SE2050283A1 - Body electrode for electrophysilogical signals monitoring and recording - Google Patents

Abstract

The present invention relates to a body electrode for electrophysiological signal monitoring comprising a conductive compartment area stabilizer and a floating lid. The conductive compartment area stabilizer and the floating lid are arranged so that they may protect the conductive compartment from mechanical disturbances.

Description

BODY ELECTRODE FOR ELECTROPHYSILOGICAL SIGNALS MONITORING ANDRECORDING Field of the inventionThe present invention relates to a body electrode for recording of electrophysiological signals from a body.

Background of the invention Electrodes applied on the skin surface of a subject, e.g. a human, can be used to record electrophysiological signals produced e.g. by the heart, i.e. anelectrocardiogram (ECG), by the brain, i.e. an electroencephalogram (EEG), by theeyes, i.e. an electroretinogram (ERG) and/ or an electrooculogram (EOG). The qualityof such a recording is limited by the performance of the used electrodes, i.e. the bodyelectrodes. The body electrodes may be subject for different disturbances that in turngive rise to disturbances in the output of the recorded electrophysiological signals.One such disturbance is motion induced disturbances causing motion induceddisturbances in the recorded signal or signals. Motion induced disturbances may becaused by movements, deformations, and/ or vibrations of the skin adjacent to theelectrode, or of a combination of these. Such artifacts may increase in magnitudeWhen the subject moves e.g. during ambulatory monitoring. The origin of thedisturbances can also be movements of the electrode itself caused by external forceson the electrode from surrounding objects and from the electrode lead. Motioninduced disturbances may impair a recording of electrophysiological signals, as theymay create signal amplitudes that can be many times the amplitude of theelectrophysiological signal to be recorded or that the disturbances themselves maybe interpreted as electrophysiological signals. Additionally, the signals from motioninduced artifacts may be in the frequency range overlapping the frequency range ofthe electrophysiological signals Which makes it difficult to use conventional soft- and hardware filters to remove the artifacts from the recording.

Prior solutions to reduce motion artifacts include to have a collar provided With thebody electrode and have it attached to the skin by an adhesive. This partially preventmovements of the body electrode preferably from longitudinal forces on the bodyelectrode or from stretches of the skin. Further, such a collar could be flexible to be able to follow the skin. An alternative to the adhesive is to use vacuum to attach the body e1ectrode. A design that is often used today is to have the actual body e1ectrodeconductive skin contacting area enc1osed by a cup and thus protected in the bottom of the cup, together With an e1astic co11ar adhering to the skin.

Webster in IEEE Transactions on Biomedical Engineering, vo1 BME-13, issue 12,1984 disc1oses a floating Ag/AgC1 e1ectrode that has reduced motion artifacts causedby the e1ectrode.

EPO199694 disc1oses a ho1der for medical use fixed by vacuum. The ho1der comprisesa rigid backpiece, an intermediate e1astomeric element, and the diagnostic ortherapeutic device. The intermediate element comprises a comparative1y stiff sea1ing ring that is moveab1e and s1ight1y resi1ient.

Despite the prior art there is sti11 a need for an improved body e1ectrode that are at1east part1y prevented from being influenced by external forces longitudinal as Wellas perpendicu1ar to the skin, and for a body e1ectrode that reduces the effect ofdisp1acement and/ or deformation of the conductive area at the interface between the skin and body e1ectrode.

Summary It is an object of the invention to provide a body electrode With an improved protection against mechanical disturbances. This is achieved by the body electrode in claim 1.

According to an aspect of the invention there is a body electrode forelectrophysiological signal monitoring. The body electrode during use arranged to beattached to the skin of a subject, wherein the body electrode comprises a collar withat least one through opening, a transducer element at least partly arranged withinthe opening of the collar. A skin facing surface arranged to, during use, be in contactwith the skin and a free surface opposite of the skin facing surface. A connector inelectrical contact with the transducer element, the connector arranged on the freesurface, and a conductive compartment formed by the inner wall of the collar, theconductive compartment arranged to, at least during use, comprise an electrolytemedium. The body electrode further comprises a conductive compartment areastabilizer at least partly surrounding the conductive compartment, and a floating lidarranged within the through-opening of the collar and at a distance from the skin facing surface covering the conductive compartment.

According to one embodiment of the invention the conductive compartment areastabilizer has perpendicular stiffness of at least 0.5 N / mm. In one embodiment the conductive compartment area stabilizer has longitudinal stiffness of at least 1 N / mm.

According to one embodiment of the invention the conductive compartment areastabilizer) is arranged 0.01-10 mm from the skin facing surface. In one embodimentthe conductive compartment area stabilizer is arranged so that it is at least partlyembedded inside the collar. In one embodiment the body electrode comprises two ormore conductive compartment area stabilizer. In one embodiment the two or moreconductive compartment area stabilizer are a combination of any of the following forms: a ring, a washer, and a circular disc.

According to one embodiment the conductive compartment area stabilizer is in theform of a circular disc. In one embodiment the circular disc comprises a polymer with a thickness c of O.1-1 mm.

According to one embodiment the conductive compartment area stabilizer is in theform of washer. In one embodiment the washer comprises a polymer with a thickness ofO.1-1 mm.

According to one embodiment the conductive compartment area stabilizer is in theform of ring. In one embodiment the ring comprises a polymer with a height of 0.5mm- 2.5 mm and a width of 1-3 mm.

It is an advantage with the invention that a body electrode and the interface betweenthe body electrode and the skin may be protected from mechanical disturbancescaused by movements of the skin, e.g. stretching as well as by external forces from e.g. clothes etc.

It is an advantage with the invention that stretching and de-stretching movements ofthe skin surrounding the body electrode may be prevented from reaching the skin at the interface between the skin and the body electrode.

It is an advantage with the invention that the skin surface at the interface betweenthe skin and the body electrode is allowed to move freely perpendicular to the skinwithout building up pressure and/ or deformation in the skin at the interface, for example during body movements.

According to one embodiment of the invention the body electrode comprises aprotective cover arranged at the side of the free surface, at a distance from the floating lid and to cover at least the conductive compartment.

According to one embodiment of the invention the body electrode comprises avibration reducing laminate arranged to at least partly cover the collar at the side of the free surface.

According to one embodiment of the invention the vibration reducing laminatecomprises at least two layers that are joint together, wherein the first layer comprisesa first material having a tensile elasticity according to Youngs modulus of 0.2 GPa orless, and the second layer comprises a second material having tensile elasticity according to Youngs modulus of at least 2 GPa.

According to one embodiment of the invention the vibration reducing laminatecomprises at least two layers that are joint together, wherein the first layer comprisesan elastomer with a tensile elasticity according to Youngs modulus of 0.00 1 -0.08 GPaand a thickness of 0.1-1 mm, and the second layer comprises a metal sheet havingan tensile elasticity according to Youngs modulus of at least 60-240 GPa and a thickness of 0.01-0.1 mm.

According to one embodiment of the invention the vibration reducing laminate is amultilayer structure comprising at least three layers that are joint together Whereinevery first layer has a tensile elasticity according to Youngs modulus of at least 2 GPa. and every second layer has a Youngs modulus of 0.2 GPa or less.

In one embodiment the vibration reducing laminate and the protective cover are formed as a single component.

According to one embodiment the collar is comprised of an elastomer or an elastomer foam.

It is an advantage With the invention that the body electrode may be prevented from mechanical disturbances such as bumping.

It is an advantage With the invention that the presence of a protective cover togetherWith a conductive compartment area stabilizer may provide a longitudinal as Well as transversal stiffness to a body electrode.

In one embodiment the body electrode comprises a dome-shaped pressure coverhaving a first radial region and second a radial region second. The dome-shapedpressure cover arranged on the free surface, forming at least part of the free surface,at a distance from the transducer element, Wherein the dome-shaped pressure covercovers at least the conductive compartment, Wherein gas is present in between the pressure cover and the transducer element.

It is advantage With the invention that an increased pressure on the skin surface atthe interface With the body electrode may be achieved, Which may be beneficial inin the skin and reducing and/or stabilizing the potential and impedance skin/ electrolyte interface resulting in a higher signal to noise ratio.

Description of drawings Figure 1 shows a cross-section of a schematic illustration of a body electrode according to the invention; Figure 2 a shows an exploded view of a schematic illustration of a body electrodeaccording to the invention, Figure 2 b shows a schematic illustration of a bodyelectrode according to the invention from an elevated view and Figure 2c showsschematic illustration of a body electrode according to the invention from a below angle; Figure 3 shows a cross-section of a schematic illustration of a body electrode according to the invention; Figure 4 a shows an exploded view of a schematic illustration of a body electrodeaccording to the invention, Figure 4 b shows a schematic illustration of a bodyelectrode according to the invention from an elevated view and Figure 4 c showsschematic illustration of a body electrode according to the invention from a below angle; Figure 5 a and b show cross-sections of schematic illustrations of a body electrode according to the invention; Figure 6 a shows a schematic illustration of a body electrode according to theinvention in elevated view, Figure 6 b shows a cross-section of a schematic illustration of a body electrode according to the invention; Figure 7 shows a cross-section of a schematic illustration of a body electrode according to the invention; Figure 8 shows a cross-section of a schematic illustration of a body electrode according to the invention; Figure 9 a and b shows electrocardiograms recorded using body electrodes; and Figure 10 shows a cross-section of a schematic illustration of a conductive area stabilizer according to the invention.

Detailed description The function of a body electrode is to receive and record electrophysiological signalsfrom a body. The signals are recorded by a transducer element and transmitted tovarious medical instruments. A transducer element is contacted with the skin of abody via an electrolyte medium, e.g. a liquid gel, a hydrogel (solid), sweat etc. Thearea where the electrolyte medium is in contact with the skin is sensitive tomechanical disturbances. Hence, in order to reduce disturbances in the recordedelectrocardiogram the area where the electrolyte medium is in contact with the skin,should be protected from mechanical disturbances. Mechanical disturbancescomprise both longitudinal, i.e. in the plane of the skin, disturbances, andperpendicular, i.e. perpendicular to the skin plane, disturbances e.g. disturbancescaused by clothes, movements in the skin etc. Today, most electrodes comprise acollar that is used to attach the body electrode to the skin. The collar generallycomprises a through-hole in which the transducer element is arranged. A body electrode of the invention comprises an improved way of protecting the area where the electrolyte medium is in contact With the skin from mechanical disturbances.

Figure 1 shows a schematic illustration of a body electrode 100 according to theinvention in cross-section through the midpoint. The body electrode 100 is arrangedto be attached to the skin 101 of a subject, e.g. a human or an animal. The bodyelectrode 100 has two surfaces: a skin facing surface 102 arranged to be in contactwith the skin 101 and an opposite free surface 103. The body electrode 100 comprisesa collar 104 having at least one through-opening 120, the collar 104 is arranged ona film 114 that is in contact with the skin 101. In other embodiments the bodyelectrode 100 may be attached to the skin by other means, or the film 114 may beintegrated with the collar 104. The collar 104 is arranged in between the skin facingsurface 102 and the free surface 103. Alternatively, the upper side of the collar 104forms the free surface 103, or part of it, and/ or the lower side of the collar 104 formsthe skin facing surface 102, or part of it. A transducer element 105 is arranged atleast partly in the through-opening of the collar 120, and a connector 106 is arrangedat a distance from the transducer element 105, the connector 106 is in electricalcontact with the transducer element 105 via a lead 107 made for example a thinmetal strip with a strain relief 107a. The connector 106 is formed by an eyelet/ snap design wherein the eyelet or connector cover 1 15 is snapped onto the connector 106, so that the connector 106 is covered by a connector cover 115 forming a leadconnector receptacle. The body electrode 100 further comprises a conductivecompartment 108 Which in the direction parallel to the skin facing surface 102 islimited by the wall 104a of the through-opening of the collar 120, the conductivecompartment 108 comprises an electrolyte medium 109. The conductivecompartment 108 is at least partly surrounded by a conductive compartment areastabilizer 1 10 and covered by a floating lid 1 1 1. The floating lid 1 1 1 is arranged overthe through-opening of the collar 120, at a distance from the skin facing surface 102and covering the conductive compartment 108. The transducer element 105 and thefloating lid 111 are covered by a protective cover 112 arranged on the side of the freesurface 103, the protective cover 112 is arranged at a distance from the floating lid11 1. The protective cover 112 comprises at least one opening or through-hole 1 12a.A vibration reducing laminate 113 comprising three layers; 113a, 1 13b and 1 13c, isarranged on the surface of the collar 104, covering the collar 104 and the film 114 sothat the vibration reducing laminate 1 13 forms a portion of the free surface 103. Thevibration reducing laminate 113 is arranged at a distance from the conductive compartment area stabilizer 110. The three layers 113a, 113b, 113c are alternately though and stiff, e.g. layers 1 13a and 113c are stiff and 1 13b are though.

Figure 2a shows an exploded view of the body electrode 100 of Figure 1. As can beseen in the Figure the protective cover 112 comprises eight through-holes/openings1 12a. In other embodiments the number of through-holes may vary between one andup to for example 20. Figure 2b shows the body electrode 100 of Figure 1 from anelevated view and Figure 2c shows the body electrode 100 of Figure 1 from a below angle.

Figure 3 shows a schematic illustration of one embodiment of the invention whereinthe body electrode 200 is shown in a cross-section view through the midpoint. Thebody electrode 200 is arranged to be attached to the skin 201 of a subject, e.g. ahuman or an animal. The body electrode 200 has two surfaces: a skin facing surface202 arranged to during use of the body electrode 200 be in contact with the skin 201,and an opposite free surface 203. The body electrode 200 comprises a collar 204having at least one through-opening 220, and a transducer element 205 arranged inthe through-opening of the collar 204. The transducer element 205 is in electrical contact with a connector 206 via a lead 207 made for example a thin metal strip with a strain relief 207a. The connector 206 is formed by an eyelet/snap design whereinthe eyelet or connector cover 215 is snapped onto the connector 206, so that theconnector 206 is covered by a connector cover 215 forming a lead connectorreceptacle. The collar 204 is arranged in between the skin facing surface 202 and thefree surface 203. Alternatively, the upper side of the collar 204 forms the free surface203, or part of it, and/ or the lower side of the collar 204 forms the skin facing surface202, or part of it. The body electrode 200 further comprises a conductivecompartment 208 formed by the inner wall 204a of the collar 204, the conductivecompartment comprises an electrolyte medium 209. The body electrode 200 furthercomprises a conductive compartment area stabilizer 210 that surrounds theconductive compartment 208 and a floating lid 21 1. The floating lid 21 1 is arrangedover the through-opening of the collar 220 covering the conductive compartment 208.The floating lid 211 comprises a through-opening in which the transducer element205 is arranged. The body electrode 200 further comprises a protective cover 212that forms at least a portion of the free surface 203, the protective cover 212 isarranged at a distance from the floating lid 21 1. The protective cover 212 comprisesat least one opening or through-hole 212a. A vibration reducing laminate 213 isarranged on the surface of the collar 204, covering the collar 204 and forming at leasta portion of the free surface 203. The vibration reducing laminate 213 comprisesthree layers: 213a, 213b, and 213c. The layers are alternately though and stiff, e.g.layers 213a and 213c are stiff and 213b is though.

Figure 4a shows an exploded view of the body electrode 200 of Figure 3. As can beseen in the Figure the protective cover 212 comprises eight through-holes/ openings212a. Figure 4b shows the body electrode 200 of Figure 3 from an elevated view andFigure 4c shows the body electrode 200 of Figure 3 from a below angle.

Figure 5 a and b shows a schematic illustration of one embodiment of the inventionwhere a body electrode 300 is shown in cross-section through the midpoint. The bodyelectrode 300 is arranged to be attached to the skin 301 of a subject, e.g. a humanor an animal. The body electrode 300 has two surfaces: a skin facing surface 302arranged to be in contact with the skin 301 and an opposite free surface 303. Thebody electrode 300 comprises a collar 304 having at least one through-opening 320.A transducer element 305 is arranged in the through-opening of the collar 320, and in electrical contact with a connector 306 via a lead 307 made for example a thin metal strip With a strain relief 307a arranged at a distance from the collar 304. Theconnector 306 is covered by a connector cover 315. The connector 306 is formed byan eyelet/snap design wherein the eyelet or connector cover 315 is snapped onto theconnector 306, so that the connector 306 is covered by a connector cover 315,forming a lead connector receptacle. The body electrode 300 further comprises aconductive compartment 308 formed by the inner wall 304a of the collar 304, theconductive compartment 308 comprises an electrolyte medium 309. The conductivecompartment 308 is surrounded by a conductive compartment area stabilizer 310and covered by a floating lid 31 1. The floating lid 31 1 is arranged over the through-opening of the collar 320 covering the conductive compartment 308. A vibrationreducing laminate 313 is arranged on the surface of the collar 304, covering the collar304 so that it forms a portion of the free surface 303. The vibration reducing laminate313 comprises three layers: 313a, 313b, and 313c. The layers are alternately thoughand stiff, e.g. layers 313a and 313c are stiff and 313b is though. The body electrode300 further comprises a pressure cover 316 arranged at a distance from the floatinglid 31 1, forming a portion of the free surface 303. The pressure cover 316 is shapedlike a dome having a first 316a and a second radial region 316b. When pressure isapplied on the first region 316a of the pressure cover 316 it changes to a secondstable form, shown in Figure 5b. The pressure cover 316 comprises no through-holes or openings.

Figure 6 a shows a schematic illustration of one embodiment of the invention, wherea body electrode 400 is shown in elevated view and Figure 6 b shows a cross-sectionthrough the mid-point of the body electrode 400 in Figure 6a. The body electrode 400is arranged to be attached to the skin 401 of a subject, e.g. a human or an animal.The body electrode 400 has two surfaces: a skin facing surface 402 arranged to be incontact with the skin 401 and an opposite free surface 403. The body electrode 400comprises a collar 404 having at least one through-opening 420, the collar 404 isarranged on a film 414 that is in contact with the skin 401 during use of the bodyelectrode 400. A transducer element 405 is partly arranged in the through-openingof the collar 420, the transducer element 405 is in electrical contact with a connector(not shown). The connector is arranged at a distance from the transducer element405 and covered with a connector cover 415. The body electrode 400 furthercomprises a conductive compartment 408 formed by the inner wall 404a of the collar 404, the conductive compartment 408 comprises an electrolyte medium 409. The body electrode 400 further comprises a conductive compartment area stabilizer 410that surrounds the conductive compartment 408 and a floating lid 411. The floatinglid 41 1 is arranged over the through-opening of the collar 420 covering the conductivecompartment 408. The body electrode 400 further comprises a protective cover 412that forms at least a portion of the free surface 403, the protective cover 412 isarranged at a distance from the floating lid 41 1. A vibration reducing laminate 413 isarranged on the surface of the collar 404 and the film 414. The vibration reducinglaminate 413 is arranged at a distance from the conductive compartment areastabilizer 410. The vibration reducing laminate 413 comprises three layers: 413a,413b, and 413c. The layers are alternately though and stiff, e.g. layers 413a and 413care stiff and layer 413b is though. The body electrode 400 further comprises a strap419 arranged on the free surface 403 of the body electrode 400. The strap 419 isattached to the body electrode 400 by means for attachment 419a;419b arranged onthe vibration reducing laminate 413. The strap 419 comprises a first 421a and a second 42 lb vibration reducing part.

Figure 7 shows a schematic illustration of one embodiment of the invention, it showsa body electrode 500 in cross-section through the mid-point. The body electrode 500is arranged to be attached to the skin 501 of a subject, e.g. a human or an animal.The body electrode 500 has two surfaces: a skin facing surface 502 arranged to be incontact with the skin 501 and an opposite free surface 503. The body electrode 500comprises a collar 504 having at least one through-opening 520. The collar 504 isarranged in between the skin facing surface 502 and the free surface 503.Alternatively, the upper side of the collar 504 forms the free surface 503, or part ofit, and/or the lower side of the collar 504 forms the skin facing surface 502, or partof it. A transducer element 505 is arranged at least partly in the through-opening ofthe collar 520, and a connector is 506 arranged at a distance from the transducerelement 505, the connector 506 is in electrical contact with the transducer element505 via a lead 507 made for example a thin metal strip with a strain relief 507a. Theconnector 506 is formed by an eyelet/snap design wherein the eyelet or connectorcover 515 is snapped onto the connector 506, so that the connector 506 is coveredby a connector cover 515, forming a lead connector receptacle. The body electrode500 further comprises a conductive compartment 508 which in the direction parallelto the skin facing surface 502 is limited by the wall 504a of the through-opening of the collar 520, the conductive compartment 508 comprises an electrolyte medium 509 and is covered by a floating lid 511. The body electrode 500 comprises a first510a and a second 510b conductive compartment area stabilizer. The conductivecompartment area stabilizers 510a; 510b are arranged so that they at least partlysurround the conductive compartment 508, and so that the conductive compartmentarea stabilizers 510a; 510b are arranged at a distance from each other, e.g. thesecond conductive compartment area stabilizer is arranged within the collar 504 andthe first conductive compartment area stabilizer 510b is arranged on the surface ofthe collar 504 facing towards the free surface 503. The floating lid 511 is arrangedover the through-opening of the collar 520, at a distance from the skin facing surface502. The transducer element 505 and the floating lid 51 1 are covered by a protectivecover 512 arranged on the side of the free surface 503, the protective cover 512 isarranged at a distance from the floating lid 511. A vibration reducing laminate 513comprising three layers; 513a, 513b and 513c, is arranged on the surface of the collar504, covering the collar 504 so that it forms a portion of the free surface 503. Thevibration reducing laminate 513 is arranged at a distance from the conductivecompartment area stabilizer 510. The three layers 513a, 513b, 513c are alternatelythough and stiff, e.g. layers 513a and 513c are stiff and 513b is though.

Figure 8 shows a schematic illustration of one embodiment of the invention, it showsa cross-section through the mid-point of a body electrode 600. The body electrode600 is arranged to be attached to the skin 601 of a subject, e.g. a human or ananimal. The body electrode 600 has two surfaces: a skin facing surface 602 arrangedto be in contact with the skin 601 and an opposite free surface 603. The bodyelectrode 600 comprises a collar 604 having at least one through-opening 620. Thecollar 604 is arranged in between the skin facing surface 602 and the free surface603. Alternatively, the upper side of the collar 604 forms the free surface 603, or partof it, and/ or the lower side of the collar 604 forms the skin facing surface 602, or partof it. A transducer element 605 is arranged at least partly in the through-opening ofthe collar 620, and a connector is 606 arranged at a distance from the transducerelement 605, the connector 606 is in electrical contact with the transducer element605 via a lead 607 made for example a thin metal strip with a strain relief 607a. Theconnector 606 is formed by an eyelet/snap design wherein the eyelet or connectorcover 615 is snapped onto the connector 606, so that the connector 606 is coveredby a connector cover 615, forming a lead connector receptacle. The body electrode 600 further comprises a conductive compartment 608 which in the direction parallel to the skin facing surface 602 is limited by the wall 604a of the through-opening ofthe collar 620, the conductive compartment 608 comprises an electrolyte medium609 and is covered by a floating lid 611. The body electrode 600 comprises a first610a and a second 610b conductive compartment area stabilizer. The conductivecompartment area stabilizers 610a; 610b are arranged so that they at least partlysurround the conductive compartment 608, and so that the conductive compartmentarea stabilizers 610a; 610b are arranged at a distance from each other, e.g. thesecond conductive compartment area stabilizer is arranged within the collar 604 andthe first conductive compartment area stabilizer 610b is arranged on the surface ofthe collar 604 facing towards the free surface 603. The floating lid 611 is arrangedover the through-opening of the collar 620, at a distance from the skin facing surface602. The transducer element 605 and the floating lid 61 1 are covered by a protectivecover 612 arranged on the side of the free surface 603, the protective cover 612 isarranged at a distance from the floating lid 611. The protective cover 612 comprisesat least one opening or through-hole (not shown). A vibration reducing laminate 613comprising three layers; 613a, 613b and 613c, is arranged on the surface of the collar604 and covering the conductive compartment 608 so that it forms a portion of thefree surface 603. In the body electrode 600 schematically illustrated in Figure 6 theprotective cover 612 is integrated with the vibration reducing laminate 613. Thevibration reducing laminate 613 and the protective cover 612 may be formed as a single component.

Figure 9 a and b show two electrocardiogram recordings using body electrodes on ahuman at close locations using electrocardiogram amplif1ers with the sameamplif1cations. Each spike shown on the curves represents disturbances in thesignals obtained for the same type of mechanical disturbance in the form of tappingon the body electrodes. Figure 9a shows a recording using two body electrodes 100according to the invention. Figure 9b shows a recording using two body electrodes according to the prior art.

Figure 10 shows one embodiment of the invention, it shows a cross-section of aconductive compartment area stabilizer 710 having a height a, an outer diameter b,an inner diameter d, and a thickness c. The conductive compartment area stabilizer 710 comprises at least one through-hole 71 1.

As discussed above, in order to reduce disturbances in a recorded electrocardiogram the conductive compartment 108; 208; 308; 408; 508; 608 should be protected from mechanical disturbances, both perpendicular and longitudinal disturbances.

According to all embodiments of the invention this is achieved by two major components: A conductive compartment area stabilizer 110; 210; 310; 410; 510; 610;710 for example in the form of a ring, oval, rectangle, or square that at leastpartly surrounds the conductive compartment 108; 208; 308; 408; 508; 608,as illustrated in Figure 1-8, or in the form of a circular disc, as illustrated inFigure 10, an oval, or a washer, the washer may be round, or oval, orrectangular, or a squared shape. The conductive compartment area stabilizer could consist of a combination of two or more parts of different geometries.

A conductive compartment area stabilizer 110; 210; 310; 410; 510; 610; 710allows the conductive compartment 108; 208; 308; 408; 508; 608 area to keepits form (area integrity) if subjected to external forces, at least longitudinalforces. The conductive compartment area stabilizer 110; 210; 310; 410; 510;610; 710 may further allow the conductive compartment 108; 208; 308; 408;508; 608 area to keep its form if subjected to both longitudinal andperpendicular forces. To be able to protect the area of the conductivecompartment 108; 208; 308; 408; 508; 608 the conductive compartment areastabilizer 1 10; 210; 310; 410; 510; 610; 710 should preferably have a circularor oval shape and a certain structural stiffness e.g. by being fabricated in astiff material such as plastic, metal etc. or in a mixture of material wherein the mixture forms a stiff material.

An example of a conductive compartment area stabilizer 110; 210; 310; 410;510; 610 is a circular washer having a 25-35 mm diameter, e.g. a 30 mmdiameter, with a through-hole having a diameter of 12-17 mm, e.g. 15 mm,arranged centrally at the circular washer. The circular washer may havethickness of at least 0.1 mm and be fabricated in polyethylene terephthalate(PET).

Another example of a conductive compartment area stabilizer 110; 210; 310; 410; 510; 610 is a washer comprising a plastic sheet in the form of a square with a side of 25-35 mm, e.g. 30 mm, and a thickness of at least 0.1 mm, thewasher comprising a circular through-hole having a diameter of 12-17 mm, e.g. 15 mm, arranged centrally at the square-shaped washer.

The longitudinal stiffness for the above described washers can be measuredby applying a 2 Newton tensile force parallel to the washer and measure thedeformation of the through-hole. An example of a measurement set-up forsuch a measurement is two clamps that are firmly attached to the outeropposite sides of the washer, without deforming the washer, the clamps arepositioned at least 2 mm from the edge of the through-hole. After attachmenta 2 N tensile force is applied to the clamps. The deformation may be less than2 mm., i.e. at least a longitudinal stiffness of the conductive area stabilizer of1 N/mm is desirable. The perpendicular stiffness of the above describedwashers may however be lower than 0.5 N/ mm. A higher perpendicularstiffness may be achieved by adding a ring-shaped conductive compartment area stabilizer 110; 210; 310; 410; 510; 610 onto a washer as described above.

Another example of a conductive compartment area stabilizer 110; 210; 310;410; 510; 610 is in the form of a ring. Such a conductive compartment areastabilizer 110; 210; 310; 410; 510; 610; may allow the conductivecompartment to keep its area integrity when subjected to both longitudinal aswell as perpendicular forces. Such a ring may have an inner diameter of 15mm, an outer diameter of 19 mm, and a thickness of 2 mm and be made ofnylon have a longitudinal stiffness of at least 10 N / mm and a perpendicularstiffness of 10 N / mm, as measured for a force applied perpendicular to the conductive compartment area stabilizer 1 10; 210; 310; 410; 510; 610.

For a conductive compartment area stabilizer 110; 210; 310; 410; 510; 610having any of the forms and dimensions as described above the perpendicularstiffness may be at least 0.5 N /mm. The longitudinal stiffness should at least be 1 N / mm as previously described.

The perpendicular stiffness may be measured by applying a force of oneNewton vertically to the conductive compartment area stabilizer 1 10; 210; 310;410; 510; 610. The perpendicular deformation after such a force should be less than 2 mm, for the conductive compartment area stabilizer 1 10; 210; 310; 410; 510; 610 to be able to maintain the area integrity of the conductivecompartment 108; 208; 308; 408; 508; 608.

The perpendicular stiffness may be measured using the measurement set-updescribed below. The conductive compartment stabilizer 110; 210; 310; 410;510; 610 under test is placed on top of two support pillars having parallel endsurfaces. The distance between the support pillars is equal to the innerdiameter of the conductive compartment stabilizer 110; 210; 310; 410; 510;610. The perpendicular force may be applied with an edge shaped straightobject having an approximately 1 mm flat surface contacting the conductivecompartment area stabilizer 110; 210; 310; 410; 510; 610. The force is applied at the center at equal distance to the support pillars.

The stiffness of the conductive compartment area stabilizer 110; 210; 310;410; 510; 610 to be able to maintain the area integrity of the conductivecompartment 108; 208; 308; 408; 508; 608 may depend on the size, materialcomposition and shape of the conductive compartment area stabilizer 110; 210; 310; 410; 510; 610, as may be realized by persons skilled in the art.

Another example of design for a conductive compartment area stabilizer 710having at least a longitudinal stiffness of 1 N / mm and perpendicular stiffnessof 0.5 N / mm as outlined above is a circular disc made of for examplepolyethylene terephthalate (PET), as illustrated Figure 10 with a trough-hole711 of about 0.5 mm in diameter in order to pressure compensate to thesurrounding. The disc may have a thickness c of 0.1- 1 mm, e.g. 0.3 mm, anouter diameter b of 20-30 mm, e.g. 25 mm, a height a of 0.5-2.5 mm, e.g. 1mm and an inner diameter d of 15 - 20 mm, e.g. 17 mm. Such a disc-shapedconductive compartment area stabilizer 710 may be arranged to cover theconductive compartment 108; 208; 308; 408; 508; 608 and optionally thetransducer element 105; 205; 305; 405; 505; 605, The conductive compartment area stabilizer 110; 210; 310; 410; 510; 610; 710may be attached to, or comprised in, the collar 104; 204; 304; 404; 504; 604,see for example Figure 7. A body electrode 100; 200; 300; 400; 500; 600 may comprise one or several conductive compartment area stabilizers 110; 210; 310; 410; 510; 610; 710, for example two conductive compartment area stabilizers 510a; 510b as illustrated in Figure 7.

The conductive compartment area stabilizer 110; 210; 310; 410; 510; 610; 710may be fabricated in a polymeric material or a mixture of polymeric materials.Examples of polymeric materials include polybutylene terephthalate (PBT),polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT),polyamide (Nylon), polycarbonate (PC), polyethylene (PE), polypropylene (PP),and acrylonitrile butadiene styrene (ABS).

A floating lid 111; 211; 311; 411; 511; 611, arranged to cover at least theconductive compartment 108; 208; 308; 408; 508; 608. A floating lid 1 11; 21 1;311; 411; 511; 611 may be attached to the collar 104; 204; 304; 404; 504; 604and/or the conductive compartment area stabilizer 1 10; 210; 310; 410; 510;610; 710 so that the it can function as a separator that prevents the electrolytemedium 109; 209; 309; 409; 509; 609 from escaping the electricallyconductive compartment 108; 208; 308; 408; 508; 608. See illustrations inFigure 1-8.

The floating lid 1 1 1; 211; 31 1; 41 1; 51 1; 611 may additionally allow the skin101; 201; 301; 401; 501; 601 in contact with conductive compartment 108;208; 308; 408; 508; 608 during use of the body electrode 100; 200; 300; 400;500; 600 to move freely without any formation of deformations and/ orpressure build up in the conductive compartment 108; 208; 308; 408; 508;608. The skin 101; 201; 301; 401; 501; 601 may move freely since theelectrolyte medium 109; 209; 309; 409; 509; 609 may move together with theskin due to the presence ofthe floatinglid 111; 211; 311; 411; 511; 611. Theelectrolyte medium 109; 209; 309; 409; 509; 609 may be a viscoelastic gel, ora hydrogel, or a liquid with a low compressibility. Thus, in order to not buildup pressure and/or deform the skin 101; 201; 301; 401; 501; 601 underneaththe conductive compartment the floating lid 1 1 1; 21 1; 31 1; 41 1; 51 1; 61 1 needto be able to move in response to skin movements. The floating lid 1 11; 21 1;31 1; 41 1; 51 1; 61 1 may comprise a flexible and/or elastic material, at least atthe attachment points where it is attached to the collar 104; 204; 304; 404;504; 604 or to the compartment area stabilizer 110; 210; 310; 410; 510; 610;710. Examples of such a material include low density polyethylene (LDPE) foil, or an elastomer, having a thickness of 10-300 um. EXamples of elastomersinclude block (TPS, TPS-s),polyolefinelastomers (TPO, TPE-o), thermoplastic vulcanizates (TPV, TPE-v), styrenic co-polymers thermoplasticthermoplastic polyurethanes (TPU), thermoplastic copolyester (TPC, TPE-E),thermoplastic polyamides (TPA, TPE-A), natural rubber (NR), (IR), (BR), synthetic polyisoprene polybutadiene chloroprene rubber (CR),polychloroprene, neoprene, baypren, butyl rubber (IIR), halogenated butylrubbers (CIIR, BIIR), styrene-butadiene rubber (SBR), nitrile rubber (NBR),hydrogenated nitrile rubbers (HNBR), ethylene propylene rubber (EPM),ethylene propylene diene rubber (EPDM), epichlorohydrin rubber (ECO),polyacrylic rubber (ACM, ABR), silicone rubber (SI, VMQ), flourosilicone rubber(FVMQ), flouroelastomers (FKM, FPM), perfluoroelastomers (FFKM), polyetherblock amides (PEBA), chlorosulfonated polyethylene (CSM), and ethylene-vinyl acetate (EVA).

In embodiments when the floating lid 11 1; 21 1; 31 1; 411; 511; 611 comprisesmore than one material, the first material may be a material as described aboveand the second material may be a polymer, e.g. polybutylene terephthalate(PBT), polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT),polyamide (Nylon), polycarbonate (PC), polyethylene (PE), polypropylene (PP),or acrylonitrile butadiene styrene (ABS).

In order for the floating lid 111; 211; 311; 411; 511; 611 to allow movementsofthe skin 101; 201; 301; 401; 501; 601 and the electrolyte medium 109; 209;309; 409; 509; 609, the mass per surface area of the floating lid 11 1; 21 1; 31 1;411; 511; 611 may be lower than 5 mg/mm2, or lower than 2.5 mg/mm2, or lower than 1 mg/ mm2.

According to one embodiment of the invention the body electrode 100; 200; 400; 500;600 may be covered by a protective cover 112; 212; 412; 512; 612 in order to providea protection against mechanical disturbances. Such a protective cover 1 12; 212; 412;512; 612 is arranged on the free surface 103; 203; 403; 503; 603 of the body electrode100; 200; 300; 400; 500; 600 covering at least the conductive compartment 108; 208;308; 408; 508; 608 and the conductive compartment area stabilizer 110; 210; 410;510; 610. The protective cover 112; 212; 412; 512; 612 may comprise one or severalholes/through-openings 112a; 212a, as illustrated in Figures 2 and 4, that can be used to pressure compensate the volume between the protective cover 1 12; 212; 412;512; 612 and the floating lid 111; 211; 411; 511; 611 against the surroundingatmosphere. The protective cover 112; 212; 412; 512; 612 comprises a stiff material,e.g. plastic and/ or metal, that may Withstand normal forces Without being deformed.In such Way the protective cover 1 12; 212; 412; 512; 612 protects at least theconductive compartment 108; 208; 408; 508; 608 from external forces. The protectivecover 112; 212; 512; 612 may be attached to the body electrode 100; 200; 400; 500;600 at the collar 104; 204; 404; 504; 604, or at the vibration reducing laminate 1 13;213; 413; 513; 613. In other embodiments (not shown) the protective cover may alsobe part of an external protecting device and hence not part of the body electrode 100;200; 400; 500; 600. For example, the connector may be placed centrally at a bodyelectrode and in such case the connector may comprise a protective cover. Theconnector may also be connected to the body electrode at a contact point placedcentrally at a protective cover. A protective cover may be provided in a connectordevice that is attached to the body electrode during use, hence the protective cover may not be part of the body electrode.

A body electrode 100; 200; 400; 500; 600 comprising a floating lid 111; 211; 411;511; 611, a conductive compartment area stabilizer 110; 210; 410; 510; 610; 710and a protective cover 112; 212; 412; 512; 612 limits the degree to Which externalforces, longitudinal and/ or perpendicular, can propagate to the electricallyconducting compartment 108; 208; 308; 408; 508; 608. By preventing thispropagation, the area of the skin of the electrically conducting compartment 108;208; 308; 408; 508; 608 can remain substantially unchanged during the signalrecording period. In this Way the potential at the area of the electrically conductingcompartment 108; 208; 308; 408; 508; 608 remains substantially stable and the levelof disturbance in the recording, i.e. in the electrocardiogram, is reduced. The term “potential” refers herein to an electric potential and/ or electrochemical potential, typically measurable With a common voltmeter and/ or oscilloscope.

Forces applied to the protective cover 112; 212; 412; 512; 612 may propagate to theconductive compartment area stabilizer 110; 210; 410; 510; 610; 710, and hence atleast partly avoiding acting on the floating lid 11 1; 21 1; 41 1; 51 1; 61 1. Therefore, aprotective cover 112; 212; 412; 512; 612 minimizes forces acting on the floating lid 111; 211; 411; 511; 611 and hence the conductive compartment 108; 208; 408; 508; 608. In this Way the area integrity of the conductive compartment 108; 208; 408;508; 608 may be, at least partly, kept.

The conductive compartment area stabilizer 110; 210; 310; 410; 510; 610; 710 maymove during use ofa body electrode 100; 200; 300; 400; 500; 600. In such a case themovements by the conductive compartment area stabilizer 110; 210; 310; 410; 510;610; 710 can propagate to the collar 104; 204; 304; 404; 504; 604 since theconductive compartment area stabilizer 110; 210; 310; 410; 510; 610; 710 may beconnected to the collar 104; 204; 304; 404; 504; 604 and/or comprised Within thecollar 104; 204; 304; 404; 504; 604. The collar 104; 204; 304; 404; 504; 604 maycomprise e.g. an elastomer or foam or be in the form of a tape made of Woven or non-Woven material. The collar 104; 204; 304; 404; 504; 604 may further be made of amaterial With vibration damping properties i.e. a material With energf dissipationproperties converting mechanical energi to thermal energy suitable materials may beelastomer foams, for example styrenic block co-polymers (TPS, TPS-s), thermoplastic(TPO, TPE-o), (TPV, TPE-v),(TPU), (TPC, TPE-E), polyolefinelastomers thermoplastic vulcanizates thermoplastic polyurethanes thermoplastic copolyesterthermoplastic polyamides (TPA, TPE-A), natural rubber (NR), synthetic polyisoprene(IR), polybutadiene (BR), chloroprene rubber (CR), polychloroprene, neoprene,baypren, butyl rubber (IIR), halogenated butyl rubbers (CIIR, BIIR), styrene-butadiene rubber (SBR), nitrile rubber (NBR), hydrogenated nitrile rubbers (HNBR),ethylene propylene rubber (EPM), ethylene propylene diene rubber (EPDM),epichlorohydrin rubber (ECO), polyacrylic rubber (ACM, ABR), silicone rubber (SI,VMQ), flourosilicone rubber (FVMQ), (FKM, FPM),perfluoroelastomers (FFKM), polyether block amides (PEBA), chlorosulfonated polyethylene (CSM), and ethylene-vinyl acetate (EVA). flouroelastomers The collar may have a thickness of 0.1-4 mm. The collar 104; 204; 304; 404; 504;604 should preferably have damping properties in the frequency spectrum up to 400Hz, so that it may dampen movements. According to some embodiments the collar104; 404 may be attached to the skin 101; 401 by a film 114; 414; that is adhesive.In another embodiments the collar 204; 304; 504; 604 may be made in a materialhaving a high friction such as an elastomer and be attached to skin 201; 301; 501;601 by for example a strap 419, or another suitable means for attachment.

Motion induced disturbances may also occur due to movements and stretches of theskin itself, especially in areas close to the body electrode 100; 200; 300; 400; 500;600. Such movements are at least partly hindered from occurring in the skin 101;201; 301; 401; 501; 601 in the electrically conducting compartment 108; 208; 308;408; 508; 608 due the conductive compartment area stabilizer 110; 210; 310; 410;510; 610; 710. The conductive compartment area stabilizer 110; 210; 310; 410; 510;610; 710 is connected to the collar 104; 204; 304; 404; 504; 604 that is connected toskin 101; 201; 301; 401; 501; 601. Ifmovements in the skin 101; 201; 301; 401; 501;601 come in contact With the collar 104; 204; 304; 404; 504; 604 they may first bedamped by the collar 104; 204; 304; 404; 504; 604 or by the vibration reductionlaminate 113; 213; 313; 413; 513; 613 attached to the collar 104; 204; 304; 404;504; 604, in the case that some movements propagate further they reach theconductive compartment area stabilizer 110; 210; 310; 410; 510; 610; 710 and arein that case at least partly prevented from entering the electrically conductingcompartment 108; 208; 308; 408; 508; 608. In this Way all types of movements of theskin, such as for example stretching/ de-stretching and /or rotational andperpendicular movements, may be prevented from disturbing the electricallyconducting compartment 108; 208; 308; 408; 508; 608 and its area may maintainunchanged during the measurement/ recording period. The conductive compartmentarea stabilizer 110; 210; 310; 410; 510; 610; 710 may be regarded as a breakWaterconstruction for (Wave-like) movements in the skin 101; 201; 301; 401; 501; 601.

In some embodiments the body electrode 100; 200; 300; 400; 500; 600 comprises avibration reducing laminate 1 13; 213; 313; 413; 513; 613 arranged on the collar 104;204; 304; 404; 504; 604 on the side of the collar that faces the free surface 103; 203;303; 403; 503; 603. Such a vibration reducing laminate 113; 213; 313; 413; 513; 613may comprise at least two layers: a stiff layer 113a; 113c; 213a; 213c; 313a; 313c;413a; 413c; 513a; 513c; 613a; 613c and a though layer 113b; 213b; 313b; 413b;513b; 613b. The layers 113a-c; 213a-c; 313a-c; 413a-c; 513ac-c; 613a-c are jointtogether to form a single component. The though 113b; 213b; 313b; 413b; 513b;613b and stiff113a; 113c; 213a; 213c; 313a; 313c; 413a; 413c; 513a; 513c; 613a;613c layers should be alternated. Such a combination of layers forms a vibrationreducing laminate 113; 213; 313; 413; 513; 613 that may dampen movementsreaching the body electrode 100; 200; 300; 400; 500; 600 so that they do notpropagate further and reach the electrically conducting compartment 108; 208; 308; 408; 508; 608. An example of a vibration reducing laminate 113; 213; 313; 413; 513;613 is a first layer 113a; 1130; 213a; 2130; 313a; 3130; 413a; 4130; 513a; 5130;613a; 6130 comprising natural rubber With an tensile elasticity according to Young'smodulus of approximately 0.0015-0.0025 GPa, having a thickness of 0.3 mm, otherexamples include elastomers such elastomer sheets, having a thickness of at least0.1 mm, and up to 1 mm. An elastomer sheet may include a support layer, primarilyused for production purposes, in the form of a mesh made of Woven material (e.g.cotton). A second layer 113b; 213b; 313b; 413b; 513b; 613b comprising a metalsheet/ foil, e.g. aluminum With a tensile elasticity of approximately 69 GPa accordingto Young's modulus, having a thickness of 0.05 mm. Other examples of metal sheetsinclude copper or stainless-steel having thickness of at least 0.01 mm, and up to 0.1 ITIITI.

Examples of elastomers having a tensile elasticity according to Young's modulus ofapproximately 0.001-0.08 GPa includes styrenic block co-polymers (TPS, TPS-s),thermoplastic polyolef1nelastomers (TPO, TPE-o), thermoplastic vulcanizates (TPV,TPE-v), thermoplastic polyurethanes (TPU), thermoplastic copolyester (TPC, TPE-E),thermoplastic polyamides (TPA, TPE-A), natural rubber (NR), synthetic polyisoprene(IR), polybutadiene (BR), chloroprene rubber (CR), polychloroprene, neoprene,baypren, butyl rubber (IIR), halogenated butyl rubbers (CIIR, BIIR), styrene-butadiene rubber (SBR), nitrile rubber (NBR), hydrogenated nitrile rubbers (HNBR),ethylene propylene rubber (EPM),epichlorohydrin rubber (ECO), polyacrylic rubber (ACM, ABR), silicone rubber (SI,vMQ), rubber (FvMQ), (FKM, FPM),polyether block amides (PEBA), ethylene propylene diene rubber (EPDM),flourosilicone flouroelastomers perfluoroelastomers (FFKM) , chlorosulfonated polyethylene (CSM), and ethylene-vinyl acetate (EVA).

The layers are combined by acrylic tack that is adhesive. Other suitable combinationsof materials include though materials having a tensile elasticity of < 0.2 GPaaccording to Young's modulus, alternated With stiff materials having a tensileelasticity of > 2 GPa according to Young's modulus. Having more than two layers inthe vibration reducing laminate 1 13; 213; 313; 413; 513; 613 may increase its ability to attenuate vibrations.

A vibration reducing laminate 1 13; 213; 313; 413; 513; 613 have vibration damping properties, i.e. ability to convert mechanical energy to thermal energy. A vibration reducing laminate 1 13; 213; 313; 413; 513; 613 should preferably have the ability to dampen vibrations and other movements having a frequency of up to 400 Hz.

In an embodiment of the invention the area integrity of the conductive compartment308 may be further protected by a spring action induced by gas pressure. Such abody electrode 300 is schematically illustrated in Figures 5a and b. A spring actioninduced by gas is enabled by a pressure cover 316 arranged on at least parts of thefree surface 303 of a body electrode 300. A pressure cover 316 is formed as a domeand has two stable forms, schematically illustrated in Figures 5a and b. Figure 5ashows the first stable form of the pressure cover 316, when pressure is applied onthe first part of the pressure cover 316a, for example by press of a finger, it changesconformation into its second stable form, schematically illustrated in Figure 5b. Oncethe second stable conformation is formed it creates a gas pressure inside the bodyelectrode 300 in the volume in between the pressure cover 316 and the floating lid311. In contrast to the protective cover 112; 212; 412; 512 the pressure cover 316 comprises no holes or openings on the free surface 303.

According to one embodiment the body electrode 400 may be attached to a body usinga strap 419 that is attached to the body electrode 400 by means for attachment 419a;419b. An example of such an embodiment is schematically illustrated in Figure 6. Byusing a strap 419 for attachment a force is applied on the body electrode 400 so thatit becomes attached to the skin 401. Such a force may further protect the areaintegrity of the conductive compartment area 408. Such a strap 419 may furthercomprise two vibration reducing parts 421a; 42 lb. The vibration reducing parts421a; 421b may prevent or minimize vibrations propagating in the strap generated by external object such as clothes etc., from reaching the body electrode 400.

According to one embodiment the body electrode 500 may comprise more than oneconductive compartment area stabilizer 510a, such as two conductive compartmentarea stabilizers 510a; 510b. A schematic illustration of such an embodiment can beseen in Figure 7. Two conductive compartment area stabilizers 510a; 510b may bearranged so that one is comprised within the collar 504 and one is arranged on topof the collar 504. A conductive compartment area stabilizer may also be arranged so that it is partly within the collar 504 and partly on top of the collar 504 (not shown).

According to one embodiment the body electrode 600 may comprise a vibrationreducing laminate 613 that is arranged on the free surface 603 of the body electrode600 so that it forms at least a part of the free surface 603. A schematic illustration ofsuch an embodiment can be seen in Figure 8. The vibration reducing laminate 613may cover the protective cover 612 and the collar 604. In another example thevibration reducing laminate 613 and the protective cover 612 may be formed in a single component.

A body electrode 100; 200; 300; 400; 500; 600 comprising a conductive compartmentarea stabilizer 110; 210; 310; 410; 510; 610; 710, a protective cover 112; 2 12; 3 12;412; 512; 612, a floating lid 111; 211; 311; 411; 511; 611 and a vibration reducinglaminate 113; 213; 413; 513; 613 may result in a reduced amount and/or reducedamplitude of disturbances in a recorded electrocardiogram. This can be seen in Figure9 and b, Figure 9a shows an electrocardiogram recorded using a body electrode 100as described herein, and Figure 9b shows an electrocardiogram recorded using a bodyelectrode according to the prior art. Both electrocardiograms were recorded using the same amplif1er and subjected to the same disturbances.

The body electrode 100; 200; 300; 400; 500; 600 may during use be connected to alead having a lead connector. Such a lead connector may be attached to the protective cover 112; 212; 312; 412; 512; 612.

All embodiments and variants may be combined with each other unless stated otherwise.

Claims (22)

1.A body electrode (100; 200; 300; 400; 500; 600) for electrophysiologicalsignal monitoring, the body electrode (100; 200; 300; 400; 500; 600) duringuse arranged to be attached to the skin (101; 201; 301; 401; 501; 601) ofasubject, Wherein the body electrode (100; 200; 300; 400; 500; 600)comprises: a collar (104; 204; 304; 504; 604) With at least one through-opening (120;220; 320; 420; 520; 620); a transducer element (105; 205; 305; 405; 505; 605) at least partly arrangedWithin the opening of the collar (120; 220; 320; 420; 520; 620); a skin facing surface (102; 202; 302; 402; 502; 602) arranged to, during use,be in contact With the skin (101; 201; 301; 401; 501; 601) and a free surface(103; 203; 303; 403; 503; 603) opposite of the skin facing surface (102; 202;302; 402; 502; 602); a connector (106; 206; 306; 406; 506; 606) in electrical contact With thetransducer element (105; 205; 305; 405; 505; 605), the connector (106; 206;306; 406; 506; 606) arranged on the free surface (103; 203; 303; 403; 503;603); and a conductive compartment (108; 208; 308; 408; 508; 608) formed by theinner Wall (104a; 204a; 304a; 404a; 504a; 604a) of the collar (104; 204; 304;504; 604), the conductive compartment (108; 208; 308; 408; 508; 608)arranged to, at least during use, comprise an electrolyte medium (109; 209;309; 409; 509; 609); characterized in that the body electrode (100; 200; 300; 400; 500; 600)further comprises: a conductive compartment area stabilizer (110; 210; 310; 410; 510; 610) atleast partly surrounding the conductive compartment (108; 208; 308; 408;508; 608), and a floatinglid (111; 211; 311; 411; 511; 611) arranged Withinthe through-opening of the collar (120; 220; 320; 420; 520; 620) and at adistance from the skin facing surface (102; 202; 302; 402; 502; 602) coveringthe conductive compartment (108; 208; 308; 408; 508; 608).

2. The body electrode (100; 200; 400; 500; 600) according to claim 1 further comprising a protective cover (112; 212; 412; 512; 612) arranged at the sideof the free surface (103; 203; 403; 503; 603), at a distance from the floatinglid (111; 211; 311; 411; 511; 611) and to cover at least the conductivecompartment (108; 208; 408; 508; 608).

3. The body electrode (100; 200; 300; 400; 500; 600) according to claim 1 or 2 further comprising a vibration reducing laminate (1 13; 213; 313; 513; 613)arranged to at least partly cover the collar (104; 204; 304; 504; 604) at theside of the free surface (103; 203; 303; 403; 503; 603).

4. The body electrode (100; 200; 300; 400; 500; 600) according to claim 3 Wherein the vibration reducing laminate (113; 213; 313; 413; 513; 613)comprises at least two layers that are joint together, Wherein the first layer(113a; 213a; 313a; 413a; 513a; 613a) comprises a first material having atensile elasticity according to Youngs modulus of 0.2 GPa or less, and thesecond layer (113b; 213b; 313b; 413b; 513b; 613b) comprises a secondmaterial having tensile elasticity according to Youngs modulus of at least 2 GPa.

5. The body electrode (100; 200; 300; 400; 500; 600) according to claim 4 Wherein the first layer (113a; 113c; 213a; 213c; 313a; 313c; 413a; 413c;513a; 513c; 613a; 613c) comprises an elastomer With a tensile elasticityaccording to Youngs modulus of 0.001-0.08 GPa and a thickness of 0.1 - 1mm., and the second layer (113b; 213b; 313b; 413b; 513b; 613b) comprisesa metal sheet having a tensile elasticity according to Youngs modulus of 60 -240 GPa and a thickness of 0.01 - 0.1 mm

6. The body electrode (100; 200; 300; 400; 500; 600) according to claim 3 Wherein the vibration reducing laminate (113; 213; 313; 413; 513; 613) is amultilayer structure comprising at least three layers (1 13a; 1 13b; 1 13c;213a; 213b; 213c; 313a; 313b; 313c; 413a; 413b; 413c; 513a; 513b; 513c;613a; 613b; 613c) that are joint together Wherein every first layer (1 13a;113c; 213a; 213c; 313a; 313c; 413a; 413c; 513a; 513c; 613a; 613c) has a tensile elasticity according to Youngs modulus of at least 2 GPa. and every second 1ayer (113b; 213b; 313b; 413b; 513b; 613b) has a Youngs modulus of0.2 GPa or 1ess.

7. The body e1ectrode (100; 200; 300; 400; 500; 600) according to c1aim 6Wherein the first 1ayer (113a; 1130; 213a; 2130; 313a; 3130; 413a; 4130;513a; 5130; 613a; 6130) comprises a metal sheet having a tensi1e e1asticityaccording to Young's modulus of 60 -240 GPa and a thickness of 0.01 - 0.1mm, and the second 1ayer (113b; 213b; 313b; 413b; 513b; 613b) compriseselastomer With a tensi1e e1asticity according to Young's modulus of 0.001- 0.08 GPa and a thickness of 0.1 - 1 mm.

8. The body e1ectrode (100; 200; 300; 400; 500; 600) according to c1aim 1Wherein the conductive compartment area stabi1izer (1 10; 210; 310; 410; 510; 610; 710) has a perpendicular stiffness of at 1east 0.5 N/mm.

9. The body e1ectrode (100; 200; 300; 400; 500; 600) according to c1aim 1Wherein the conductive compartment area stabi1izer (1 10; 210; 310; 410; 510; 610; 710) has a 1ongitudina1 stiffness of at 1east 1 N/mm.

10.The body e1ectrode (100; 200; 300; 400; 500; 600) according to any of thepreceding c1aims Wherein the conductive compartment area stabi1izer (1 10;210; 310; 410; 510; 610; 710) is arranged 0.01-10 mm from the skin facingsurface (102; 202; 302; 402; 502; 602).

11.The body e1ectrode (100; 200; 300; 400; 500; 600) according to any of thepreceding c1aims Wherein the conductive compartment area stabi1izer (1 10;210; 310; 410; 510; 610; 710) is arranged so that it is at 1east part1yembedded inside the co11ar (104; 204; 304; 504; 604).

12.The body e1ectrode (100; 200; 300; 400; 500; 600) according to any of thepreceding c1aims Wherein the body e1ectrode (100; 200; 300; 400; 500; 600)comprises two or more conductive compartment area stabi1izers (1 10; 210; 310; 410; 510; 610; 710).

13.The body e1ectrode (100; 200; 300; 400; 500; 600) according to any of thepreceding c1aims Wherein the conductive compartment area stabi1izer (710) is in the form of a circu1ar disc.

14.The body e1ectrode (100; 200; 300; 400; 500; 600) according to c1aim 13Wherein the circu1ar disc comprises a po1ymer With a thickness c of 0.1-1ITIITI.

15. The body e1ectrode (100; 200; 300; 400; 500; 600) according to any of c1aims1-12 Wherein the conductive compartment area stabi1izer (1 10; 210; 310; 410; 510; 610) is in the form of Washer.

16.The body e1ectrode (100; 200; 300; 400; 500; 600) according to c1aim 15 Wherein the Washer comprises a po1ymer With a thickness of 0.1-1 mm.

17.The body e1ectrode (100; 200; 300; 400; 500; 600) according to any of c1aims1-12 Wherein the conductive compartment area stabi1izer (1 10; 210; 310; 410; 510; 610) is in the form of ring.

18.The body e1ectrode (100; 200; 300; 400; 500; 600) according to c1aim 17Wherein the conductive compartment area stabi1izer (1 10; 210; 310; 410;510; 610) comprises a po1ymer With a height of 0.5-2.5 mm and a Width of 1-3 mm.

19.The body e1ectrode (100; 200; 300; 400; 500; 600) according to c1aim 12Wherein the two or more conductive compartment area stabi1izers (1 10; 210;310; 410; 510; 610) are a combination of any of the fo11oWing forms: a ring, a Washer, and a circu1ar disc.

20.The body e1ectrode (300) according to c1aim 1 Wherein the body e1ectrode(300) further comprises a dome-shaped pressure cover (316) having a firstradia1 region (316a) and a second radial region (316b), the dome-shapedpressure cover arranged on the free surface (303), forming at 1east part of thefree surface, at a distance from the transducer e1ement (306), Wherein the dome-shaped pressure cover covers at 1east the conductive compartment (308), Wherein gas is present in between the pressure cover (316) and the transducer element (306).

21. 2 1 .The body electrode (600) according to any of the preceding c1aims Wherein5 the vibration reducing 1aminate (613) and the protective cover (612) are formed as a single component.

22.The body electrode (600) according to any of the preceding c1aims Whereinthe co11ar (104; 204; 304; 504; 604) comprises an e1astomer or an e1astomer 10 foam.