Background of the Invention

The present invention relates to a method and apparatus for applying a magnetic field to a subject, and in particular a method and apparatus for applying a magnetic field for therapeutic purposes such as pain relief.

Description of the Prior Art

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Magnetic field gradients are determined by the rate of change of the strength of a magnetic field over a distance. In general, charged particles experience a force when exposed to a changing magnetic field. Accordingly, as a charged particle moves through a magnetic field gradient, the change in the magnitude of the field with distance results in a varying net force on the charged particle.

Within the mammalian body there are numerous systems that involve the movement of charged particles. One such example is the active and passive transport of ions across the cell membrane. The transport of Sodium, Potasium and Calcium ions across the cell membrane combine to generate an action potential, which is relevant to the transmission of nerve impulses, which in turn has an impact on pain responses within mammals. Published data suggests that quadrapolar static magnets generating steep field gradients have an effect on nerves that is not shared with the more common bipolar magnets that possess only slight field gradients. The most likely mechanism for this impact is that the magnetic field gradient is altering nerve excitability as a result of changes in membrane permeability to sodium and calcium ions (McLean et al., 1997; McLean et al., 1995 Cavopol et al., 1995). "Static Magnetic Fields for the Treatment of Pain" by Michael McLean, M.D., Ph.D., 1 Stefan Engstro m, Ph.D., and Robert Holcomb, M.D., Ph.D. Epilepsy & Behavior 2, S74-S80 (2001) describes the use of such therapeutic magnets constructed with multiple permanent magnets that generate static magnetic fields for the purpose of suppressing nerve action.

This arrangement is disclosed in US-5,312,321, which describe a device and a method for suppressing nerve cell action potentials. In this example, an octapolar magnetic device is disposed near a mammalian sensory neuron so that the magnetic field generated by one quadrapolar face of the device is symmetrically disposed about the neuron. The magnetic device is comprised of four magnetic bodies, each having two opposite magnetic poles. Two positive and two negative magnetic poles are disposed substantially in a single plane and to define the four vertices of a quadrilateral shape, the two positive poles defining two diagonal vertices, and the two negative poles defining the opposite two diagonal vertices of the quadrilateral shape. A housing is provided to hold the magnetic bodies in a fixed relative position and thus maintain the quadrilateral orientation of the poles. US-6,461,288 describes a similar device that also incorporates a flux ring for focusing the magnetic flux.

However, such arrangements have a number of drawbacks. For example, the magnets used are circular discs, and as a result, this places physical constraints on the nature of the resulting gradient field, not least because separation of the poles is limited by the physical constraints of the round discs, and the field is generated by each magnet over a limited physical area. This in turn limits the magnet mass enclosed within the device which in turn limits the strength and depth of penetration of the magnetic flux. In addition, it limits the gradient that can be applied to the subject and as the nerve impulse blocking effect is related to the steepness of the applied field gradient, this limits the effectiveness of the arrangement.

Additionally, as the arrangement uses multiple separate magnetic bodies, it is necessary for them to be encased in a housing in order to maintain the required physical relationship between the magnets. This adds to the construction costs and complexity of the arrangement, and can also lead to problems in the event that the housing becomes damaged, which can result in the physical arrangement of the magnets being disturbed. The housing also adds significantly to the size of the resulting device, making the device unwieldy and uncomfortable in use, which in turn, reduces patient compliance with use requirements, and therefore reduces its effectiveness.

In the case of US-6,461,288, this document describes the use of a flux ring for focussing the magnetic field. However, the flux ring provides only limited benefit as the ring includes a central aperture, that allows leakage of the magnetic field through the flux ring, thereby limiting the effectiveness of the ring, and in particular, preventing the ring from providing effective shielding. As a result, the device can still be attracted to magnetic materials whilst being worn by a user, thereby making the device uncomfortable in use.

US-5, 871,438 describes a flexible magnetic pad provided with constantly alternating polarity zones which therapeutically affect blood vessels to increase blood flow, irrespective of the orientation of any blood vessel with respect to the pad, the polarity zones being arranged in an alternating pattern throughout the pad. The pads are formed from a flexible material impregnated with magnetic material, which limits the field strength that can be applied to the subject. Additionally, the pad of material is thin in order to maintain flexibility, and as a result, the device includes only a limited field gradient, thereby limiting the effectiveness of the arrangement. In particular, this prevents the system adequately interfering with nerve action, and hence makes the arrangement much less effective for use in treating pain.

Additionally, as the arrangement uses an impregnated flexible substrate, construction requires the formation of an appropriate material, which in turn adds to the construction costs and complexity of the arrangement.

Summary of the Present Invention

In a first broad form the present invention seeks to provide apparatus for applying a magnetic field to a subject, the apparatus including: a) a body comprising a magnetic material having a plurality of magnetic regions, each magnetic region generating a magnetic field having a polarity opposed to that of magnetic fields generated by adjacent magnetic regions, thereby generating magnetic field gradients; and, b) a shield positioned on a first side of the body, wherein in use, a second side of the body is positioned adjacent to the subject such that at least one magnetic field gradient penetrates the subject.

Typically the body includes a magnetic material magnetised to thereby define the magnetic regions.

Typically each magnetic region is a respective body portion made of a respective magnetic material magnetised to thereby define the magnetic regions.

Typically the magnetic regions are circumferential Iy arranged circular sectors, the field gradients being generated along radii bounding adjacent magnetic regions.

Typically the magnetic regions are at least one of quadrants, sextants and octants.

Typically the apparatus includes a housing, and wherein the body is movably mounted within the housing, thereby allowing the body to move relative to a user in use.

Typically the apparatus include an axle for rotatably mounting the body in the housing.

Typically the apparatus include a ratchet and pawl for allowing rotation of the body in a single direction.

Typically the body includes a coating provided on the magnetic material.

Typically the coating is substantially inert.

Typically the coating is at least one of: a) gold; b) nickel; c) silver; d) platinum; e) epoxy; and, f) plastic. Typically the shield is for at least partially reducing a magnitude of magnetic fields extending away from the subject in use.

Typically the shield is for at least partially increasing a magnitude of magnetic fields permeating the subject in use.

Typically the shield is for at least partially increasing the magnetic field gradients.

Typically the shield is formed from a metal.

Typically the apparatus includes at least one marking defining an orientation, and wherein in use, the body is applied to the subject in accordance with the at least one marking.

Typically the at least one marking is provided on the flux shield.

Typically the apparatus includes at least one marking defining an orientation, and wherein in use, the body is applied to the subject in accordance with the at least one marking.

Typically the apparatus is for therapeutic use.

Typically the apparatus is for use in at least one of administering pain relief, reducing inflammation and negating the effects of muscle memory.

Typically the apparatus is for altering a charge distribution across membranes within a subject.

In a second broad form the present invention seeks to provide a method for applying a magnetic field to a subject, using apparatus including: a) a body comprising a magnetic material having a plurality of magnetic regions, each magnetic region generating a magnetic field having a polarity opposed to that of magnetic fields generated by adjacent magnetic regions, thereby generating magnetic field gradients; and, b) a shield positioned on a first side of the body, wherein the method includes, positioning a second side of the body adjacent to the subject such that at least one magnetic field gradient penetrates the subject. Typically the method includes positioning the apparatus so that at least one magnetic field gradient interferes with a nerve.

Typically the method includes positioning the apparatus so that at least one magnetic field gradient interferes with at least one nerve associated with pain in the subject.

Typically the method includes positioning the apparatus for a predetermined time period.

Typically the method includes, positioning the apparatus to thereby alter a charge distribution across membranes within a subject.

Typically the method includes, positioning the apparatus to thereby at least one of administer pain relief, reduce inflammation and negate the effects of muscle memory.

Brief Description of the Drawings

An example of the present invention will now be described with reference to the accompanying drawings, in which: -

Figure IA is a schematic top perspective view of an example of apparatus for applying a magnetic field to a subject; Figure IB is a schematic underside perspective view of the apparatus of Figure IA;

Figure 1C is a schematic side view of the apparatus of Figure IA;

Figure ID is a schematic side view of an example of the magnetic field generated by an unshielded body;

Figure IE is a schematic side view of an example of the magnetic field generated by a shielded body;

Figure 2A is a schematic plan view of an example of a body showing the magnetisation of four magnetic regions;

Figure 2B is a schematic side view of the body of Figure 2 A in the apparatus of Figure 1 A;

Figure 2C is a schematic plan view of an example of a body showing the magnetisation of six magnetic regions;

Figure 2D is a schematic plan view of an example of a body showing the magnetisation of eight magnetic regions; Figures 3A and 3B are graphs of an example of field gradients generated by the body of

Figure 2A and a prior art apparatus, respectively;

Figure 4A is a schematic plan view of an example illustrating the location of a field gradient along the boundaries of four magnetic regions formed by magnetising a single magnetic material;

Figure 4B is a schematic plan view of an example illustrating the location of a field gradient along the boundaries of eight magnetic regions formed by magnetising a single magnetic material;

Figure 4C is a schematic plan view of an example illustrating the location of a field gradient in a traditional magnetic apparatus;

Figure 5 A is a schematic diagram of an example of the positioning of apparatus for applying a magnetic field between the vertebrae of a subject;

Figure 5B is a schematic diagram of an example of the positioning of apparatus for applying a magnetic field spanning the vertebrae of a subject; Figure 5C is a schematic diagram of a second example of the positioning of apparatus for applying a magnetic field spanning the vertebrae of a subject;

Figures 6A and 6B are side and plan views of a further example of apparatus for applying a magnetic field to a subject;

Figures 6C and 6D are side and plan views of a second further example of apparatus for applying a magnetic field to a subject;

Figure 7A is a diagram of an example of the magnitude and direction of the magnetic induction vector generated by apparatus including the body of Figure 2A;

Figure 7B is a diagram of an example of the z component of the magnetic induction vector generated on the unshielded side of apparatus including the body of Figure 2A in a plane parallel to the surface of the body;

Figure 7C is a diagram of an example of the z component of magnetic induction vector generated on the shielded side of apparatus including the body of Figure 2A in a plane parallel to the surface of the body;

Figure 7D is a diagram of an example of the z component of the magnetic induction vector generated on the unshielded side of apparatus including the body of Figure 2A in a plane perpendicular to the surface of the body; Figure 7E is a diagram of an example of the y component of the magnetic induction vector generated on the unshielded side of apparatus including the body of Figure 2A in a plane perpendicular to the surface of the body;

Figure 7F is a diagram of an example of the y component of the magnetic induction vector generated on the unshielded side of apparatus including the body of Figure 2A in a plane of polarity change;

Figure 7G is a diagram of an example of the x component of the magnetic induction vector generated on the unshielded side of apparatus including the body of Figure 2A in a plane perpendicular to the surface of the body; Figure 8 A is a diagram of an example of the magnitude and direction of the magnetic induction vector generated by apparatus including the body of Figure 2C;

Figure 8B is a diagram of an example of the z component of the magnetic induction vector generated on the unshielded side of apparatus including the body of Figure 2C in a plane parallel to the surface of the body; Figure 8C is a diagram of an example of the z component of magnetic induction vector generated on the shielded side of apparatus including the body of Figure 2C in a plane parallel to the surface of the body;

Figure 8D is a diagram of an example of the z component of the magnetic induction vector generated on the unshielded side of apparatus including the body of Figure 2C in a plane perpendicular to the surface of the body;

Figure 8E is a diagram of an example of the y component of the magnetic induction vector generated on the unshielded side of apparatus including the body of Figure 2C in a plane perpendicular to the surface of the body;

Figure 8F is a diagram of an example of the y component of the magnetic induction vector generated on the unshielded side of apparatus including the body of Figure 2C in a plane of polarity change; and,

Figure 8G is a diagram of an example of the x component of the magnetic induction vector generated on the unshielded side of apparatus including the body of Figure 2C in a plane perpendicular to the surface of the body. Detailed Description of the Preferred Embodiments

An example of apparatus for applying a magnetic field to a subject will now be described with reference to Figures IA to 1C.

In this example, the apparatus 100 includes a magnetic body 1 10 coupled to a shield 120. The magnetic body has a plurality of magnetic regions, each magnetic region generating a magnetic field having a polarity opposed to that of magnetic fields generated by adjacent magnetic regions, thereby generating an overall magnetic field having at least one magnetic field gradient.

The magnetic regions are typically shaped so that there are substantially no gaps between the regions, with the magnetic regions being in contact along boundaries, so that the field gradient generated is maximised along the length of the boundary.

In one example, the magnetic body 110 is formed from a solid body of magnetisable material. Whilst any material may be used, typically the magnetic body is formed from a rare earth material, such as neodymium, samarian-cobalt, or the like, as this allows permanent high field strengths to be achieved. In this example, the magnetic regions are typically formed by selectively magnetising different regions of the magnetisable material that forms the magnetic body. This can be achieved using any suitable technique, as known in the art. This typically involves cycling the magnetic material under varying conditions of applied magnetic field and temperature, until desired magnetisation is achieved, as described, for example, in US-4,920,326.

However, the use of a single body of magnetisable material is not essential and alternatively, each magnetic region could be formed from a respective body portion of magnetisable material. In this example, each body portion is individually magnetised before the body portions are coupled together into an appropriate arrangement, to thereby provide a single body having a plurality of magnetic regions. As mentioned above, the magnetic regions, and hence the body portions are typically shaped so that there are substantially no gaps between the regions, thereby forming a unitary body once the body portions are coupled together. In the current example, the magnetic body 110 has a substantially cylindrical shape, with the shield 120 being coupled to a first end 111 of the magnetic body 1 10. In use the magnetic body 110 is positioned so that a second end 112 of the magnetic body 1 10, opposite the first end 111, is positioned substantially adjacent the subject S. As a result, the magnetic field near the second end 112 permeates the subject S.

In use, the shield 120 acts to modify the magnetic field generated by the magnetic body 1 10, in particular by shielding the first end 1 11 of the magnetic body 110. Accordingly, the shield 120 is typically formed from a shielding material having a high magnetic permeability. Examples include iron or metal alloys such as Permalloy and Mu-metal, as well as steel, or the like.

In one example, the shield 120 is in the form of a solid laminar plate, conforming to the size and shape of the first end 111 of the magnetic body 110. This helps maximise the shielding effect, which will now be described in more detail with respect to Figures ID and IE, which show examples of the field lines generated by an unshielded and a shielded magnetic body respectively.

In one specific example, the shield is formed from a magnetic stainless steel. The steel acts as a cheap effective shield material, whilst the use of a magnetic stainless steel allows the shield to be exposed to the environment without risk of corrosion. This avoids the need to encase the shield in a housing to avoid deterioration of the shield material.

As shown in Figure ID, field lines 115 extend equally from each of the first and second ends 111, 112 of the magnetic body 110. In contrast, in the case of Figure IE, the shield 120 redirects field lines extending from the first end 11 1, so that the field lines 121 pass through the body of the shield 120, extending from sides of the shield 120 to the second end 112, as shown at 122.

The absence (or reduction) of field lines in the area immediately adjacent to the shield 120 highlights that the magnitude of any external magnetic field adjacent to the shield 120 is significantly reduced as compared to the scenario of Figure ID. The reduction in external field away from the subject reduces the chance of the apparatus 100 being attracted to other magnetic materials, which can cause discomfort or inconvenience to a wearer, in use.

The shielding effect also deflects the field, thereby increasing penetration of the magnetic field into the subject S, and increasing the field gradient to which the subject is exposed. In particular, in the unshielded arrangement of Figure ID, the magnetic field penetrates a distance dj, whilst in the shielded arrangement of Figure IE, the magnetic field penetrates a distance d ₂ , where di < d ₂ -

As mentioned above, in this example, the shield 120 is a solid shield extending across the entire first end 111 surface of the magnet. This maximises the shielding effect, and in particular prevents leakage of the field through any gaps as occurs during the use of flux rings, as described for example in the prior art. As a result, this also increases deflection of the magnetic field to thereby maximising the field gradient to which the subject is exposed.

An example of the magnetisation of the magnetic body will now be described with reference to Figure 2A, which shows the magnetic body and Figure 2B, which shows the magnetic body incorporated into apparatus 100.

In this example, the magnetic body 110 is divided into four "pie" (circular segment) shaped magnetic regions 201, 202, 203, 204. The magnetic regions 201, 202, 203, 204 are polarised with such that the magnetic dipole is substantially parallel to an axis 215 (shown in Figure 2B) of the magnetic body 110, with adjacent regions 201, 202, 203, 204 having opposing polarisations. However, this is not essential, and the poles of the magnetic regions could be aligned at an angle to the axis 215, depending on the preferred implementation. In any event, in the example of Figure 2A, the regions 201, 203 have polarisations with the north pole of the dipole at the first end 111, indicated by the "+" symbol, whilst the regions 202, 204 have polarisations with the north pole at the second end 112, indicated by the "-" symbol.

The use of opposing polarisations for adjacent regions generates magnetic field gradients substantially along at least boundaries 211, 212, 213, 214 between the adjacent regions 201, 202, 203, 204. Thus, in this example, the magnetic regions 201, 202, 203, 204 are circumferentially arranged circular sectors, with the field gradients being generated along boundaries 211, 212, 213, 214, which in this example are the radii bounding adjacent magnetic regions.

In contrast to prior art devices apparatus, the use of a single magnetic body 110, can avoid the need to provide a housing, as is required by the four magnet arrangements of US- 5,312,321 and US-6,461,288. This significantly reduces the size of the apparatus 100 compared to prior art devices capable of generating a magnetic field of a similar strength, making the device more comfortable to wear, in use.

Additionally, the use of a body 110 having magnetised regions 201, 202, 203, 204, allows the magnetic regions to be adjacent to each other substantially along entire boundaries, rather than just at four physical points, as in the case of the four magnet arrangements of US- 5,312,321 and US-6,461,288. This maximises both the magnitude and physical dimensions of the field gradient, which in turn maximises exposure of the subject to the field gradient.

An example of the field gradient generated using the apparatus 100 of Figure 2B, as compared to a prior art device according to US-6,461,288 is shown in Figures 3A and 3B, respectively. The graphs indicate the rate of change of the magnetic field, that is, the field gradient measured in mT/mm (milliTesla per millimeter) as measured at the surface of the device. In this example, the magnets in the prior art device were 6.35mm thick, whilst those of the apparatus 100 were 6mm thick, thereby ensuring comparison of devices having similar properties.

At peak, the magnetic body of Figure 2A generates a magnetic field gradient that is over 50% steeper than the prior art arrangement. This highlights that the gradient generated for the single magnetic body, when divided into magnetic regions, is greater than that generated when multiple magnetic bodies are used. Despite the improved gradient, achieved using similar thickness magnets, the apparatus 100 is 30% smaller than the prior art device, thereby further highlighting the improved performance and comfort of the arrangement.

It will be appreciated that a range of different region sizes and shapes can be implemented, depending for example on the arrangement of the apparatus used to magnetise the magnetic body 110. Accordingly, whilst four regions are shown in Figure 2A, this is for the purpose of example only, and in practice any number of regions may be provided. Examples of this are shown for example, in Figures 2C and 2D, in which six and eight region arrangements are shown, although greater numbers of regions, such as up to 28, can be used. Thus, it will be appreciated that the magnetic regions can be quadrants, sextants or octants of a circular body. However, this is not intended to be limiting, and other arrangements can be used.

As mentioned above, the magnetic regions can be formed from separate magnetic material. In this example, the body 110 is formed by creating physically separate body portions corresponding to each of the magnetic regions 201, 202, 203, 204. Each body portion is individually magnetised in a manner similar to that described above. Once magnetised, the body portions can be coupled together to form the body 110. In this regard, the body portions are shaped so that when coupled together the body portions form a unitary body, so that there are no physical gaps between adjacent body portions.

It will be appreciated that in this instance, as adjacent magnet regions have opposing polarities, the body portions will tend to be attracted to each other and can therefore be held together by the magnetic attraction between body portions. Additionally, the use of the shield 120 can assist in holding the body portions in position.

One of the reasons for using separate body portions is that when magnetising a single magnetic material with multiple regions, there tends to be a transition between the magnetisation of adjacent regions, caused by the magnetisation process. An example of this is shown in Figure 4 A. In this example, a portion at the edge of each of the regions 201, 202, 203, 204 has low field strength along the boundaries 211, 212, 213, 214, as shown by the dotted lines 400. As a consequence, the field gradients near the boundaries 211, 212, 213, 214 are reduced. The effect of this is magnified in the event that additional regions are included, as shown for example in Figure 4B, for an eight region configuration. In this example, a relatively large circular region 401 about the centre of the body 110 has a low field strength and hence low field gradient.

In contrast, by magnetising individual body portions, this ensures that the magnetisation extends to the very edge of the body portion. Consequently, when the body portions are integrated into body 110, this maximises field strengths at the boundaries between adjacent magnetic regions, which in turn increases the field gradients, and hence the effectiveness of the apparatus 100.

It will be appreciated that in the above described arrangement, the body portions are shaped to cooperate and thereby define a unitary body that does not include any gaps. Consequently, the magnetic regions are in contact along the entire length of their boundary, so that the field gradients have substantial strength along the full length of the boundaries.

This should be contrasted with the traditional arrangement in which four circular magnets are used, as described for example in US-5,312,321, and shown in Figure 4C. In this instance it will be appreciated that the field gradients are only substantial where the magnets 420 touch, as shown at 421. This results in a substantially reduced overall field gradient, as discussed above. As the high field gradient is important in achieving a pain relieving effect, this results in a device of far lower effectiveness than that described above. Furthermore, the configuration makes it difficult to align the points 421 with nerves, which is generally needed in order to ensure efficacy.

In contrast, the above described magnetic body 110 can be of any size and configuration, depending on the intended use, as will now be described with reference to Figures 5A and 5B.

For example, when targeting back pain, it is typical to position on the apparatus 100 in the interspinous space between the spinous process of adjacent vertebrae 500. However, in the event that adjacent vertebrae 500 are to be targeted, it is often not possible to position each individual apparatus 100 on either side of a vertebra 500, as shown in Figure 5 A. The reason for this is that the adjacent interspinous spaces are typically separated by approximately 20mm and this is the recommended distance between individual apparatus 100 otherwise the neighbouring magnetic fields interfere with each other and hence reduce the overall field gradients. Additionally, the magnetic attraction between each apparatus 100 will be too great, thereby generating a force between each apparatus 100, which can in turn cause discomfort in use. Accordingly, in one example, the arrangement of Figure 5 A could be modified by providing an additional interspinous space between each apparatus 100. Thus, for example, one apparatus 100 could be between the vertebrae at L3/4, with another apparatus 100 being positioned between the vertebrae at L5/S1.

Using the above described arrangement it would not generally be possible to concurrently provide a therapeutic effect for adjacent interspinous spaces, as the arrangement of Figure 5 A is generally unsuitable for use. However, an enlarged version of the apparatus 100 can be used to span multiple vertebrae, as shown in Figure 5B, thereby allowing adjacent interspinous spaces to be targeted.

Dermatomes are areas of skin supplied with different nerve fibre by a single nerve root. For the back, the nerve typically extends from the spinal chord in the interspinous space, as shown at 501. Accordingly, in the arrangement of Figure 5B, the relevant nerves may not align with (or travel or transit across the field gradient boundary) the boundaries 510 between magnetic regions 511. Accordingly for this reason an alternative magnetic region configuration may be used, similar to that shown in Figures 2C or 2D. As shown in Figure 5C, this can be used to ensure that the boundaries 510 intersecting the nerve 501. It will therefore be appreciated from this that the size and particular magnet region geometry selected will therefore depend on the preferred application, and in particular can be used to ensure exposure of relevant nerves to high magnetic field gradients.

Thus, it will be appreciated that the greater number of regions then the greater the number of magnetic field gradients that can be generated, which can be advantageous in therapeutic use. In particular, this can be used to enhance the likelihood of the magnetic field gradients interfering with nerve action on nerves associated with pain being felt by the subject. Accordingly, in some instances, a greater number of regions are preferred, although this is not essential.

Furthermore, whilst the regions are shown as circular segments ("pie" shaped regions), this is also for the purpose of example only, and any suitable shaped regions can be used. In a further example shown in Figure 6A, the body 110 and shield 120 can be mounted on an axle 610 provided in a housing 600. This allows for rotational movement of the body 110 within the housing 600, as shown by the arrow 620. In use, this allows the housing 600 to be secured to the user, whilst allowing the body 110 to freely rotate within the housing 600, so that the body 110 can move relative to the user. This may occur for example in response to movement of the user.

Allowing rotation of the body 110 can assist in a number of different ways. Firstly, this can be used to help ensure that the boundaries (shown generally at 211 in this example) between magnetic regions will align with nerves for at least some of the time the arrangement is worn. This can assist with ensuring efficacy, whilst avoiding the need for careful alignment of the boundaries 211 with nerves. Secondly, this means that nerves will be exposed to a moving field gradient, as opposed to a static field gradient, and this can help further increase device effectiveness.

It will be noted that whilst the shield 120 is shown coupled to the body 110 in the above example, this is not essential and alternatively, the shield 120 may be coupled to the housing 600, so that it is not rotatably mounted.

In another further example, the apparatus 100 may include a ratchet and pawl mechanism 630, 631, designed so that the body 110 only rotates in a single direction, as shown by the arrow 640. This can be assisted by the use of an off-centre arrangement in which a centre of gravity of the body is not aligned with the axle 610, so that movement of the housing 600 will tend to induce rotation of the body 110. It will be appreciated that this can help ensure that the orientation of the body 110 varies, and does not become orientated in a single direction. In one example, the ratchet 120 could be formed from suitable configuration of the shield 120, or the body 110, and a separate physical component may not therefore be required.

In any event, it will be appreciated from the above that the use of a moving body 110, mounted in a housing which is statically positioned on the user, can help ensure alignment of nerves with the magnetic region boundaries, thereby further assisting in the pain relief, inflammation reduction, or muscle memory negation functions of the device. The magnetic body can be coated by a suitable coating, such as an inert material. This can be used to provide a hypo-allergenic coating, reducing the likelihood of an allergic reaction caused by prolonged contact with the skin. Example coatings materials include gold, nickel, silver, platinum, plastic and epoxy, although any suitable coating material can be used.

In use, as described above, the apparatus 100 is positioned with the first side adjacent the subject S. The magnetic field generated by the magnetic body 110 penetrates the body of the subject S, exposing at least one nerve to at least one of the magnetic field gradients. As described above, the magnetic field gradient interferes with nerve impulse, by disrupting ion transfer across cell membranes, which in turn effects the generation of action potentials required for nerve firing. As a result, the magnetic apparatus can be used to provide pain relief. In addition, as ion transport is also a factor in inflammation and muscle memory, the above described apparatus can also be used to reduce the effects of inflammation and negating the effects of muscle memory.

In achieving this, the apparatus 100 is positioned adjacent a nerve, selected so as to maximise the effect on the particular pain being targeted. Examples of this include:

The apparatus is typically held in position by use of adhesive tape, such as sticking plasters, or the like, although any suitable strap, bandage, or the like may be used. The apparatus is typically held in place for a time period ranging from an hour to several hours, or days, as required to provide pain relief.

In one example, the magnet arrangement is also aligned with the nerves, to thereby maximise the field gradient to which the nerve is exposed. However, this is not essential, particularly if a large number of regions are used, in which case a greater number of field gradients are present on the device.

When aligning the apparatus with nerves, in one example, the apparatus can be provided with one or more visual indicators indicative of the alignment of field gradients. This can be used to align the apparatus with the nerves, thereby maximising the pain reliving effect.

Examples of the fields generated by the magnetic bodies of Figures 2A and 2C are shown in Figures 7A to 7G and 8A to 8G, respectively.

In this regard, the figures highlight that the arrangements described are capable of generating a magnetic field with high field gradients. In addition, this highlights how the body arrangement of Figure 2A produces a greater overall maximum field, albeit with a reduced number of field gradients. It will therefore be appreciated form this that the particular arrangement used will depend on the particular situation, and in particular whether a higher overall field or greater number of field gradients are preferred.

In addition to this, Figures 7B and 7C, as well as Figures 8B and 8C show a comparison of the fields generated on the unshielded and shielded sides of the apparatus. This highlights how the field generated on the shielded side of the apparatus is lower than that on the unshielded side, thereby highlighting the effectiveness of the shield at maximising the fields and hence gradients to which the subject is exposed. Whilst the above examples have focussed on a subject such as a human, it will be appreciated that the measuring device and techniques described above can be used with any animal, including but not limited to, primates, livestock, performance animals, such race horses, or the like.

Persons skilled in the art will appreciate that numerous variations and modifications will become apparent. All such variations and modifications which become apparent to persons skilled in the art, should be considered to fall within the spirit and scope that the invention broadly appearing before described.