Patent Publication Number: US-2022230562-A1

Title: Training Prosthetic for Self-Cannulation Training

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a continuation-in-part application of, and claims priority from, Patent Cooperation Treaty (PCT) Application No. PCT/US2021/053876 filed Oct. 7, 2021, which in-turn claims priority to U.S. patent application Ser. No. 17/082,573, filed Oct. 28, 2020, both of which are incorporated herein in their entireties by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a training system and method for learning and practicing self-cannulation as would be needed for home hemodialysis patients. 
     BACKGROUND OF THE INVENTION 
     Self-cannulation is a huge hurdle for patients to overcome when moving into the arena of home hemodialysis. Self-cannulation is a stressful process that can take weeks or months to achieve and master. A need exists for a device that can help augment a training regimen for self-cannulation and help a patient to achieve self-cannulation sooner than would be achieved with traditional training methods. A need also exists for a training method that enables a home hemodialysis trainee to build confidence and muscle memory prior to a first real self-cannulation experience. 
     SUMMARY OF THE INVENTION 
     An objective of the present invention is to provide a training opportunity for self-cannulation as a means of building confidence and developing muscle memory prior to actual self-cannulation for home hemodialysis patients. This and other objectives are achieved according to the present invention by using the modular training system described herein. The system provides a device that produces a realistic “flash” of blood-like fluid in a simulated cannula upon proper cannulation. The system provides tactile feedback if the simulated access is improperly cannulated or infiltrated during cannulation. The system provides realistic skin-like material on outermost layers to create an illusion and feel as though the user is cannulating their own appendage. The system provides adjustable anchor-points for the simulated access to mimic a planned, existing, or potential access location and configuration in the patient&#39;s body. The system uses materials for and in the simulated access to give a trainee a realistic sensation and pressure when the simulated cannula needle is inserted into the simulated access. 
     The modular system can include a synthetic skin covering or overlay, for example, a layer of replaceable synthetic skin or fabric that can be anchored to other system components as a covering. The simulated skin covering can exhibit a correct resistance to puncturing by the simulated cannula needle, a material that enables a trainee or user to discern the position of a simulated access underneath the simulated skin covering, a correct skin-like stretching and movement, combinations thereof, and the like. The simulated skin covering can comprise a material that enables a trainee or user to see a bulge, highlights, and shadows caused by an underlying simulated access so that the trainee or user can visibly identify where the simulated access is located underneath the simulated skin covering. The simulated skin covering can exhibit a skin tone color to match the skin color of the trainee. 
     The simulated access can be made from actual graft material, or a reasonable facsimile, to produce a realistic cannulating experience. The simulated cannula can comprise flexible conductive wires and can mimic standard hemodialysis cannulation needles. The cannulation pad can comprise an underlying, protective, highly puncture-resistant layer, anchor, or shielding that prevents a trainee or user from stabbing himself or herself. The system can include a flexible adjustable armband in the form of a stretchy closable band that wraps around a trainee&#39;s appendage enabling the trainee to attach the modular system components to the trainee&#39;s appendage. Although many embodiments described herein exemplify the system being used on a forearm, it is to be understood that embodiments of the invention are also provided for using the system on a leg or on other parts of a body, which might be viable for hemodialysis cannulation for a particular trainee. 
     According to the present invention, a self-cannulation training system is provided that comprises a cannulation pad, a simulated access, a simulated cannula, a control unit, and at least one indicator. The cannulation pad comprises a cannulation electrical circuit conductor, an infiltration electrical circuit conductor, and an insulating layer electrically insulating the cannulation electrical circuit conductor from the infiltration electrical circuit conductor. The simulated access is configured to be electrically connected to the cannulation electrical circuit conductor and comprises an outer sheath and an electrically conductive material retained inside the sheath. The simulated cannula has a length and comprises a cannulation needle at a first end thereof, a cannula connector at a second, opposite end thereof, and an electrical conductor extending along the length and electrically connecting the cannulation needle with the cannula connector. The control unit comprises a power source and an electrical connector for connecting the power source to both the cannulation electrical circuit conductor and to the infiltration electrical circuit conductor. The control unit also has a second electrical connector for connecting the power source to the cannula connector of the simulated canula. 
     According to exemplary embodiments, the indicator is in electrical contact with the electrical conductor and is configured to be activated when the cannula needle electrically contacts the cannulation electrical circuit conductor to form a completed cannulation electrical circuit. The second indicator can be different than the first indicator and can be in electrical contact with the electrical conductor of the simulated cannula. The second indicator can be configured to be activated when the cannula needle electrically contacts the infiltration electrical circuit conductor to complete an infiltration electrical circuit. The first indicator can be, for example, a red LED and can signal that a proper cannulation of the simulated cannula into the simulated access, has taken place. The second indicator can be, for example, a buzzer and can indicate when an infiltration has taken place. 
     The system can include modular, replaceable, interchangeable components that can include, for example, an armband and wrist band, an arm cradle, a pair of simulated cannulas, a simulated skin covering, a replaceable battery, or a combination thereof. By using the training system, a method of training a patient or trainee for self-cannulation can be provided according to the present invention. 
     The training method of the present invention can comprise mounting the cannulation pad on the trainee or on a different person or dummy for the purpose of training a trainee. For example, the cannulation pad can be mounted on an armband worn by the trainee himself or herself. Alternatively, the trainee, helper, or dummy can have an arm placed inside the arm cradle and the cannulation pad can be mounted on the arm cradle. The cannulation pad can be a cannulation pad as described herein and can comprise a cannulation electrical circuit conductor, an infiltration electrical circuit conductor, and an insulating layer electrically insulating the cannulation electrical circuit conductor from the infiltration electrical circuit conductor. The method can involve electrically connecting a simulated access to the cannulation electrical circuit conductor. The method can involve electrically connecting a power source to both the cannulation electrical circuit conductor and to the infiltration electrical circuit conductor. The method can involve electrically connecting the power source to a simulated cannula. The simulated cannula can be a simulated cannula as described herein and can have a length, a cannulation needle at a first end, a cannula connector at a second, opposite end, and an electrical conductor extending along the length and electrically connecting the cannulation needle with the cannula connector. The cannula connector can be electrically connected to the power source. The method can comprise having the trainee insert the cannulation needle into a simulated access to train for inserting a real cannulation needle into a real access. The simulated access can be a simulated access as described herein and can comprise an outer sheath and an electrically conductive material retained inside the sheath. By practicing artificial cannulation using the training system, a trainee can become proficient at self-cannulation and be better prepared to perform true cannulation into an access or fistula when the time comes. 
     Methods of manufacturing the modular training system described herein are also provided and can include preparing an electrically conductive gel for filling the electrically conductive simulated access. Preparing the electrically conductive gel can comprise mixing together borax, glue, salt, and water. Preparing the cannulation pad can involve assembling together the various pad layers and components shown and described herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may be more fully understood with reference to the accompanying drawings. The drawings are intended to illustrate, not limit, the present teachings. 
         FIG. 1  is a schematic top view of a modular self-cannulation training system according to an embodiment of the present invention. 
         FIG. 2  is a top view of the modular system shown in  FIG. 1 , assembled, on an arm of a trainee, and further including a power source and two simulated cannulas connected to the control unit. 
         FIG. 3  is a top view of a modular system according to an embodiment of the present invention, assembled, on an arm of a trainee, and including the arm cradle shown in  FIG. 1 . 
         FIG. 4  is a perspective view of yet another modular system according to an embodiment of the present invention, and that includes two simulated cannulas extending from a control unit of the system, and a simulated access. 
         FIG. 5  is an exploded, top, front perspective view of the fabric layers, hook fastener layers, loop fastener layers, elastomeric layers, armor layer, and other layers that together, with an electrical system, make-up the modular system shown in  FIG. 4 . 
         FIG. 6  is a schematic view of an electrical system including modular electrical components and circuitry, according to various embodiments of the present invention, and that can be used in the modular system shown in  FIG. 4 . 
         FIG. 7  is an exploded, front, perspective view of the simulated access shown in  FIG. 4  and showing two pairs of serially-connected mini motors and two pairs of magnetic electrical connectors wherein one pair of magnetic electrical connectors is provided at each respective end of the simulated access. 
         FIG. 8  is a bottom view of a cannulation pad according to another embodiment of the present invention. 
         FIG. 9  is a top, perspective view of the cannulation pad shown in  FIG. 8  and showing respective connector pair holders each configured for holding a pair of magnetic connectors. 
         FIG. 10  is a top view of the needle end of a simulated cannula that can be used with the modular system shown in  FIGS. 4-9 , before and after insertion into an electrically-conductive cannula needle tip. 
         FIG. 11A  is a side view of a simulated cannula, according to various embodiments of the present invention. 
         FIG. 11B  is a top view of the simulated cannula shown in  FIG. 11A . 
         FIG. 11C  is a side view of the simulated cannula, shown in  FIGS. 11A and 11B , showing in partial cutaway a needle coupler assembly. 
         FIG. 11D  is an enlarged view of section  11 D, taken from  FIG. 11C . 
         FIG. 12A  is a top perspective view of a replaceable needle assembly and a needle coupler assembly, according to various embodiments of the present invention, prior to assembly. 
         FIG. 12B  is a top perspective view of the replaceable needle assembly and the needle coupler assembly show in  FIG. 12A , assembled together. 
         FIG. 13  is a top perspective view of a needle coupler assembly and a connecting cable, according to various embodiments of the present invention, disconnected from one another. 
         FIG. 14A  is a top, right perspective view of a needle coupler assembly secured to a hollow flexible tube of a replaceable needle assembly, according to various embodiments of the present invention. 
         FIG. 14B  is an exploded view of the needle coupler assembly shown in  FIG. 14A , without the compression nut secured, and showing an optical fiber and conductor extending through the coupler front housing and bonded to the fiber optic and conductor adapter. 
         FIG. 14C  is an enlarged, top, left perspective view of the fiber optic and conductor adapter shown in  FIG. 14B . 
         FIG. 14D  is an enlarged, top, left, perspective view of the inside of the fiber optic and conductor adapter shown in  FIG. 14C . 
         FIG. 15A  is an enlarged view of a wave-shaped electrical conductor in and extending out from the end of a transparent, hollow, flexible tube of a simulated cannula, according to various embodiments of the present invention. 
         FIG. 15B  is a top perspective view of the wave-shaped electrical conductor and hollow flexible tube shown in  FIG. 15A , after assembly to a needle and set of wings, to form a simulated cannula according to various embodiments of the present invention. 
         FIG. 16A  is a top plan view of a simulated cannula including a coupler, according to another embodiment of the present invention, connected to a connector cable. 
         FIG. 16B  is a side cross-sectional view of the simulated cannula with connector cable shown in  FIG. 16A , taken along line  16 B- 16 B. 
         FIG. 16C  is an enlarged view of section  16 C shown in  FIG. 16B . 
         FIG. 17  is a top perspective view of a training prosthetic for self-cannulation training, according to an embodiment of the present invention, showing a simulated access bridging a cannulation pad, without a simulated skin covering being attached thereto. 
         FIG. 18A  is a plan view of a training prosthetic for self-cannulation training, according to an embodiment of the present invention, including the training prosthetic shown in  FIG. 17  with a simulated skin covering attached thereto. 
         FIG. 18B  is a side view of the training prosthetic for self-cannulation training, shown in  FIG. 18A . 
         FIG. 19A  is a top perspective view of a training prosthetic for self-cannulation training, according to another embodiment of the present invention, that does not include a simulated skin covering. 
         FIG. 19B  is an enlarged view of section  19 B taken from  FIG. 19A , and showing leveling patches adjacent the simulated access. 
         FIG. 19C  is a side view of the training prosthetic for self-cannulation training, shown in  FIGS. 19A and 19B . 
         FIG. 20  is a top perspective view of a control unit for a training prosthetic for cannulation training, according to various embodiments of the present invention. 
         FIG. 21  is a bottom view of the battery circuit used for powering the control unit shown in  FIG. 20 . 
         FIG. 22  is an exploded top perspective view of components of a training prosthetic according to various embodiments of the present invention. 
         FIG. 23  is a top perspective view of the assembly of parts shown in  FIG. 22 , ready to receive a needle shield within a complimentary recess formed in the cannulation pad frame. 
         FIG. 24  is a top, perspective, partially exploded view of the assembly shown in  FIG. 23 , assembled together, and prior to the fastening of a battery compartment cover, a control unit compartment cover, and strap bars. 
         FIG. 25  is a top perspective view of an assembly comprising the components shown in  FIG. 24 , after being assembled together. 
         FIG. 26  is a top perspective view of the assembly shown in  FIG. 25 , after the hook and loop fastener patches shown in  FIG. 25 , have been applied. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention provides a self-cannulation training system to enable patients, such as hemodialysis patients, to learn how to self-cannulate. The system comprises a cannulation pad, a simulated access, a simulated cannula, and a control unit. The cannulation comprises a cannulation electrical circuit conductor, an infiltration electrical circuit conductor, and an insulating layer electrically insulating the cannulation electrical circuit conductor from the infiltration electrical circuit conductor. The simulated access is configured to be electrically connected to the cannulation electrical circuit conductor. The simulated access comprises an outer sheath and an electrically conductive material retained inside the sheath. The electrically conductive material can be, for example, an electrically conductive gel. The simulated cannula has a length, a cannulation needle at a first end thereof, and a cannula connector at a second, opposite end thereof. An electrical conductor is provided extending along the length of the simulated cannula and electrically connects the cannulation needle with the cannula connector. The electrical conductor of the simulated cannula can be shielded. The electrical conductor can comprise, for example, a co-axial cable and the cannula connector can comprise an RCA cable connector. The control unit can comprise electrical circuitry, cable connectors, a power source, or a combination thereof. The cable connectors of the control unit can be shielded, co-axial, a combination thereof, or the like. The cable connectors of the control unit can be RCA cable connectors or the like. 
     The control unit can include a first electrical connector for connecting the power source to the cannulation electrical circuit conductor. The control unit can include a second electrical connector for connecting the power source to the infiltration electrical circuit conductor. The first and second connectors can be the same or different connectors. Another connector can be provided for connecting the control unit, the power source, or both, to the cannula connector. 
     To provide a patient with feedback during training, a first indicator can be provided in electrical contact with the electrical conductor. The first indicator can be configured to be activated when the cannula needle properly electrically contacts the conductive material retained inside the simulated access when the simulated access is in electrical connection with the cannulation electrical circuit conductor. As such, the system can be configured such that the cannula needle completes and forms a cannulation electrical circuit. The first indicator can be, for example, a light, a flashing light, a red light, an LED, a vibrator, a sound generator, a combination thereof, or the like. 
     A second indicator, different than the first indicator, can also be provided in electrical contact with the electrical conductor. The second indicator can be configured to be activated when the cannula needle misses or passes through the simulated access and electrically contacts the infiltration electrical circuit conductor. The system can be configured such that, in such an event, the cannula needle completes and forms an infiltration electrical circuit. The second indicator can be, for example, a light, a flashing light, a red light, an LED, a vibrator, a sound generator, a combination thereof, or the like. As an example, the first indicator can comprise a light indicator and the second indicator can comprise a vibrator, a sound alarm, or a combination thereof. The first indicator can comprise a red-light-emitting diode. 
     The self-cannulation training system can further comprise a second simulated cannula. The second simulated cannula has a length and can comprise a second cannulation needle at a first end thereof, a second cannula connector at a second, opposite end thereof, and a second electrical conductor extending along the length. The second electrical conductor can electrically connect the second cannulation needle with the second cannula connector. The second electrical conductor of the second simulated cannula can be shielded and can comprise a co-axial cable and the second cannula connector can comprise an RCA cable connector. 
     The simulated access can be electrically connected to the cannulation electrical circuit conductor or can be configured to be electrically connected to the cannulation electrical circuit conductor, for example, electrically connected using magnets. According to various embodiments, a first electrical connector can connect the power source to both the cannulation electrical circuit conductor and to the infiltration electrical circuit conductor, and a second electrical connector can connect the power source to the cannula connector. 
     To connect the cannulation pad to a patient, for example, to a forearm of a patient, armband can be used and can be provided as part of the system. The armband and the cannulation pad can be configured to be fastened together. A simulated skin covering can also be provided and the armband and the simulated skin covering can be configured to be fastened together, for example, with the simulated access being positioned in between. The simulated access can be positioned to be made in electrical contact with the cannulation electrical circuit conductor before the simulated access is covered by the simulated skin covering. 
     The simulated skin covering can exhibit a correct resistance to puncturing by the simulated cannula needle, a material that enables a trainee or user to discern the position of a simulated access underneath the simulated skin covering, a correct skin-like stretching and movement, combinations thereof, and the like. The simulated skin covering can comprise a material that enables a trainee or user to see a bulge, highlights, and shadows caused by an underlying simulated access so that the trainee or user can visibly identify where the simulated access is located underneath the simulated skin covering. The simulated skin covering has an outer surface and the outer surface can have a skin tone color, for example, tan, beige, brown black, peach, or the like. The skin tone color of the simulated skin covering can be selected to match the skin color of the patient. The outer surface can be made of a material similar to artificial human skin, for example, a material that is able to give and stretch consonant with the other components and layers. The outer surface can serve the cosmetic purpose of looking like real human skin. A skin tone color can be selected to different patient populations. Moles, freckles, tattoos, scars, combinations thereof, and the like can be added to the outside surface to replicate a particular skin and individual. 
     The training system can also comprise a wrist band. The wrist band and the control unit can be configured to be fastened together. The wrist band can comprise a fastener, for example, a fastener patch including at least one of hook fasteners and loop fasteners. The control unit can comprise a fastener, for example, a fastener patch including at least one of hook fasteners and loop fasteners. The fastener of the wrist band and the fastener of the control unit can be complementary to each other. The wrist band can comprise a pocket, a strap, or the like, for accommodating the power source, such as a battery pocket for accommodating a battery. 
     Instead of or in addition to an arm band, the self-cannulation training system can further comprise an arm cradle. The arm cradle can be, for example, tubular in shape and can have a through-hole for accommodating an arm. The arm cradle and the cannulation pad can be configured to be fastened together. The arm cradle can comprise a fastener, for example, a fastener patch including at least one of hook fasteners and loop fasteners. The cannulation pad can comprise a fastener, for example, a fastener patch including at least one of hook fasteners and loop fasteners. The arm cradle and the control unit can be configured to be fastened together. The arm cradle can comprise a second fastener patch including at least one of hook fasteners and loop fasteners, and the control unit can comprise a fastener patch including at least one of hook fasteners and loop fasteners. The arm cradle can comprise a plastic material, such as polyvinylchloride (PVC). The arm cradle can be wrapped with a fabric, rubber, textile, or elastomeric material, for example, wrapped with a NEOPRENE® material, NEOPRENE® being a registered trademark of DuPont Company, Wilmington, Del. 
     For the hook and loop fasteners described herein, VELCRO® (available from Velcro BVBA, Deinze, Belgium) can be used. Each of the simulated skin covering, wrist band, armband, cradle cover, cannulation pad, and simulated access can independently comprise any suitable material. Exemplary materials that can be used include cotton, linen, spandex, polyester, rayon, nylon, ragadon, elastone, modal, silk, satin, leather, LYCRA® (E. I. DU PONT DE NEMOURS AND COMPANY, Wilmington, Del.), bamboo, hemp, dry-fit materials, wicking materials, breathable materials, blends of such materials, and the like materials. Organic materials can be used. The material can be comfortable. As an example, the material can comprise cotton, polyester, nylon, spandex, LYCRA®, a foamed NEOPRENE® material, a textile material, a blend of materials, a cotton-polyester blend material, a nylon-spandex blend material, or the like. As a further example, the material can comprise at least one of a nylon-spandex blend material and a foamed NEOPRENE® material. The material can comprise a stretchable material. 
     The electrically conductive material of the simulated access can comprise an electrically conductive material, for example, a liquid, gel, polymer, suspension, emulsion, dispersion, or the like. The electrically conductive material can be a gel, for example, a an electrically conductive gel comprising the reaction product of borax, glue, salt, and water. Sodium chloride or other salts can be used. The outer sheath of the simulated access can comprise a self-sealing material. GORE-TEX® (W. L. Gore &amp; Associates, Inc., Newark, Del.) can be used. Septa material as are used in self-sealing, resealing caps for vials of liquids, can be used. 
     The present invention also provides a method of training a patient for self-cannulation. The method involves mounting a cannulation pad on the patient. The patient can mount the cannulation pad or someone else. The cannulation pad can be a pad as described herein, for example, including a cannulation electrical circuit conductor, an infiltration electrical circuit conductor, and an insulating layer electrically insulating the cannulation electrical circuit conductor from the infiltration electrical circuit conductor. The method can further involve electrically connecting a simulated access to the cannulation electrical circuit conductor. The simulated access can be, for example, as described herein. The simulated access can comprise an outer sheath and an electrically conductive material retained inside the sheath. The method can involve, but is not limited to, electrically connecting a power source to both the cannulation electrical circuit conductor and to the infiltration electrical circuit conductor. The method can involve, but is not limited to, electrically connecting the power source to a simulated cannula, for example, a simulated cannula as described herein. The simulated cannula has a length and can comprise a cannulation needle at a first end thereof, a cannula connector at a second, opposite end thereof, and an electrical conductor extending along the length. The electrical conductor can electrically connect the cannulation needle with the cannula connector. The cannula connector can already be electrically connected to the power source or the method can involve connecting the cannula connector to the power source. The method can involve of be limited to having the patient insert the cannulation needle into the simulated access to train the patient for inserting a real cannulation needle into a real access of the patient, e.g., to carry out a self-cannulation. The method can also help train others how to carry out a cannulation of the patient. 
     According to the method, the patient can receive feedback about the self-cannulation carried out. For example, when the patient inserts the cannulation needle into the simulated access such that a distal tip of the cannulation needle rests inside the access, a first indicator is activated to indicate that a proper cannulation into the simulated access has been achieved. For example, if the insertion results in a positioning of the needle that enables an unrestricted fluid communication between the interior of the simulated access and an opening at the distal tip of the needle, the first indicator is activated. 
     The method can involve providing feedback in the form of signaling a fault, error, or alarm, when the cannulation does not result in a proper positioning of the tip of the needle. For example, when the patient inserts the cannulation needle into the cannulation pad such that the distal tip of the cannulation needle contacts the infiltration electrical circuit conductor, a second indicator can be activated to indicate that an improper cannulation into the simulated access has resulted. The first indicator can comprise a red light, for example, a red-light emitting LED. The second indicator can comprise, for example, a vibrator or sound-generator. 
     The method can involve mounting the cannulation pad on the patient. The mounting can comprise fastening an arm band to a forearm of the patient. The method can involve fastening the cannulation pad to the arm band. Mounting the cannulation pad on the patient can comprise placing a forearm of the patient into an arm cradle. The method can involve fastening the cannulation pad to the arm cradle. The method can involve fastening a simulated skin covering over the simulated access before inserting the cannulation needle into the simulated access. The method can involve selecting a skin tone color that matches the skin tone of the patient. 
     With reference now to the drawings,  FIG. 1  is a schematic top view of a modular self-cannulation training system  100  according to an embodiment of the present invention. Modular self-cannulation training system  100  comprises a cannulation pad  104 , an armband  108 , an arm cradle  112 , a simulated access  116 , a set  120  of simulated cannulas  121 ,  122 , a control unit  124 , a battery  128 , a simulated skin covering  132 , and a wrist band  136 . As can be seen from the top view shown, cannulation pad  104  includes a cannulation electrical circuit conductor  808  in the form of a frame, and an insulator layer  812  separating cannulation electrical circuit conductor  808  from underlying components. More details of cannulation pad  104  are shown in, and described in connection with, FIG. 8 of PCT Application No. PCT/US2021/053876, filed Oct. 7, 2021, which is incorporated herein in its entirety by reference. A two-terminal electrical connector  804  can be used to electrically connect cannulation pad  104  to a two-terminal electrical connector  510  of control unit  124 . A second two-terminal electrical connector  511  is provided to connect control unit  124  to battery  128 . More details of control unit  124  are shown in, and described in connection with, FIGS. 5 and 11 of PCT Application No. PCT/US2021/053876, filed Oct. 7, 2021, which is incorporated herein in its entirety by reference. 
     Simulated access  116  includes a stack of magnets  712  at each end thereof and left and right magnet housings  708  for respectively housing stacks of magnets  712 . More details of simulated access  116  are shown in, and described in connection with, FIGS. 7A and 7B of PCT Application No. PCT/US2021/053876, filed Oct. 7, 2021. Simulated cannulas  121  and  122  can comprise a simulated arterial cannula and a simulated venous cannula. Cannula needles at the tips of simulated cannulas  121  and  122 , are protected by needle sheaths  123  and  125 , respectively. Each of simulated cannulas  121  and  122  terminates at an RCA jack, for example, male RCA connector  612  having a connector post  652  and a cup-shaped metal conductor  653 . Suction cups  150  are provided for attaching simulated cannulas  121  and  122  to a trainee&#39;s skin or to another surface and can be color-coded, for example, red for the simulated arterial cannula and blue for the simulated venous cannula. More details of simulated cannula  121  are shown in, and described in connection with, FIGS. 6 and 11 of PCT Application No. PCT/US2021/053876, filed Oct. 7, 2021. 
     Armband  108  can comprise a sleeve configuration through which a trainee&#39;s arm can pass. Armband  108  can comprise a longitudinal opening or access so that armband  108  can be pushed onto an arm. One or more hook or loop or other fastener material patches  908  can be provided so that other modular components of the system can be fastened to and retained by armband  108 . More details of armband  108  are shown in, and described in connection with, FIGS. 3 and 9 of PCT Application No. PCT/US2021/053876, filed Oct. 7, 2021. 
     Arm cradle  112  can comprise a tube  1004  covered on its inside surface with a NEOPRENE® or other elastomeric material  1020  intended to make contact with the skin of a trainee&#39;s arm. An outer surface of arm cradle  112  can also be coated or wrapped with a NEOPRENE® or other elastomeric material. Outer surface  1008  can include a wide patch  1012  of hook fasteners configured to fasten and retain a cannulation pad such as cannulation pad  104  shown in  FIG. 1 . More details of arm cradle  112  are shown in, and described in connection with, FIGS. 4 and 10 of PCT Application No. PCT/US2021/053876, filed Oct. 7, 2021. 
     Simulated skin covering  132  can be used to cover simulated access  116  and attach to armband  108  or arm cradle  112  so as to mimic an access or fistula of the trainee, under the surface of trainee&#39;s skin. Simulated skin covering  132  can comprise first and second fastener patches  133  and  135  that can be, for example, in the form of loop fastener patches adapted to fasten simulated skin covering  132  to armband  108  or arm cradle  112  and retain simulated skin covering thereon. 
     Wrist band  136  is provided with a fastener patch  136  that can be, for example, in the form of a loop fastener patch or a hook fastener patch adapted to fasten wrist band  136  around the wrist of a trainee or other user and configured to fasten and retain a control unit, battery, or both, to wrist band  136 . Wrist band  136  can be used together with armband  108 , in some embodiments. 
       FIG. 2  is a top view of the modular system shown in  FIG. 1 , assembled, on an arm of a trainee, and further including a power source in the form of battery  128 , connected to two-terminal connector  511 , and wherein control unit  124  is also connected to two simulated cannulas including cannula  121 . As can be seen in  FIG. 2 , control unit  124  is fastened to wrist band  136 , on fastener strip  137 , and simulated skin covering  132  covers simulated access  116  so it appears as, or mimics, a bulging fistula on the arm of a trainee  300 . 
       FIG. 3  is a top view of a modular system according to an embodiment of the present invention, assembled, on an arm of a trainee, and including arm cradle  112  shown in  FIG. 1 . In the embodiment shown in  FIG. 3 , arm cradle  112  is used. The arm of a trainee  300  is cradled in arm cradle  112 . Cannulation pad  104  is fastened to a hook fastener patch on arm cradle  112  by a hook and loop fastener engagement. The bottom of cannulation pad  104  is fastened to arm cradle  112  via engagement of complementary hook and loop fasteners. other complementary fasteners and engagement devices can be used. Simulated access  116  can be magnetically secured to a cannulation electrical circuit conductor of cannulation pad  104 . Simulated access  116  is covered by simulated skin covering  132  that is attached to arm cradle  112  via a hook and loop fastener engagement. At the training step shown in  FIG. 3 , trainee  300  is holding simulated cannulas  121  and  122  protective sheaths  123  and  125  remain covering and protecting the cannula needle tips of simulated cannulas  121  and  122 , respectively.  FIG. 3  also shows control unit  124  fastened to arm cradle  112  and retaining battery  128 . As can be seen, control unit  124  is connected to cannulation pad  104  through the connection between connectors  510  and  804 . 
     According to training methods provided herein, cannulation and self-cannulation can be practiced by cannulating simulated access  116  with a needle of a simulated cannula. For the cannulation pad, different layers can be assembled together with an insulator layer electrically separating a cannulation electrical circuit conductor from an infiltration electrical circuit conductor. The insulator layer can comprise a polymer, an elastomer, NEOPRENE®, or the like. An exemplary cannulation pad that can be used or that results from such assembling is shown as pad  104  in  FIG. 1 . Related useful and optional components, for example, those shown in and described in connection PCT Application No. PCT/US2021/053876, filed Oct. 7, 2021, can also be incorporated into the cannulation pad. 
     As described in PCT Application No. PCT/US2021/053876, filed Oct. 7, 2021, simulated access  116  can be electrically attached at one or both ends to a cannulation electrical circuit conductor, for example, to a top surface of the cannulation electrical circuit conductor. Simulated cannula  121  can be connected at a jack  612  to jack  542 , connectors  510  and  804  can be connected together, and the needle of a simulated cannula can be used to cannulate simulated access  116 . Simulated access  116  can comprise a tube filled with a conductive gel and having magnetic ends magnetically attached to and in electrical communication with cannulation electrical circuit conductor  808 . Cannulation electrical circuit conductor  808  can comprise a metal frame, for example, a stainless steel or other metallic frame. Infiltration electrical circuit conductor can comprise a stainless steel or other metallic plate or frame, for example, a double-layer of aluminum foil. 
     Upon properly cannulating simulated access  116 , a cannulation electrical circuit is formed such that electrical current runs through the entire cannulation electrical circuit including through LED in or optically communicating with the simulated cannula. As a result, the LED lights-up, signaling a proper cannulation. In the event that simulated access  116  is not properly cannulated by the needle, for example, via an overshoot through or by missing simulated access  116 , and the needle contacts the infiltration electrical circuit conductor, a buzzer is activated signaling an improper cannulation, an infiltration, or both. The buzzer can be activated whether or not the LED is also activated. 
       FIG. 4  is a perspective view of a modular system  1200  according to another embodiment of the present invention. Modular system  1200  includes two simulated cannulas  1204 ,  1208  extending from a control unit (not shown) of the system. A simulated access  1500  extends across a cannulation pad  1600 . Simulated access  1500  is connected at a first end ( 1512  in  FIG. 7 ) by a first pair  1220  of electrically-conductive magnetic connectors, on one side of cannulation pad  1600 . Simulated access  1500  is connected at a second end by a second pair  1224  of electrically-conductive magnetic connectors, on an opposite side of cannulation pad  1600 . More details about simulated access  1500  are provided in connection with the description of  FIG. 7 , herein. 
       FIG. 5  is an exploded, top, front perspective view of the fabric layers, hook fastener layers, loop fastener layers, elastomeric layers, puncture-resistant layers, and other layers that, together with a separate electrical system, make-up the modular system shown in  FIG. 4 . The layers include a bottom, downward-facing loop fastener patch  1304 , a bottom nylon layer  1308 , and a three-layer stack  1312  comprising three layers of puncture-resistant fabric such as ANSI/ISEA 105 standard-compliant, needle-resistant material, for example, SUPERFABRIC® material available from Higher Dimensions Materials, Inc. (HDM) of Oakdale, Minn., and available from HexArmor of Grand Rapids, Mich. 
       FIG. 5  also shows a punch-out layer  1316  comprising a thin layer of material, for example, having a thickness of from 1.0 to 4.0 mm, provided with a punch-out or cut-out  1340  arranged and sized for providing access to a cannulation pad as described herein. Alternatively, cut-out  1340  can be omitted in which case infiltration would require piercing the material of punch-out layer  1316 , which can be, for example, a 1.5 mm-thick layer of NEOPRENE® material. The various layers shown in  FIG. 5  can be secured together by sewing, stitching, gluing, welding, adhesives, rivets, staples, laces, combinations thereof, and the like. 
     Punch-out layer  1316  can have a length of from 300 mm (11.8 inches) to 600 mm (23.6 inches), from 400 mm (15.7 inches) to 500 mm (19.7 inches), or, for example, of 450 mm (17.7 inches). Punch-out layer  1316  can have a width of from 100 mm (3.9 inches) to 200 mm (7.9 inches), from 120 mm (4.7 inches) to 160 mm (6.3 inches), or, for example, of 140 mm (5.5 inches). Each of bottom nylon layer  1308  and three-layer stack  1312  can independently have the same or similar dimensions as those of punch-out layer  1316 . 
     Cannulation pad cover  1336  can have can have a length of from 100 mm (3.9 inches) to 200 mm (7.9 inches), from 125 mm (4.9 inches) to 175 mm (6.9 inches), or, for example, of 150 mm (5.9 inches). Cannulation pad cover  1336  can have a width of from 100 mm (3.9 inches) to 200 mm (7.9 inches), from 120 mm (4.7 inches) to 160 mm (6.3 inches), or, for example, of 140 mm (5.5 inches). Each of hook fastener patch  1320  and loop fastener patch  1304  can independently have the same or similar dimensions as those of cannulation pad cover  1336 . 
     Each of loop fastener strips  1328  and  1332 , and hook fastener patch  1324 , can independently have a width of from 15 mm (0.6 inch) to 50 mm (2.0 inches), of from 20 mm (0.8 inch) to 30 mm (1.2 inches), or, for example, of 25.4 mm (one inch). Each of loop fastener strips  1328  and  1332 , and hook fastener patch  1324 , can independently have a length of from 100 mm (3.9 inches) to 200 mm (7.9 inches), from 120 mm (4.7 inches) to 160 mm (6.3 inches), or, for example, of 140 mm (5.5 inches). 
     Punch-outs or cut-outs  1350  and  1352  are also provided through punch-out layer  1316  to provide access for the connector ends of two simulated cannulas as described herein. The connector ends of simulated cannulas can pass through cut-outs  1350  and  1352  to enable connections with electrical circuitry underneath punch-out layer  1316 . Through-holes  1354  for wires are also provided through punch-out layer  1316  to enable electrical connections between magnetic electrical connectors on the top of punch-out layer  1316  and electrical circuitry underneath punch-out layer  1316 . 
     Two hook fastener patches  1320  and  1324  are secured to punch-out layer  1316  and each has exposed hook fasteners once the patches are secured to punch-out layer  1316 . Hook fastener patches  1320  and  1324  are configured to fasten to two respective loop fastener strips  1328  and  1332  that are secured to the underside of a cannulation pad cover  1336 . Loop fastener strips  1328  and  1332 , once secured to the underside of a cannulation pad cover  1336 , have exposed loop fasteners. The hook fasteners and the loop fasteners can be used together to secure the assembled training system onto an arm, for example, onto a dummy&#39;s arm, onto a trainee&#39;s arm, or onto a volunteer&#39;s arm. 
       FIG. 6  is a schematic view of an electrical system  1400  including modular electrical components and circuitry, according to various embodiments of the present invention, and that can be used in the modular system shown in  FIG. 4 . Electrical system  1400  comprises cannulation pad contacts  1404 . Cannulation pad contacts  1404  include an electrically-conductive mesh patch  1408  connected, via wiring  1412 , to a battery  1416 . Battery  1416  can be, for example, a USB port-rechargeable lithium battery or a coin-sized battery such as a CR  2023  battery. Cannulation pad contacts  1404  also comprise electrically-conductive magnetic contacts  1421 ,  1423 ,  1425 ,  1427 ,  1429 , and others, serially connected to a first pad lead  1420 . Cannulation pad contacts  1404  also comprise electrically-conductive magnetic contacts  1431 ,  1433 ,  1435 ,  1437 ,  1439 , and others, serially connected to a second pad lead  1430 . A motor-powering circuit  1450  is provided that includes cannulation pad contacts  1404 , first pad lead  1420 , second pad lead  1430 , a second battery  1440 , a switch  1444 , and an indicator light  1448  such as a blue LED to indicate when electricity is switched on through motor-powering circuit  1450 . When switched on, and a simulated access is properly connected to the cannulation pad, motor-powering circuit  1450  sends current through both serially-connected motors of a simulated access, powering the motors to vibrate and provide a haptic response at the simulated access. An exemplary simulated access  1500 , that can be used with or be a part of circuit  1450 , is shown in  FIG. 7 . 
     As shown in  FIG. 6 , electrical system  1400  also comprises a cannulation verification circuit  1460  for providing confirmation of a successful cannulation, alarm notification in the event of an infiltration, or both. Cannulation verification circuit  1460  can be configured to activate a success indicator in the event of a successful cannulation. Activating the success indicator can comprise the activation of a red LED, of a pulsing LED, of a combination thereof, or the like. A pulsing red LED to mimic a blood pulse in a patient, is provided with appropriate circuitry. 
     Cannulation verification circuit  1460  can comprise a buzzer  1464 , for example a 5-volt buzzer. In combination, a 6-volt battery can be provided as battery  1416 . A lead  1466  connects buzzer  1464  to an Ex-OR gate  1468  and/or to other circuitry to configure a desired result. Stemming from lead  1466  are two branches  1461 ,  1471 , respectively, with each also connected to a respective diode  1463 ,  1473  that in-turn connects to a respective connector  1465 ,  1475 . The circuitry can be configured such that, if the buzzer goes off due to an infiltration, then the LED indicator light provided along the simulated cannula can be made to turn off. 
     Also connected to Ex-OR gate  1468  is a lead  1467  stemming from motor-powering circuit  1450  and completing a circuit through a simulated cannula upon proper cannulation into a simulated access. An indicator, for example, an indicator light such as an LED  1482 , or more specifically, a red LED, can be configured to light-up upon a proper cannulation of a simulated access, in the event that a simulated cannula  1494 , including such an LED  1482 , is connected at connectors  1484  and  1486  to respective connectors  1487  and  1465  of cannulation verification circuit  1460 . Although not shown, circuitry can also be provided to pulse LED  1482 , for example, to further mimic a blood pulse through the simulated cannula. Similarly, a second simulated cannula can be connected to connectors  1475 ,  1485  to similarly test whether the second simulated cannula is properly cannulated into the simulated access or whether an infiltration has taken place. A resistor  1481  is provided between connector  1485  and Ex-OR gate  1468  and is matched with LED  1482  to prevent burn-out of LED  1482  of simulated cannula  1494 . Similarly, a resistor  1483  is provided between connector  1487  and Ex-OR gate  1468  and is also matched with LED  1482 , or with an LED in a simulated cannula configured to connect to connector  1487 , to prevent burn-out of the LED. 
       FIG. 7  is an exploded, front, perspective view of simulated access  1500  shown in  FIG. 4 . At the ends of simulated access  1500 , two pairs of magnetic electrical connectors are provided. More specifically, at a first end  1512  of simulated access  1500 , a first pair of magnetic electrical connectors  1514 ,  1516  is provided. At a second end  1518  of simulated access  1500  a second pair of magnetic electrical connectors  1520 ,  1522  is provided. 
     As shown in  FIG. 7 , a simulated access  1500  is provided with two motors  1504 ,  1508 , for example, mini, coreless motors. Each motor can comprise a coreless motor, a mini-motor, an asymmetric-weight motor, an impeller, a cell-phone vibrator motor, a combination thereof, or the like. Motors  1504  and  1508  can be connected to each other, in series, through a wired connection, through the conductive slime in the simulated access, or through a combination thereof. In the embodiment shown in  FIG. 7 , motors  1504  and  1508  are connected to each other in series by both a through wire  1560  and conductive slime filled in the simulated access. Motors  1504  and  1508  are configured to spin respective asymmetric weights  1505 ,  1509  such that vibratory motion is caused at each end of the simulated access. The vibratory motion provides a haptic response to the cannulation training and more effectively mimics a real cannulation experience. Coupled with an indicator such as a pulsing red LED to indicate a successful simulated cannulation, a more realistic, haptic, training experience can be realized. 
     Although magnetic electrical connectors  1516  and  1522  are shown in  FIG. 7  as being in electrical contact with each other via through wire  1560 , through wire  1560  can be omitted such that magnetic electrical connectors  1516  and  1522  electrically connect to one another through only the conductive slime inside simulated access  1500 . The inclusion of through wire  1560 , however, provides a pathway for double-dipping and ensures a pathway of very low resistance between magnetic electrical connectors  1516  and  1522 , independent of the conductive slime provided in simulated access  1500 . 
       FIG. 8  is a bottom view of cannulation pad  1600  that is also shown in  FIG. 4 . Cannulation pad  1600  comprises a 3-D printed layer  1604  of electrically insulative material that defines a plurality of pairs of tabs, for example, pair  1608  consists of tab  1612  and tab  1616 . Tabs  1612  and  1616 , along with the other tabs, are used for mounting on the top of cannulation pad  1600  respective magnetic connector holders each of which is configured to hold a pair of magnets as described herein with respect to  FIG. 9 . Tabs  1612 ,  1616 , and the others, comprise tab through-holes  1620  for threading therethrough an electrically conductive wire that can be used for securing the magnet holders on the top of cannulation pad  1600 . Wires threaded through tab through-holes  1620  can also be electrically connected to electrically-conductive magnetic connectors held in the magnet holders, for example, by soldering or by using a conductive epoxy adhesive. 
     Cannulation pad  1600  also comprises electrically-conductive mesh patch  1408  that is described in more detail above in connection with the circuitry shown in  FIG. 6 . Two inwardly extending tabs  1628  are also formed as part of 3-D printed layer  1604  and can be sewn to electrically-conductive mesh patch  1408  to maintain the mesh patch in place. 3-D printed layer  1604  can be ring-shaped, that is, open in the middle so as not to obstruct access to electrically-conductive mesh patch  1408 , from above. Alternatively, 3-D printed layer  1604  can be circular in shape, not open in the middle, in which case infiltration would require piercing the material of 3-D printed layer  1604  before making contact with electrically-conductive mesh patch  1408 . An electrical lead or connector tab (not shown) can be provided, electrically attached to electrically-conductive mesh patch  1408 , to facilitate the connection and disconnection of a circuit wire to and from electrically-conductive mesh patch  1408 . 
       FIG. 9  is a top, perspective view of cannulation pad  1600  shown in  FIG. 8  and showing respective connector pair holders  1704 ,  1708 ,  1712 ,  1716 , and others, each configured for holding a pair of magnetic connectors. For example, pair holder  1712  comprises a first cup  1713  and a second cup  1715  configured to snugly hold magnetic connectors  1717  and  1719 , respectively. As can be seen, the connector pair holders are mounted on the top surface  1317  of punch-out layer  1316 . More details about punch-out layer  1316  are described in connection with  FIG. 5  herein. For the sake of simplicity, only two pairs of magnetic connectors are shown in  FIG. 9 , in only two of the pair holders, namely, magnetic connectors  1717  and  1719  in cups  1713  and  1715 , respectively, make-up one pair of magnetic connectors, and magnetic connectors  1737  and  1739  in cups  1733  and  1735 , respectively, make-up a second pair of magnetic connectors. A simulated access such as simulated access  1500  shown in  FIG. 7  can be connected at its two ends to the respective pairs of magnetic connectors such that the simulated access can extend across cannulation pad  1600  and be well-positioned to detect a proper cannulation of the simulated access. Also, with such positioning of the simulated access, cannulation pad  1600  is well-positioned to detect an infiltration of a simulated canula needle in the event that the simulated access is not properly canulated. 
     As shown in  FIG. 9 , besides pair holders  1712  and  1732 , the other pair holders, for example, pair holders  1704 ,  1708 ,  1716 , do not yet have magnetic connectors fixed therein but instead show a conductive trace or wire  1750  or  1755  in the bottom of the cups ready to make contact with and be soldered or glued to respective magnetic connectors. Wires  1750  and  1755  can be connected to an electronics circuit primarily housed in an electronics unit  1760 . In an example, the circuit shown in  FIG. 6  can be used with cannulation pad  1600  of  FIGS. 8 and 9 , and wire  1755 , threaded through the bottom of every other cup, can be connected to a first lead such as lead  1420  shown in  FIG. 6 . Wire  1750  can pass through the bottoms of the remaining cups, on the other hand, and be connected to a second lead such as lead  1430  shown in  FIG. 6 . 
     For each pair of magnetic connectors of cannulation pad  1600 , one of the magnets can be oriented with it north magnetic pole facing outwardly whereas the other magnet of the pair can be oriented with its south magnetic pole facing outwardly. A simulated access, such as simulated access  1500  shown in  FIG. 7 , can thus be provided with its first pair of magnetic electrical connectors  1514 ,  1516  mounted in a side-by-side arrangement, for example, in an end cap having side-by-side cup holders such that one of the magnets (e.g.,  1514 ) can be oriented with it north magnetic pole facing outwardly whereas the other magnet of the pair (e.g.,  1516 ) can be oriented with its south magnetic pole facing outwardly. For the opposite end of simulated access  1500 , the two outwardly facing magnet polarities can be switched. As such, magnet connector  1516  of simulated access  1500  contacts one of the leads  1420  or  1430  of motor-powering circuit  1450  shown in  FIG. 6 , magnet connector  1522  of simulated access  1500  contacts the other of the leads  1420  or  1430  of motor-powering circuit  1450  shown in  FIG. 6 , and through wire  1560  of simulated access  1500  bridges leads  1420  and  1430 . By bridging leads  1420  and  1430 , motor-powering circuit  1450  can be closed, enabling motors  1504  and  1508  of simulated access  1500  to be powered when switch  1444  is turned on. 
     With such an arrangement of magnet pairs along the periphery of cannulation pad  1600 , and such an arrangement of magnets at the ends of simulated access  1500 , simulated access  1500  can only be connected in a proper fashion to cannulation pad  1600 . A proper connection is useful in setting up proper electrical circuitry and powering the motors in the simulated access. Once fully assembled, ten pairs of electrically-conductive magnets are provided. The first magnet of each respective pair can be serially connected to the other first magnets of the pairs. The second magnet of each respective pair can be serially connected to the other second magnets of the pairs. As such, the pairs of magnets can be arranged as shown in  FIG. 6 . 
       FIG. 10  is a top view of the wound needle end  1804  of a simulated cannula dual wire  1808  that can be used in a simulated canula and with the modular system shown in  FIGS. 4-9 .  FIG. 10  shows wound needle end  1804  before and after insertion into a separately provided electrically-conductive hollow cannula needle tip  1812 , which is shown in  FIG. 10  protected by a cap  1816 . A user, trainee, or prescriber can order and/or use a cannula needle tip  1812  of his or her own choosing and the simulated cannula does not need to be shipped or delivered with a cannula needle tip. The configuration enables a user to use any off-the-shelf needle or needle set, with the simulated cannula dual wire device and the simulated cannula training system. The user, trainee, or prescriber can insert wound needle end  1804  of dual wire  1808  into the hollow cannula needle tip  1812  and friction alone can be used to maintain wound needle end  1804  inside and in electrical contact with hollow cannula needle tip  1812 . 
     As can be seen in  FIG. 10 , electrically-conductive hollow cannula needle tip  1812  can be capped and protected by cap  1816  right up until the start of cannulation training with the modular system. Electrically-conductive hollow cannula needle tip  1812  can be connected to a set of wings  1820  that facilitate handling the hollow cannula needle tip, uncapping and capping the hollow cannula needle tip, and securing the hollow cannula needle tip. Securing can involve, for example, taping the needle tip to the arm of a user, patient, or trainee, taping the needle tip to an arm band, or taping the needle tip to an arm cradle. In  FIG. 10 , a protective, insulative sheath has been peeled away from the simulated cannula shown to expose first and second conductive wires  1824  and  1828  that run the length of the simulated cannula, for example, as shown in  FIG. 6 . In  FIG. 6 , similarly, almost all of the protective, insulative sheath  1490  has been peeled away to show first and second conductive wires akin to first and second conductive wires  1824  and  1828 . Either or both of first and second conductive wires  1824  and  1828  can be insulated along its length or their lengths, except for at the ends of first and second conductive wires  1824  and  1828  where the two wires are wound together, to each other, to form wound needle end  1804 . One of first and second conductive wires  1824  and  1828  is configured to be electrically connected to resistor  1481  or  1483 , while the other of first and second conductive wires  1824  and  1828  is configured to connect to the circuit including buzzer  1464  through lead  1466 . 
       FIGS. 11A-15B  show various views of a simulated cannula according to yet a further embodiment of the present invention.  FIG. 11A  is a side view of a simulated cannula  1100 , according to various embodiments of the present invention.  FIG. 11B  is a top view of simulated cannula  1100 , shown in  FIG. 11A .  FIG. 11C  is a side view of simulated cannula  1100 , shown in  FIGS. 11A and 11B , and showing, in partial cutaway, a needle coupler assembly  1116 .  FIG. 11D  is an enlarged view of section  11 D shown in  FIG. 11C . 
     As show in  FIGS. 11A-11D , simulated cannula  1100  includes a replaceable needle assembly  1102 . Replaceable needle assembly  1102  has a needle  1104 , a set of wings  1108 , and a hollow flexible tube  1112 . Simulated cannula  1100  further includes a needle coupler assembly  1116 . Needle coupler assembly  1116  that includes a coupler housing  1120 , a compression nut  1124 , and a connector  1128 . Extending from coupler housing  1120  and into hollow flexible tube  1112  are a fiber optic or optical fiber  1156  and a conductor  1160 . A connecting cable  1180  electrically connects needle coupler assembly  1116  with a power source and with signal sending and receiving circuitry of a control unit. Connecting cable  1180  has a first male connector  1184   a  and a second male connector  1184   b . First male connector  1184   a  is releasably connected to needle coupler assembly  1116 , while second male connector  1184   b  releasably connects to the control unit. 
       FIG. 11D  illustrates internal components that are housed within coupler housing  1120 . As can be seen, optical fiber  1156  and conductor  1160  terminate within coupler housing  1120 . A proximal end of conductor  1160 , within coupler housing  1120 , is connected to a spring finger  1172 , which will be described in more detail below. 
       FIG. 12A  is a top perspective view of replaceable needle assembly  1102  and needle coupler assembly  1116 , according to various embodiments of the present invention, and prior to being assembled together.  FIG. 12B  is a top perspective view of replaceable needle assembly  1102  and needle coupler assembly  1116  show in  FIG. 12A , assembled together. Needle  1104 , set of wings  1108 , and hollow flexible tube  1112 , of replaceable needle assembly  1102 , can also be seen in  FIG. 12B . Prior to assembly, compression nut  1124  of needle coupler assembly  1116  is detached from coupler housing  1120 . Compression nut  1124  is then fit over the end of hollow flexible tube  1112  opposite the end connected to needle  1104  and set of wings  1108 . Extending from coupler housing  1120  are optical fiber  1156  and conductor  1160 . Coupler housing  1120  includes a male threaded hollow shaft  1136  ( FIG. 12A ) that mates with female threads of compression nut  1124 . During assembly, conductor  1160  and optical fiber  1156  are inserted through compression nut  1124  and into hollow flexible tube  1112 . An opening of coupler housing  1120  at the end of male threaded shaft  1136  meets with the end of hollow flexible tube  1112  within compression nut  1124 . Compression nut  1124  is then screwed onto male threaded shaft  1136 , or vice versa, which in clamps compression nut  1124  against hollow flexible tube  1112 , and connects needle coupler assembly  1116  to replaceable needle assembly  1102 . 
       FIG. 13  is a top perspective view of needle coupler assembly  1116  shown in  FIGS. 11A-12B , and a connecting cable  1180 , according to various embodiments of the present invention, disconnected from one another. Needle coupler assembly  1116  is shown without compression nut  1124 , in  FIG. 13 . As can be seen, conductor  1160  and optical fiber  1156  extend from coupler housing  1120 . Connecting cable  1180  can include any type of connecting cable  1180  that releasably connects with needle coupler assembly  1116  to electrically connect needle coupler assembly  1116  to a control unit. For example, connecting cable  1180  can be a phone connector, audio cable, headphone cable, USB cable, RCA cable, or the like. Each end of the connecting cable  1180  can include a male connector  1184   a ,  1184   b . Each of male connectors  1184   a ,  1184   b  can independently be a 2.5 mm jack plug, a 3.5 mm jack plug, a 4.4 mm jack plug, a 6.35 mm jack plug, an RCA plug, a USB plug, a mini-USB plug, a lightning wire plug, or any other type of plug. First male connector  1184   a  releasably attaches to connector  1128  of needle coupler assembly  1116  and second male connector  1184   b  releasably attaches to the control unit. Second male connector  1184   b  can instead be in the form of a 90-degree connector, a flat connector, or have another design. 
       FIG. 14A  is a top, right perspective view of needle coupler assembly  1116  connected to hollow flexible tube  1112 , according to various embodiments of the present invention.  FIG. 14B  is an exploded view of needle coupler assembly  1116  shown in  FIG. 14A , but without showing compression nut  1124  or hollow flexible tube  1112 . As mentioned above, needle coupler assembly  1116  includes coupler housing  1120  ( FIG. 14A ). Coupler housing  1120  includes a coupler front housing  1132  and a coupler rear housing  1146  that are releasably or permanently connectable, for example, via connectors. Once assembled, coupler front housing  1132  and coupler rear housing  1146  are connected together. Coupler front housing  1132  includes male threaded shaft  1136  and an axial opening defined therethrough. Coupler rear housing  1146  also has an axial opening that aligns with the axial opening of coupler front housing  1132  when coupler front housing  1132  is connected with coupler rear housing  1146 . Connector  1128  can be, for example, elastomer connector that fits within a rear opening of coupler rear housing  1146 . Connector  1128  also includes an axial opening that aligns with the axial opening of coupler rear housing  1146  when connector  1128  is connected to coupler rear housing  1146 . Disposed within coupler housing  1120  is a fiber optic and conductor adapter  1154 . 
       FIG. 14C  is an enlarged, top, left perspective view of fiber optic and conductor adapter  1154  shown in  FIG. 14B .  FIG. 14D  is an enlarged, top, left, perspective view of the inside of fiber optic and conductor adapter  1154  shown in  FIGS. 14B and 14C , with a cover  1164  removed. As can be seen, adapter  1154  includes a printed circuit board  1168 . A female jack  1176 , a spring finger  1172 , and a light emitting diode  1174  are connected to printed circuit board  1168  as is appropriate electrical circuitry. Light emitting diode  1174  can instead be an organic LED, comprise quantum dots, include a filament, or any other type of light emitter. Spring finger  1172  and light emitter  1174  can be electrically connected to printed circuit board  1168 , for example, by circuitry (not shown) on the underside of printed circuit board  1168 . Optical fiber  1156  and conductor  1160  are bonded or otherwise attached to cover  1164 , and cover  1164  aligns optical fiber  1156  with LED  1174  thus guiding light emitted from LED  1174  into and through optical fiber  1156 . Cover  1164  also protects the connection between conductor  1160  and spring finger  1172 . Conductor  1160  passes through a spring-biased opening of spring finger  1172  and makes electrical contact with spring finger  1172 . 
     When assembled, cover  1164  fits within the axial opening of coupler front housing  1132 . Printed circuit board  1168  rests on a ledge  1148  within coupler rear housing  1146 . Coupler front housing  1132  and coupler rear housing  1146  are connected together, securing fiber optic and conductor adapter  1154  there within. When needle coupler assembly  1116  is in its assembled state, and first male connector  1184   a  of connecting cable  1180  is inserted through connector  1128  and into female jack  1176 , as shown in  FIG. 11D , a tip of first male connector  1184   a  electrically engages with conductor  1160  so that conductor  1160  can be electrically connected to a control unit. Another lead of connecting cable  1180  can be configured to be electrical contact with and supply power to LED  1174  under certain conditions such as when a cannulation circuit is completed without infiltration. 
       FIG. 15A  is an enlarged view of conductor  1160  extending from the distal end of hollow flexible tube  1112  of simulated cannula  1100 , shown in  FIGS. 11A-14D . As can be seen, the distal end of conductor  1160  extends out of hollow flexible tube  1112  such that the conductor  1160  can make electrical contact with a metal or metallic needle  1104  ( FIG. 15B ). Conductor  1160  is provided with a wave, wavy, or sinusoidal shape to ensure that at least a portion of conductor  1160  contacts needle  1104  to make electrical contact therewith.  FIG. 15B  is a top perspective view of conductor  1160  and fiber optic line  1156  within hollow flexible tube  1112 , after assembly to needle  1104  and set of wings  1108 . Conductor  1160  extends far enough within and/or through wings  1108  so that conductor  1160  makes electrical contact with needle  1104 . 
       FIG. 16A  is a top plan view of a simulated cannula  1600  according to yet another embodiment of the present invention.  FIG. 16B  is a cross-sectional side view of simulated cannula  1600  shown in  FIG. 16A  and taken along line B-B in  FIG. 16A .  FIG. 16B  shows a section C centered around a coupler  1604 .  FIG. 16C  is an enlarged view of section C shown in  FIG. 16B . As shown in  FIGS. 16A-16C , simulated cannula  1600  is shown connected to a connector cable  1696 . Simulated cannula  1600  includes a coupler  1604  that enables a flexible, needle unit  1608  to be coupled with connector cable  1696 . Herein, coupler  1604  is also referred to as a needle coupler assembly. Connector cable  1696  is a four-lead electrical conductor. Each of the two opposite male jacks at the respective ends of electrical conductor  1696  include four separate electrical contacts. Coupler  1604  is configured with four corresponding electrical contacts along the female jack at the connector end of coupler  1604 , into which connector cable male jack is inserted. Although a particular arrangement of female jacks and male jacks is depicted, any suitable combination can be used. Each jack can comprise two leads, three leads, four leads, or the like. 
     As can be seen from comparing  FIG. 16A  with  FIG. 16B , coupler  1604  can have a width that is greater than its thickness. Coupler  1604  secures a first end of an electrical conductor  1612 , also referred to herein as a needle conductor, that extends through the entire length of a flexible tube component  1616  of flexible, needle unit  1608 . In addition, coupler  1604  also secures a first end of an optical fiber  1620  that extends into, but not entirely through, flexible tube component  1616 . Coupler  1604  comprises a coupler housing  1630  and a compression nut  1634 . A micro-LED  1640  is mounted within coupler  1604  and positioned to direct light emitted therefrom into the first end of optical fiber  1620 . Coupler  1604  comprises a printed circuit board  1650  to provide electrical circuitry between connector cable  1696  and the respective components of coupler  1604 , including electrical conductor  1612  and micro-LED  1624 . 
       FIG. 17  is a top perspective view of a training prosthetic  720  for self-cannulation training, according to an embodiment of the present invention, showing a simulated access  724  bridging a cannulation pad  728 , without a simulated skin covering being attached thereto. In use, a simulated skin covering can be attached to the top of the prosthetic to mimic vasculature underneath skin.  FIG. 17  shows a battery compartment cover  732  and a control unit cover  736 , each of which is provided on a top surface thereof with a layer of hook-and-loop fastener, for example, as shown, a layer  782 ,  786 , respectively, of hook fasteners. The hook-and-loop fasteners can be used to removably fasten a simulated skin covering (not shown) across cannulation pad  728 , battery compartment cover  732 , and control unit cover  736 . The simulated skin covering can be designed to be a continuation of the material of the top surface of a belt  760  to which a frame  764  of cannulation pad  728  is secured. Frame  764  can be permanently or removably secured to belt  760 . A pair of belt couplers  768 ,  769  can be configured to secure frame  764  of cannulation pad  728  to belt  760 . Belt couplers  768 ,  769  can comprise plastic, NEOPRENE, or another suitable material, can be rigid, semi-rigid, or flexible, and can be bolted or otherwise fastened to be battery compartment cover  732  and a control unit cover  736 , respectively, with a cannulation pad bottom layer, such as a NEOPRENE layer, pinched therebetween. 
     Simulated access  724  has a first end  740  and a second end  742 , each of which can include a cap  744 ,  746 , respectively, that holds or retains an electrically-conductive magnetic connector for magnetically securing the respective end of the simulated access to a respective connector holder  750 ,  752 ,  754 ,  756 , and others. Each connector holder is configured for holding an electrically conductive magnetic connector of the simulated access. Each electrically conductive magnetic connector can independently comprise one or more magnets, for example, a plurality of magnets stacked one on top of the other. 
     Each connector holder  750 ,  752 ,  754 ,  756 , and others, includes an electrical contact or terminal, for example, terminal  758  shown in connector holder  756 . The terminals are electrically connected to a cannulation circuit such that, upon proper cannulation into simulated access  724 , completes or closes a cannulation circuit through (1) an electrical conductor in a simulated cannula, (2) electrically conductive media within simulated access  724 , (3) one or both electrically conductive magnetic connectors at ends  740 ,  742  of simulated access  724 , (4) the terminal in the respective connector holder, and (5) a control unit that is in electrical contact with both the terminal and the simulated cannula. Although simulated access  724  is shown, in  FIG. 17 , as being connected to two opposing connector holders, the cannulation circuit could nonetheless by completed if the simulated access is connected at just one end, to a single connector holder. 
     Simulated access  724  can be connected to just a single connector holder or to any two connector holders, whether opposing, adjacent, spaced apart, or the like. Simulated access  724  can be conformed to any of a variety of different orientations, including, but not limited to, curved designs. Simulated access  724  can be conformed to mimic the actual fistula, vasculature, or access, of the trainee or of the patient for which the trainee is training to cannulate. 
       FIG. 18A  is a plan view of a training prosthetic for self-cannulation training, according to an embodiment of the present invention, including training prosthetic  720  shown in  FIG. 17 , with a simulated skin covering  790  attached thereto.  FIG. 18B  is a side view of the training prosthetic for self-cannulation training, shown in  FIG. 18A . As can be seen from  FIGS. 18A and 18B , simulated skin covering  790  extends past battery compartment cover  732  and extends past control unit cover  736 , longitudinally, and gently slopes to merge areas  792  and  794 , respectively, where simulated skin covering  790  connects with belt  760 . At merge areas  792  and  794 , one or more patches or strips of fastener can be provided on belt  760 , on simulated skin covering  790 , or on both, to removably secure belt  760  and simulated skin covering  790 , together. 
       FIG. 19A  is a top perspective view of a training prosthetic  900  for self-cannulation training, according to another embodiment of the present invention. Training prosthetic  900  can be used with or without a simulated skin covering, and  FIGS. 19A-19C  show training prosthetic  900  without a simulated skin covering.  FIG. 19B  is an enlarged view of section  19 B taken from  FIG. 19A , and showing leveling patches  902 ,  904  adjacent a simulated access  906 .  FIG. 19C  is a side view of the training prosthetic for self-cannulation training, shown in  FIGS. 19A and 19B . 
     Leveling patch  902  is configured to fill the volume between simulated access  906  and the inside face of a battery compartment with cover,  912 . Leveling patch  904  is configured to fill the volume between simulated access  906  and the inside face of a control unit with cover,  914 . The top surfaces of one, or more, or all, of leveling patch  902 , simulated access  906 , battery compartment with cover  912 , leveling patch  904 , and control unit with cover  914 , can be flush with one or more of the other top surfaces. The top surfaces of all of leveling patch  902 , simulated access  906 , battery compartment with cover  912 , leveling patch  904 , and control unit with cover  914 , can be flush with one another. As can be seen particularly in  FIG. 19C , the top surface of simulated access  906  can protrude above, bulge above, or otherwise slightly rise above, the top surfaces of one or more of leveling patch  902 , battery compartment with cover  912 , leveling patch  904 , and control unit with cover  914 . A cannulation pad  918  is secured to a belt  920  that is configured to wrapped around or straddle a limb of a trainee or of a patient to be cannulated by a trainee. 
     Training prosthetic  900  shown in  FIGS. 19A-19C  can be used with or without a simulated skin covering attached thereto. If a simulated skin covering is used, it can be designed to extends past battery compartment cover  732  and extends past control unit cover  736 , longitudinally, and gently slopes to merge areas  792  and  794 , respectively, where simulated skin covering  790  connects with belt  760 . At merge areas  792  and  794 , one or more patches or strips of fastener can be provided on belt  760 , on simulated skin covering  790 , or on both, to removably secure belt  760  and simulated skin covering  790 , together. 
       FIG. 20  is a top perspective view of a control unit  600  according to various embodiments of the present invention. Control unit  600  includes a printed circuit board  604  having a plurality of electrical leads or traces (not shown) formed on the underside thereof. On the top of printed circuit board  604  are mounted a plurality of components, including a first cable connector female jack  610 , a second cable connector female jack  614 , a charging cable female jack  618 , a reset switch  622 , a light pipe  626 , a push button  630 , a battery connecting cable jack  634 , and a variety of processing chips, resistors, buses, capacitors, and other electrical components. A battery connecting cable  638  having a connecting jack  640  at an end thereof is shown connected to battery connecting cable jack  634 . Light pipe  626  can guide light emitted from a source, for example, from a micro-LED source mounted on printed circuit board  604  and directed into a first end of light pipe  626 . 
     The circuitry of the control unit can be configured to cause light pipe  626  to form different lights or patterns of light to indicate (1) whether the battery is charging, for example, by showing a steady pulse, (2) whether the battery is low, for example, by rapidly flashing, or (3) whether the power is on, for example, by showing a steady light. Different colored lights can be used to indicate different statuses of the control unit and battery. Push button  630  can be configured to glide along the top surface of printed circuit board  604  and can be guided by rails formed on or in printed circuit board  604 . Push button  630  can be provided with a spring mechanism configured to alternate the distal end of the push button between an extended position and a depressed or retracted position. 
     Each of first cable connector female jack  610  and second cable connector female jack  614  can be sized and shaped to receive a 3.5 mm male jack, for example, at the end of a four-lead electrical cable. Other arrangements including other jacks and cables can be used. The electrical cables for which first cable connector female jack  610  and second cable connector female jack  614  are configured to receive can be connected at respective opposite ends to first and second cannulas, for example, cannulas as shown in  FIGS. 11A-15B . 
       FIG. 21  is a bottom view of a battery circuit used for powering control unit  600  shown in  FIG. 20 . Battery connecting cable  638  is connected, at connection jack  640 , to battery connecting cable jack  634 . Battery connecting cable  638  extends around and underneath a series of electrically connected cannulation pad contacts  660 ,  662 ,  664 ,  666 , and  668  arranged along a cannulation pad branch  670  that is in electrical contact with the cannulation circuit including portions in control unit  600 . Battery connecting cable  638  can be, for example, a two-lead or three-lead cable that terminates at and is in contact with a battery  672 . Battery  672  can be, for example, a USB port-rechargeable lithium battery, a single-cell battery, a multi-cell battery, a nickel battery, an alkaline battery, a rechargeable alkaline battery, a coin-sized battery such as a CR  2023  battery, or the like. 
     The cannulation pad contacts are in electrical contact with respective terminals within respective connector holders, such as connector holders  750 ,  752 ,  754 , and  756  shown in  FIG. 17 . An exemplary terminal is terminal  758  shown in  FIG. 17 . Cannulation pad contacts  660 ,  662 ,  664 ,  666 , and  668  along with branch  670  can comprise an electrically-conductive mesh patch or a metallic layer or film, for example a 0.5 mm-thick stainless-steel layer cut, punched, molded, or otherwise formed from a stainless-steel sheet. Exemplary thicknesses include metallic layer thicknesses within the range of from 0.01 mm to 1.0 mm, from 0.05 mm to 0.8 mm, from 0.075 mm to 0.5 mm, from 0.1 mm to 0.5 mm, and 0.05 mm. Construction from a thin layer of metal can beneficially provide flexibility enabling the training prosthetic to be wrapped around or curved to conform to a limb. Steel, iron-containing, neodymium, cobalt, nickel, copper, gold, metal alloys, and the like can be used for the cannulation pad branch and cannulation pad contacts. Magnetic materials can be used. 
     A second cannulation pad branch  680  extends opposite cannulation pad branch  670 , and in the exemplary embodiment shown, along a semi-circular arc like first cannulation pad branch  670 . A plurality of cannulation pad contacts including cannulation pad contact  681  are provided along cannulation pad branch  680 . Second cannulation pad branch  680  can be made of the same or different materials relative to first cannulation pad branch  670 . While the bottom surface of cannulation pad contact  756  is shown in  FIG. 21 , the opposite, top surface of cannulation pad contact  756  would, have formed thereon, terminal  758  shown in  FIG. 17 . 
       FIG. 22  is an exploded top perspective view of components of a training prosthetic according to various embodiments of the present invention, including the control unit  600  shown in  FIG. 20  and the cannulation circuit circuitry shown in  FIG. 21 . As shown in  FIG. 22 , cannulation pad  728  includes a frame  764  to which are secured belt couplers  768 ,  769 , a battery compartment  671 , a control unit compartment  601 , first cannulation pad branch  670 , second cannulation pad branch  680 , and a bottom layer comprising, for example, NEOPRENE that is bonded, once assembled, to the underside of frame  764 . 
     Subsequent to assembly of the layers shown in  FIG. 22 , or as part of the assembly, a needle shield  692  is secured within a complimentary recess  694  formed in frame  764 , as shown in  FIG. 23 . Needle shield  692  can comprise a flat 0.010 inch-thick stainless-steel layer attached to frame recess  694  by a pressure sensitive adhesive, double-sided tape, hook and loop fasteners, or the like. Needle shield  692  is provided with a stem  696  terminating in a contact tip  698  that makes appropriate electrical contact with a corresponding contact on or in control unit  600 . 
       FIG. 24  is a top, perspective, partially exploded view of the exploded assembly shown in  FIG. 23 , but assembled together, and prior to the fastening of battery compartment cover  732 , control unit compartment cover  736 , and strap bars  771  and  773 . Strap bars  771  and  773  can comprise a plastic, elastomeric, metal, rubber, or polymeric material, or the like. Strap bars  771  and  773  can comprise NEOPRENE. Screws  775  can be used to fasten strap bars  771  and  773  to battery compartment cover  732  and control unit compartment cover  736 , respectively. Instead of or in addition to screws  775 , bolts, rivets, or other fasteners can be used. M3 thread-forming screws can be used. Screws  775 , but for their heads, can pass through respective through-holes in strap bars  771  and  773 , and through-holes through belt couplers  768 ,  769 . 
       FIG. 25  is a top perspective view of an assembly comprising the components shown in  FIG. 24  assembled together, subsequent to fastening screws  775  into respective, aligned, threaded receiving bores (not shown) provided in the undersides of battery compartment cover  732  and control unit compartment cover  736 . As can be seen, battery compartment cover  732  has a ridge along the periphery of its top surface, which defines a fastener patch receiving area or pocket  791 . Control unit compartment cover  736  has a ridge along the periphery of its top surface, which defines a fastener patch receiving area or pocket  793 . A hook and loop fastener patch  790 , for example, comprising only hook fasteners, can be secured within pocket  791 . The securing can be provided, for example, by a layer of pressure sensitive adhesive. A hook and loop fastener patch  792 , for example, comprising only hook fasteners, can be secured within pocket  793 , with the securing can be provided, for example, by a layer of pressure sensitive adhesive. Once assembled, the assembly is as shown in  FIG. 26 .  FIG. 26  also shows a simulated access  724  connected to cannulation pad  728  and bridging needle shield  692 . 
     The training system of the present invention can be used in conjunction with a virtual reality (VR) simulation system, for example, through a first-person (self) cannulation simulation or through a second-person cannulation simulation. The VR simulation system can be operatively connected to the training system. The simulation can be presented in a way that utilizes the tactile elements of the training system to augment what the user would be viewing through a VR headset. A VR headset can be used to afford a more realistic appearance for the simulation and to enable a lesson to be immersive and surrounded by contextual digital materials, such as labeling, tips, suggestions, other lesson-appropriate information, combinations thereof, and the like. For example, an angle-of-approach, a direction of a needle, and the like, can be evaluated digitally to provide automated feedback. Bruit, other sounds, and the like can be added to the experience via a VR headset. 
     The training system can be used in conjunction with an augmented reality (AR) simulation system, for example, through a first-person (self) cannulation simulation or through a second-person cannulation simulation. The AR simulation system can be operatively connected to the training system. An AR headset can be used. When using an AR headset, a self-cannulating user can be enabled to have the same auditory benefits as with a VR headset, but an image stream can be layered on top of what the user is actually viewing. The tactile elements of the device can be partnered with additional digitally placed elements and cues from the AR simulation system to afford a richer experience for the user. 
     With a VR or AR simulation system, a guidance system can be included. The guidance system can include at least an augmented reality device having a display, a camera configured to capture image data, and a computing system. The computing system can include at least a processor and a memory. The memory can store computer-readable instructions that, upon execution by the processor, configure the computing system to perform steps. The computing system can receive a user input from a user, and the user input can include a target internal vein or artery of the patient. The computing system can process image data captured by the camera, and the image data can include at least an image of the vasculature of the patient or of the cannulation training system, for example, an image of the simulated access. Processing the image data can include identifying at least one vasculature or access feature of the patient or training system. The computing system can determine a cannulation location based on the processed image data and the user input. The computing system can generate output data for the display of the VR or AR device. The output data can include target indicia. With an AR system, the target indicia can overlay an image of the patient or training system at the vasculature or simulated access location. 
     An augmented reality device can be used that includes the computing system, the display, and the camera. Alternatively, the augmented reality device can be separate from the computing system and the camera, and, in such embodiments, the computing system, the augmented reality device, and the camera can communicate with one another via a hard-wired interface, a wireless interface, or a combination thereof. 
     The augmented reality device can include a smart device. The smart device can be, for example, a smart phone, a tablet, a smart watch, smart glasses, or the like. The smart device can be a smart phone that can include, for example, a touchscreen interface. The computer-readable instructions can be in the form of application software loaded on the memory, for example, an app loaded on a smart phone or tablet. 
     The smart device can be in the form of a head mount, such as smart glasses. The head mount can include the computing system, the display, the camera, and other sensors. The display of the head mount can be at least partially transparent. The at least partially transparent display can be configured to display augmentation graphics such as semi-opaque images that appear to a user to be superimposed on at least a portion of a natural field of view of the user. Other apparatus, devices, components, systems, and methods related to VR and AR, which can be used or incorporated in accordance with the present invention, include those described, for example, in U.S. Pat. No. 10,726,744 B2, which is incorporated herein in its entirety by reference. 
     The entire contents of all references cited in this disclosure are incorporated herein in their entireties, by reference. Further, when an amount, concentration, or other value or parameter is given as either a range, preferred range, or a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether such a range is separately disclosed. Where a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range. It is not intended that the scope of the invention be limited to the specific values recited when defining a range. 
     All patents, patent applications, and publications mentioned herein are incorporated herein in their entireties, by reference, unless indicated otherwise. 
     Other embodiments of the present invention will be apparent to those skilled in the art from consideration of the present specification and practice of the present invention disclosed herein. It is intended that the present specification and examples be considered as exemplary only with a true scope and spirit of the invention being indicated by the following claims and equivalents thereof.