Patent Publication Number: US-11039775-B2

Title: Electrical interface system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/627,717, filed 20 Jun. 2017, which claims the benefit of U.S. Provisional Application Ser. No. 62/352,387 filed 20 Jun. 2016, U.S. Provisional Application Ser. No. 62/468,624 filed 8 Mar. 2017, and U.S. Provisional Application Ser. No. 62/486,348 filed 17 Apr. 2017, which are each incorporated in its entirety herein by this reference. 
     This application is related to U.S. application Ser. No. 15/250,070 filed 29 Aug. 2016, U.S. application Ser. No. 15/355,499 filed 18 Nov. 2016, and U.S. application Ser. No. 15/335,240 filed 26 Oct. 2016, which are each incorporated in its entirety herein by this reference. 
    
    
     TECHNICAL FIELD 
     This invention relates generally to the bioelectrical device field, and more specifically to a new and useful electrical interface system in the bioelectrical device field. 
     BACKGROUND 
     Transducer interface systems are used to sense inputs from a contextual environment and/or provide outputs to a contextual environment (e.g., a user, an environment surrounding a user). In a specific application, such an interface system can include an electrode that provides stimulation to a body region of the user, and/or an electrode that senses signals from the body region of the user (e.g., electrical potentials from the brain or scalp). In consideration of modularity, it is sometimes desirable to design such transducer interface systems in a manner that facilitates easy interchange of transducer units (e.g., to provide different functions), facilitates easy attachment and/or removal of transducer units (e.g., for storage), or facilitates easy replacement of worn or damage transducer units (e.g., to allow replacement of contaminated electrodes). 
     Coupling regions between transducers and their support devices are often prone to corrosion and other forms of degradation, especially if such transducers are used in environments that enhance corrosion (e.g., saline/electrolyte environments, environments that promote crevice corrosion, environments that promote galvanic corrosion, etc.). Current systems, however, fail to adequately prevent corrosion of contact regions between transducers and their support devices, fail to achieve corrosion prevention (or other forms of damage prevention) in a low-cost manner, fail to achieve damage prevention in a space-efficient manner, and/or fail to achieve damage prevention in a manner that accounts for user considerations. Furthermore, in the context of electrodes, current systems fail to prevent undesired bridging between multiple contacts of the same or different electrodes, which can substantially damage the electrical contacts involved and/or divert stimulation current through an undesired path. Even further, in applications that involve persistent voltage differentials between electrode contacts, and/or stimulation using waveforms other than charge-balanced biphasic pulses (e.g., transcranial direct current stimulation), traditional techniques for protecting electrode contacts, such as some plating techniques, are often insufficient in preventing corrosion. 
     Thus, there is a need in the bioelectrical device field for a new and useful electrical interface system. This invention provides such a new and useful system. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIGS. 1A and 1B  depict schematics of embodiments of an electrical interface system; 
         FIGS. 2A and 2B  depict schematics of an example of an embodiment of an electrical interface system; 
         FIG. 3  depicts a schematic of an example of an embodiment of an electrical interface system; 
         FIGS. 4A and 4B  depict schematics of a variation of an embodiment of an electrical interface system; 
         FIG. 5  depicts a schematic of an example of an embodiment of an electrical interface system; 
         FIG. 6  depicts an operation mode of a variation of an embodiment of an electrical interface system; 
         FIGS. 7A-7B  depict embodiments and examples of support devices associated with an electrical interface system; 
         FIGS. 7C-7D  depict examples of relationships between an electrical interface system and a support device; 
         FIG. 7E  depicts an example of a relationship between an electrical interface system and an electrode for stimulation of a user; and 
         FIG. 8  depicts an operation mode of a variation of an electrical interface system, in relation to an electrode and a user. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description of preferred embodiments of the invention is not intended to limit the invention to these preferred embodiments, but rather to enable any person skilled in the art to make and use this invention. 
     1. System 
     As shown in  FIG. 1A , an embodiment of a system  100  for providing an electrical interface between a transducer  2  and a transducer support device  5  includes a body  110  mounted to the transducer support device  5 , the body  110  comprising, contiguous with, or otherwise coupled to (e.g., in communication with): an interface-to-transducer electrical coupling region  120 ; an interface-to-electrical-subsystem coupling region  130  in electrical communication with (e.g., joined to by a continuous path of electrically conductive material) the interface-to-transducer electrical coupling region  120 ; and a fluid sealing region  140  coupled to the transducer support device  5  and surrounding the interface-to-electrical-subsystem coupling region  130  and support device contact  53 . In this embodiment, the system  100  can include an operation mode (not shown) defining a sealed electrical pathway between the transducer  2  and the transducer support device  5 , wherein: the fluid sealing region  140  is coupled to a complementary transducer sealing region  22 , and the interface-to-transducer electrical coupling region  120  is biased against an electrical contact  23  of the transducer  2  with the fluid sealing region  140  preventing fluid from reaching the electrical contact  23  of the transducer  2 . 
     In another embodiment, as shown in  FIG. 1B , a system for providing an electrical interface between a transducer  2  and a transducer support device  5  can include a body  110 ′ mounted to the support device  5 , the body  110 ′ comprising, contiguous with, or otherwise coupled to (e.g., in communication with): an interface-to-transducer coupling region  120 ′; an interface-to-electronics-subsystem coupling region  130 ′ in electrical communication with (e.g., joined to by a continuous path of electrically conductive material) the interface-to-transducer electrical coupling region  120 ′; a first sealing region  142 ′ coupled to a complementary transducer sealing region  22 ′ and surrounding the interface-to-transducer coupling region  120 ′ and transducer contact  23 ; and a second sealing region  152 ′ coupled to the support device  5  and surrounding the interface-to-electronics-subsystem coupling region  130 ′ and support device contact  53 . The system can further comprise an operation mode defining a fully sealed electrical pathway between the transducer and the support device, wherein the first fluid sealing region  142 ′ and second fluid sealing region  152 ′ are contiguous or coupled to prevent fluid ingress or contact with electrically conductive portions of the system, and the first fluid sealing region  142 ′ and the second fluid sealing region  152 ′ are electrical insulators. 
     The system  100  functions to provide a robust and reliable interface between a transducer and a transducer support device, in a manner that facilitates easy interchange of transducer units (e.g., to provide different functions), facilitates easy attachment and/or removal of transducer units (e.g., for storage), or facilitates easy replacement of worn or damage transducer units (e.g., to allow replacement of contaminated electrodes). Furthermore, the system  100  functions to provide a corrosion-proof (or substantially corrosion-resistant) interface between transducers and their support devices, especially in use cases that would otherwise promote active and/or passive corrosion of electrical interfaces (e.g., saline/electrolyte environments, environments that promote crevice corrosion, environments that promote galvanic corrosion, etc.). The system  100  can thus mitigate corrosion and also seal associated metallic conductors from ingress of fluids that would otherwise enhance corrosion. In particular, the system  100  can provide a mechanism that prevents undesired bridging between multiple contacts of a single electrode or multiple electrodes of a stimulation system, thereby preventing damage to the electrical contacts involved. Embodiments of the system  100  can even operate robustly in applications that involve persistent voltage differentials between electrode contacts, and/or stimulation using waveforms other than charge-balanced biphasic pulses (e.g., transcranial direct current stimulation) in comparison to some techniques such as plating, which are often insufficient in preventing or reducing corrosion. In particular, the system  100  can also provide a mechanism that allows and/or tolerates bridging between multiple contacts of a single electrode or multiple electrodes of a stimulation system in the case of presence or ingress of electrolyte fluid into the system, but minimizes or in some cases prevents corrosion and/or damage due to corrosion (e.g. by ensuring that the only electrically active surfaces that are exposed to electrolyte are formed of a material that minimizes corrosion or damage due to corrosion, such as carbon-bearing silicone rubber. In some embodiments of the system  100 , the undesirability, economic, and/or cosmetic impact of corrosion damage is minimized because the portions of the system  100  that are built into the support device  5  and/or are difficult or expensive to replace, such as an electrical contact of the electronic subsystem, are protected from exposure to corrosion promoting agents (e.g., electrolyte) while portions of the system that are easy to replace (such as electrical contact  23  mounted on replaceable transducer  2 ) are less protected from exposure to corrosion promoting agents (e.g., electrolyte). 
     Variations of the system  100  are configured for stimulation devices situated outside the body of a user, such as stimulation devices delivering transcranial electrical stimulation, wherein the stimulation devices are designed for wearability (e.g., in a manner that reduces bulkiness). As such, in contrast to other implanted devices (e.g., pacemakers, etc.), the system  100  can be designed in a manner that is streamlined for wearability and does not require a level of robustness (e.g., corrosion resistance over a lifetime of implanted use) associated with implanted medical devices. 
     In some applications, the system  100  can provide an electrical interface between transducers/electrodes and an electronic device that supports and positions the transducers/electrodes at a body region of a user. In a specific application, the system  100  can provide an electrical interface between electrodes for electrical stimulation (e.g., such as the electrodes described in U.S. application Ser. No. 14/470,683 titled “Electrode System for Electrical Stimulation” and filed on 27 Aug. 2014, U.S. application Ser. No. 14/878,647 titled “Electrode System for Electrical Stimulation” and filed on 8 Oct. 2015, and U.S. application Ser. No. 15/426,212 titled “Method and System for Improving Provision of Electrical Stimulation” and filed on 7 Feb. 2017, which are each incorporated in their entireties by this reference) and an electrode support device (e.g., such as the support devices described in U.S. application Ser. No. 15/335,240 titled “Electrode Positioning System and Method” and filed on 26 Oct. 206, which is herein incorporated in its entirety by this reference). Additionally or alternatively, the system  100  can support or otherwise facilitate methods described in one or more of U.S. application Ser. No. 14/470,747 titled “Method and System for Providing Electrical Stimulation to a User” and filed on 27 Aug. 2014 and U.S. application Ser. No. 15/059,095 titled “Method and System for Providing Electrical Stimulation to a User” and filed on 2 Mar. 2016, which are each incorporated in their entireties herein by this reference. 
     The system  100  can additionally or alternatively support or interface any other transducers (e.g., optical sensors, optical emitters, ultrasonic transducers, etc.), additional sensors (e.g., temperature sensors, activity detecting sensors, sensors associated with position, velocity, or acceleration detection, biometric sensors, etc.) for sensing signals from the user, additional sensors (e.g., temperature sensors, barometric pressure sensors, light sensors, microphones, etc.) for sensing signals from the environment of the user, and any other suitable device in a robust manner. Similarly, the system  100  can additionally or alternatively be used to provide a corrosion-resistant and/or leakage-current-resistant electrical interface with any other suitable support device (e.g., non-wearable device, wrist-borne wearable device, limb-coupled wearable device, wearable device not coupled to a head region of a user, non-wearable device where robustness and compact form factor are desirable, etc.) 
     In embodiments of the system  100 , regions of the body  110  such as the interface-to-transducer coupling region  120 , the interface-to-electronics-subsystem coupling region  130 , and the sealing region  140  can be multiple surfaces or couple at multiple points with other surfaces; for instance, the sealing region  140  can comprise a surface that couples with the support device  5  forming a first part of a gasket-like seal, and a second surface that couples with the support device at a different position or different set of points to form a second part of a gasket-like seal, wherein the first part and second part of the gasket-like seal operate together or redundantly to prevent or minimize electrolyte ingress. In another example, the interface-to-transducer coupling region  120  can comprise a surface that couples with the transducer contact  23  at a first contact area, and a second surface that couples with the transducer contact at a second contact area, wherein the first and second contact areas provide increased electrical contact or redundant electrical contact. 
     1.1 System—Body 
     As described above, the body  110  can be coupled to the transducer support device  5 , and functions to provide, along with other elements of the system, electrical conductivity and sealing functions in a manner that mitigates corrosion of metallic contacts (e.g., of transducer elements, of electrode elements, of a support device, etc.). Various surfaces and/or regions of the body no can mate with surfaces of the transducer support device  5  and any transducers  2 . The body no can thus function as a substrate to which other functional elements of the system  100  are coupled, as described in further detail below. 
     The body  110  is preferably composed of a material that is relatively stable in an environment with electrolytic reactions. In one variation, the body no includes carbon (e.g., graphite), which is electrically conductive and exhibits stability in the presence of electrolytic reactions (e.g., exhibits only gradual loss of structure in the form of elemental carbon when used as the anode of an electrolytic cell), and is resistant to passive corrosion. The body  110 , can however, additionally or alternatively include any other suitable molecular form of carbon, any other suitable non-metallic conductive materials (e.g., silicon, germanium) in any form, and/or any other suitable metallic conductive material. 
     The body  110  can additionally or alternatively include a matrix of material supporting conductive components. In one variation, the matrix can be composed of a polymer material, in order to provide sealing properties (e.g., in relation to prevention of fluid penetration past regions of the system) and properties associated with corrosion resistance. In embodiments in which the conductive component is carbon (e.g. carbon black), the matrix may act to hold carbon particles in place and prevent or retard the loss of structure which might otherwise occur (e.g., when carbon is used as the anode of an electrolytic cell). In specific examples, the matrix can be composed of silicone rubber. However, in other variations, the matrix can additionally or alternatively be composed of any other suitable polymeric or non-polymeric material. 
     In variations of the body  110  including a conductive component and a support matrix, the conductive component can be distributed throughout the support matrix (e.g., with a uniform distribution, with a non-uniform distribution), in order to provide electrical conductivity through the body  110 . Alternatively, the conductive component can be patterned onto and/or within the support matrix, thereby defining electrically conductive pathways throughout the body no. However, the body no can additionally or alternatively be configured in any other suitable manner in relation to conductive components and support matrix components. 
     In relation to mechanical properties, the body no is preferably flexible, but can alternatively include rigid regions (e.g., in order to provide regions of intentional rigidity and/or deformation). In flexible variations, the body no can be elastically deformable during normal use, or can alternatively be plastically deformable during normal use. The body no can, however, have any other suitable mechanical properties (e.g., in relation to elasticity, in relation to hardness, in relation to stiffness, in relation to compressibility, in relation to density, in relation to porosity, in relation to strength, in relation to any other suitable mechanical properties). The body  110  is preferably impermeable to water and/or other polar fluids, and can exhibit a low level of wettability (e.g., in terms of contact angle). As such, the body  110  can be composed of a hydrophobic material. The body  110  can additionally or alternatively have any other suitable characteristics (e.g., in terms of hydrophilicity, in terms of hydrophobicity), any other suitable thermal properties, any other suitable electrical properties, any other suitable optical properties, and/or any other suitable material properties. 
     In a specific example, the body no can be composed of an elastomeric material (e.g., molded silicone rubber elastomer) containing or otherwise doped with a conductive component (e.g., carbon black particles). As such, the specific example of the body  110  can function to provide stability in relation to electrochemical reaction products that would otherwise result with use of other materials (e.g., metal) in electrolytic environments associated with electrical stimulation. Furthermore, such a composition can be readily configured to conform with metallic contacts to complete electrical pathways, while sealing off access to the metallic contacts, as described in more detail below. Thus, elastic properties of this material composition can facilitate a press-fit, snap-fit, or other interface against metal (or other conductive components) to ensure reliable contact. Furthermore, such a composition can ensure good conductivity, and in cases where conductivity is less than that of a traditional metallic contact (e.g., the conductivity achieved in embodiments of the present invention when using a conductive rubber material with volume resistivity of ˜1 to 100 Ohm-cm), such a composition can still provide a desired amount of current flow and the resulting resistance to current flow can be materially less than the resistance presented by the transducer  23  and/or its connection to a target region such as the human scalp. As well, use of an imperfectly conducting substance such as carbon rubber can ensure a desirable distribution of current across multiple transducers. In more detail, in a system with multiple transducers, if the path to each transducer or electrode involved has some resistance (e.g., a low but non-trivial amount of resistance in comparison to the tissue resistance), it is more likely that all such endpoints will receive approximately similar amounts of current even in the presence of differences between the electrode-to-tissue resistance across each electrode or transducer. In the specific example, the carbon-bearing silicone rubber has a volume resistivity of 10-Ohm-cm and a Shore A hardness of 70. However, variations of the specific example can comprise a material having any other suitable volume resistivity (e.g., from 1-1000 Ohm-cm, any other suitable resistivity) and/or hardness (e.g., Shore A hardness from 20-90, any other suitable hardness). 
     In a version of this specific example, the body  110  and/or its regions that require electrical conductivity (e.g., interface-to-transducer coupling region  120  and/or interface-to-electronics-subsystem coupling region  130 ) can be created or extended by use of conductive adhesives or gasketing compounds such as carbon-conductive room-temperature vulcanizing silicone rubber (also known as carbon-conductive RTV) or similar materials. For instance, increased conductivity and adhesion between interface-to-electronics-subsystem coupling region  130  and the support device contact  53  can be created during manufacturing of support device  5  by depositing conductive RTV between the interface-to-electronics-subsystem coupling region  130  and the support device contact  53  and allowing it to cure such that the RTV adhesive becomes part of region  130 . Also for instance, increased sealing ability between sealing region  140  and the support device  5  may be created during manufacturing of support device  5  by depositing non-conductive RTV between sealing region  140  and support device  5  and allowing it to cure such that the RTV adhesive becomes part of sealing region  140 . 
     Furthermore, any other suitable material (e.g., metallic conductor, rubber doped with metal, etc.) can be used in the body no. For instance, in some variations involving lower current levels, the body  110  can be composed of another conductive polymer composition (e.g., polypyrrole, non-conductive polymer with a distribution of conductive components, etc.). 
     The body no preferably has a morphology that is complementary to corresponding regions of the transducer support device  5  and/or any transducers  2  or electrodes involved. As such, various surfaces of the body no can mate with surfaces of the transducer support device  5  and any transducers  2 . In an example shown in  FIGS. 2A and 2B , the body no can provide a substantially planar rear surface mounted to a portion of the support device  5 , and have a suitable thickness that supports other portions of the system  100 , as described in further detail below. Protrusions, recesses, ridges, troughs, regions of concavity, regions of convexity, and any other suitable morphological features associated with functions of the system  100  are described in further detail below. 
     Furthermore, the body no and other elements of the system  100  associated with the body  110  can be fabricated using a molding process (e.g., single shot molding, multi-shot molding, etc.), using a casting process, using an etching process, using a lithographic process, using a machining process, using a printing process, using a thermal process, or using any other suitable process. 
     1.2 Interface-to-Transducer Coupling Region 
     As described above, the body  110  includes an interface-to-transducer electrical coupling region  120 , which functions to make elastic contact with a metallic contact on a transducer  2  (e.g., electrode) that is reversibly coupleable to (e.g., may be attached to and removed from) the support device  5 . The interface-to-transducer electrical coupling region  120  can operate in an undeformed configuration prior to coupling with a corresponding conductive region (e.g., metallic contact) of a transducer  2  or electrode, and can operate in a deformed configuration upon coupling with a corresponding conductive region (e.g., metallic contact) of a transducer  2  or electrode, thereby ensuring and maintaining contact with the transducer  2  or electrode during use. As such, coupling between the interface-to-transducer electrical coupling region  120  and a corresponding conductive region (e.g., metallic contact) of a transducer  2  or electrode preferably produces a biasing force between the elastically deformable coupling region and at least some portion of the corresponding conductive region  23  of a transducer  2  or electrode. In more detail, implementing materials that elastically deform, in at least one of the interface-to-transducer electrical coupling region  120  and a corresponding conductive region of the transducer  2 , can provide proper and reliable electrical contact between two similar or dissimilar contacts (e.g., a carbon-rubber contact and a metallic contact), by providing greater contact area between the two contacts. In some embodiments, the conductive contact  23  of a transducer  2  or electrode may be metallic or substantially metallic; in other embodiments, the conductive contact  23  may comprise non-metallic materials, such as carbon-bearing silicone rubber. 
     The interface-to-transducer electrical coupling region  120  preferably has the same material composition as the body  110 , as described above; however, the interface-to-transducer electrical coupling region  120  can alternatively have any other suitable material composition in relation to material properties associated with electrical conductivity and elastic deformation behavior. The interface-to-transducer electrical coupling region  120  is preferably of unitary construction with the material of the body  110  (e.g., in relation to a single molding process); however, the interface-to-transducer electrical coupling region  120  can alternatively be physically coextensive with the body  110 . Still alternatively, the interface-to-transducer electrical coupling region  120  can be formed separately from the body  110 , but otherwise coupled to the base in any other suitable manner (e.g., with a thermal bonding process, with an electrically conductive adhesive layer, etc.). 
     The interface-to-transducer electrical coupling region  120  preferably comprises a protrusion of material coupled to the body  110 , wherein, in operation modes of the system  100 , the protrusion interfaces with a contact on a transducer  2  (e.g., electrode) that is reversibly coupleable to the support device  5 . In one variation, the protrusion includes a ridge of material extending from the body  110  in a manner that allows the interface-to-transducer electrical coupling region  120  to couple to a corresponding contact  23 . In a specific example of this variation, as shown in  FIG. 3 , the ridge of material protrudes away from the rear surface of the body  110 ′ along the height of the body  110 , wherein the rear surface of the body  110  has an elongated recess (e.g., trough) immediately opposite the ridge of material in order to further allow the ridge to deform elastically upon making contact with a contact  23  of a corresponding transducer  2  or electrode as the contact  23  moves substantially in the direction shown by the arrow in  FIG. 3 . 
     In other variations, the interface-to-transducer electrical coupling region  120  can comprise any other suitable form of protrusion (e.g., protruding region, convex surface, etc.), an array of protrusions (e.g., array of protruding regions, array of convex surfaces, etc.), any suitable form of recess (e.g., recessed region, concave surface, etc.) and/or an array of recesses. Protrusions/recesses can have polygonal cross sections, circular cross sections, semi-circular cross sections, ellipsoidal cross sections, hemi-ellipsoidal cross sections, amorphous cross sections, and/or any other suitable cross section defined along any axis of the protrusion/recess. Similarly, in relation to arrays, arrays of protrusions/recesses can be rectangular, circular, ellipsoidal, or any other suitable type of array. 
     In an alternative example of the interface-to-transducer electrical coupling region  120 ′, as shown in  FIGS. 4A and 4B , the interface-to-transducer electrical coupling region  120 ′, with the interface-to-electrical-subsystem coupling region  130 ′, comprises a concave surface (e.g., circular recess) physically coextensive with a base region mounted to a support device  5 , wherein the concave surface is compliant and mates with a protruding region of a transducer  2  or electrode. However, variations of the alternative example can be configured in any other suitable manner, for instance where the interface-to-transducer electrical coupling region  120 ′ presents a convex surface to the transducer contact  23 ′ wherein the convex surface is compliant. 
     Furthermore, while the interface-to-transducer electrical coupling region  120  is described above as being positioned approximately centrally and spanning a width of the body  110 , the interface-to-transducer electrical coupling region  120  can alternatively have any other suitable position in relation to alignment with conductive contacts on a corresponding transducer  2  or electrode that is supported by the support device  5 . As such, the interface-to-transducer electrical coupling region  120  can be located centrally with another orientation (e.g., spanning a height dimension of the body  110 ), peripherally located (e.g., along any edge of the body  110 ), or positioned in any other suitable manner relative to the body  110 . 
     1.3 Interface-to-Electrical-Subsystem Coupling Region 
     As shown in  FIGS. 1A and 1B , the system  100  comprises an interface-to-electrical-subsystem coupling region  130  coupled to the body  110  and contiguous, physically coextensive, or in electrical communication with (e.g., joined to by a continuous path of electrically conductive material) the interface-to-transducer electrical coupling region  120 , wherein the interface-to-electrical-subsystem coupling region  130  functions to make electrical contact with a pad (e.g., a metallic pad) of an electronics subsystem associated with at least one of the transducer  2  and the support device  5  (described in further detail below). The interface-to-electrical-subsystem coupling region  130  also cooperates with the body  110  to define a fluid sealing region  140  surrounding the interface-to-electrical-subsystem coupling region  130 , which seals portions of the interface-to-electrical-subsystem coupling region  130  and support device contact  53  against ingress and prevents fluid (e.g., electrolyte fluid) from reaching corrosion-prone components of the electrical interface between the transducer  2  or electrode and the support device  5 . 
     The interface-to-electrical-subsystem coupling region  130  preferably has the same material composition as the body  110 , as described above; however, the interface-to-electrical-subsystem coupling region  130  can alternatively have any other suitable material composition in relation to material properties associated with electrical conductivity and elastic deformation behavior. The interface-to-electrical-subsystem coupling region  130  is preferably of unitary construction with the material of the body  110  (e.g., in relation to a single molding process); however, the interface-to-electrical-subsystem coupling region  130  can alternatively be physically coextensive with the body  110 . Still alternatively, the interface-to-electrical-subsystem coupling region  130  can be formed separately from the body  110 , but otherwise coupled to the base in any other suitable manner (e.g., with a thermal bonding process, with an electrically conductive adhesive layer, etc.). 
     In some variations, the interface-to-electrical-subsystem coupling region  130  can extend from the body  110 . Furthermore, as shown in  FIGS. 2A and 4A , the interface-to-electrical-subsystem coupling region  130 ,  130 ′ can also be coupled to the interface-to-transducer electrical coupling region  120 ,  120 ′ in a manner that is of unitary construction with the interface-to-transducer electrical coupling region  120 ,  120 ′, physically coextensive with the interface-to-transducer electrical coupling region  120 , or otherwise coupled to the interface-to-transducer electrical coupling region  120  in any other suitable manner that facilitates electrical communication (e.g., a manner in which the regions are joined by a continuous path of electrically conductive material). In some variations, as shown in  FIG. 2A , the interface-to-electrical-subsystem coupling region  130  can extend orthogonally from a surface of the body  110 , in relation to providing electrical contact and sealing functions at corresponding positions of the transducer  2 , electrode, or support device  5 . 
     In one variation, as shown in  FIGS. 2A, 2B, 3 and 5 , the interface-to-electrical-subsystem coupling region  130  extending from the body  110  includes: a first broad surface  40  bounded by a first fluid sealing region  142 , and a second broad surface  150  opposing the first broad surface  40  and bounded by a second fluid sealing region  152 . 
     The first broad surface  40  is configured to span a portion of the transducer  2  supporting a conductive contact that interfaces with the interface-to-transducer electrical coupling region  120  described above, wherein the first fluid sealing region  142  further seals the interface with the conductive contact and prevents ingress of fluid (e.g., electrolyte fluid) into regions surrounding the conductive contact. The first fluid sealing region  142  preferably includes a ridge of compliant material (e.g., the same material composition as the body  110 , a different material composition from the body  110 , etc.) peripherally surrounding edges of the first broad surface  40 , in order to define an internal volume within which the conductive contact of the transducer  2  can be positioned to contact the interface-to-transducer electrical coupling region  120 . In a specific example, as shown in  FIG. 5 , the first broad surface  40  is approximately rectangular (aside from a side of the first broad surface  40  abutting the elastically deformable coupling region), and the fluid sealing region  142  includes three peripherally situated ridges of material protruding from the three edges of the first broad surface  40  that do not abut the interface-to-transducer electrical coupling region  120 . 
     Variations of any surfaces (e.g., broad surface  40 ) and fluid sealing regions can, however, be configured in any other suitable manner. For instance, the first broad surface may not be a broad surface, but a surface that otherwise complements the conductive contact or a support of the conductive contact of the transducer in any other suitable manner. Similarly, the fluid sealing region  142 ′ can comprise any other suitable morphology of protruding material coupled to a surface of the interface-to-electrical-subsystem coupling region  130  in any other suitable manner. Alternatively, the first fluid sealing region  142 ′ can comprise one or more of: a recessed region (e.g., a channel), an o-ring, a fluid sealant (e.g., silicone putty, hydrophobic material, etc.), and any other suitable combination of elements that provides a seal against undesired fluid (e.g., electrolyte) ingress into regions of the system  100 . 
     Similar to the first broad surface  40 ′, the second broad surface  150 ′ of the variation described above is configured to span a portion of the support device associated with a conductive contact of an electronics subsystem (e.g., printed circuit board), wherein the second fluid sealing region  152 ′ further seals the interface with the conductive contact of the electronics subsystem and prevents ingress of fluid (e.g., electrolyte fluid) into regions surrounding the conductive contact. The second fluid sealing region  152 ′ preferably also includes a ridge of compliant material (e.g., the same material composition as the body  110 , a different material composition from the body  110 , etc.) peripherally surrounding edges of the second broad surface  150 ′, in order to define an internal volume within which the conductive contact of the electronics subsystem can be positioned to form an electrical pathway with the body  110 . In a specific example, as shown in  FIG. 5 , the second broad surface  150 ′ is approximately rectangular (aside from a side of the second broad surface  150 ′ abutting the body no), and the fluid sealing region  152 ′ includes three peripherally situated ridges of material protruding from the three edges of the second broad surface  150 ′ that do not abut the body  110 . 
     Variations of the second broad surface  150 ′ and the second fluid sealing region  152 ′ can, however, be configured in any other suitable manner. For instance, the second broad surface may not be a broad surface, but a surface that otherwise complements the conductive contact or a support of the conductive contact of the electronics subsystem in any other suitable manner. Similarly, the second fluid sealing region  152 ′ can comprise any other suitable morphology of protruding material coupled to a surface of the interface-to-electrical-subsystem coupling region  130  in any other suitable manner. Alternatively, the second fluid sealing region  152 ′ can comprise one or more of: a recessed region (e.g., a channel), an o-ring, a fluid sealant (e.g., silicone putty, hydrophobic material, etc.), and any other suitable combination of elements that provides a seal against undesired fluid (e.g., electrolyte) ingress into regions of the system  100 . 
     In the variations described above, the system preferably comprises an operation mode defining a sealed electrical pathway between the transducer  2  and the support device  5 , wherein: the interface-to-transducer coupling region  120  is biased against an electrical contact of the transducer  2  and the first fluid sealing region  142  prevents fluid from reaching the space partially defined by the first broad surface  40  and containing the electrical contact of the transducer  2 . Furthermore, in this operation mode, the interface-to-electronics-subsystem coupling region  130  is electrically coupled to an electrical contact  53  of the support device  5  and the second fluid sealing region  152 ′ prevents fluid from reaching the space partially defined by the second broad surface  150 , with the interface-to-electronics-subsystem coupling region  130  contacting the electrical contact of the support device  5 . 
     In a variation of the operation mode, as shown in  FIG. 6 , the system  100  can define a sealed electrical pathway between the transducer  2  and the transducer support device  5 , wherein: the fluid sealing region  140  defined by mating features of an interface-to-transducer electrical coupling region  120 ′ is coupled to a complementary transducer sealing region  22 , and the interface-to-transducer electrical coupling region  120 ′ is biased against an electrical contact  23  of the transducer  2  with the fluid sealing region  140 ′ preventing fluid from reaching the electrical contact  23  of the transducer  2 . 
     In examples of this variation, sealing features of the transducer  2  can comprise a soft protrusion, and corresponding sealing features on the support device  5  can be hard or rigid, such that the components more likely to suffer damage are associated with a replaceable part (i.e., a replaceable transducer  2 ). Furthermore, any seal that is provided between the transducer  2  and the support device  5  does not have to be perfect or unusually robust (e.g., not in the manner of an implantable pulse generator header or large marine connector) in order to usefully minimize corrosion or effects of current leakage between transducer contacts. In examples of this variation, the transducer sealing region  22  may be formed of an electrically insulating material and configured to wrap partially or completely around exposed areas of the conductive region of the transducer  2 , leaving only the porous region of the transducer  2  exposed, which may be desirable for controlling current flow to a body region e.g. the scalp and preventing current flow directly from the conductive region to a body region. 
     Variations of the operation modes can, however, be defined with system elements in any other suitable manner to form the electrical pathway from the support device  5  to the transducer  2  or electrode. 
     1.4 System—Example Electrodes and Support Devices Associated with the System 
     In examples, the system  100  can provide an electrical interface between electrodes for electrical stimulation (e.g., such as the electrodes described in U.S. application Ser. No. 14/470,683 titled “Electrode System for Electrical Stimulation” and filed on 27 Aug. 2014, U.S. application Ser. No. 14/878,647 titled “Electrode System for Electrical Stimulation” and filed on 8 Oct. 2015, and U.S. application Ser. No. 15/426,212 titled “Method and System for Improving Provision of Electrical Stimulation” and filed on 7 Feb. 2017, which are each incorporated in their entireties by this reference) and an electrode support device (e.g., such as the support devices described in U.S. application Ser. No. 15/335,240 titled “Electrode Positioning System and Method” and filed on 26 Oct. 206, which is herein incorporated in its entirety by this reference). Additionally or alternatively, the system  100  can support or otherwise facilitate methods described in one or more of U.S. application Ser. No. 14/470,747 titled “Method and System for Providing Electrical Stimulation to a User” and filed on 27 Aug. 2014 and U.S. application Ser. No. 15/059,095 titled “Method and System for Providing Electrical Stimulation to a User” and filed on 2 Mar. 2016. 
     In one such example, as shown in  FIGS. 7A and 7B , wherein the support device  5  comprises a set of pads  210   a  configured at opposing head regions of the user during use of the system; a band  220   a  having a first end coupled to a first pad of the set of pads and a second end coupled to a second pad of the set of pads; a bridge  230   a  coupled to the band and to at least one electrode  240   a  during use of the system; and a set of links  250   a  associated with the set of pads  210   a , each of the set of links coupled at a first region to an interior portion of its corresponding pad, and coupled at a second region to the bridge  230   a , units of the system  100  can be coupled to elements of the bridge  230   a  supporting the at least one electrode  240   a , as shown in  FIGS. 7C, 7D , and  7 E. In more detail, the body  110  of the system  100  can be coupled to an internal wall of a recess of the bridge  230   a  configured to retain the electrode  240   a , wherein the system  100  is oriented in a manner that allows the interface-to-transducer electrical coupling region  120  to make elastic contact with a metallic contact on the electrode  240   a , the first broad surface  40  of the interface-to-electrical-subsystem coupling region  130  interfaces with material of the electrode (e.g., a tab) supporting the metallic contact of the electrode  240   a  with the first fluid sealing region  142  preventing ingress of electrolyte fluid, and the second broad surface  150  of the interface-to-electrical-subsystem coupling region  130  makes electrical contact with a contact point (e.g., metallic pad, exposed wire, or exposed electrically conductive surface) of a printed circuit board of the bridge  230   a  of the support device  5  with the second fluid sealing region  152  preventing fluid ingress toward the metallic pad. In a specific implementation of this example, each recess of the bridge  230   a  can include three units of the system, which correspond to three metallic contacts of a corresponding electrode  240   a  for stimulation of a head region of the user. However, variations of these examples can alternatively include any suitable number of units of the system  100  mounted to any suitable region(s) of a support device, in order to establish an electrical interface that supports removable/replaceable transducers  2  or electrodes in a manner that is robust against corrosion. 
     In another variation, an example of which is shown in  FIG. 8 , units of the system can be mounted to a support device  5 , wherein the body  110  of the system  100  is mounted to a recessed surface of the support device  5  configured to retain an electrode  340 , and wherein the system  100  includes an interface-to-electrical-subsystem coupling region  130  extending orthogonally from the body  110 , wherein the interface-to-electrical subsystem  130  is in communication with the support device electrical contact  53  and contiguous with the body  110  and an interface-to-transducer electrical coupling region  120 . In this example, the interface-to-transducer coupling region  120  comprises a concave surface surrounded by a fluid sealing region  140 , wherein the fluid sealing region  140  of the system  100  comprises an annular recess defined within a bulk of elastically deformable and non-electrically conductive material circumscribing the interface-to-transducer coupling region  120 . In relation to the electrode  340 , a corresponding electrically conductive protrusion  23  of the electrode  340  can be configured to reversibly mate with the interface-to-transducer coupling region  120  of the system  100 , wherein the protrusion  23  is circumscribed by an annular protrusion  22  of non-electrically conductive material (e.g., an annular non-conductive protrusion) that interfaces with the annular recess  140  of the system  100  (e.g., in a snap fit, in a press fit) to seal the electrical interface established by the electrically conductive protrusion  23  of the electrode  340  and the interface-to-electrical-subsystem coupling region  130  of the system  100  from fluid ingress. In this example, the electrically conductive protrusion  23  of the electrode  340  can be composed of the same material as the interface-to-electrical-subsystem coupling region  130  of the system  100 , as described above; however, the electrode  340  can alternatively be composed of any other suitable materials and/or be configured in any other suitable manner. For instance, the annular protrusion  22  can be associated with the fluid sealing region of the system  100 , and the annular recess  140  can be associated with the transducer  2 . 
     Similar to the previously described examples, variations of this example can include any suitable number of units of the system  100  coupled to a support device  5  in any other suitable manner, in order to establish an electrical interface with any other suitable number of electrodes or transducers  2 . Additionally, variations of this example can include embodiments where the sealing region  140  is configured to act as a mechanical attachment point (e.g., a sole mechanical attachment point or a supplementary mechanical attachment point) between electrode  340  and the support device  5 . For instance, in one variation, the sealing region  140  can comprise an annular recess and the sealing feature  23  can comprise an annular protrusion which when mated together offer resistance to removal, torsion, etc. Additionally or alternatively, variations of this example may include one or more of the following embodiments: where the sealing region  140  comprises a feature such as a thumbnail recess or pull tab to aid separation of the electrode  340  and support device  5 ; where the sealing region  140  and/or other components of the system  100  are configured to provide flexion or limited flexion (e.g., between 1 and 20 degrees) of the joint between electrode  340  and support device  5  to aid in conforming the electrode  340  to a body part; and/or where the sealing region  140  and/or other components of the system  100  are configured to only allow connection of the electrode  340  at a particular angle of rotation with respect to support device  5  (e.g. a sealing region  140  having a keyed shape or a polygonal shape without rotational symmetry). 
     1.5 System—Conclusion 
     Examples of the system  100  can, however, comprise any other suitable element(s) or combination of elements that establish an electrical interface that supports removable/replaceable transducers  2  or electrodes in a manner that is robust against corrosion. For instance, some examples of the system  100  can implement one or more of: an o-ring, a fluid sealant (e.g., silicone putty, hydrophobic material, etc.), or any other material or morphology that prevents fluid ingress into regions of the system  100  in an undesired manner. 
     The system  100  and any methods associated with the preferred embodiment and variations thereof can be embodied and/or implemented at least in part as a machine configured to receive a computer-readable medium storing computer-readable instructions. The instructions are preferably executed by computer-executable components preferably integrated with the system  100  and one or more portions of the processor and/or a controller. The computer-readable medium can be stored on any suitable computer-readable media such as RAMs, ROMs, flash memory, EEPROMs, optical devices (CD or DVD), hard drives, floppy drives, or any suitable device. The computer-executable component is preferably a general or application specific processor, but any suitable dedicated hardware or hardware/firmware combination device can alternatively or additionally execute the instructions. 
     Methods associated with the system(s) described herein can support stimulation including one or more of: transcranial electrical stimulation (TES) configured to stimulate a brain region of the user in the form of at least one of: transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS), transcranial magnetic stimulation (TMS), transcranial random noise stimulation (tRNS), transcranial pulsatile stimulation (tPS), and/or transcranial variable frequency stimulation (tVFS, as described in one or more of: U.S. application Ser. No. 14/470,747 titled “Method and System for Providing Electrical Stimulation to a User” and filed on 27 Aug. 2014; U.S. application Ser. No. 15/426,212 titled “Method and System for Improving Provision of Electrical Stimulation” and filed on 7 Feb. 2017; and U.S. application Ser. No. 15/059,095 titled “Method and System for Providing Electrical Stimulation to a User” and filed on 2 Mar. 2016, each of which is incorporated herein in its entirety by this reference. 
     The FIGURES illustrate the architecture, functionality and operation of possible implementations of systems, methods and computer program products according to preferred embodiments, example configurations, and variations thereof. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block can occur out of the order noted in the FIGURES. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions. 
     As a person skilled in the field of biosignals or neurostimulation will recognize from the previous detailed description and from the figures and claims, modifications and changes can be made to the preferred embodiments of the invention without departing from the scope of this invention defined in the following claims.