Muscle stimulation

Abstract

To provide a wearable article configured to provide stimulation to muscles of a wearer, and a system for providing such stimulation.SOLUTION: A stimulation system for use in a wearable article includes an actuator (12) controllable to deliver mechanical stimulation to a muscle of a wearer of the article and one or more electrical diagnostic sensors operable to sense muscle activity from the wearer. The actuator may include a structure formed of a piezoelectric nanofiber mesh. Also described are wearable articles, methods of providing stimulation to muscles, and methods of making actuators.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to wearable articles configured to provide muscle stimulation to a wearer and methods of providing such stimulation, and in particular, but not exclusively, to garments configured to provide muscle stimulation to a wearer suffering from muscle weakness. [Background technology]

[0002] Limb weakness, including upper limb weakness, is a debilitating result of stroke or other neurological disorders. Such muscle weakness affects 87% of stroke survivors, and more than 40% of survivors are left with muscle weakness. If left untreated, weakened muscles can further stiffen and restrict movement, increasing survivor pain and disability over time. Decreased strength, control, and reflexes can sometimes lead to increased hyperreflexia / tonia, resulting in distinct changes in limb posture and position that can result in both pain and weakness.

[0003] Stimulating affected muscles in individuals suffering from limb weakness can improve flexibility, strength, and coordination. However, extensive physical therapy is not available and / or practical for all affected patients. Systems have been proposed that aim to stimulate the sensory system of the affected area in an attempt to improve the wearer's muscle tone, flexibility, and / or strength without the physical therapist physically working the affected limb. For example, electrodes may be placed on the surface of the wearer's skin to stimulate the cutaneous sensory nerves (afferent nerves).

[0004] U.S. Patent Application Publication No. 2013 / 018289 describes a post-stroke stimulation device that includes a garment, such as a glove, that is applied to a body part, such as the hand, of a stroke patient being treated. The post-stroke stimulation device includes at least one tactile actuator adapted to deliver tactile stimulation to the stroke patient's skin. Examples of such actuators include pneumatic pads that generate a jet of air or light pressure when inflated, or small rollers that are operable to apply gentle pressure when rotated. The tactile actuator is controlled to operate and stop in a random pattern or a pattern selected by a medical professional, applying gentle stimulation to various locations on the body part being treated.

[0005] International Patent Application Publication No. WO 2008 / 088985 describes a neurostimulation system for treating stroke patients that uses a stimulator that may include an electrode device and / or a vibrating element. In response to an electrical signal, the stimulator delivers electrical and / or mechanical stimulation to a body part of the wearer. The stimulation may be subthreshold, i.e., stimulation that is insufficient to activate the wearer's sensory cells but is believed to bias those cells toward activation.

[0006] Targeting a patient's muscle spindle afferents (i.e., nerve afferents deep within a patient's muscles) has been shown to be an effective way to treat and prevent weakness. However, most of the stimulation systems currently proposed for the treatment of post-stroke weakness can only stimulate afferents within the wearer's skin. Summary of the Invention

[0007] According to a first aspect of the present invention, there is provided a stimulation device for use in a wearable article, the stimulation device having a controllable piezoelectric actuator that deforms to deliver mechanical stimulation to muscles of a wearer of the article.

[0008] According to another aspect of the present invention, there is provided a stimulation system for use in a wearable article. The stimulation system comprises an actuator controllable to deliver mechanical stimulation to muscles of a wearer of the article, and one or more electrodiagnostic sensors, e.g., electromyographic sensors, operable to sense muscle activity from the wearer. The actuator may deform to deliver the mechanical stimulation, the actuator may move to deliver the mechanical stimulation, or a combination of both.

[0009] The actuator may be a piezoelectric actuator. The piezoelectric actuator may comprise a tubular or partial tubular structure. The partial tubular structure may be a semi-cylinder or a semi-cylinder with a varying radius. The tubular / partial tubular structure may be composed of piezoelectric nanofibers or formed of a piezoelectric nanofiber mesh. The structure may be woven.

[0010] The piezoelectric actuator may further include a first electrode and a second electrode. The first electrode may be disposed inside the tubular or partial tubular structure, and the second electrode may be disposed outside the tubular or partial tubular structure. The inside of the structure may refer to a concave surface of the partial tubular structure. The outside of the structure may refer to a convex surface of the partial tubular structure.

[0011] The first electrode may comprise a first tubular electrode structure, which may be formed from conductive nanofibers, such as a conductive nanofiber mesh. The second electrode may comprise a second tubular electrode structure, which may be formed from conductive nanofibers, such as a conductive nanofiber mesh. The first tubular electrode structure may be at least partially inside the second tubular electrode structure or may be offset from the second tubular electrode structure. The first and second tubular electrode structures may be knitted. Rather than being tubular, the first and second electrodes may be partially tubular.

[0012] Alternatively, the actuator may comprise an electromagnetic actuator, such as a solenoid or a voice coil. The stimulation device may further comprise a casing surrounding the actuator. The casing may be a rigid casing or may be insulating (i.e., non-conductive). The casing may surround one or more electrodiagnostic sensors, such as an electromyography sensor. The casing may comprise one or more sensors. The casing may comprise one or more EMG sensors. The one or more EMG sensors may be external to the casing. The EMG sensor(s) may be sEMG (surface EMG) sensors. The casing may comprise one or more ECG (electrocardiogram) sensors. The one or more ECG sensors may be external to the casing. The casing may comprise one or more EEG (electroencephalogram) sensors. The one or more EEG sensors may be external to the casing.

[0013] The casing may include a depression region that may be operable to depression a muscle of the wearer, and the actuator may be operable to tap the inside of the casing at least in the depression region when the actuator moves and / or deforms to deliver the mechanical stimulus.

[0014] The stimulation device or system may further comprise at least one conductive plate between the actuator and the casing. The casing may be a flexible casing.

[0015] The casing may be bead-shaped, may be rotationally symmetric about a longitudinal axis, or may be asymmetric and include a flat region opposite a recessed region.

[0016] The casing may be shaped to recess into the wearer's muscles and may be generally ellipsoidal or partially ellipsoidal (e.g., an ellipsoid with a flat region) in shape. The casing may include a raised portion, such as an annular or partially annular raised portion, that may be disposed in the recessed region of the casing. The casing may include first and second ends, and the raised portion may be located midway between the ends of the casing.

[0017] The casing (or at least the recessed region thereof) may be internally tubular or part-tubular to cooperate with the shape of the tubular or part-tubular actuator received therein.

[0018] The casing may include one or more holes through which a thread can be threaded to allow the casing to be connected to a wearable article. In the case of beads having a flat region, the holes may be adjacent to the flat region.

[0019] The casing may be configured to clip around a thread to enable connection to the wearable article. The casing may include a first portion and a second portion that may be hinged to one another. Each of the first and second portions may include one or more recesses configured to align when the casing is closed and defining one or more thread holes.

[0020] The casing may include multiple parts: The casing may comprise a first portion (which may be configured to attach to a garment) and a second portion configured to move relative to the first portion to deliver mechanical stimulation to muscles of the wearer.

[0021] The stimulation device or system may comprise at least one, for example two, electrical connectors operable to connect the first and second electrodes to a power source.

[0022] The stimulation device or system may additionally or alternatively include any of the features of the specific examples described in the Detailed Description section below.

[0023] According to a second aspect of the present invention, there is provided a wearable article comprising a stimulation device or system for use with the wearable article. The stimulation device may comprise a piezoelectric actuator controllable to deform to deliver mechanical stimuli to muscles of a wearer of the article. The stimulation system may comprise an actuator controllable to deliver mechanical stimuli to muscles of a wearer of the article, and one or more electromyographic sensors operable to sense muscle activity from the wearer.

[0024] The wearable article may include any of the features described above in connection with the stimulation device and / or system and / or any selected features from the detailed description below.

[0025] The wearable article may include one or more electromyography sensors operable to sense muscle activity from the wearer. One or more of the EMG sensors may be included in or disposed within the casing. The wearable article may include a power source operable to supply electrical current to the stimulation device and / or the one or more electromyography sensors. The power source may be included in or disposed within the casing.

[0026] The power source may comprise one or more energy harvesting yarns and may further comprise at least one capacitor operable to store electrical energy harvested by the one or more energy harvesting yarns. The energy harvesting yarns may be composed of piezoelectric nanofibers. The wearable article may include two layers, and the energy harvesting yarn may be disposed between the two layers such that the wearer's skin does not come into contact with the energy harvesting yarn and / or such that the energy harvesting yarn is not visible on the exterior of the garment.

[0027] The wearable article may further comprise a controller operable to control the stimulation device to deliver mechanical stimuli to the wearer's muscles. The controller may be operable to receive electromyogram signals from one or more electromyogram sensors, and the controller may be operable to deliver mechanical stimuli in response to the received electromyogram signals. The controller may be included within or disposed within the casing. Alternatively, the controller may be disposed outside the casing, for example, elsewhere on the wearable article and / or in separate bead(s) shaped to house the controller components. Alternatively or additionally, the wearable article may comprise a switch, and the controller may be operable to deliver mechanical stimuli in response to wearer input, such as operation of the switch.

[0028] The wearable article may be shaped to be worn adjacent a selected muscle stimulation site, and the stimulation device may be positioned at a selected location on the wearable article to deliver mechanical stimulation to the selected muscle stimulation site when the wearable garment is worn by a wearer. "Worn by a wearer" in this context means worn in the manner intended by the designer, for example, so that the wearable article is correctly sized to fit the wearer (e.g., not too big and therefore not too loose or too small, such that the relationship between the selected location and the selected muscle stimulation site changes).

[0029] The wearable article may be a garment. The stimulation device may be positioned at a selected location on a sleeve of the garment to deliver mechanical stimulation to a selected muscle stimulation site on the wearer's upper extremity. The selected muscle stimulation site may be a muscle in the forearm. The stimulation device may be positioned at a selected location on the sleeve of the garment below the elbow. The stimulation device may be positioned at another selected location within the garment to deliver stimulation to a selected muscle stimulation site in another region of the body.

[0030] The wearable article may include a first region having a first tension and a second region having a second tension, with the selected location provided in the first region, and the first tension being higher than the second tension. For example, the first region may be configured by the elbow region of a sleeve of a garment. The second, lower tension region may be provided at the head and / or shoulder of the sleeve and / or the body of the garment. The first region may be configured with a different combination of yarns to increase its compressive strength, which may increase contact between the beads and / or EMG sensor(s) and the body.

[0031] The wearable article may additionally or alternatively include any of the features of the specific examples described in the Detailed Description section below.

[0032] According to a third aspect of the present invention, there is provided a method for manufacturing a piezoelectric actuator, the method comprising weaving one or more piezoelectric nanofiber yarns into a tubular mesh to produce a piezoelectric tubular or partially tubular structure.

[0033] The method can include electrospinning one or more piezoelectric nanofiber yarns and can further include coating the piezoelectric nanofiber yarns.

[0034] The method may include twisting one or more piezoelectric nanofiber yarns together prior to knitting the tubular mesh, for example, twisting 2, 3, 4, 5, 6, 7 or more piezoelectric nanofiber yarns together.

[0035] The method may include weaving one or more conductive nanofiber yarns into tubular meshes to produce first and second tubular or partial tubular electrode structures, respectively. The first tubular or partial tubular electrode structure may be weaved inside the piezoelectric tubular or partial tubular structure, and the second tubular or partial tubular electrode structure may be weaved outside the piezoelectric tubular or partial tubular structure, such that the piezoelectric tubular or partial tubular structure is located between the first and second tubular or partial tubular or partial tubular electrode structures.

[0036] The method may further include weaving one or more conductive nanofiber yarns into another shape. The nanofiber yarns may be woven into a non-tubular mesh.

[0037] Braiding may include varying the tension in the nanofiber yarn so that the tension is less at the center of the tubular structure than at the beginning and end of the tubular structure.

[0038] The method may further include offsetting the first and second electrode structures relative to the piezoelectric tubular structure.

[0039] The method may further include disposing the piezoelectric actuator within the casing, and optionally further include disposing one or more conductive plates between the piezoelectric actuator and the casing.

[0040] The method may include connecting the first and second tubular electrode structures to a power source.

[0041] The method may additionally or alternatively include any of the features of the specific examples described in the Detailed Description section below.

[0042] According to a fourth aspect of the present invention, there is provided a method of delivering stimulation to a wearer. The method may include providing a wearable article including a stimulation device or stimulation system, and delivering stimulation to a muscle of the wearer using the stimulation device or stimulation system. The method may be performed using a stimulation device or system or wearable article described herein.

[0043] The devices and methods described herein may stimulate afferent muscles in patients, such as those affected by limb weakness after a stroke. It will be appreciated that such systems and methods may be useful in treating other forms of limb weakness or spasticity, such as those present in other neurological disorders, such as cerebral palsy. The systems and methods may also find utility in providing muscle stimulation to other wearers, for example, to improve circulation and / or lymphatic drainage and for muscle training for general sports performance. [Brief explanation of the drawings]

[0044] The invention will now be described in more detail, by way of example only, with reference to the following drawings:

[0045] [Figure 1] 1A-1C show schematic representations of a muscle stimulation device, in particular (a) a cross-sectional view of the device, (b) an end view of the device, and (c) a side view of the device. [Figure 1a] 2A and 2B show further details of components within the muscle stimulation device of FIG. 1. [Figure 2] (a) is a schematic cross-sectional view of a piezoelectric actuator, and (b) is an image showing the structure of the piezoelectric mesh. [Figure 2a] 1A-1C are schematic diagrams illustrating exemplary knitting structures. [Figure 3] FIG. 1 is a cross-sectional view of a twisted nanofiber yarn. [Figure 3a] FIG. 10 illustrates alternative thread construction options. [Figure 4] FIG. 1 is a diagram showing an example of an electrospinning apparatus. [Figure 5] FIG. 1 illustrates nine possible shapes for the casing of a stimulation device. [Figure 6] 1 is a diagram illustrating a schematic of a garment including a muscle stimulation device. [Figure 7] (a) is an image showing the electrical connections within the garment, and (b) is a schematic diagram showing the electrical connections to the muscle stimulation device. [Figure 8]FIG. 1 illustrates an example of a garment pattern including an electrical component layout. [Figure 9] FIG. 10 is an inside view of a front panel of an exemplary garment showing conductive tracks at the neckline and a close-up view of the conductive tracks. [Figure 10] 1A and 1B show (a) an inside view of a sleeve panel of a first exemplary garment showing conductive paths, and (b) an outside view of the same sleeve panel. [Figure 11] FIG. 10 illustrates an inside view of a sleeve panel of a second exemplary garment showing conductive paths. [Figure 12] (a) Exemplary block diagrams of energy harvesting yarn, (b) supercapacitor, and (c) electromyography (EMG) sensor and switch. [Figure 13] 1 shows alternative examples of sleeve head patterns for clothing. [Figure 14] FIG. 10 is a diagram showing another example of a clothing pattern. [Figure 15] 10A and 10B are diagrams illustrating further examples of clothing patterns. [Figure 16] 17 shows an exemplary sleeve construction at the top of the sleeve, while the bottom of the sleeve is shown in FIG. [Figure 17] 1A-1C illustrate an exemplary sleeve configuration at the bottom of the sleeve. [Figure 18] 1A-1C illustrate exemplary sleeve structures including sensors. [Figure 19] 1 shows an example of a conductive path branching within a sleeve. [Figure 20] FIG. 1 illustrates an example of an alternative stimulation system. [Figure 20A] FIG. 10 illustrates an alternative stimulation device having a knitted actuator. [Figure 20B] FIG. 10 illustrates a further alternative stimulation device having a compound actuator. [Figure 20C] 10A-10C show alternative casing designs. [Figure 21A] 10A-10C show further alternative casing designs. [Figure 21B] 10A-10C show further alternative casing designs. [Figure 22] 10A-10C illustrate another alternative casing design for the stimulation device. [Figure 23] 13A-13C show further alternative casing designs for stimulation bios. [Figure 23A] FIG. 24 shows some further details of the casing design of FIG. 23. [Figure 24A] 10A-10C show alternative constructions for garments. [Figure 24B] 10A-10C show alternative constructions for garments. [Figure 25] FIG. 1 is a diagram showing a cross section of a sleeve structure of a garment. [Figure 26] FIG. 10 is a diagram illustrating an example of an actuator. [Figure 27] FIG. 10 illustrates further examples of actuators. [Figure 28] 10 is a graph showing how actuator force affects indentation. DETAILED DESCRIPTION OF THE INVENTION

[0046] Detailed Description Figure 1 shows a stimulation device 10 for a wearable article. The stimulation device has a controllable piezoelectric actuator 12 that deforms to provide mechanical stimulation to muscles of a wearer of the article.

[0047] The piezoelectric effect refers to the ability of some materials to acquire an electric charge when subjected to mechanical stress. When mechanical stress is applied to a piezoelectric material, the crystalline structure of the material becomes polarized, resulting in the generation of an electric charge between opposite sides of the material and the flow of an electric current. The piezoelectric effect is reversible; applying an electric current to a piezoelectric material has the opposite effect of generating mechanical stress in the material, resulting in a deformation of the material. Piezoelectric materials are therefore capable of deforming (i.e., changing their physical shape) when an electric current is applied to such a material.

[0048] 1 is shaped so that when an electric current is applied to the actuator 12, it deforms to a sufficient degree to deliver a mechanical stimulus to an afferent muscle of a wearer of the article. Such a stimulus is referred to herein as a "tap."

[0049] To be effective in stimulating the wearer's afferent muscles, rather than simply the surface of the wearer's skin, the stimulation device 10 is shaped to indent the flesh of the wearer's limb. To this end, the stimulation device includes a casing 34 (discussed in more detail below) that substantially surrounds the piezoelectric actuator 12. The piezoelectric actuator 12 is operable to deform an amount sufficient to tap the casing of the stimulation device. Thus, the force generated by the tap is delivered by the shaped casing to a desired location within the wearer's muscle, tendon, or nerve.

[0050] The piezoelectric actuator 12 is shown in more detail in Figure 2, where it can be seen that the piezoelectric actuator 12 includes a piezoelectric structure 14 that is substantially tubular in shape. That is, the piezoelectric structure 14 is formed from a tube of piezoelectric material that defines a hollow interior. The tube of piezoelectric material shown in Figure 2 is formed from a piezoelectric nanofiber mesh. An example image of the structure of such a mesh is shown in image (b) of Figure 2.

[0051] The piezoelectric actuator 12 further includes a first electrode 16 and a second electrode 18. The electrodes are operable to supply an electrical current to the piezoelectric structure 14 to deform the piezoelectric material according to the inverse piezoelectric effect.

[0052] The first electrode 16, in the example shown, is formed from a conductive nanofiber mesh and is disposed on the inside of the piezoelectric tubular structure 14. The second electrode 18, in the example shown, is also formed from a conductive nanofiber mesh and is disposed on the outside of the piezoelectric tubular structure 14.

[0053] FIG. 2a schematically illustrates one exemplary knitting structure, whereby the piezoelectric structure 14 is knitted as a structure of interlocking sections 14a and tubes 14b with tuck spacers 15 for connecting inner and outer electrodes (not shown) to the piezoelectric structure 14.

[0054] Both electrodes 16, 18, like the piezoelectric structure, are substantially tubular, each having a respective first and second end. Thus, piezoelectric actuator 12 includes three nested tubular layers: a first inner layer including first electrode 16, a second outer layer including second electrode 18, and a third, middle layer including piezoelectric structure 14 sandwiched between the two electrodes. In the example shown, all three layers are generally ellipsoidal in shape and are all formed from nanofiber mesh.

[0055] The casing 34 surrounds the piezoelectric actuator 12. The casing provides a rigid surface for the piezoelectric actuator 12 to tap against as it deforms. To protect the wearer of the article from the conductive portions of the device (i.e., the electrodes, the piezoelectric structure), the casing is not conductive. The casing may be formed from any non-conductive material that is rigid enough to retain its shape, such as carbon fiber, nylon, elastic polyurethane, or a flexible polyurethane resin. When the stimulation device is incorporated into an article intended to be worn in close contact with the user's skin, such as clothing (as described in more detail below), the casing is shaped so that at least a portion of the casing indents the wearer's flesh when the article is properly worn (i.e., worn as intended). The indented portion of the casing indents the wearer's flesh by at least 1 mm, preferably between 1 mm and 20 mm, or between 1 mm and 16 mm, to transmit the tapping force to the wearer's muscles.

[0056] The nanofiber mesh shown in Figure 2 may be composed of one or more nanofibers, both in the electrodes and in the piezoelectric structure. Suitable nanofibers may be made using any suitable nanofiber formation method, such as electrospinning from a polymer solution or melt having the desired piezoelectric and / or conductive properties.

[0057] Early samples used traditional electrospinning methods to deposit PVDF nanofibers (from solution) directly onto a conductive yarn substrate. However, this resulted in a large amount of waste PVDF nanofibers, making it difficult to scale up. Therefore, a pull-and-twist electrospinning method (using a metal funnel and yarn spool setup, see Figure 4) was subsequently used. This not only allows for the formation of continuous nanofiber yarns (the yarn volume depends on the amount of solution contained in the syringe and therefore on the syringe size), but it also appears to produce a larger piezoelectric response. Twisting and pulling the nanofibers from the metal funnel cone aligns the nanofibers externally, improving their orientation. In some studies, this method has been shown to produce effective piezoelectric properties without the need for poling using a PVDF copolymer, PVDF-TrFe.

[0058] Indeed, techniques such as drawing, fiber formation at a given temperature including melt extrusion, or a combination of drawing and poling can be used to increase the β-phase content of such polymers. Electrospinning is the most effective method, due to what is referred to as the "high pulling force exerted on the electrically charged solution jet."

[0059] In an exemplary electrospinning process, the electrospinning solution held in two syringes 400a, 400b is released at a defined flow rate. While this occurs, the solution is polled by a high-voltage meter (not shown) connected to each syringe needle by high-voltage connections 402a, 402b, which (in this example) terminate in an alligator clip attached to the needle of each syringe. The applied voltage can be varied to achieve different results (particularly affecting the dipole orientation and piezoelectric output of the yarn). The nanofibers are accumulated in a rotating metal funnel cone 404, from which they are pulled and twisted onto a rotating yarn spool 406. The distance from the syringe tips to the metal funnel cone 404 (tip-to-collector distance) and the rotational speeds of the collector (metal funnel cone 404) and yarn spool 406 can all be varied. Each of these variables directly affects the quality of the yarn produced.

[0060] Two examples of suitable electrospinning parameters are shown in Table 1 below for two different solutions. [Table 1]

[0061] Both solutions involve a piezoelectric material such as polyvinylidene fluoride (PVDF), although other piezoelectric materials may also be used.

[0062] A number of samples were made from the above solution, the details of which are shown below in Table 2. The sample nanofibers were made using the modified electrospinning technique as described above. [Table 2]

[0063] Using a metal funnel cone and spool, as previously described, conductive particles such as silver or graphene can be incorporated into PVDF while spinning continuous nanofiber yarns. The amount of filler that can be incorporated varies depending on the particle being incorporated. When using graphene, the maximum saturation point for using graphene as a filler is currently 0.1 wt%. NiO / SiO2 nanoparticles at 0–16 wt% have been shown to enhance the piezoelectric effect. Alternatively, Ag particles can be incorporated into the yarn, increasing the piezoelectric effect from 3 wt%.

[0064] Polarization in piezoelectric materials arises as a result of interfacial space charges that arise at electrodes and at inhomogeneities such as grain boundaries. This can be used to suggest that the increased proportion of the beta phase results from the alignment of graphene nanoparticles into an "all-trans" (TTT) conformation. Electrostatic interactions between the surface charges of the nanoparticles and dipoles present in the carbon backbone of the polymer matrix are thought to play a key role in promoting this alignment.

[0065] Compared to "pure" PVDF, the addition of graphene shifts the -CH2- vibration band towards the lower frequency region, confirming the presence of interfacial interactions between the -CH2- dipoles and graphene nanoparticles.

[0066] Increasing the filler concentration (graphene) increases the shift in the peak position due to damping of the -CH2- dipole vibration.

[0067] Increasing the graphene content increases the conversion of the alpha phase with a "TGTG" conformation to the beta phase with a "TTT" conformation. The locally oriented beta crystals then aggregate to form the beta crystals believed to be necessary for enhanced piezoelectric properties. Adding more filler causes all the beta crystals to aggregate from the alpha polymorph to the beta polymorph, up to a saturation point observed in this study at 1 wt.%.

[0068] Any of the nanofibers listed in the table above may be suitable for constructing piezoelectric structures 14. For example, sample (Si-3) was used to create the example piezoelectric knit structure shown in Figure 2 (b), with 0.1% graphene added by weight.

[0069] The electrodes 16, 18 are not constructed of piezoelectric nanofibers, but may be constructed of any conductive nanofiber yarn, such as, for example, stainless steel yarn, e.g., 100% Inox conductive yarn, etc. Alternative conductive yarns include copper, and / or silver, and / or composite yarns, such as yarns comprising 97% Inox / 3% copper or 97% silver / 3% nylon.

[0070] The resulting nanofiber yarns may be coated, e.g., dip-coated, with polyvinyl butyrol (PVB) or similar to improve strength and / or durability. Silver particles may be included within the coating to improve charge transfer from the outer electrode mesh to the inner piezoelectric (e.g., PVDF / graphene) mesh. Thus, PVB (containing Ag particles) can be used to anchor the nanofibers and reduce their degradation rate in response to tensile stress, such as that encountered during wear and washing.

[0071] Multiple nanofiber yarns may be combined together to improve the strength and / or increase the diameter of the final yarn. An example of such a composite nanofiber yarn 35 is shown in FIG. 3. The composite yarn 35 is formed from multiple nanofibers twisted together, specifically seven nanofibers twisted together. The core nanofiber yarn 37 may be untwisted. Multiple additional nanofiber yarns 39 (six shown) may be twisted around the core nanofiber in a generally helical manner. A measure of yarn weight / thickness is dtex (decitex). The yarn shown in FIG. 3 was twisted until the yarn reached at least 200, e.g., 220, dtex.

[0072] All nanofiber yarns in such a composite yarn 35 may have the same or different compositions. The composite yarn shown in Figure 3 has a core of conductive material, such as a metal such as steel, and in this particular example, is composed of 100% Inox yarn. The surrounding nanofiber yarn is composed of twisted electrospun PVDF nanofibers containing 0.1 wt% graphene particle filler and dip-coated with a PVB / Ag encapsulation layer. In particular, the nanofibers may be electrospun from sample (Si-3) in Table 2 above, but with 0.1 wt% graphene added. It will be understood that more or fewer nanofibers may be twisted together as desired.

[0073] Figure 3a shows several other possible composite nanofiber yarn structures. The configurations of the yarn structures shown are outlined below in Table 3. It will be understood that these are only example yarn structures, and that other piezoelectric yarn structures may be used to create piezoelectric structures 14 of the type discussed herein. [Table 3]

[0074] Tubular nanofiber meshes, such as the mesh forming the piezoelectric actuator 12 described above, may be made from nanofiber yarns, such as composite nanofiber yarn 35. One method of making such meshes is to knit a continuous circular tube using, for example, a knitting machine. Machines such as the "Multi-Gauge Stoll CMS ADF 32W" can be used. Other machines of similar or finer gauge can also be used.

[0075] The yarn tension may be set high at the beginning of the knitting, decreased toward the middle of the knitting, and increased again toward the end of the knitting. Decreasing the knitting tension has the effect of increasing the diameter of the knitted tube; therefore, decreasing the tension toward the center of the tubular structure can create a generally ellipsoidal shape. Referring again to FIG. 2, the tubular shape of the piezoelectric structure 14 and electrodes 16, 18 shown there may be created using a tension of 8 at the beginning and end of the knitting (position t1) and a tension of 10.5 at the center (position t2). It will be appreciated that other tensions may be selected depending on the machine being used, as tensions may vary slightly depending on the machine. The tension may vary gradually between these positions to ensure a smooth shape.

[0076] One challenge Applicant faced in designing a muscle stimulation device operable to indent the wearer's muscles, rather than just the surface of the wearer's skin, was ensuring the device was operable to provide taps of sufficient force (e.g., 6-10 N). Piezoelectric meshes of the type described above have been found to be capable of delivering taps of sufficient force. The ellipsoidal shapes described above have been found to be particularly useful for providing large indentations. Shapes of the type described above may be operable to deform up to 2 mm, e.g., between 1 mm and 2 mm, upon application of an electric charge, resulting in a force of between 6-10 N being transmitted to the device casing, which then transmits the tap force to the wearer's muscles. The amount of deformation, and therefore the tap force, can be increased by providing additional piezoelectric layers.

[0077] The first and second electrodes each include a respective pair of electrical connections 24a, 24b and 26a, 26b, using which the stimulation device may be connected to a power source (not shown) via one or more conductive threads 28.

[0078] In the illustrated example, the first electrode is offset from the second electrode by a separation distance d. This offset causes a first end of the first electrode to extend from the inside of the second electrode to the outside. A first electrical connection 24a to the first electrode 16 is provided at the protruding first end, and a second electrical connection 24b to the first electrode is provided at the opposite, nested second end. Conversely, a first electrical connection 26a to the second electrode is provided at the first end of the second electrode, and a second electrical connection 26b to the second electrode 18 is provided at the opposite end of the second electrode. Offsetting the electrodes allows for easier access to the electrical connections.

[0079] The conductive connector 30a may be electrically connected to the first electrical connection 24a of the first electrode 16 via the first connecting loop 31a and to the first electrical connection 26a of the second electrode 18 via the second connecting loop 31b. Similarly, the second conductive connector 30b may be electrically connected to the second electrical connection 24b of the first electrode 16 via the third connecting loop 31c and to the second electrical connection 26b of the second electrode 18 via the fourth connecting loop 31d. Then, a conductive thread 28 may be connected to the respective contact loops 32 of each connector 30 to connect the stimulation device 10 to a power source. The connectors may be formed of any suitable conductive material, such as silver.

[0080] As described above, the piezoelectric actuator 12, including the piezoelectric structure 14 and electrodes 16, 18, is encapsulated within a casing 34. To protect the wearer of the article from the conductive portions of the device (i.e., the electrodes, piezoelectric structure), the casing 34 is not conductive. The conductive regions of the stimulation device exposed through the casing for connection to the conductive threads 28 (e.g., portions of the connector 30 and / or portions of the electrodes 16, 18) may also be insulated. For example, after the piezoelectric actuator is encapsulated within the casing, an insulating coating may be applied over the conductive portions of the stimulation device.

[0081] One or more intermediate plates 36 may be disposed between the piezoelectric actuator and the casing 34. The intermediate plate(s) 36 may be formed of a deformable material, in this case, a conductive material such as steel, to help increase tapping force. The intermediate plates 36 may be free-floating within the stimulation device so that they can be pushed outward and / or deformed by deformation of the piezoelectric structure. FIG. 1a shows an exemplary stimulation device 10 including two curved intermediate plates 36, also shown in perspective view for clarity. Each intermediate plate 36 is shaped to fit between the piezoelectric actuator 12 and the casing 34 on either side of the stimulation device. To this end, the intermediate plates have a generally C-shaped cross-section, with a diameter tapering toward the ends to resemble the cross-section of the piezoelectric actuator 12.

[0082] It will be appreciated that more than one intermediate plate may be provided if desired, and furthermore, that if the tap does not need to be symmetrical, only one intermediate plate may be provided, for example, on one half of the stimulation device.

[0083] The stimulation device 10 includes at least one eyelet 38 through which a base thread 40 can be threaded. As described in more detail below, the eyelet 38 allows the stimulation device 10 to be connected to a wearable article. The base thread 40 can be any thread that can be used to construct a wearable article, such as cotton, silk, viscose, polycotton, or wool, or it can be a stretch thread, such as a thread containing Lycra or elastane. The thread can be impregnated with an antibacterial agent, such as zinc oxide. This reduces the need to wash the garment due to its antibacterial and odor-resistant properties. This is particularly beneficial for garments used in stroke rehabilitation, where mobility issues can affect activities of daily living (ADLs), including washing garments. Therefore, reducing the need to wash garments while maintaining optimal hygiene standards is useful both at home and when garments are used in hospitals.

[0084] The stimulation device 10 preferably has a curved outer surface to avoid sharp edges that may cause pain during tap delivery. The stimulation device may be generally ellipsoidal in shape, giving it the overall appearance of a bead. Nine such bead examples are shown in FIG. 5. Each bead has one or more recessed portions 41, which are the portions of the bead shaped to press into the wearer's flesh when the stimulation device is incorporated into a wearable article. All of the beads shown have at least one pair of diametrically opposed recessed portions with substantially the same shape to ensure equal recession regardless of the bead's orientation on the base thread 40.

[0085] In the illustrated example, the stimulation device 10 has rotational symmetry about a longitudinal axis 42, which may be the axis of the thread located between one or more thread holes 38. The shape of the stimulation device is selected to control the amount of indentation produced by the stimulation device. For example, an ellipsoid with its major axis perpendicular to the hole axis, as in the case of the beads in row A, produces more indentation than a substantially spherical bead, as shown in row C. The beads in both rows B and C all produce more indentation than an ellipsoid with its major axis parallel to the hole axis, as in the case of the beads in row B. Thus, the amount of indentation produced by the stimulation device may be controlled by selecting the size of a dimension of the stimulation device perpendicular to the hole axis. The dimension may be a radius perpendicular to the hole axis, and the size of the radius may be between 1 mm and 20 mm, e.g., between 1 mm and 16 mm, between 1 mm and 10 mm, or between 1 mm and 5 mm.

[0086] In the illustrated example, the rotational symmetry axis 42 substantially coincides with the thread axis, as do the contact points 32 of the conductive thread disposed between each pair of thread holes 38. The rotational symmetry further helps ensure that the strength of the delivered tap is independent of the orientation of the stimulation device when it is sewn into the wearable article.

[0087] The first row of Figure 5 shows two substantially ellipsoidal beads and one substantially spherical bead. The second and third rows show similar ellipsoidal beads, further including an annular ridge 44 adjacent the widest portion of the ellipsoid. The annular ridge can increase the strength of the tap delivered by the stimulation device by concentrating the force of the tap over a smaller surface area at the concave portion.

[0088] 1 to 5 may be sized to have a maximum diameter between 2 mm and 20 mm, for example between 3 mm and 10 mm. Such a device may be included in a wearable article 50.

[0089] The wearable article 50 is shaped to be worn adjacent to a selected muscle stimulation site 51 on a wearer's limb. Thus, the stimulation device 10 is placed at a selected location 52 on the wearable article, and when the wearer puts on the wearable garment, the stimulation device 10 is positioned next to the selected muscle stimulation site 51 and provides mechanical stimulation to the selected muscle stimulation site 51 as needed. The wearable article may be a garment.

[0090] It will be appreciated that the garment into which the stimulation device is incorporated will depend on the limb that needs to be stimulated. In the example shown in Figure 6, the wearable article is a long-sleeved garment 54 and the limb to be treated is the wearer's upper leg.

[0091] Control of human hand function is governed by the corticospinal tract (CST), with other pathways, such as the reticulospinal tract (RST), contributing to hand control. Just as the RST partially promotes recovery and is particularly important in motor recovery, following corticospinal injury, such as that resulting from stroke, the level of input from the CST and RST to upper limb and hand function changes. Flexor muscles are selectively strengthened, while extensor muscles remain weak. This suggests that increased input from the RST may not only limit the quality of recovered movement, but may also present barriers to engaging in upper limb training. Prolonged disuse can lead to contractures and increased pain, further affecting limb use, the body's physical identity, and behavior.

[0092] Within the first six weeks after injury, natural biological recovery occurs, and certain neuronal plastic changes are observed. These plastic processes result in muscle hyperactivity, hyperreflexia, and ultimately spasticity. Therefore, altering RST levels is thought to improve functional recovery in the upper limbs, and this has been demonstrated.

[0093] In the example shown in FIG. 6 , stimulation of the RST can be provided via mechanical activation of muscle spindle afferents at selected muscle stimulation sites on the wearer's arm. The selected muscle stimulation site 51 may be located on a muscle in the wearer's lower arm. Thus, a stimulation device may be positioned on the garment such that, when the garment is worn, the stimulation device can be controlled to deliver taps to muscles adjacent the wearer's elbow, such as one or more of the muscles controlling hand function. An alternative (or additional) muscle stimulation site 53 can be selected on the wearer's upper arm, just below the shoulder. Stimulation site 53 may be preferred if the stimulation device is incorporated into a short-sleeved garment. For example, if stimulation of the lower leg is desired, it will be understood that different muscle stimulation sites can be selected, and those stimulation sites may be unrelated to the RST.

[0094] The wearable article 50 further includes one or more electromyography (EMG) sensors 56. The EMG sensors 56 are operable to sense muscle activity. In particular, the EMG sensors 56 may be operable to sense that the wearer is moving or attempting to move one or more muscles. Thus, detection of muscle activity by the EMG sensor(s) 56 may be used to trigger operation of a stimulation device.

[0095] The garment further includes a power source operable to supply electrical current to the stimulation device 10 when it is desired to deliver muscle stimulation. In the example shown in FIGS. 6 through 11 , the power source includes one or more energy harvesting yarns 58 and at least one capacitor 60, such as a supercapacitor, operable to store electrical energy harvested by the one or more energy harvesting yarns. The energy harvesting yarns 58 may include piezoelectric material, thereby making the energy harvesting yarns operable to generate electricity when the wearer of the garment moves. Suitable energy harvesting yarns may be constructed from nanofibers in the same manner as described above with respect to piezoelectric structures. That is, piezoelectric yarns suitable for constructing piezoelectric structures 14 can be equivalently used as energy harvesting yarns.

[0096] The energy harvesting yarns 58 may be provided in one or more of the energy harvesting regions 62 of the wearable article. The energy harvesting yarns may be protected from direct contact with the wearer's skin. This may be achieved, for example, by constructing the wearable article from two layers and disposing the energy harvesting yarns between these two layers. An example of such a configuration is shown in FIG. 7, where the energy harvesting yarns are woven between two outer layers of a non-conductive base fabric 64, such as Lycra.

[0097] The energy harvesting yarn may comprise piezoelectric nanofibers, such as composite piezoelectric nanofibers of the type described above. The nanofibers may be coated with insulating materials to protect the wearer, as well as (or instead of) coatings to improve durability, as described above.

[0098] Not all regions of a wearable article need include energy harvesting yarns. Thus, a wearable article may include non-energy harvesting regions 66 formed solely from the base fabric. Using energy harvesting yarns as a power source may increase the wearer's physical mobility, potentially benefiting people suffering from stroke or lymphedema.

[0099] The wearable article further includes a controller 68, such as a microcontroller, operable to control the stimulation device 10 to deliver mechanical stimulation to the wearer's muscles. The controller is electrically coupled to the stimulation device by a conductive thread 70, for example a silver thread.

[0100] A switch 72 may be provided. The switch is electrically coupled to the controller and the stimulation device. The switch 72 may be operable by a wearer of the garment, thereby causing the controller to activate the stimulation device. Alternatively or additionally, the switch may be operable to disable the stimulation device.

[0101] All electrical components and connections are shielded from the wearer, for example, by insulating conductive parts. It may be necessary to remove insulating coatings from the conductive connections of the stimulation device before attaching the electrical connections to the device. Such insulating coatings may be reapplied after connection.

[0102] Referring now to Figure 8, a pattern 74 is shown for a long-sleeve garment, such as garment 54 of Figure 6. The pattern includes a front body section 76, a back body section 78, and left and right sleeve sections 80a and 80b, respectively. The sleeve sections are "grown" in that they are formed (e.g., cut) from the same piece of material as the front and back body sections. Thus, the two sleeve sections 80a and 80b are connected to the front and back sections 76 and 78 at sleeve head regions 82 of the garment pattern. Thus, energy harvesting yarns and / or conductive yarns do not need to be joined at the shoulder seams of the garment, but can be threaded between the sleeve and body sections of the garment through the connected sleeve head regions 82.

[0103] FIG. 9 shows a front inside view of an alternative garment in the form of a crew neck jumper featuring conductive tracks that can be used to connect electrical components of the garment. A first conductive track 84 adjacent the shoulder seam of the neckline provides electrical connection to the back of the garment, while second and third conductive tracks 86, 88 adjacent each sleeve seam provide electrical connection to the garment's sleeves. The second conductive track 86 may, for example, provide power from an energy harvesting yarn in the first sleeve, while the third conductive track 88 may provide power to a stimulation device in the second sleeve. Space 90 is provided in the conductive tracks to incorporate a fabric switch. Similarly, another space 92 is provided to incorporate a microcontroller. The conductive tracks are not visible on the exterior of the garment. In the example shown, the exterior of the garment is solid black, making it indistinguishable from regular clothing to reduce the stigma associated with the aesthetics of medical devices when their functionality is visible.

[0104] Figure 10 shows the inside and outside views of the second sleeve. Figure 11 shows the inside view of the first sleeve. Either sleeve can be a left- or right-hand sleeve, depending on the limb to which stimulation is desired to be delivered. Again, conductive paths 94, which serve to collect energy harvested from the PVDF yarn, are visible on the inside of both sleeves. Figure 10 also shows conductive paths that can be used to connect the front microcontroller to the sleeve components (EMG sensors and stimulation beads). In contrast, the sleeve in Figure 11 features conductive paths throughout the sleeve to collect energy harvested from the PVDF yarn, but does not have a connection point for a stimulation device. This sleeve can be worn on the unaffected side of the body and, therefore, can capture more energy than the affected side because it has more freedom of movement and can move more than usual to compensate for the loss of ability in the affected arm.

[0105] 12 illustrates example structures of (a) energy harvesting yarn, (b) supercapacitor, and (c) electromyography (EMG) sensor and switch. While these are included for context, it will be understood that any suitable capacitor, sensor, and / or switch may be used.

[0106] FIG. 13 shows three alternative sleeve head patterns, as well as another conventional pattern in which the sleeve and body portions are separate. FIGS. 14 and 15 show further pattern variations. It will be appreciated that numerous pattern variations are available depending on the requirements of the finished garment appearance. The sleeves do not need to be connected to the body portion of the garment pattern. However, providing separate sleeves complicates the garment manufacturing process (due to the need to bond electrical connections) and can result in hot spots where the conductive yarn is joined at the seam.

[0107] To ensure that the stimulation device can deliver stimulation to the selected muscle stimulation site and that sufficient stimulation is delivered to indent the muscle, garments can be used to hold the stimulation device in a tight fit against the wearer's limb, preventing movement of the stimulation device relative to the stimulation site as the wearer moves the limb. This can be achieved by tensioning the garment or by varying the yarn combination, including but not limited to elastane or Lycra, to affect the stretch rate of the garment to which the stimulation device is attached, to a level sufficient to hold the stimulation device against the wearer's limb through the range of motion that can be expected to be experienced while wearing the garment. However, depending on the tension and stretch rate of the garment, the force required to press the limb into the garment may be large. This can make it difficult to wear, especially for those suffering from limb weakness.

[0108] To mitigate this potential problem, garments may be constructed so that the thread tension and / or stretch rate is different in different regions of the garment. In particular, regions of higher tension and / or stretch rate may be provided in bands around selected stimulation device locations 52, while other portions of the garment, such as the sleeve heads, cuffs, and / or body of the garment, may have lower tension and / or stretch rate. Regions of different tension may be created by knitting the garment using a knitting machine that varies the thread tension and / or stretch rate during the knitting process.

[0109] Varying the tension and / or stretch in a garment can affect the shape and overall silhouette of the garment, especially the sleeves. To maintain a smooth sleeve silhouette, different fabrics, thread combinations, fabric constructions, and machine settings can be used in areas with higher tension, and in areas with lower tension. For example, a higher stretch fabric construction and tighter tension (e.g., 8) may be used to provide a tighter fit, or a fabric construction with less stretch or less stretch and looser tension (e.g., 12.5) may be used to provide a looser fit.

[0110] As mentioned above, the beads should preferably indent the muscle belly by at least 1 mm, thus requiring a tight fit in the area of ​​the stimulation device. However, due to limb weakness or other comorbidities or motor disorders, tight clothing can make it difficult to push the affected limb through the sleeve and make it difficult to get dressed. As a result, varying degrees of stretch and tension may be applied to different areas of the sleeve. For example, a tight fit can be assigned to a limited band / circumference / area where the beads and EMG sensor are positioned for contact. Adjusting or loosening the fit can be done beyond the elbow (while being careful not to affect the overall silhouette). This limits the area where more energy is required to push the limb through the sleeve.

[0111] The tight fit around the beads and sensors also helps prevent the sleeve from moving around and changing the bead position. To support sleeve placement, the sleeve seam (under the arm) provides a guide, ensuring the sleeve stays aligned under the arm and the beads are correctly positioned for easy (and intuitive) wearing. Thus, garment shaping can be controlled by utilizing base yarn type and base yarn tension as variables.

[0112] Figures 16-17 show example sleeve configurations for the upper sleeve (Figure 16) and lower sleeve (Figure 17). Figure 18 shows an example sensor configuration, and Figure 19 shows an example of a branching conductive path to direct energy to the bead location directly below the EMG sensor. The parameters used to construct the garment portions shown in Figures 16-19 are set forth in Table 4 below. [Table 4]

[0113] Again, such garments can be knit as needed, or panels of different fabrics can be sewn together to create areas of different stretch / tension.

[0114] The garment 50 including the stimulation device 10 may be worn by a wearer, for example, as the wearer goes about their normal life. During exercise, the energy harvesting yarns 58 generate electricity from movement and store the electricity in the capacitors 60.

[0115] The EMG sensor 56 monitors the electrical activity of the wearer's muscles and returns sensed data to the microcontroller 68. The microcontroller 68 may determine that stimulation should be sent to the wearer's muscles in response to the sensed data. The sensed data may indicate, for example, that the wearer is able to move the muscle at the stimulation site or is about to move the muscle at the stimulation site.

[0116] A muscle tapper may tap only when the muscle is activated, as detected by electromyography (EMG). Muscle length and rate of change are used to deliver rapid taps with micron sensitivity. EMG recordings can be used to quantify the rate of recovery via the muscle's response to the provided stimulus (tap). EMG recordings are obtained from the target muscle, from which short-latency responses following the tap stimulus can be looked for. These grow with voluntary contraction and decrease with vibration of the antagonist muscle. This is the expected characteristic of a tendon tap reflex.

[0117] Further assessment of the long-latency stretch reflex (LLSR) can provide information on its influence on the RST. Because the LLSR is thought to be substantially connected to the primary motor cortex and CST, assessment of the LLSR is performed using sensors to partially measure reticulospinal output.

[0118] When it is desired to stimulate a wearer's muscle, the microcontroller activates the stimulation device 10. Electricity is supplied from the capacitor 60 to the electrodes 16, 18, which deforms the piezoelectric structure and delivers a tap.

[0119] Alternatively, the wearer may determine that their muscles require stimulation, in which case the wearer may use a switch to directly activate the stimulation device.

[0120] Previous studies have demonstrated the ability of transcutaneous electrical stimulation (TES) pairing of clicks and shocks to induce plastic changes in motor pathways. To further enhance muscle activation, the tap delivered by the stimulation device described herein may be paired with an acoustic cue provided via earphones. For example, a sharp tap (e.g., 10 ms duration) may be immediately followed (e.g., 10 ms later) by an acoustic cue. This combination is then repeated again after an interval of, e.g., 1.5 s.

[0121] Additionally, continuously activating the stimulation device to generate vibrations can induce muscle responses.

[0122] The stimulation device is driven using some, all, or none of the following parameters: -0.002 second response time, 0 to 300Hz range -Adjustable frequency range between 1kHz, 3kHz and 6kHz Drive voltage range from -25 to 290V -Limiting heat to a 50°C limit (to prevent damage to the electrodes) using a voltage amplifier included in the microcontroller button

[0123] Wearable articles of the type described above may allow users suffering from limb weakness to receive stimulation of their limbs as needed. Regular muscle stimulation may improve mobility and quality of life over time, improving long-term outcomes.

[0124] The stimulation devices described herein can be incorporated into any wearable article, including, but not limited to, upper body clothing (shirts, blouses, t-shirts, base layers, dresses, etc.), lower body clothing (leggings, tights, pants, shorts, socks, underwear, etc.), and bandages / dressings.

[0125] The stimulation device described above includes one or more piezoelectric structures and electrodes created using a knitting machine. It will be understood that equivalent piezoelectric structures can be created by methods other than the example methods described above. For example, a tubular shape can be created from a sheet of mesh that is rolled to create a tube. The advantage of using a continuous circular knit mesh is that the mesh is continuous, without any breaks or bonds. This ensures even distribution of mechanical forces when applying current to the structure to create the tap. Furthermore, bonds can affect the conductivity of the nanofibers and can result in heat spots.

[0126] The energy harvesting system described above may be provided with an alternative power source. For example, the microcontroller may be powered via a battery. In such a variant, the energy harvesting thread and storage capacitor may be omitted. For compactness, the power source may be provided internally to the stimulation device.

[0127] It will be appreciated that the controller, capacitor (if present), and switch (if present) need not be positioned as shown in the accompanying figures, but may be positioned in any suitable location on the garment taking into account the desired finished garment appearance. If energy harvesting is not used, the controller etc. may be positioned in the same pattern portion as the stimulation device (e.g., in the sleeve).

[0128] It will be appreciated that in some circumstances other actuators may be used in place of the types of piezoelectric actuators described above (provided, as described above, that these actuators can be configured to deliver taps of sufficient force to deliver stimulation to the wearer's muscles).

[0129] 20 shows examples of stimulation systems 110a, 110b, 110c for wearable articles. Each stimulation system 110a, 110b, 110c comprises an actuator 120 controllable to deliver mechanical stimuli to muscles of a wearer of the article and one or more electromyographic sensors 130 operable to sense muscle activity from the wearer.

[0130] The actuator 120 may be a piezoelectric actuator 12 of the type described above. However, as discussed more fully below, other actuators configured to deliver stimuli to the wearer's muscles may also be used.

[0131] Stimulation systems 110c, 110b, 110a each include a casing 34. Actuator 12 is enclosed within casing 34 and is operable to deliver stimuli through the casing to the wearer's muscles in the manner described above.

[0132] As shown in system 110a, EMG sensor 130 may be enclosed within or configured as part of the casing, or, as in systems 110b and 110c, the EMG sensor may be located outside of casing 34.

[0133] As described above, the system may include a controller 140. The controller 140 may be enclosed within or configured as part of the casing, as shown in systems 110a and 110b. Alternatively, the controller may be located outside the casing 34, as in system 110c. Additional EMG sensors may be included in the system, if desired.

[0134] As in the examples described above with respect to FIGS. 1, 1a, and 5, the casing 34 of the stimulation device shown in FIG. 20 includes a recessed region 141 that is shaped to recess into the wearer's muscle and, therefore, recess the wearer's muscle by a predetermined amount. In each of the stimulation systems shown in FIG. 20, the casing 34 has a generally partial ellipsoid shape. That is, rather than being generally spherical or ellipsoidal as shown in FIGS. 1, 1a, and 5 above, the casing 34 has a flat region 134. The flat region is located on a portion of the casing opposite the recessed region 141. The flat region allows the casing 34, and thus the stimulation system, to have a lower profile when attached to clothing.

[0135] Another stimulation system 10a, 10b is shown in Figures 20A and 20B. For simplicity, like reference numerals are used to refer to like elements within the stimulation device of Figure 1. The stimulation systems 10a, 10b are shown connected to a wearable article 200.

[0136] Similar to device 10 of FIG. 1, systems 10a, 10b include piezoelectric actuators 12a, 12b. In contrast, however, piezoelectric actuators 12a, 12b are partially tubular rather than fully tubular. The use of partially tubular actuators allows for the flattening of portion 134 of the casing 34 of the bead portion of the system, as described above. In the example shown in FIGS. 20A and 20B, piezoelectric actuators 12a, 12b are partially ellipsoidal, and more specifically, approximately hemispherical.

[0137] The piezoelectric actuator 12a of the device in Figure 20A, like the actuators described above, may be formed from a piezoelectric nanofiber mesh and woven in a manner similar to that described above. In contrast, the piezoelectric actuator 12b of Figure 20B is formed from a composite material.

[0138] 20A and 20B each have a casing 34 that, in the particular example shown, is substantially hemispherical. Such a hemispherical casing includes a flat portion 134 and a recessed region 141 configured to recess into the wearer's flesh by a predetermined amount (e.g., at least 1 mm, at least 2 mm, as discussed above).

[0139] In each stimulation system 10a, 10b, a part-tubular piezoelectric actuator 12a, 12b is nested within a curved portion of a hemispherical casing 34. Thus, as the actuator deforms during use, the actuator is operable to provide a tap (possibly via an intermediate plate of the type described above) against the inside of the casing adjacent the recessed area.

[0140] Similar to the stimulation device 10 described above in connection with FIGS. 1 and 1a, the stimulation systems 10a, 10b of FIGS. 20A and 20B both include a first electrode disposed on the inside of the piezoelectric actuator and a second electrode disposed on the outside of the piezoelectric actuator. In the context of a partial tubular actuator, the term "inside" refers to the concave side of the piezoelectric actuator, and the term "outside" refers to the convex side of the piezoelectric actuator. The electrodes may be woven with a conductive nanofiber mesh as described above, or may be constructed in another manner (e.g., with wire or foil).

[0141] Unlike the device shown in FIG. 1, both stimulation systems 10 a , 10 b further include an integrated EMG sensor 130 .

[0142] In Figure 20A, the EMG sensor 130 is provided as an electromyography (EMG) sensor layer 130 within the casing 34 of the stimulation device 10a, specifically within the portion of the casing adjacent the flat region. In Figure 20B, the EMG sensor 130 is embedded within a recessed region 141 of the casing 34. Thus, the EMG sensor is contained within the casing 34 (albeit in different portions) in both stimulation devices 10a, 10b. In each system 10a, 10b, the controller 140 is embedded within the core of the stimulation device 10a, 10b. The controller 140 is connected to the EMG sensor layer 130 via a conductive element 150.

[0143] Power may be provided to the actuators 12a, 12b in any suitable manner, such as via energy harvesting yarns (as described above) and / or via a battery. In the case of the stimulation system 10b shown in FIG. 20B, the casing 34 includes an energy harvesting portion 155, which may be provided in addition to or instead of an external energy source. The energy harvesting portion 155 of the casing includes a material, such as PVDF, operable to harvest energy from mechanical stimulation. Additional electrodes 160 are provided within the casing, configured to extract charge from the PVDF casing and provide it to the microcontroller element 140. If desired, the entire casing may be made of energy harvesting material, or multiple portions of the casing may be made of such material. The housing may be 3D printed.

[0144] Both stimulation systems 10a, 10b may further include a spring 170. The spring 170 abuts the piezoelectric actuator 12a, 12n, thereby compressing the spring 2 when the piezoelectric actuator 12 is mechanically deformed. The spring 2 stores energy from the piezoelectric actuator and suddenly releases it to deliver a force to the casing 34.

[0145] Figure 20C shows three additional variations of casing 34 with flat regions. In these examples, the flat region extends to a diameter wider than the diameter of the widest part of the recessed region (which is ellipsoidal in the example shown). Thus, the illustrated example has a flared flat region 135, giving the casing a generally bell-shaped cross section. The purpose of the flared flat region is to provide additional stability to the casing when used as a bead by preventing the casing from rotating sideways during use and maintaining a vertical orientation of the tap to the rim. The flared region also provides a larger area to accommodate the thread hole.

[0146] 21A and 21B show alternative embodiments of casings 34a, 34b. The leftmost illustration shows a top view of casings 34a, 34b. The center and rightmost illustrations show side views of casings 34a, 34b, with the rightmost illustration showing the casings in an open position. Casings 34a, 34b are formed in two sections and are configured to open and close so that they can be connected to a garment. For example, the two sections of the casing may be hinged together so that they clip or snap closed around a thread. The two sections may be connected together in any suitable manner, such as by press-fitting, threading, or adhesive.

[0147] The casings 34a, 34b include thread holes 38 for connecting the casings to the threads of the garment. The thread holes 38 may be defined at the seam of the casing so that recesses in each portion of the casing cooperate to form the thread holes when the two parts are joined. In this way, the casing clips around the threads and, when closed, is free to move over the threads. Alternatively, the thread holes may be provided in one or other portions of the casing, as described in the examples above.

[0148] Casings 34a and 34b further include a central hole 43. The central hole may allow conductive thread 28 to pass, for example, into and / or out of the casing, for example, for electrical connection.

[0149] FIG. 22 shows a further example of a casing 34 that can be used with stimulation device 10. Similar to the casings of FIGS. 20, 20A, and 20B, casing 34c is a partial ellipsoid and includes a flat region with a thread hole adjacent to the flat region. Similar to casings 34a and 34b of FIGS. 21A and 21B, casing 34c is comprised of two hinged sections configured to be clipped closed by a press fit. Thread hole 38 is located in the curved portion of the casing, rather than on the seam between the two sections. Casing 34 includes raised ribs 44 in recessed region 141.

[0150] FIG. 23 shows five alternative casing 34 designs for the stimulation device 10.

[0151] Design (a) in Figure 23 shows a simple hemispherical casing 34. The casing 34 has either a hard or soft surface for the actuator to tap against. In this embodiment, the casing is single. A recessed area in the casing 34 is shaped to transmit force to the user when the actuator taps the inside of the casing 34.

[0152] Design (b) of Figure 23 shows a hemispherical casing 234 formed from two sections 234a and 234b that are movable relative to one another. Tip section 234b is captured within base section 234a and is configured to move in and out of the base section. During use, base section 234a may be secured to clothing. An actuator within the casing can deliver a tap to the user via movable tip section 234b. Allowing relative movement between the casing components in this manner allows for a more compact system for a given tapping force.

[0153] Design (c) of Figure 23 is similar to design (b), but has an additional flat rigid surface 234c positioned below the casing 234. The casing 234 can hit or tap the flat rigid surface, thereby delivering a force to the user.

[0154] Design (d) of Figure 23 is similar to design (c), but the flat rigid surface is replaced by the fabric 200 of the garment material. That is, the casing 234 may be placed between two layers of a multi-layer garment. The yarn composition may be configured to stiffen the material of at least the bottom layer of the garment (through which the tap is delivered) to aid in delivering the force or tap to the user.

[0155] Design (e) of Figure 23 shows a deformable casing 334, where the tip of the casing deforms when subjected to a tap or force from an actuator. The casing 34 may be formed from or include elastane or other suitable material that is flexible enough to deform but stiff enough not to absorb the force of the tap.

[0156] FIG. 23A shows in more detail a two-piece casing 234 with relative movement between the tip portion 234b and the base portion 234a, similar to that shown in designs (b), (c), and (d) of FIG. 23 . FIG. 23A shows cross-sectional views of an exemplary two-piece casing in a recessed position (photo (a)) and a retracted position (photo (b)). The mechanical deformation of the bead tip when pushed outward by an actuator (not shown) is clearly shown in photo (a), as opposed to the retracted position when not deformed by an internal actuator; instead, the tip portion 234b is pushed inward by contact with the wearer's muscles. The casing further includes an internal stop feature 236 that limits the extent of inward movement of the tip portion 234b to avoid damage to the internal components of the bead. The base portion may have a hinge structure of the type described above in connection with FIG. 22 or may be formed as a single piece.

[0157] 24a and 24b show alternative garment patterns 74 to those shown in FIGS. 8, 13, 14, and 15. In FIG. 24a, the pattern 74 is significantly simplified compared to the pattern 74 of FIG. 8 because the EMG and controller components are contained within the stimulation device 10. In FIG. 24b, the pattern 74 is similar to that of FIG. 24a, but the EMG sensor 3 is external to the stimulation device 10. Features of each pattern are interchangeable with those described above; for example, the controller could be located elsewhere on the garment in the patterns shown in FIGS. 24a and 24b. Additionally, one or more energy harvesting wires could be included if desired.

[0158] FIG. 25 shows a cross-section of a sleeve garment structure 80 according to one embodiment of the present invention. The structure includes an upper section 8 and a lower section 9, with the upper section 8 being closer to the garment body and the lower section being closer to the cuff of the sleeve. The upper section 8 and lower section 9 have lower tension and different stretch rates than the center section of the sleeve structure. The structure is designed to fit the user more closely in the center section than in the upper and bottom sections 8 and 9, as described in detail above. The tight fit of the center section ensures that the EMG sensor 3 and beads are in close contact with the user. The first and second conductive paths of the EMG sensor are connected via a float switch 93.

[0159] As noted above, stimulation systems of the type described herein may be configured to provide beneficial muscle stimulation without piezoelectric actuators, and other actuators may be used instead. Figures 26 and 27 show examples of such alternative actuators.

[0160] For example, an example of an electronic actuator is shown in part (a) of Figure 26. Electronic actuators may be driven using a solenoid or a motor. Solenoid-driven actuators may provide a higher initial force than other actuators, but may overcome the shorter distance required between a system held within the garment adjacent to the arm and the muscles beneath the skin. Voice coil-driven actuators may provide a lower peak force, but maintain a constant force throughout the stroke (throughout actuation). A solenoid actuator is shown in part (b) of Figure 26. A voice coil actuator is shown in part (c) of Figure 26.

[0161] Alternatively, a fluidic actuator may be used. Such an actuator may be driven by the movement of a fluid. The actuator may be powered by a pressure reservoir. The actuator may be powered by a pump. Multiple fluidic actuators may be used, all powered using a single pump or pressure reservoir. An example of a fluidic actuator is shown in part (a) of Figure 27.

[0162] Pneumatic actuators may also be used. Pneumatic actuators typically use pressurized gas to drive a piston or expand a cavity. If the actuation frequency is low, a single pressurized gas cartridge, such as a CO2 cartridge, may be sufficient for several hours of continuous operation. An example of a pneumatic actuator is shown in part (b) of Figure 27.

[0163] A crank arm actuator may be used, in which a rotating wheel rotates to drive a piston to deliver the impact. An example of a crank arm actuator is shown in part (c) of Figure 27.

[0164] A spring release actuator may also be used. In such an actuator, a motor may compress a spring configured to apply an impact via a release mechanism when required. An example of a spring release actuator is shown in part (d) of Figure 27.

[0165] A curved actuator may be used. The piston actuated by this actuator may be curved to reduce the overall size of the stimulation device. Having a curved actuator allows the stimulation device to lie flat against the body. Multiple curved actuators may be used to compensate for the reduction in force caused by curving the actuator. Multiple curved actuators may be operated simultaneously to provide a greater cumulative resultant force. An example of a curved actuator is shown in part (e) of Figure 27.

[0166] Any actuators used within the system, of the type described herein, must be capable of delivering at least 1 Newton of force for 1 milliminute (mmin) of displacement in order to deliver sufficient tap to stimulate the wearer's muscles.

[0167] The table below shows examples of actuator criteria. [Table 5]

[0168] The casings described above have been primarily ellipsoidal or partial ellipsoidal. These shapes have been selected to provide good traction on the wearer's muscles while maximizing the force delivered to the casing by the internally tubular or partially tubular actuator. However, it will be appreciated that the casing may have other shapes as needed, particularly when accommodating non-tubular actuators. In the case of tubular or partially tubular actuators, the casing may be internally tubular or partially tubular, but may have a different external shape.

[0169] Such contours should include a depression area operable to depression into the user's muscles by a pre-specified amount, such as 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, or more, which means that any attachment points of the garment, such as thread holes, should be located at least 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, or more from the leading edge of the casing to ensure that the depression area of ​​the casing will be pressed into the user's muscles when incorporated into a garment worn by the user.

[0170] Preferably, any such casing shape should avoid sharp edges in the recessed area.

Claims

1. 1. A stimulation system for use in a wearable article, the stimulation system comprising: an actuator controllable to deliver mechanical stimulation to muscles of a wearer of the article; and one or more electrodiagnostic sensors operable to sense muscle activity from the wearer.

2. The stimulation system of claim 1 , wherein the one or more electrodiagnostic sensors are electromyographic sensors.

3. The stimulation system of claim 1 or claim 2, wherein the actuator is a piezoelectric actuator.

4. 4. The stimulation system of claim 1, claim 2, or claim 3, wherein the actuator comprises a structure formed of a piezoelectric nanofiber mesh.

5. The structure is (i) tubular, or (ii) Partially tubular The stimulation device according to claim 4 , wherein the stimulation device is at least one of the above.

6. 6. The stimulation system of claim 2, wherein the piezoelectric actuator further includes a first electrode and a second electrode, the first electrode being disposed inside the tubular structure and the second electrode being disposed outside the tubular structure.

7. 7. The stimulation system of claim 6, wherein the first electrode comprises a first electrode structure formed of a conductive nanofiber mesh, the second electrode comprises a second electrode structure formed of a conductive nanofiber mesh, and the first electrode structure is at least partially inside and offset from the second electrode structure.

8. The stimulation system of claim 1 , further comprising a casing surrounding the actuator.

9. The stimulation system of claim 8 , wherein the casing surrounds or comprises one or more of the electrodiagnostic sensors.

10. 10. The stimulation system of claim 8 or claim 9, wherein the casing surrounds or comprises one or more electromyographic sensors.

11. 11. The stimulation system of claim 8, claim 9, or claim 10, wherein the casing comprises a depression area operable to depression a muscle of the wearer, and the actuator is operable to tap the inside of the casing at least in the depression area.

12. The stimulation system of claim 8 , further comprising at least one conductive plate between the actuator and the casing.

13. 13. The stimulation system of claim 8, wherein the casing is at least partially ellipsoidal, and optionally the casing comprises an annular ridge around the widest portion of the ellipsoid.

14. The stimulation system of claim 8 , wherein the casing comprises one or more thread holes that allow the casing to be connected to the wearable article.

15. 15. The stimulation system of claim 8, wherein the casing is configured to clip around a thread to connect the casing to the wearable article.

16. 16. The stimulation system of claim 14 or claim 15, wherein the casing is an ellipsoid having a flat region, and the eyelet is adjacent to the flat region.

17. 10. The stimulation system of claim 6 or any claim dependent on claim 6, wherein the stimulation system comprises one or more electrical connectors operable to connect the first electrode and the second electrode to a power source.

18. 18. The stimulation system of claim 8, wherein the casing comprises a movable portion configured to increase the intensity of the mechanical stimulation provided to the user.

19. A wearable article comprising the stimulation system of any one of claims 1 to 18.

20. 20. The wearable article of claim 19, comprising a power source comprising one or more energy harvesting yarns and at least one capacitor operable to store electrical energy harvested by the one or more energy harvesting yarns.

21. 21. The wearable article of claim 20, wherein the article comprises two layers, and the energy harvesting yarn is located between the two layers.

22. 22. The wearable article of any one of claims 19 to 21, further comprising a controller operable to control the stimulation system to deliver the mechanical stimulation to the muscles of the wearer.

23. 23. The wearable article of any one of claims 19 to 22, wherein the wearable article is shaped to be worn adjacent to a selected muscle stimulation site, and when the wearable garment is worn by the wearer, the stimulation system is positioned at a selected location on the wearable article to deliver mechanical stimulation to the selected muscle stimulation site.

24. The wearable article according to any one of claims 19 to 23, wherein the wearable article is clothing, and may be clothing with extended sleeves.

25. 25. The wearable article of claim 24, wherein the stimulation system is positioned at a selected location on a sleeve of the garment to deliver mechanical stimulation to selected muscle stimulation sites on the wearer's upper extremity.

26. 26. The wearable article of claim 23 or 25, wherein the wearable article includes a first region having a first tension and a second region having a second tension, the selected position is provided in the first region, and the first tension is higher than the second tension.

27. A method of manufacturing a piezoelectric actuator, comprising weaving one or more piezoelectric nanofiber yarns into a tubular or partial tubular mesh to produce a piezoelectric tubular or partial tubular structure.

28. Before knitting the tubular or partially tubular mesh, electrospinning the one or more piezoelectric nanofiber yarns; coating the piezoelectric nanofiber yarn; and 28. The method of claim 27, further comprising twisting one or more piezoelectric nanofiber yarns together.

29. 29. The method of claim 27 or claim 28, further comprising braiding one or more conductive nanofiber yarns to create first and second tubular or partial tubular electrode structures, wherein the first tubular or partial tubular electrode structure is braided inside the piezoelectric tubular or partial tubular structure, the second tubular or partial tubular structure is braided outside the piezoelectric tubular or partial tubular structure, and the piezoelectric tubular or partial tubular structure is disposed between the first and second tubular or partial tubular electrode structures.

30. 30. The method of claim 29, wherein the method further comprises offsetting the first and second electrode structures relative to the piezoelectric structure.

31. 31. The method of any one of claims 27-30, wherein the braiding step comprises varying the tension of the nanofiber yarn during braiding so that the center of the resulting braided tubular or partial tubular structure is in lower tension than the beginning and end of the tubular or partial tubular structure.

32. 32. The method of any one of claims 27 to 31, wherein the method further comprises disposing the piezoelectric actuator in a casing, and optionally disposing one or more conductive plates between the piezoelectric actuator and the casing.

33. 1. A method of delivering a stimulus to a wearer, comprising: Providing a wearable article according to any one of claims 19 to 26, and delivering stimulation to a muscle of the wearer wearing the stimulation device.

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