WO2005117768A1 - Remote tactile sensory perception system - Google Patents

Abstract

A tactile sensory perception system comprises a flexible sheet material through which are disposed a plurality of stimulus transmitting rods, each rod connected at one end to a stimulus receptor and at the other end to a stimulus transmitter. The plurality of stimulus transmitters is aligned on the side of the flexible sheet material placed onto body skin surfaces and transmits thereto tactile stimuli from the plurality of stimulus receptors. External tactile stimuli and the stimulus receptors are separated from the body surface by the flexible sheet material. The stimulus receptors may be adapted with sensors for detecting light spectra, electrical pulses or wireless signals, and transforming such stimuli into electrical pulses for transfer to the stimulus transmitters and conversion to mechanical protraction and retraction.

Description

REMOTE TACTILE SENSORY PERCEPTION SYSTEM

TECHNICAL FIELD This invention relates to systems that promote, enable or enhance tactile sensory perception in humans or animals. More particularly, the invention relates to such systems associated with protective coverings for skin surfaces, or for generating tactile sensations for amputees or persons with medical conditions that degrade tactile sensory perception.

BACKGROUND ART The human body is equipped with receptors integrally connected to and cooperating with the central nervous system, to sense, process and interact with five general types of external environmental stimuli which include sight, smell, taste, sound, and touch. The sensory receptors signal changes in: (a) the environment, or (b) in the human body relative to the environment, and relay this information to the central nervous system. External tactile environmental stimuli are detected and monitored by a class of receptors called exteroreceptors. Skin contains a variety of exteroceptors distributed throughout the epidermal, dermal and subcutaneous layers of cells. Each type of exteroceptor is specialized to detect only one specific stimulus e.g., heat or cold (i.e. thermoreceptors), pain (i.e. nociceptors), and tactile stimuli such as touch and pressure (i.e. mechanoreceptors). Nociceptors are primarily comprised of nerve endings distributed throughout the body, and are especially prevalent in the dermal and subcutaneous layers of cells. Mechanoreceptors are distributed throughout the epidermal, dermal and subcutaneous layers of cells. Delicate intermittent tactile stimuli applied to the hands and face can be precisely sensed and localized by phasic receptors such as hair follicles and Meissner's corpuscles distributed throughout the epidermal and dermal cell layers, while constant but very light cutaneous stimuli are detected by tonic receptors such as Ruffmi endings and Merkel cells, also primarily located in the epidermal and dermal layers. These specific types of exteroceptors are intimately involved in the body's ability to sense and organize a dynamic topographical map of tactile stimuli based on the plurality of signals transmitted to the brain from the individual exteroceptors. This ability enables manual dexterity, the ability to precisely and delicately manipulate objects, and the abilities to sense and respond to pleasant and pleasurable tactile stimuli. Pacinian corpuscles are deep-phasic pressure- sensitive receptors that are primarily distributed throughout the subcutaneous regions of the body and function primarily to sense significant squeezing and pressing forces. These types of forces are also sensed by nociceptors, but tend to mask and overwhelm the function of phasic and tonic exteroceptors located in the epidermal and dermal cell layers. The Pacinian corpuscles are also responsible for modulating responses related to the regulation of grasping and gripping, but do not significantly assist in the body's fine motor skill responses required for precisely controlled manual dexterity. Nociceptors and mechanoreceptors are not evenly distributed throughout the skin of various parts of the body. For example, a square centimetre of skin on an adult finger tip contains approximately sixty nociceptors and one hundred mechanoreceptors, whereas a square centimetre on the back of a hand contains about one hundred nociceptors but only about nine mechanoreceptors. The skin surface areas are delicate and fragile, and therefore, very susceptible to damage and injury caused by sudden and/or excessive external stimuli such as heat or cold, pressure, piercing and other types of physical trauma commonly encountered during work and recreational activities. Quite often, abraded and damaged skin surfaces are sites for primary and secondary infections caused by bacteria, viruses and other types of pathogens. Consequently, a wide variety of protective gear such as gloves, footwear and body suits, have been developed for protecting parts of or entire body surfaces. Most types of protective gear provide various insulating and/or protective barriers between the skin surface and the external environment. The protective barriers effectively mask the mechanorceptors located in the epidermal and dermal cell layers and thereby prevent them from sensing and transmitting subtle and delicate tactile stimuli resulting in significantly reduced manual dexterity and tactile interaction with the external environment.

DISCLOSURE OF THE INVENTION The exemplary embodiments of the present invention, at least in preferred forms, are directed to remote tactile sensory perception systems that separate skin surfaces from external environments, but precisely map and transmit external tactile stimuli to exteroreceptors distributed throughout the epidermal and dermal cell layers. According to one aspect of the invention, there is provided a remote tactile sensory perception system comprising a flexible sheet support material through which is disposed a plurality of stimulus transmitting rods, each rod connected at one end to a stimulus receptor for receive tactile stimuli and connected at the other end to a stimulus transmitter for transmitting said tactile stimuli to skin surfaces. The remote tactile sensory perception system may be fashioned into, or alternatively, incorporated into protective gear for body surfaces. According to a second aspect of the invention, there is provided a remote tactile sensory perception system comprising a flexible sheet support material through which is disposed a plurality of stimulus transmitting rods adapted at one end to receive a tactile stimulus and adapted at the other end to transmit said tactile stimulus. The plurality of stimulus receiving ends and transmitting ends of the transmitter rods are covered with a flexible flat sheet of protective material. Alternatively, the plurality of stimulus receiving ends and the plurality of stimulus transmitting ends may be covered with separate sheets of protective material. According to another aspect of the invention, the remote tactile sensory perception system is fashioned into covering for a portion of the outer surface of prosthetic limbs. The transmitter ends of the stimulus transmitter rods are connected by circuitry to a microprocessor which converts a plurality of external tactile stimuli into topographical electronic maps which are transmitted by circuitry to a tactile transmission device situated in the socket of the prosthetic device fitted to the stump of an amputated limb. The tactile stimuli are transmitted from the transmission device to viable nerve endings in the stump where it contacts the device. According to yet another aspect of this invention, the remote tactile sensory perception system is provided with stimulus receptors adapted with sensors for detecting electrical pulses, light spectra or wireless signals and converting such stimuli into electrical pulses which are transmitted to a microprocessor wherein they are converted into a dynamic topographical electronic map of the stimuli. The topographical electronic map is transmitted by circuitry to the stimulus transmitters wherein they are converted to mechanical forces causing protraction and retraction of the transmitter thereby transferring the tactical stimuli to skin surfaces.

According to yet another aspect of the invention there is provided a prosthetic device designed to replace a missing extremity of a human or animal having a residual stump, comprising an artificial replica of the extremity provided with a socket for engaging the stump, and having a plurality of stimulus receptors positioned over at least part of an external surface of the replica, means for converting tactile sensations received by the receptors into electrical signals, and a plurality of stimulus transmitters positioned within the socket for contact with the stump, the transmitters being adapted to convert the electrical signals into mechanical movement transmitted to the stump.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be described in conjunction with reference to the following drawings in which: Fig. 1 is a perspective view of a first embodiment of the remote tactile sensory perception system of the present invention; Fig. 2 is a close-up partial side view of the remote tactile sensory perception system shown in Fig. 1; Fig. 3 is a perspective view of a manufacturing method for a second embodiment of the present invention; Fig. 4 is a close-up partial side view of the remote tactile sensory perception system shown in Fig. 3; Fig. 5 is a close-up partial side view of a third embodiment of the remote tactile sensory perception system of the present invention; Fig 6A is a side view of another embodiment of the present invention; Fig. 6B is a schematic diagram of the embodiment shown in Fig 6 A; Fig 7 is a close-up view of the schematic diagram shown in Fig. 6B; Fig. 8 A is perspective view of a further embodiment of the present invention; and Fig. 8B is a close-up schematic view of the embodiment shown in Fig. 8 A.

BEST MODES FOR CARRYING OUT THE INVENTION A first embodiment of the present invention is illustrated in Figs. 1 and 2 in which a remote tactile sensory perception system 30 includes a flat and flexible support material 31 through which a plurality of rigid tactile stimulus transmitter rods 32 are inserted, so that each transmitter rod has a first section 32a which extends from the outer surface of the support material 31 toward a stimulus receptor end 33, and a second section 32b which extends from the inner surface of the support material 31 and terminates in an endpoint 34 which transmits the tactile stimulus to the skin surface 10. The stimulus receptor end 33 has a diameter or shape which is larger than the diameter of the stimulus transmitter rod 32 so that the support material 31 will prevent transmitter rod 32 from slipping through and disengaging from support material 31. The shape of the stimulus receptor 33 can vary and may be an ellipse as shown in Fig. 1, a flat disc as shown in Fig. 2, or a sphere as shown in Fig. 4. The endpoint 34 of stimulus transmitter section 32b which extends toward the skin surface 10, has a larger diameter than transmitter rod 32 so that the transmitter rod will not slip through and disengage from the support material 31 in a direction toward the stimulus source. It is preferable that end point 34 has a shoulder region 35 adjacent the second section 32b of the transmitter rod 32, said shoulder region 35 having a larger diameter than that of the transmitter rod. It is also preferable that the end point 34 tapers toward a smaller-diameter tip 36 which will contact the skin surface 10 when a tactile stimulus is applied to the stimulus receptor 33. Tip 36 may be flat as shown in Fig. 2 or rounded as shown in Fig. 4. Although it is preferable that the remote tactile sensory perception system 30 should have between three to 15 transmitter rods per square centimetre of support material, fewer or more transmitter rods may be provided if so desired. Referring to Figs. 1 and 2, when a tactile stimulus such as touch, pressure or vibration is applied to stimulus receptors 33, the stimulus is transmitted along stimulus transmitter rods 32 to transmitter endpoints 34 whereby tips 36 contact the skin surface 10 and/or hair follicles 14. The varying intensities and surface areas of the stimulus will result in one or more tips 36 pressing against the skin surface 10 thereby stimulating a sensory perception in one or more of the exteroceptors including Meissner's corpuscles 15, Ruffmi endings 16, and Merkel cells 17 distributed through the epidermal 11 and dermal 12 cell layers. More intense levels of tactile stimuli will result in increasing pressures applied by tips 36 against the skin surface 10 thereby resulting in sensory perception by the Pacinian corpuscles 18 distributed throughout the subcutaneous cell layers 13. The stimuli detected by the various exteroceptors will be transmitted along neurons and nerve cords 19 to the central nervous system. Remote tactile sensory perception system of the present invention can be used in the form of sheets applied to body surfaces for therapeutic or sensory stimulation applications. Alternatively, the remote tactile sensory perception system can be used to construct, or alternatively, be incorporated into protective gear such as gloves and body suits for enhancing perception of tactile stimuli during workplace or recreational activities. Regardless of the intended application, the lengths of the transmitter rods 32 can be selected and matched to the specific skin areas of the body against which the remote tactile sensory perception system 30 will be placed. For example, if used to construct gloves, it may be desirable to have more transmitter rods 32, e.g., between 10-20 per square centimetre of support material 31, along the portions that will be adjacent to the finger tips and the undersides of fingers and palms because these surface areas have relatively larger numbers of exteroreceptors per square centimetre. The portions of the remote tactile sensory perception system 30 that will be in contact with skin surfaces such as the backs of hands, arms, the torso, and legs could have fewer transmitter rods, e.g., 5-9 per square centimetre since these parts of the body have fewer exteroceptors. Regardless of the body surface area that the remote tactile sensory perception system 30 will be in contact with, the lengths of the transmitter rods 32 should be limited to prevent excessive stimulation of the Pacinian corpuscles 18 in the subcutaneous cell layers 13 (e.g. not more than approximately 4-millimetre extension beyond the support material 31). The transmitter rods 32 may extend between one to four millimetres above and between one to four millimetres below the support material 31. However it is preferable that the transmitter rods 32 extend 2 mm above and 2 mm below the support material 31. For use in applications where it is not necessary to protect the skin surfaces from exposure to temperature fluctuations, moisture or fluids, the support material can be selected from flat sheets of a variety of flexible mesh materials comprised of natural or synthetic fibres. The stimulus transmitter rods can be selected from metal, plastics or composite materials. The diameters of transmitter rods 32 should be small enough to freely slide up and down through openings 37 in the mesh support material 31, while the stimulus receptors 33 and transmitter endpoints 34 should be larger than openings 37 to prevent the transmitter rods from becoming separated from support material 31. In applications where it is necessary to protect skin surfaces from exposure to moisture or fluids, then the junctures 38 between the support material 31 and transmitter rods 32 may be sealed using a variety of means known to those skilled in the art. Alternatively as shown in Figs. 3 and 4, a sprayable liquid polymeric material 41 maybe applied to an assembled remote tactile sensory perception system 30 through sprayer tips 40 and allowed to dry, thereby sandwiching the system 30 between two layers of a water-impermeable film 42. In applications where it is necessary to protect skin surfaces from temperature fluctuations or from severe physical traumas such as piercing or cuts, then two or more layers of support materials may be used as shown in Fig. 5 wherein support material 31 comprises an outer layer 50 selected from suitable moisture- and heat-repellent materials which sealed are to transmitter rods 32 with disc 51, and an inner layer 52 of insulating material selected from natural and/or synthetic fibres sealed to transmitter rod 32 with disc 53. The remote tactile sensory perception system of the present invention can be used to construct or alternatively, be incorporated into protective gear for use in workplace or recreational applications e.g., space suits, deep sea diving, fire- fighting, military and paramilitary gear, cold weather protection, protection from excessive heat or noxious chemicals, protective clothing and gloves for medical, police and other related service professions, safe sex applications, protective gear developed for heavy industrial manufacturing and repair industries among others. Another embodiment of the present invention is shown in Figs. 6A, 6B, and 7 wherein the remote tactile sensory perception system of the present invention is incorporated into socket 115 of prosthetic limb 120 wherein amputated limb 95 is secured. The opposite end of prosthetic limb 120 is provided with a hand- or mitt- shaped portion 125. The inner surface of hand portion 125 corresponds with the palm of a hand, to which is secured tactile sensing device 126 equipped with a mapping grid having regularly spaced sensors capable of converting tactile stimuli into discrete electrical pulses. The electrical pulses are transmitted via circuitry 100 to microprocessor 60 located on the surface of the prosthesis or alternatively within in prosthetic limb 120 wherein the electrical pulses received from a plurality of sensors situated in tactile sensing device 126 are compiled into a dynamic topographical electronic map of the tactile stimuli applied to tactile sensing device 126. The topographical electronic map is transmitted from the microprocessor 60 through circuitry 110 to tactile sensory transmission device 130 situated on the outer surface of socket 115 where it is fitted onto amputated limb 95. Tactile sensory transmission device 130 is provided with a grid-like support material 131, a plurality of tactile transmission rods 134 provided with stimulus transmitter endpoints 135, with each transmission rod 134 having a first connection point 132a attached to support material 131 at corresponding connection point 132b, and a second connection point 133a attached to support material 131 at corresponding connection point 133b, and a protective polymeric film 136 overlaying stimulus transmitter endpoints 135. The electronic topographical map created by tactile stimuli provided to tactile sensing device 126, is transmitted via discrete electrical pulses 137 delivered to individual transmission rods 134 by circuitry 110 thereby causing a transmitter rod 134 to protract when it receives an electrical pulse, and to retract when the electrical pulse ceases. Consequently, this embodiment of the present invention enables a person with an amputated limb to sense and interact with tactile stimuli applied to the surfaces of a replacement prosthetic limb configured as described herein. Another embodiment is illustrated in Figs. 8A and 8B wherein the remote tactile sensory perception system of the present invention is incorporated into body coverings such as gloves and suits adapted to enable the wearer to sense and interact with electronically (i.e., computer) generated images and/or holograms and/or remotely generated electrical pulses transmitted by wireless devices. For example, the palm portion of glove 200 shown in Fig. 8 A is provided with remote tactile sensory perception system 210 having a plurality of stimulus transmitting rods 214 mounted in a mapping grid pattern within support material 212. Each stimulus transmitting rod 214 is provided with an light sensor/detector 215 capable of distinguishing different light spectra as well as intensity of light spectra which are transmitted through wiring 216 connected to circuitry 217 to microprocessor 220 wherein the plurality of electronic pulses are configured into a dynamic electronic topographical map. The topographical electronic map is transmitted via circuitry 218 back to the remote tactile sensory perception system 210 wherein endpoints 225 of individual stimulus transmitter rods 214 protract and retract as electronic pulses are delivered through wiring 221. The type and intensity of light spectra detected at one end of stimulus transmitting rod 214 will cause increased protraction and duration of protraction by endpoint 225. This embodiment of the present invention enables users to sense and interact with computer-generated holographic images comprised of projected light spectra. Alternatively, the palm portion of glove 200 shown in Fig. 8A could be provided with stimulus transmitting rods having electronic detectors 215 for receiving wireless-transmitted electronic stimuli which are transmitted as pulses through wiring 216 connected to circuitry 217 to microprocessor 220 wherein the plurality of electronic pulses are configured into a dynamic electronic topographical map. The topographical electronic map is transmitted via circuitry 218 back to the remote tactile sensory perception system 210 wherein endpoints 225 of individual stimulus transmitter rods 214 protract and retract as electronic pulses are delivered through wiring 221. Increased magnitude of electronic pulses detected at one end of stimulus transmitting rod 214 will cause increased protraction and duration of protraction by endpoint 225. It is envisioned that this embodiment could be extended to incorporate a second glove 200 configured as described above wherein endpoints 225 are wireless transmitters. Second glove 200 could be incorporated onto robotic appendages that are remotely controlled to grasp and manipulate objects. The tactile sensory stimuli detected and processed into a dynamic topographical map by the tactile sensory perception system 210 incorporated into second glove 200 would be electronically transmitted by the wireless transmitters within second endpoints 225 to electronic detectors 215 incorporated into the tactile sensory perception system 210 of first glove 200, thereby enabling the wearer to remotely interact from a distance with objects being grasped and manipulated by a robot. It is preferred that the tactile sensory perception system 210 with detectors 215, the microprocessor 220, and endpoints 225 are integrally incorporated into protective gear. For example, a glove according to this embodiment could be comprised of two integrally conjoined or interwoven sections. The first section would be in contact with the palm, the undersides of the fingers and the finger tips, and would consist of at least two layers wherein the innermost layer, i.e., endpoints 225 would be in contact with the skin when the glove is worn by the user. The stimulus transmitting rods 214 and support material containing therein the mapping grid, and the detectors comprise the second section. If so desired, the second section may be overlaid with one or more additional layers of protective coverings to provide increased durability and wearability to the glove. The second section of the glove would be in contact with the top surface of the hands and fingers, and if so desired, may be comprised of any suitable natural or synthetic fibres. It is preferable that microprocessor 220 is incorporated into the second section of the glove. While this invention has been described with respect to the preferred embodiments, it is to be understood that various alterations and modifications can be made to components of the remote tactile sensory perception system of the present invention within the scope of this invention, which are limited only by the scope of the appended claims.

Claims

1. A tactile sensory perception apparatus comprising: a plurality of stimulus receptors paired with a plurality of stimulus transmitters; a plurality of stimulus transmitter rods, each rod interconnecting a stimulus receptor with a stimulus transmitter; and a flexible sheet of support material for supporting juxtaposed therethrough and containing therein the plurality of stimulus transmitter rods, said material having one side and an opposite side; wherein the plurality of stimulus receptors is aligned on said one side of the flexible sheet material and the plurality of paired stimulus transmitters is aligned on said opposite side of the flexible sheet material.

2. The apparatus of claim 1 wherein the flexible sheet of support material is a substrate woven from fibres.

3. The apparatus of claim 2 wherein the fibres are naturally occurring fibres.

4. The apparatus of claim 2 wherein the fibres are man-made fibres.

5. The apparatus of claim 2 wherein the woven flexible sheet of support material forms a resilient repeating grid pattern.

6. The apparatus of claim 1 wherein the flexible sheet of support material is a substrate impervious to moisture.

7. The apparatus of claim 1 wherein the flexible sheet of support material is a substrate impervious to liquids.

8. The apparatus of any one of claims 1 to 7 wherein the flexible sheet support material consists of one layer of substrate.

. The apparatus of any one of claims 1 to 7 wherein the flexible sheet of support material comprises multiple layers of substrates, the layers being sealed together.

10. The apparatus of any one of claims 1 to 9 wherein a portion of each stimulus transmitter rod is sealably fixed within the flexible sheet support material.

11. The apparatus of any one of claims 1 to 9 wherein each stimulus transmitter rod is freely slidable within the flexible sheet support material.

12. The apparatus of any one of claims 1 to 11 wherein the plurality of stimulus receptors is covered with a layer of protective flexible sheet material.

13. The apparatus of any one of claims 1 to 11 wherein the plurality of stimulus transmitters is covered with a layer of protective flexible sheet material.

14. The apparatus of any one of claims 1 to 11 wherein the plurality of stimulus receptors and the plurality of stimulus transmitters are each covered with a layer of protective sheet material.

15. The apparatus of any one of claims 1 to 14 wherein each stimulus receptor is equipped with a sensor for converting tactile stimuli to electrical signals.

16. The apparatus of any one of claims 1 to 14 wherein each stimulus receptor is equipped with a sensor for converting light spectra into electrical signals.

17. The apparatus of any one of claims 1 to 14 wherein each stimulus receptor is equipped with a sensor for converting wireless signals into electrical signals.

18. The apparatus of any one of claims 15 to 17 wherein each stimulus transmitter is equipped with a device for converting electrical signals into mechanical movement.

19. An article of clothing made of the apparatus of any one of claims 1 to 18 wherein the plurality of stimulus transmitters are positioned to contact one or more body skin surfaces of a wearer of said article of clothing.

20. An article of clothing incorporating the apparatus of any one of claims 1 to 18 wherein the plurality of stimulus transmitters are positioned to contact one or more body skin surfaces of a wearer of said article of clothing.

21. A glove made of the apparatus of any one of claims 1 to 18 wherein the plurality of stimulus transmitters are positioned to contact one or more body skin surfaces of a wearer of said glove.

22. A glove incorporating the apparatus of any one of claims 1 to 18 wherein the plurality of stimulus transmitters are positioned to contact one or more body skin surfaces of a wearer of said glove.

23. A prosthetic device incorporating the apparatus of claim 18 wherein the plurality of stimulus tiansmitters are positioned to contact a stump of a severed limb when the prosthetic device is fitted onto the stump.

24. A prosthetic device designed to replace a missing extremity of a human or animal having a residual stump, comprising an artificial replica of said extremity provided with a socket for engaging said stump, and having a plurality of stimulus receptors positioned over at least part of an external surface of said replica, means for converting tactile sensations received by said receptors into electrical signals, and a plurality of stimulus transmitters positioned within said socket for contact with said stump, said tiansmitters being adapted to convert said electrical signals into mechanical movement transmitted to said stump.