assemblies 10, 20 and other sensor elements disposed on the subject's head. The control unit 44 then generates instructions for the user to move the combined / cross coil array 30 by a predetermined displacement in an appropriate direction to position the coil assembly over a desired target brain region of the subject. The holder device 41 is further configured to connect the coil assemblies 10, 20 of the combined / cross coil array 30 to one or more stimulation devices (e.g., as illustrated in Figures 4A-4C) and to direct a cooling medium through the cooling medium conduits 41s toward the coil assemblies 10, 20 to prevent overheating. A handle 41h is provided in some embodiments to facilitate positioning the holder device 41 and the combined / cross coil array 30 on the subject's head.

[0092] Figure 3D illustrates a combined / crossed coil array 30 that is readily operable to be placed on the subject's head 17 and apply an electromagnetic field thereto. In the combined / crossed coil configuration illustrated in Figure 3D, the elliptical butterfly wing coil structure / lobes 20a, 20b of the coil assembly 20 are placed in direct contact with the subject's head and the circular wing coil structure / lobes 10a, 10b of the coil assembly 20 are placed over the wing coil structure / lobes of the coil assembly 20. The combined / crossed coil array 30 is illustrated in Figure 3D without the fixation device 12 and holder device 41 for simplicity.

[0093] Because the elliptical butterfly wing coil structures / lobes 20a, 20b are laterally flexible, they are positioned close to the midline so that most or all of the loops on the underside of the wing coil structures / lobes 20a, 20b conform to and directly contact the shape of the head.

[0094] 3E shows the combined / crossed coil array 30 attached to the subject's head 17 in a lateral position, with the interaction zone of the combined / crossed coil array 30 approximately above the right hand motor cortex representation in the left hemisphere. As shown, the tilt angle between the circular wing-like coil structure / lobes 10a, 10b of the lower coil assembly 10 is adjusted so that most or all of the lower loops are in direct contact with the subject's head 17. Also, as shown in FIG. 3E, the flexibility of the upper wing-like coil structure / lobes 20a, 20b of the coil assembly 20 allows their lateral portions to approximately conform to the shape of the head 17 and directly contact the head.

[0095] The winged coil structures / lobes of the coil assemblies 10, 20 of the combined / crossed coil array 30 may be secured to the subject's head 17 by one or more head straps 10k.

[0096] Also, throughout this disclosure, when a process or method is disclosed or described, it should be understood that the steps / actions of the method may be performed in any order and / or simultaneously and / or with other steps / actions not shown / described herein, unless it is clear from the context that one step is dependent on another step being performed first. In possible embodiments, not all of the steps / actions shown / described are necessarily required to practice the method.

[0097] Relative terms such as "lower," "upper," "horizontal," "vertical," "upper," "lower," "up," "bottom," "top," and "bottom" and their derivatives (e.g., "horizontally," "downward," "upward," etc.) and similar adjectives relating to the orientation of the described elements / components refer to the way the illustrated items are oriented on paper and do not limit the orientation in which those elements / components may be used in actual application.

[0098] As described above and shown, the present application provides a bendable / deformable TMS coil and associated methods for efficiently applying an electromagnetic field to a brain region of a subject. Although specific embodiments of the invention have been described, it will be understood that the invention is not limited to those embodiments, as modifications may be made by those skilled in the art, especially in light of the teachings set forth above. As will be appreciated by those skilled in the art, the invention can be implemented in a wide variety of ways, employing techniques from those described above, without departing from the scope of the claims.

Claims

1. 1. A TMS coil assembly for magnetically stimulating a brain region of a subject, comprising: one or more coil assemblies, each of which includes adjacently or spaced apart flexible wing-like coil structures, the wing-like coil structures being configured to adjustably deform along a tilt axis passing between the wing-like coil structures to apply a desired tilt angle between the wing-like coil structures to conform to a curvature of a subject's head and to bring a majority of the loops of the wing-like coil structures into direct contact with the curvature of the head, thereby maximizing the portion of the loops tangential to the curvature of the head and minimizing the portion of the loops tangential to the curvature of the head; and a fixation device configured, when positioned on a subject's head during a TMS treatment, to maintain a desired tilt angle between the wing-like coil structures, thereby maximizing the strength of the electric field induced on the head.

2. 2. The TMS coil assembly of claim 1, 11. A TMS coil assembly configured to define a field application axis passing between said wing coil structures.

3. 3. The TMS coil assembly of claim 2, 11. A TMS coil assembly, wherein said tilt axis and said field application axis are substantially parallel or coincident.

4. 4. The TMS coil assembly according to claim 2, 11. A TMS coil assembly configured to define a central interaction zone relative to said field application axis within which additive electric and magnetic fields generated by said wing coil structure are at a maximum strength.

5. 13. A TMS coil assembly according to any one of the preceding claims, comprising:

4. The TMS coil assembly according to claim 1, wherein the desired tilt angle is a straight angle.

6. 13. A TMS coil assembly according to any one of the preceding claims, comprising:

11. A TMS coil assembly, comprising: a first coil support structure configured to support the first coil structure and a second coil support structure configured to support the first coil structure and to support the second coil structure.

7. 7. The TMS coil assembly of claim 6, 11. A TMS coil assembly, wherein the one or more coil retention structures are hinged at one or more pivots.

8. 8. The TMS coil assembly according to claim 6 or 7, 11. A TMS coil assembly comprising: a coil holder device and one or more lever members coupled to at least one of the coil holding structures, respectively, to facilitate setting a desired tilt angle between the wing-like coil structures.

9. 9. The TMS coil assembly of claim 8, 11. A TMS coil assembly comprising: a locking mechanism configured to maintain the lever member locked relative to the coil holder arrangement to prevent further tilting of the wing coil structure.

10. 10. The TMS coil assembly of claim 9, 11. A TMS coil assembly comprising one or more releasable connectors, each configured to couple one of said lever members to said coil holder arrangement.

11. 11. The TMS coil assembly of claim 10, A TMS coil assembly, characterized in that each releasable connector is connected to a respective lever member by a respective elastic and / or adjustable strap.

12. 13. A TMS coil assembly according to any one of the preceding claims, comprising: A TMS coil assembly comprising a fixing means configured to attach the TMS coil assembly to the head of a subject.

13. 13. The TMS coil assembly of claim 12, 11. A TMS coil assembly, wherein the fastening means comprises a head strap configured to fasten the TMS coil assembly to the head and to have a majority of its loops in direct contact with the head.

14. 13. A TMS coil assembly according to any one of the preceding claims, comprising: A TMS coil assembly characterized in that the wing-like coil structure is configured to have a certain degree of flexibility so that the coil loops can conform to the subject's head and most of the loops can directly contact the head.

15. 13. A TMS coil assembly according to any one of the preceding claims, comprising: A TMS coil assembly, characterized in that the loops of the wing-like coil structure are configured to flexibly conform and contact the head in all coil portions facing the head.

16. 13. A TMS coil assembly according to any one of the preceding claims, comprising:

11. A TMS coil assembly, wherein the wing coil structure has a generally circular shape.

17. A TMS coil assembly according to any one of claims 1 to 15, 11. A TMS coil assembly, wherein the wing coil structure has a generally elliptical shape.

18. A TMS coil assembly according to any one of claims 1 to 15, 11. A TMS coil assembly, wherein the wing coil structure has a generally rectangular shape.

19. 1. A TMS coil array for magnetically stimulating a brain region of a subject, comprising:

18. A TMS coil array comprising two or more TMS coil assemblies according to any one of claims 1 to 17, each of the TMS coil assemblies having a deployment axis substantially perpendicular to its tilt axis, and wherein the deployment axis of each of the two or more TMS coil assemblies intersects with the deployment axis of at least one other of the TMS coil assemblies.

20. 20. The TMS coil array of claim 19, 13. A TMS coil array, wherein two of said TMS coil assemblies are connected to two different sides of a single fixation device.

21. 21. The TMS coil array of claim 20, 11. A TMS coil array, comprising: a TMS coil array having a tilt axis of about 90 degrees between said tilt axes of said TMS coil assemblies.

22. The TMS coil array according to any one of claims 19 to 21, 5. A TMS coil array comprising: two or more TMS coil assemblies each having a central interaction zone as defined in claim 4; and wherein the TMS coil array is configured such that the interaction zones of the two or more TMS coil assemblies substantially coincide.

23. The TMS coil array according to any one of claims 19 to 22, 11. A TMS coil array, wherein each of the TMS coil assemblies is electrically connected to a respective independent channel of a stimulation device configured to control timing of operation of the TMS coil assembly.

24. The TMS coil array according to any one of claims 19 to 22, 1. A TMS coil array configured to induce a rotational field in brain tissue by manipulating a phase difference between at least two currents in the TMS coil assembly.

25. The TMS coil array according to any one of claims 19 to 24, A TMS coil array, characterized in that each wire or some of the wires of the TMS coil assembly are separately electrically insulated.

26. The TMS coil array according to any one of claims 19 to 24, 11. A TMS coil array comprising one or more layers of electrically insulating shielding surrounding all of the wires of said TMS coil assembly.

27. The TMS coil array according to any one of claims 19 to 26, A TMS coil array configured for neuronal navigation of the position of a coil assembly on the head.

28. 28. The TMS coil array of claim 27, A TMS coil array, wherein the neuronal navigation is based on optical and / or electromagnetic tracking.

29. 1. A method for treating a neurophysiological disorder, comprising: placing at least one TMS coil assembly having a winged coil configuration on a subject's head; setting an inclination angle between the wing-shaped coil structures so that the wing-shaped coil structures conform to the curvature of the head and most of the loops directly contact the head; and applying an electrical current to the at least one TMS coil assembly to stimulate a region of the subject's brain.

30. 30. The method of claim 29, changing the TMS coil assembly to a released state before setting the tilt angle, and thereafter changing the TMS coil assembly to a locked state to prevent further tilting between the wing coil structures.

31. 1. A method for treating a neurophysiological disorder, comprising: placing the TMS coil assembly according to any one of claims 1 to 16 or the TMS coil array according to any one of claims 17 to 27 on the head of a subject to be treated and setting an inclination angle between the at least two wing-like coil structures thereof to fit the curved area of ​​the head; and applying an electrical current to a TMS coil assembly of the TMS coil array to stimulate a region of the subject's brain.

32. 32. The method of claim 30 or 31, The method is characterized in that the neurophysiological disorder is at least one of depression, bipolar disorder, schizophrenia, PTSD, Parkinson's disease, dystonia, movement disorder, Alzheimer's disease, mild cognitive impairment, autism, Asperger's syndrome, multiple sclerosis, ALS, Tourette's syndrome, blepharospasm, stroke, chronic pain, eating disorders, obesity, anorexia nervosa, bulimia, any addiction including tobacco addiction, drug addiction, alcoholism or gambling addiction, ADHD, OCD, epilepsy, migraine, tinnitus.

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