WO2013010276A1 - Water retention monitoring - Google Patents
Water retention monitoring Download PDFInfo
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- WO2013010276A1 WO2013010276A1 PCT/CA2012/050490 CA2012050490W WO2013010276A1 WO 2013010276 A1 WO2013010276 A1 WO 2013010276A1 CA 2012050490 W CA2012050490 W CA 2012050490W WO 2013010276 A1 WO2013010276 A1 WO 2013010276A1
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- electrodes
- ultrasound
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- body part
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Classifications
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves
- A61B5/053—Measuring electrical impedance or conductance of a portion of the body
- A61B5/0537—Measuring body composition by impedance, e.g. tissue hydration or fat content
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/48—Other medical applications
- A61B5/4869—Determining body composition
- A61B5/4875—Hydration status, fluid retention of the body
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
- A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
- A61B5/6813—Specially adapted to be attached to a specific body part
- A61B5/6824—Arm or wrist
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- A—HUMAN NECESSITIES
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- A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
- A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
- A61B5/6813—Specially adapted to be attached to a specific body part
- A61B5/6829—Foot or ankle
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
- A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
- A61B5/683—Means for maintaining contact with the body
- A61B5/6838—Clamps or clips
Definitions
- the invention relates to medical apparatus and methods.
- Embodiments provide methods and apparatus for monitoring water retention.
- the degree of water retention in tissues is an indicator of health in humans and other mammals.
- Heart conditions which may eventually lead to heart failure may take a very long time to develop.
- monitoring is important so that timely intervention can be provided if the heart condition worsens.
- the cost of monitoring patients to determine if and when intervention may be appropriate can be undesirably high. Monitoring is especially important where the monitoring involves tests administered by health professionals. There is a need for apparatus and methods which would permit patients to monitor their health at home, without needing help from medical personnel.
- Some prior art devices for measuring water retention by electrical methods are based on impedance measurements, single sided capacitance measurements or optical measurements. Impedance methods require good electrical contact with the skin, using a special paste (similar to the paste used to ensure good contact of EKG electrodes) and are not suitable for home use.
- Single sided (i.e. both electrodes on the same side of the tissue) capacitance measurements tend to be inaccurate because the electric field from single sided electrodes is non-uniform. For example a single-sided capacitance measurement will generally provide a different reading if a fatty tissue is near the skin and a muscle is below the fatty tissue than when the same muscle is above the fatty tissue.
- This invention has various aspects.
- One aspect provides apparatus configured to monitor water retention in an individual by monitoring electrical properties of tissue.
- the apparatus comprises electrodes that can be placed on either side of a body part.
- the apparatus may evaluate water retention by monitoring capacitance between the electrodes. Capacitance may be monitored, for example, by monitoring an AC current flowing between the electrodes in response to application of an AC signal.
- the apparatus is configured to sporadically monitor capacitance between the electrodes and to generate an alarm or other indication if the capacitance deviates from an original value by more than a threshold amount.
- the apparatus includes means for determining a spacing between the electrodes and the apparatus is configured to determine an indicator of water retention by processing the capacitance (or another value related to the capacitance) together with the spacing between the electrodes. Such processing may be performed using analog and/or digital techniques.
- the device may, be provided in the form of a bracelet for a wearer's wrist or ankle.
- the apparatus comprises a member configured to extend around a body part of a subject at least from a location on one side of the body part to a location on an opposing side of the body part.
- First and second transducer elements are supported on the member.
- a circuit is supported on the member and connected to the first and second transducer elements for passing a signal through the body part and measuring a characteristic of the transmitted signal.
- a power supply e.g. a battery or a photocell
- a method comprises placing electrodes on either side of a body part (for example, an arm, leg, neck, torso of a person) and measuring capacitance between the electrodes (or some other value related to the capacitance).
- the method comprises periodically measuring capacitance between the electrodes and comparing the capacitance (or a value related to or derived from the capacitance) to an original value.
- the method comprises comparing a value of a measure related to the dielectric constant of the tissue to one or more previous values of the measure and processing the current and one or more previous values to determine whether a change in the measure satisfies a criterion for triggering an indication and/or transmitting an alarm signal.
- the criterion may, for example, comprise one or more of: a difference between the current and a previous value exceeds a threshold; an increase of the current value over a previous value exceeds a threshold; a rate of change of the value as determined from the current and one or more previous values exceeds a threshold; a rate of increase in the value as determined from the current and one or more previous values exceeds a threshold; or the like.
- the indication may comprise, for example, turning on a light or displaying other indicia.
- the method comprises determining a spacing between the electrodes and determining an indicator of water retention from the capacitance (or another value related to the capacitance such as a capacitive current, a reactive impedance, or the like) and the spacing between the electrodes.
- Methods and apparatus embodying apparatus and/or methods as described above can be applied to provide lightweight long-lasting wearable devices that can be worn by persons concerned about water retention.
- Such devices may warn the wearer and/or the wearer's care-giver(s) or physician(s) if the water retention has changed in a way that indicates a possible problem.
- a warning may be generated if: a measure of water retention increases by more than a threshold amount relative to an original level; the measure of water retention trends upward undesirably steeply; the measure of water retention has changed more than a threshold amount in a given time period (different thresholds may optionally be provided for increases and for decreases in the measure of water retention) and/or an absolute level of the measure of water retention exceeds a threshold.
- Such devices can be made to have very low power requirements. They are required to operate only intermittently. Electrical power may be provided by a long-lasting battery, such as a watch battery, solar cells, a combination thereof, or the like.
- the water content of tissue is measured by placing part of the body, such as the arm or ankle, between two capacitive electrodes and obtaining a measure of water content based on the dielectric properties of the tissue between the electrodes.
- the device may, for example, be shaped like a bracelet or hinged clip. When placed over part of the body the hinge position is measured to normalize the reading for the tissue thickness. The device can alert the user of water retention, and/or may contact a physician directly via a wireless link.
- Figure 1 is an isometric phantom view of a device according to an example embodiment of the invention.
- Figure 2 is a schematic diagram of an electronic circuit that may be applied in the device of Figure 1 and similar devices.
- Figure 3 is a graph illustrating the change in the dielectric constant of tissue as a function of the water content of the tissue.
- Figure 4 is an isometric phantom view of another example device that applies a different thickness-sensing method.
- Figure 5 is a drawing showing an example device in the shape of a bracelet. Description [0023] Throughout the following description specific details are set forth in order to provide a more thorough understanding to persons skilled in the art. However, well known elements may not have been shown or described in detail to avoid
- the electrical properties of tissue are affected by the water content of the tissue.
- a suitable electrical property for monitoring water content is the dielectric constant, also known as permittivity. Measurement of the dielectric constant can be done at a wide range of frequencies, from KHz to GHz. The range of lMHz to 100MHz is particularly useful because of the ease of implementation. Frequencies that fall in the unregulated ISM band, such as 6.78MHz, 13.5MHz or 27MHz are particularly convenient to use.
- Embodiments of the invention non-invasively monitor the dielectric constant of tissue and provide outputs that may help to warn users or others of impending heart problems.
- One way to measure the dielectric constant of tissue is to construct a capacitor in which the tissue acts as a dielectric layer. This can be done by placing electrical conductors (electrodes) on either side of a volume of tissue.
- the volume of tissue may be, for example, a body part such as an arm, leg, neck, or other suitable body part.
- the capacitance of the resulting capacitor depends on the dielectric constant of the tissue as well as the geometry of the electrodes and the tissue. For a constant geometry the capacitance will increase as the water content of the issue increases.
- the electrodes be in electrical contact with the subject's skin. It is preferable although not mandatory for the electrodes to be electrically insulated from the subject's skin. This may be accomplished for example, by providing a thin (e.g. O.Olmm-O.lmm) thick layer of an electrically-insulating material (a suitable plastic for example) on one or both of the electrodes.
- the electrically-insulating material may block direct current flow so that only capacitive currents can flow between the electrodes.
- the electrically-insulating material on the electrodes may be configured to substantially block resistive currents that would otherwise be encountered in normal operation of the apparatus.
- the electrically- insulating material may be made to be thin enough that its dielectric properties do not significantly affect measurements of the dielectric constant of the tissue.
- Figure 3 is a graph showing approximately how the dielectric constant of tissue varies with water content of the tissue. While tissue is not completely uniform and different components of tissue (bones, muscles, ligaments, fat etc.) may have dielectric constants that differ from one another, it remains meaningful to determine an overall dielectric constant of a body part. That overall dielectric constant is related to water content of the tissue as illustrated, for example, in Figure 3. [0029] By periodically monitoring capacitance of a capacitor formed by a body part between two electrodes one can determine whether the water content of the body part is changing (increasing or decreasing). One can also roughly determine the magnitude of the change in water content relative to its original value.
- Capacitance, C, of a parallel-plate capacitor is given by:
- ⁇ is the dielectric constant of the material between the electrodes
- A is the electrode area
- d is thickness of the material between the electrodes (in this case tissue). If one does not know the thickness of tissue between the electrodes (i.e. d) then one cannot determine the value of ⁇ (although one can determine whether and in what direction ⁇ is changing as long as d does not change).
- ⁇ is inversely proportional to the capacitive current /. If one wishes to also determine the value of ⁇ one needs to know the thickness of the tissue between the electrodes. Determining tissue thickness can be done in several ways, such as incorporating in apparatus a sensing element to sense the thickness of the tissue between the electrodes.
- Some embodiments of the invention provide simple low cost devices that can be used by non-medical personnel, even at home for measuring water retention.
- the devices monitor dielectric properties of tissues. Since water has a very high dielectric constant (over 80) compared to other tissue components, the dielectric constant mainly reflects the water content of the tissue.
- the dielectric constant mainly reflects the water content of the tissue.
- measurements are based on the capacitive part of the impedance of tissues rather than the resistive part. Such measurements are substantially unaffected by skin resistance, which can vary significantly from time-to-time in an individual and can vary significantly among different individuals.
- Figure 1 shows an example device 1 that can be placed over body tissue 2 (such as a subject's arm).
- Device 1 comprises parts 3 and 4 coupled by a hinge 5.
- Parts 3 and 4 incorporate electrodes 8 and 9, battery 7, electronics module 10, and readout 11.
- electrodes 8 and 9 are located on opposing sides of body tissue 2.
- the spacing between electrodes 8 and 9 depends on the size of body tissue 2.
- Hinge 5 can open and close to accommodate body tissues 2 of various dimensions.
- a spring or other bias means may be provided to clamp parts 3 and 4 against opposing sides of a body part.
- An angular position sensor 6 such as a variable resistor, an encoder, or the like measures the rotation of hinge 5 and, indirectly, the tissue thickness.
- Readout 11 may comprise a visible indicator, such as a number of LEDs, an LCD display, or the like. Readout 11 may additionally or in the alternative comprise a BluetoothTM or other wireless communication transmitter and/or an onboard memory in which readings may be stored and subsequently uploaded.
- Battery life may be very long as it is typically unnecessary to constantly monitor water content.
- a device 1 may, for example, be used to take a daily reading for which the device would need to be turned on for no more than about one second once per day. Thus even a watch- type battery may last many years. For example, assuming power consumption of 0.3W for 1 second of operation per day, a
- 3V/100mAH lithium watch battery will last about 10 years.
- Some embodiments have the form of wearable devices that include timers that cause a measurement of dielectric properties of a wearer's tissues to be taken automatically at a desired frequency (e.g. once per day).
- Electrodes 8 and 9 are preferably mounted and/or constructed such that they can fit closely against body part 2.
- a small air gap, typically below 1mm, will not introduce a large error but if the whole area of each electrode in contact with the skin accuracy is improved. This may be achieved, for example by one or more of the following.
- One option is to mount one or both of electrodes 8 and 9 so that they can tilt in one or two planes in order to better fit against the body part on which they are placed.
- Another option is to use as one or both electrodes 8 and 9 shallow sealed bags filled with a flowable electrically-conductive material such as an electrically- conductive liquid, paste or gel. Such bags will comply and fit well against any body part.
- Electrodes 8 and/or 9 of a compressible electrically-conductive material such as electrically-conductive foam.
- a compressible electrically-conductive material such as electrically-conductive foam.
- Such electrodes may be, for example, about 1-3 centimeters square and may have a thickness of one centimeter or less.
- Compressible electrodes may, for example, comprise "metal wool", i.e. fine metal wires, fine wires or other electrical conductors embedded in a compressible matrix, a combination of a polymer and a conductive material, for example a carbon-filled polymer foam, other conductive foam or the like.
- Such materials are commercially available and familiar in the art of electromagnetic shielding.
- Another option is to provide springs or the like arranged to bias electrodes 8 and 9 against a body part.
- Another option is to provide electrodes 8 and 9 in the form of patches that may be held against a body part by way of an adhesive, a strap, an inflatable balloon, or the like.
- FIG. 2 is a schematic diagram illustrating an example electronic circuit that may be used to take measurements of the dielectric constant of tissue.
- Oscillator 12 generates an AC (alternating current) signal.
- the frequency of the signal generated by oscillator 12 is not critical and is typically in the kHz or MHz range. MHz frequencies are convenient.
- the amplitude of the signal output by oscillator 12 is not critical but may, for example be on the order of 1 Volt.
- Electrodes 8 and 9 may be electrically insulated from tissue 2, for example by coating electrodes 8 and 9 with thin layers of electrical insulation. As a result any current that passes the capacitor made up of plates 8 and 9 and tissue 2 is capacitive current (any resistive component of current is blocked by the electrical insulation).
- the capacitive current is amplified by amplifier 13, detected by detector 14 (which may, for example, comprise a diode), filtered by capacitor 15 and fed to an optional normalization element 16.
- Normalization element 16 compensates the reading for the tissue thickness to make the reading independent of thickness.
- the thickness of tissue 2 is measured by variable resistor 6 sensing the configuration of hinge 5 (See Fig. 1).
- a signal representing the current passing between the electrodes may be digitized and a signal representing the hinge rotation may already be digital or may be digitized.
- the hinge rotation signal may be used as a key to a first lookup table to retrieve a value for the separation distance between the electrodes.
- the capacitive current and distance can then be used as inputs to a function or lookup table which provides as output a value indicative of the dielectric constant of the tissue.
- the capacitive current is multiplied by the thickness.
- Processing a signal representing capacitive current and a signal representing tissue thickness by multiplication may yield accuracy sufficient for some applications.
- Such multiplication may, for example, be performed by a simple analog multiplier configured to multiply a signal value representing the capacitive current by a signal value representing the thickness.
- the normalized output is fed to readout unit 17 which, in the illustrated embodiment provides an indication of water content of tissue 2 by turning on selected ones of LEDs 11 as well as generating any required alarm signal 18.
- the alarm signal may be visible, audible, a wireless transmitter to automatically alert a physician via a mobile phone network or the Internet, or any combination of the above.
- apparatus may measure the complex impedance of tissue at one or more frequencies.
- Such systems may provide more accurate water content measurements than simpler systems and may also supply more information on the type of tissue and its composition.
- a device 1 which includes a controller configured to detect a phase and amplitude of the current passed through tissue 2 between electrodes 8 and 9.
- the controller may be configured to control oscillator 12 to vary the frequency of the signal delivered to electrode 9 and to measure the amplitude of the resulting current (or the phase and amplitude of the current in some embodiments) passed through tissue 12 at two or more different frequencies.
- Dispersion can supply further information about the composition of the tissue.
- To measure dispersion oscillator 12 may be configured to generate several frequencies, either sequentially or at the same time.
- Detector 14 measures the electrical signal at each one of those frequencies. More complete data about tissue discrimination using multiple frequencies is given in US Patent Publication No. 2007/0270688, by the same inventors. This application is hereby incorporated herein by reference for all purposes.
- Electrodes 19 and 20 may be the same as electrodes 8 and 9 and device 1A may be constructed such that electrodes 19 and 20 are symmetrical to electrodes 8 and 9 about hinge 5 (e.g. so that the spacing between electrodes 8 and 9 is the same as the spacing between electrodes 19 and 20), and the signal applied across electrodes 19 and 20 are the same as the signal applied across electrodes 8 and 9.
- the ratio of the current between electrodes 8 and 9 to the current between electrodes 19 and 20 is the dielectric constant of the tissue.
- water content of the tissue may be estimated using a relationship such as the relationship illustrated graphically in Figure 3.
- an ultrasonic transducer located on or near to a first one of the electrodes may emit ultrasound toward the other (second) electrode.
- the ultrasound may be detected by an ultrasound receiver at the second electrode or the ultrasound may be detected at the first electrode after being reflected at the second electrode. Thickness of the tissues may be determined from the time between emission and detection of the ultrasound.
- Another option for determining the spacing between electrodes is to provide a mechanism such as a strap or other adjustable-size device for holding the electrodes against the body part.
- a user may adjust the device to hold the electrodes against the body part and then enter into the device using a user interface a value indicating the adjusted size of the device.
- the device may be marked with indicia indicating its adjusted size.
- Another option for determining the spacing between electrodes is to support the electrodes on a resilient clip (e.g. a resilient C-shaped bracelet that can be worn around a person's wrist or ankle).
- the clip can deform resiliently to accommodate body parts of different dimensions.
- a strain gauge may be provided to measure the deformation of the clip, the electrode spacing is related to the deformation of the clip and may be determined using a function or lookup table or the like.
- Devices according to other example embodiments of the invention can be configured in other forms, for example in the form of a bracelet that a user may wear over an extended period of time.
- the two electrodes may be provided at diametrically opposed positions on the bracelet.
- Such a bracelet may be worn, for example, on the wrist or the ankle.
- the electronic circuit can be designed to turn on for a very brief period, say one second, once per day.
- a timer may be provided to automatically turn on the electronic circuit to take measurements. This will allow even a very small battery to last many years. Since the bracelet has a fixed size, thickness compensation can be eliminated by calibration. An example of such a bracelet is shown in Figure 5.
- Electrodes 8 and 9 can be spring-loaded or made of or supported by a compliant material to assure good contact with tissue.
- the patient simply slips the device over their arm (or other body part) daily and sees the result instantly. There is minimal time delay involved in the measurement, typically less than one second.
- the patient may simply wear the bracelet at all times. A timer in the bracelet may periodically wake the device up to take a measurement.
- Electrodes may be held against a body part by a strap, such as a watch strap.
- the apparatus is integrated with a watch.
- a back face of the watch serves as one electrode.
- a second electrode is supported on the watch strap.
- the second electrode may be slidable along the strap so that it can be positioned on an opposing side of the wearer's arm from the watch.
- a battery may provide electrical power both for the watch and an impedance-measuring circuit.
- Timing circuits of the watch may optionally trigger periodic operation of the impedance-measuring circuit.
- An oscillator used to provide a time reference for the watch may optionally also provide an AC signal for use in the impedance measurement.
- Apparatus as described herein may be provided in combination with a blood- pressure meter comprising an inflatable cuff. Electrodes may be provided on the cuff so that the electrodes are pressed against opposite sides of a person's limb when the cuff is inflated.
- the apparatus may optionally be configured to automatically obtain a measure of the impedance between the electrodes each time the apparatus is operated to acquire a blood pressure reading.
- the apparatus may be configured to display and/or store and/or transmit a blood pressure reading and a reading indicative of water retention.
- An alternative method of detecting the onset of conditions that may lead to heart failure is to monitor for changes in electrical impedance (preferably capacitive impedance as discussed above). In such embodiments it is not mandatory to determine a value for the impedance. All that is required is to monitor a value that has a known relationship to the impedance (i.e. a value such that one can tell whether the impedance is increasing or decreasing through observation of the value). Any rapid decrease in impedance signifies water retention, as the impedance decreases as the dielectric constant, reflecting water content, is increasing. By setting up a baseline from daily measurements between two electrodes, a trend can be established without knowing the absolute value of the impedance. This eliminates the need to know the tissue thickness.
- An alternative embodiment provides an ultrasound transmitter and an ultrasound receiver (the ultrasound transmitter and receiver may be separate but may both be provided by a single transducer in some embodiments).
- An electronic circuit is connected to drive the ultrasound transmitter to emit ultrasound.
- the emitted ultrasound is detected at the ultrasound receiver after passing through tissues of a subject along a path having a known length or a path having a fixed length (whether or not the fixed length is known).
- the time interval between the transmission of the ultrasound and its reception depends on the speed of ultrasound propagation through the subject's tissues and on the path length.
- the apparatus may be configured to monitor for changes in the time interval where the path length is fixed and/or determine the speed of ultrasound propagation and monitor for changes in the speed of ultrasound propagation where the path length is known.
- the results of such monitoring can indicate changes in the water content of the tissues through which the ultrasound passes and can be applied as described above, for example.
- An example embodiment provides an ultrasonic wrist strap. A person's wrist contains bones, muscles, fat, saline solution (blood) and other tissues. The speed of propagation of ultrasound is different in each of these tissue components. The dispersion of ultrasound also differs among these components.
- the velocity of sound in bone can be double that of a saline solution (about 3000 m/s as opposed to about 1500 m/s) and triple that of fat.
- a saline solution about 3000 m/s as opposed to about 1500 m/s
- the composition of the wrist can be found and water retention measured, using methods similar to the ones described above for electrical impedance.
- the ultrasonic transmitter and receiver can be located at similar locations to the electrodes in the electrical impedance apparatus described above.
- an ultrasound transmitter and receiver are both located on one side of a body part and an ultrasound reflecting element is located on the opposing side of the body part such that ultrasound transmitted by the ultrasound transmitter passes through the body part to the ultrasound reflector, is reflected, and then passes back through the body part to the ultrasound receiver.
- the ultrasound reflector may comprise a metal plate or other element having an acoustic impedance significantly different from the acoustic impedance of the adjacent tissue.
- an ultrasound transmitter is provided on one side of the body part and an ultrasound receiver is provided on an opposing side of the body part.
- Some embodiments may employ both ultrasound and electrical impedance measurements and may process such measurements to determine an indication of water retention.
- Ultrasound measurements typically require more power than electrical impedance measurements. However, since suitable measurements can be obtained by operating the measuring components of a device for a few seconds or less each day, battery life can still be acceptable where ultrasound measurements are performed.
- connection means any connection or coupling, either direct or indirect, between two or more elements; the coupling or connection between the elements can be physical, logical, or a combination thereof.
- Embodiments of the invention may be implemented using specifically designed hardware, configurable hardware, programmable data processors configured by the provision of software (which may optionally comprise 'firmware') capable of executing on the data processors, special purpose computers or data processors that are specifically programmed, configured, or constructed to perform one or more steps in a method as explained in detail herein and/or combinations of two or more of these.
- specifically designed hardware are: logic circuits, application-specific integrated circuits ("ASICs”), large scale integrated circuits (“LSIs”), very large scale integrated circuits (“VLSIs”) and the like.
- configurable hardware examples include one or more programmable logic devices such as programmable array logic (“PALs”), programmable logic arrays (“PLAs”) and field programmable gate arrays (“FPGAs”).
- PALs programmable array logic
- PLAs programmable logic arrays
- FPGAs field programmable gate arrays
- programmable data processors are: microprocessors, digital signal processors ("DSPs"), embedded processors, and the like.
- DSPs digital signal processors
- one or more data processors in a control circuit for a device may implement methods as described herein by executing software instructions in a program memory accessible to the processor(s).
- Processing may be centralized or distributed. Where processing is distributed, information including software and/or data may be kept centrally or distributed. Such information may be exchanged between different functional units by way of a communications network, such as a Local Area Network (LAN), Wide Area Network (WAN), or the Internet, wired or wireless data links, electromagnetic signals, or other data communication channel.
- LAN Local Area Network
- WAN Wide Area Network
- Internet wired or wireless data links
- electromagnetic signals electromagnetic signals
- Embodiments of The invention may also be provided in the form of program products.
- the program products may comprise any non-transitory medium which carries a set of computer-readable instructions which, when executed by a data processor, cause the data processor to execute a method of the invention.
- Program products according to the invention may be in any of a wide variety of forms.
- the program product may comprise, for example, non-transitory media such as magnetic data storage media including floppy diskettes, hard disk drives, optical data storage media including CD ROMs, DVDs, electronic data storage media including ROMs, flash RAM, EPROMs, hardwired or preprogrammed chips (e.g., EEPROM
- the computer- readable signals on the program product may optionally be compressed or encrypted.
- the invention may be implemented in software.
- "software” includes any instructions executed on a processor, and may include (but is not limited to) firmware, resident software, microcode, and the like. Both processing hardware and software may be centralized or distributed (or a combination thereof), in whole or in part, as known to those skilled in the art. For example, software and other modules may be accessible via local memory, via a network, via a browser or other application in a distributed computing context, or via other means suitable for the purposes described above.
- a component e.g.
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
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DE112012002765.5T DE112012002765T5 (en) | 2011-07-18 | 2012-07-18 | Water retention Monitoring |
GB1402857.5A GB2507698A (en) | 2011-07-18 | 2012-07-18 | Water retention monitoring |
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US13/135,867 US20130023751A1 (en) | 2011-07-18 | 2011-07-18 | Water retention monitoring |
US13/135,867 | 2011-07-18 |
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WO2013010276A1 true WO2013010276A1 (en) | 2013-01-24 |
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PCT/CA2012/050490 WO2013010276A1 (en) | 2011-07-18 | 2012-07-18 | Water retention monitoring |
Country Status (4)
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US (1) | US20130023751A1 (en) |
DE (1) | DE112012002765T5 (en) |
GB (1) | GB2507698A (en) |
WO (1) | WO2013010276A1 (en) |
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EP3477257A1 (en) * | 2017-10-31 | 2019-05-01 | Vestel Elektronik Sanayi ve Ticaret A.S. | An electronic device for obtaining a measure of a user's wrist thickness |
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US9770185B2 (en) * | 2014-08-06 | 2017-09-26 | Verily Life Sciences Llc | Sharing a single electrode between skin resistance and capacitance measurements |
CN106137191A (en) * | 2015-04-07 | 2016-11-23 | 联想(北京)有限公司 | A kind of electronic equipment and information processing method |
KR101940860B1 (en) * | 2016-09-06 | 2019-01-22 | 주식회사 포스코 | Apparatus for measuring thickness of stave in furnace |
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GB2562297A (en) * | 2017-05-12 | 2018-11-14 | Univ Sheffield | Apparatus for electrical impedance spectroscopy |
EP3505046A1 (en) * | 2017-12-27 | 2019-07-03 | Koninklijke Philips N.V. | Determining a water or lipid level of skin |
JP2021531901A (en) * | 2018-07-27 | 2021-11-25 | バイオトロニック エスエー アンド カンパニー カーゲーBIOTRONIK SE & Co. KG | Devices, systems, and methods for determining fluid retention in a patient's lower extremities |
CN109938729A (en) * | 2019-03-29 | 2019-06-28 | 常州市第二人民医院 | A kind of control water early warning Intelligent foot ring |
EP4181921A1 (en) | 2020-07-15 | 2023-05-24 | Third Harmonic Bio, Inc. | Crystalline forms of a selective c-kit kinase inhibitor |
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Also Published As
Publication number | Publication date |
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DE112012002765T5 (en) | 2014-04-17 |
US20130023751A1 (en) | 2013-01-24 |
GB201402857D0 (en) | 2014-04-02 |
GB2507698A (en) | 2014-05-07 |
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