Abstract: Apparatus for use in performing impedance measurements on a subject. The apparatus includes a processing system for causing a first signal to be applied to the subject, determining an indication of a second signal measured across the subject, using the indication of the second signal to determine any imbalance and if an imbalance exists, determining a modified first signal in accordance with the imbalance and causing the modified first signal to be applied to the subject to thereby allow at least one impedance measurement to be performed.

Abstract: A method of monitoring pulmonary oedema in a subject using a processing system. The method includes, determining a measured impedance value for at least two body segments, at least one of the body segments being a thoracic cavity segment. For each body segment, the measured impedance values are used to determine an index, which is in turn used to determine the presence, absence or degree of pulmonary oedema using the determined indices.

Abstract: A method of determining frequencies for use in performing impedance measurements. The method includes determining estimates for parameter values representing an impedance response for at least one subject, using the estimated parameter values to determine a design and using the design to determine frequencies for use in impedance measurements.

Abstract: A method of detecting tissue oedema in a subject. The method includes determining a measured impedance for first and second body segments. An index indicative of a ratio of the extra-cellular to intra-cellular fluid is then calculated for each body segment, with these being used to determine an index ratio based on the index for the first and second body segments. The index ratio can in turn be used to determine the presence, absence or degree of tissue oedema, for example by comparing the index ratio to a reference or previously determined index ratios.

Abstract: A method of detecting tissue oedema in a subject. The method includes determining a measured impedance for first and second body segments. An index indicative of a ratio of the extra-cellular to intra-cellular fluid is then calculated for each body segment, with these being used to determine an index ratio based on the index for the first and second body segments. The index ration can in turn be used to determine the presence, absence or degree of tissue oedema, for example by comparing the index ratio to a reference or previously determined index ratios.

Abstract: A method of monitoring pulmonary oedema in a subject using a processing system. The method includes, determining a measured impedance value for at least two body segments, at least one of the body segments being a thoracic cavity segment. For each body segment, the measured impedance values are used to determine an index, which is in turn used to determine the presence, absence or degree of pulmonary oedema using the determined indices.

Abstract: A method of determining a measure of lean tissue mass for a segment of a subject, the method including, in a processing system, determining at least one impedance value at at least one frequency, the at least one impedance value representing the impedance of the segment, determining a tissue mass impedance parameter value using the at least one impedance value and determining a tissue mass indicator based at least in part on the tissue mass impedance parameter value.

Abstract: A method of detecting tissue oedema in a subject. The method includes determining a measured impedance for first and second body segments. An index indicative of a ratio of the extra-cellular to intra-cellular fluid is then calculated for each body segment, with these being used to determine an index ratio based on the index for the first and second body segments. The index ratio can in turn be used to determine the presence, absence or degree of tissue oedema, for example by comparing the index ratio to a reference or previously determined index ratios.

Abstract: A method for performing impedance measurements on a subject. The method includes, in a processing system, causing at least one electrical signal to be applied to the subject via first leads operatively connected to first electrodes provided on the subject, determining a first indication indicative of at least one first electrical signal measured via second leads operatively disconnected from second electrodes positioned on the subject, determining a second indication indicative of at least one second electrical signal measured via second leads operatively connected to second electrodes positioned on the subject, and determining from the indications and the at least one applied signal, at least one instantaneous impedance value.

Abstract: Apparatus for performing impedance measurements on a subject. The apparatus includes a first processing system for determining an impedance measurement procedure and determining instructions corresponding to the measurement procedure. A second processing system is provided for receiving the instructions, using the instructions to generate control signals, with the control signals being used to apply one or more signals to the subject. The second processing system then receives first data indicative of the one or more signals applied to the subject, second data indicative of one or more signals measured across the subject and performs at least preliminary processing of the first and second data to thereby allow impedance values to be determined.

Abstract: Apparatus for performing impedance measurements on a subject. The apparatus includes a first processing system for determining an impedance measurement procedure and determining instructions corresponding to the measurement procedure. A second processing system is provided for receiving the instructions, using the instructions to generate control signals, with the control signals being used to apply one or more signals to the subject. The second processing system then receives first data indicative of the one or more signals applied to the subject, second data indicative of one or more signals measured across the subject and performs at least preliminary processing of the first and second data to thereby allow impedance values to be determined.

Abstract: In various embodiments, applicants' teachings are related to an active guarding circuit and method for reducing parasitic impedance signal loading on a signal-transmission channel that is shunted by a parasitic impedance. The presence of an electrical signal on the signal-transmission channel causes a leakage current to flow through the parasitic impedance. In various embodiments, the circuit comprises an amplifier and an impedance, one terminal of the impedance is coupled to the signal-transmission channel. The input of the amplifier is coupled to the signal-transmission channel and the output is coupled to the other terminal of the impedance so as to cause a compensation current to flow through the impedance. The gain of the amplifier and the value of the impedance are selected so that the compensation current has a magnitude substantially equal to the leakage current magnitude.

Abstract: A method for use in analysing impedance measurements performed on a subject, the method including, in a processing system, determining at least one impedance value at at least one frequency, the at least one impedance value representing the impedance of a segment of the subject, determining a tissue impedance parameter value using the at least one impedance value and determining a tissue indicator based at least in part on the tissue impedance parameter value.

Abstract: A method for use in analysing impedance measurements performed on a subject, the method including, in a processing system, determining at least one impedance value at each of a number of frequencies, each impedance value representing the impedance of a segment of the subject, determining a dispersion parameter value indicative of a dispersion of the impedance values and, determining an indicator based at least in part on the dispersion parameter value.

Abstract: Apparatus for electrically connecting measurement apparatus to a biological subject, the apparatus including a signal delivery circuit including a current buffer having a current buffer input for receiving a signal from a signal source and a current buffer output for supplying a current to an electrode attached to the biological subject, and a voltage buffer having a voltage buffer input coupled to the current buffer output and a voltage buffer output for providing a voltage signal indicative of a voltage at the electrode, to a sensor.

Abstract: Apparatus for performing impedance measurements on a subject. The apparatus includes a first processing system for determining an impedance measurement procedure and determining instructions corresponding to the measurement procedure. A second processing system is provided for receiving the instructions, using the instructions to generate control signals, with the control signals being used to apply one or more signals to the subject. The second processing system then receives first data indicative of the one or more signals applied to the subject, second data indicative of one or more signals measured across the subject and performs at least preliminary processing of the first and second data to thereby allow impedance values to be determined.

Abstract: A method for use in analysing impedance measurements performed on a subject, the subject being arranged such that body fluid levels in at least one leg segment of the subject changes between a first time and a second time, the method including, in a processing system, at the first time, determining at least one first impedance value indicative of the impedance of the at least one leg segment of the subject; at the second time, determining at least one second impedance value indicative of the impedance of the at least one leg segment of the subject; and, determining an indicator based on the at least one first and at least one second impedance values, the indicator being indicative of changes in the body fluid levels.

Abstract: The present invention provides a method of assessing tissue oedema, in particular lymphoedema, by measuring bioelectrical impedance at a single frequency. Comparison of a single frequency bioelectrical impedance measurement taken at an anatomical region affected by tissue oedema to that taken at an anatomical region unaffected by tissue oedema is a reliable indicator of the presence or possible presence of lymphoedema. The present invention further provides an apparatus for determining the presence of tissue oedema.

Abstract: An electrode assembly for use with a subject, the assembly including, a substrate including at least one moveable substrate portion; first and second conductive elements provided on the substrate, the first and second conductive elements being spaced apart, and being adapted to provide an electrical connection to the subject; and, first and second terminals, each terminal being electrically coupled to a respective conductive element, and at least part of each terminal being provided on the at least one moveable substrate portion, such that movement of the substrate portion allows at least part of the terminal to extend away from the substrate to thereby facilitate connection of the terminal to a respective connector.

Abstract: A method for detecting and diagnosing disease states in a body part is described. The method starts with a preparatory step of modeling the body part as a grid of many finite elements, then calculating an electrical property between two finite elements at which current from two corresponding electrodes flows through the body part. This is termed the weight (influence) of the element. With this baseline information, electrical impedance measurements made at the plurality of electrodes on the periphery of the body part can be used in a diagnostic module to calculate a Weighted Element Value (WEVal) for each element. In a preferred embodiment of invention, the difference in WEVal magnitude between corresponding elements of homologous body parts serves as an indicator of the presence of disease.