Abstract: An adherent device is configured to adhere to the skin of the patient with an adherent patch, for example breathable tape, coupled to at least four electrodes. The device comprises impedance circuitry coupled to the at least four electrodes and configured to measure respiration of the patient to detect sleep apnea and/or hypopnea. The impedance circuitry may be used to measure hydration of the patient. An accelerometer can be mechanically coupled to the adherent patch such that the accelerometer can be coupled to and move with the skin of the patient. Electrocardiogram circuitry to generate an electrocardiogram signal may be coupled to at least two of the at least four electrodes to detect the sleep apnea and/or hypopnea.

Abstract: A system comprising implantable device, the implantable medical device including an intrinsic cardiac signal sensor, an impedance measurement circuit configured to apply a specified current to a transthoracic region of a subject and to sample a transthoracic voltage resulting from the specified current, and a processor coupled to the intrinsic cardiac signal sensor and the impedance measurement circuit. The processor is configured to initiate sampling of a transthoracic voltage signal in a specified time relation to a fiducial marker in a sensed intrinsic cardiac signal, wherein the sampling attenuates or removes variation with cardiac stroke volume from the transthoracic voltage signal, and determine lung respiration using the sampled transthoracic voltage signal.

Abstract: A method, and an apparatus to perform the method, of determining a location of a medical instrument in a patient during a medical procedure, the method including connecting at least a portion of the medical instrument to a first body region of the patient, propagating a plurality of signals at different frequencies along a conductive path of the medical instrument, measuring one or more feedback parameters corresponding to each of the plurality of signals at the first body region, determining an operational frequency from the different frequencies according to a comparison of the one or more feedback parameters, propagating a signal having the operational frequency along the conductive path as the medical instrument penetrates the body of the patient during the medical procedure, and measuring the one or more feedback parameters corresponding to the operational frequency to determine a penetration location of the medical instrument in the body of the patient.

Abstract: In embodiments, an external medical device is intended to care for a patient. If it receives an input that signifies that ventilation artifact is present in a signal of the patient, it transmits a corrective signal responsive to the received input. In further embodiments, a patient signal is received, which is generated from a patient while the patient is or was receiving chest compressions at a frequency Fc, and also receiving ventilations at frequency Fv. At least one filter mechanism may be applied to the patient signal to substantially remove artifacts at a) frequency Fc, b) a higher harmonic of frequency Fc, and c) a third frequency substantially equaling frequency Fc plus or minus frequency Fv, while substantially passing other frequencies between them. As a result, the patient signal can be cleaner, for diagnosing the patient's state more accurately.

Abstract: A method for forming an electropotential map, including: measuring locations of points on a surface of a body organ, and measuring electrical potentials of a subset of the points. The method further includes assigning respective resistances to line segments joining the points so as to define a resistor mesh, and generating an electropotential map of the surface by applying an harmonic function to the resistor mesh responsive to the measured electrical potentials.

Abstract: A wound healing system comprising an array of electrodes incorporated in a device for applying an electrical signal to a wound. The electrodes are configurable to form at least one composite electrode and the electrical signal is applied to the wound via the composite electrode(s). The system preferably includes means for determining the state of the wound, the electrode composition of the composite electrode(s) depending on the determined state of the wound. Advantageously, the electrode composition of the composite electrode(s) is adjustable in response to changes in the determined state of the wound.

Abstract: A method and system for measuring the electrical impedance of sections of a living body. The measurement is carried out utilizing a plurality of electrodes each of which is disposed on a section of the living body, where the electrodes are capable of applying an electrical current through at least one probed section, and measure the electrical voltage over the probed section. The voltages over the probed sections are measured and the impedances (Z(t)) and their changes (?Z(t)), and the resistances R(t) and their changes (?R(t)), are calculated, by considering the electrical current distortion components resulting from the electrical currents flowing in the other sections which are not probed, utilizing an electrical model based on the distribution of the electrical currents through the body sections.

Abstract: Computer-implemented techniques are disclosed for analyzing physiology data captured by biosensors and for providing alerts based on the biosensor data. The biosensor data is captured non-invasively and is analyzed to identify atypical brain activity that can result from illness, injury, disease, and seizures. The biosensor data can include electrodermal activity, skin temperature, and accelerometer data. The data is sent to a web service for analysis, and to determine whether an alert should be generated. The alerts, based on the biosensor data captured from the individual, are received from the web service. An output related to physiology is rendered based on an alert being received from the web service.

Abstract: This invention relates generally to electro-anatomical mapping method and an apparatus using a catheter and more particularly to a mapping catheter having an embedded MOSFET sensor array for detecting local electrophysiological parameters such as biopotential signals within an excitable cellular matrix geometry, for determining physiological as well as electrical characteristics of conduction path and its underlying substrate within the endocardial and epicardial spaces, the arterial structure and in ganglionic plexus. The apparatus with its MOSFET sensor is geometrically configured as a decapolar linear array and optionally with an 8×8 sensor matrix placed on a balloon-like structure.

Abstract: Techniques are provided for estimating defibrillation impedance of an implantable cardioverter/defibrillator (ICD). Briefly, at least two low-voltage resistance values are measured at different voltages using a pair of stimulation electrodes connected to the ICD. High-voltage defibrillation impedance is then estimated by the ICD based on a weighted combination of the measured resistance values. In one example, a set of weight coefficients, calculated during an initial calibration procedure, are applied to the measured resistance values to produce the estimate of the high-voltage defibrillation impedance. The weight coefficients are updated whenever a defibrillation shock is delivered, based on actual defibrillation impedance values measured during the shock.

Abstract: This version will replace all prior versions in the application: A method and a device for determining the body weight of a person, in which at least one parameter typical for a biological impedance measurement is determined and transmitted to an evaluation unit. The evaluation unit processes the measurement value together with individual or several individual data of the person as well as taking into consideration statistical data concerning other persons, in order to determine an estimated value for the weight of the person.

Abstract: A method and a device for determining biological impedance data of a person, in which least one impedance value is measured with the use of at least two electrodes and is transmitted to an evaluation unit. In the area of at least one output device, information concerning the person is made available for assuming an optimum body posture for the measurement of the biological impedance.

Abstract: A body fat measurement device includes a trunk area dimension measurement unit in which is provided a trunk area dimension detection unit for detecting a dimension of a measurement subject's trunk area. The trunk area dimension measurement unit has a frame shape that can be disposed surrounding the measurement subject's trunk area, and includes a base portion whose position relative to the trunk area does not change in a state where the trunk area dimension measurement unit is disposed surrounding the trunk area, and a mobile portion that is attached in a movable state to the base portion and whose position relative to the trunk area can change in a state where the trunk area dimension measurement unit is disposed surrounding the trunk area. The trunk area dimension detection unit includes at least a non-contact range sensor provided in the mobile portion.

Abstract: A detection portion for detecting a first potential difference between hand and foot by applying a current across the hand and the foot of a subject through both of a hand electrode and a foot electrode and detecting a second potential difference between both hands or between both feet by applying a current across both hands or across both feet of the subject through any one of the hand electrodes and the foot electrodes, a first body composition calculation portion for calculating a first whole-body composition by using whole-body impedance based on a result of detection of the first potential difference, a correction portion for correcting two-limb impedance based on a result of detection of the second potential difference, and a second body composition calculation portion for calculating a second whole-body composition by using the corrected two-limb impedance are included.

Abstract: The present invention provides a system for evaluating motor control function in the brain.

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 user may react to an interaction by exhibiting a mental state. A camera or other monitoring device can be used to capture one or more manifestations of the user's mental state, such as facial expressions, electrodermal activity, or movements. However, there may be conditions where the monitoring device is not able to detect the manifestation continually. Thus, various capabilities and implementations are described where the mental state data is collected on an intermittent basis, analyzed, and an output rendered based on the analysis of the mental state data.

Abstract: A capacitive touch screen device forms a capacitance between a body part of a user and a sensor layer. The sensor layer of the device includes capacitive sensors that allow a current to flow to the body part from the device when contact is made. The body part contacts the device through a bodily fluid. The current drawn is measured and a value for the bodily fluid is determined. This value is compared against known values to diagnose a possible medical condition or to infer characteristics of the bodily fluid.

Abstract: An apparatus and method for obtaining one or more physiological measurements associated with a user using ear-located sensors is disclosed herein. One or more of different types of sensors are configured to engage a user's ear. In some cases, the sensors will be included in one or both of a pair of earphones to capture physiological parameters. A portable device is configured to be in communication with the earphones to receive physiological parameters from the sensor(s) therein, and to potentially provide control signals to the sensors or other components in the earphones. The portable device determines physiological measurements corresponding to the received physiological parameters. The portable device is also configured to provide a user interface to interact with the user regarding the physiological measurements.

Abstract: An apparatus and method for obtaining one or more physiological measurements associated with a user using ear-located sensors is disclosed herein. One or more of different types of sensors are configured to engage a user's ear. In some cases, the sensors will be included in one or both of a pair of earphones to capture physiological parameters. A portable device is configured to be in communication with the earphones to receive physiological parameters from the sensor(s) therein, and potentially to provide control signals to the sensors or other components in the earphones. The portable device determines physiological measurements corresponding to the received physiological parameters. The portable device is also configured to provide a user interface to interact with the user regarding the physiological measurements.

Abstract: Catheter systems for measuring at least one electrical property, e.g., impedance, of cardiac tissue of a living being are disclosed. The system includes a catheter having a tip with a sensing electrode, a guard electrode and an electrical shield. The sensing electrode is arranged to engage the cardiac tissue and is coupled to circuitry for measuring the at least one electrical property of the cardiac tissue, shielding the sensing electrode from bulk blood adjacent the cardiac tissue. The measurement can gated to the cardiac cycle. Additional embodiments include multi-electrode sensor catheter tips for high density mapping. Moreover, such tips may be dynamically configurable, i.e., their electrodes can be variably assigned as sensor electrodes or guard electrodes by associated circuitry. Such multi-electrode configuration and reconfiguration can be gated to the cardiac cycle.

Abstract: Methods and apparatus for the prevention and treatment of shivering encountered during therapeutic temperature regulation are disclosed that utilize an active system of counterwarming such that the timing and intensity of warmth provided to selected body areas is regulated dynamically in response to such factors as the extent of cooling applied to the core, the degree of shivering encountered, and patient temperature. Additionally, methods and apparatus are disclosed for the measurement and quantification of shivering for use in this and other applications.

Abstract: The invention provides an electrophysiological analysis system, in particular for detecting pathological states. This system comprises: electrodes intended to be placed in different regions of the body that are well away from each other; an adjustable DC voltage source for generating successive DC voltage pulses varying in magnitude from one pulse to another, the duration of the pulses being equal to or greater than about 0.2 seconds; a switching circuit for selectively connecting a pair of active electrodes to the voltage source and for connecting at least one other high-impedance electrode; and a measurement circuit for recording data representative of the current in the active electrodes and potentials on at least certain high-impedance connected electrodes in response to the application of said pulses. The range of voltages covered causes, from one pulse to another, the appearance or disappearance of electrochemical phenomena in the vicinity of the active electrodes.

Abstract: A human skin moisture measuring device having an interdigitated resistive sensor formed on a plate-like transparent support is described, with a face designed to be placed into contact with the skin to be subjected to the moisture degree measurement. The device further comprises image sensing means turned towards the opposite face of the support and a lighting device arranged sideways relative to the support to direct the light radiation in the support at a prefixed angle. Means for processing the signal coming from the interdigitated resistive sensor and from the image sensing means give as output a value of the measured moisture degree that is normalized with respect to the actual surface of contact between skin and sensor.

Abstract: A method for treating lung tissue of a patient is provided. A pathway to a point of interest in a lung of a patient is generated. An extended working channel is advanced transorally into the lung and along the pathway to the point of interest. The extended working channel is positioned in a substantially fixed orientation at the point interest. A tool is advanced though the extended working channel to the point of interest. The lung tissue is treated at the point of interest.

Abstract: A method for identifying and activating specific axonal pathways for achieving therapeutic benefits during a neural stimulation, such as deep brain stimulation. Clinical data, diffusion tensor tractography, and computer models of patient-specific neurostimulation may be used to identify particular axonal pathways activated by deep brain stimulation and to determine their correlations with specific clinical outcomes.

Abstract: Embodiments of devices and methods for evaluating tissue are disclosed. In one embodiment, a method for measuring a characteristic of a tissue may include passing a current through the tissue, measuring a signal corresponding to the voltage resulting from passing the current through the tissue, analyzing current passed through the tissue and resulting voltage to determine the electrical characteristics of the tissue; and analyzing the electrical characteristics of the tissue to determine a status of the tissue.

Abstract: Spatial arrays of electrodes are provided, each array in a region of tissue. The electrodes of an array are connected so that some of the electrodes serve as shield electrodes relative to a pair of electrodes used for pulse stimulation or sensing of electrical activity, or both. The shield electrodes are connected together, defining an electrical node, the node defining a stable potential in predetermined relationship with power supply levels or with reference voltages for sensing circuitry. Multiplexing techniques may be employed so that sensed activity at each of several electrode locations can be communicated to electronics external to the electrode locations.

Abstract: The present invention provides a method of measuring an acoustic impedance of a respiratory system. The method comprises selecting a frequency range for an acoustic wave, directing the acoustic wave into the respiratory system and receiving an acoustic wave from the respiratory system. The method also comprises determining the acoustic impedance for a plurality of volumes or volume ranges of the respiratory system. Each volume, or the volumes within each volume range, is larger than RV or FRC and smaller than TLC whereby the determined acoustic impedances are specific for respective volumes or volume ranges. Further, the method includes determining a volume, or volume range, dependency of the acoustic impedance of the respiratory system and characterizing the respiratory system by analyzing the dependency of the acoustic impedance on the volume or volume range.

Abstract: A system and method are provided for assessing the compliance of internal patient tissue for purposes of catheter guidance and/or ablation procedures. Specifically, the system/method provides for probing internal patient tissue in order to obtain force and/or tissue displacement measurements. These measurements are utilized to generate an indication of tissue elasticity. In one exemplary embodiment, the indication of elasticity is correlated with an image of the internal tissue area and an output of this image including elasticity indications is displayed for a user.

Abstract: The present invention relates to a stress-measuring device (10) and method for determining a level (15) of stress of a user (1), in particular long-term stress. The stress-measuring device (10) comprises an input interface (12) for receiving a skin conductance signal (11) indicating the skin conductance of the user (1), the skin conductance signal (11) over time forming skin conductance trace data (13). The stress-measuring device (10) further comprises a processing unit (14) for processing the skin conductance trace data (13), the processing unit (14) adapted to determine, over at least a portion of the skin conductance trace data (13), values of a rise time (tr) between at least two different points of the skin conductance trace data (13), to determine a frequency distribution of the rise time (tr) values, and to determine the level (15) of stress of the user (1) based on the determined frequency distribution.

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 muscle-activity diagnosis apparatus includes: an acquiring section acquiring a myoelectric signal from a test subject; using the myoelectric signal as an original signal, a transformed-signal generating section generating a transformed signal by performing Hilbert transformation and inverse Fourier transformation on the original signal; a phase-velocity calculation section calculating a phase velocity of the myoelectric signal on the basis of phases of the original signal and the transformed signal; and on the basis of a plurality of feature quantities of a waveform of the myoelectric signal in a unit time and the plurality of feature quantities including at least a size of amplitude of the myoelectric signal and the calculated phase velocity, a state-identifying section identifying an activity state of a muscle of a predetermined part of a body of the test subject for each of the unit time.

Abstract: Disclosed are apparatus and methods that provide the ability to electrical stimulate a physical system, and actively eliminate interference with signal acquisition (artifacts) that arises from the stimulation. The technique implemented in the circuits and methods for eliminating interference connects a discharge path to a physical interface to the system to remove charge that is built-up during stimulation. By placing the discharge path in a feedback loop that includes a recording preamplifier and AC-coupling circuitry, the physical interface is brought back to its pre-stimulation offset voltage. The disclosed apparatus and methods may be used with piezoelectric transducers, ultrasound devices, optical diodes, and polarizable and non-polarizable electrodes. The disclosed apparatus can be employed in implantable devices, in vitro or in vivo setups with vertebrate and invertebrate neural tissue, muscle fibers, pancreatic islet cells, osteoblasts, osteoclasts, bacteria, algae, fungi, protists, and plants.

Abstract: An emotion excitement detection system includes a detection unit for engagement with human skin, an amplifier unit connected to the detection unit to amplify signal detected by the detection unit, a first control unit connected to the amplifier unit for measurement of skin conductance after the detection unit engages with the human skin and transmit result of the measurement and a processing unit producing a skin conductance slope in response to the skin conductance and excitement degree resulted from the skin conductance slope.

Abstract: Various embodiments relate to a method, apparatus, system, and a computer program product for suppressing an oscillatory signal Sosc. In the method a composite signal S comprising said Sosc and a modulating signal Smod are provided and the S is high pass filtered to produce estimates of the Sosc and the Smod, wherein the estimate of the Sosc comprises first oscillations during a first state of the modulating signal and second oscillations during a second state of the modulating signal. A first bin associated with said first state and a second bin associated with said second state are defined and assigned for said first oscillation and the second bin for said second oscillation according to a state defined from the estimate of the Smod. A first average waveform for said first oscillations and a second average waveform for said second oscillations are formed and used to suppress the Sosc signal from the composite signal S.

Abstract: The present invention relates to coupler device, processing apparatus and method of processing a plurality of body-coupled communication signals which have been detected by using an electrode arrangement with a plurality of electrodes or electrode segments (40, 42; 40, 43). Respective transmission parameters of the body-coupled communication signals are estimated and at least one of a selecting and weighting processing is applied to the detected body-coupled communication signals based on the estimated transmission parameters. Then, the processed body-coupled communication signals are combined to generate a diversity output signal. Thereby, robustness against coupler misplacement and user convenience is increased in body-coupled or body-based communication systems.

Abstract: A method and apparatus of determining the condition of a bulk tissue sample, by: positioning a bulk tissue sample between a pair of induction coils (or antennae); passing a spectrum of alternating current (or voltage) through a first of the induction coils (or antennae); measuring spectrum of alternating current (or voltage) produced in the second of the induction coils (or antennae); and comparing the phase shift between the spectrum of alternating currents (or voltages) in the first and second induction coils (or antennae), thereby determining the condition of the bulk tissue sample.

Abstract: The present invention provides a detection apparatus, including: signal outputting means configured to output signals of a frequency band within which the difference in electric characteristic between different tissues of a living organism is higher than a predetermined level individually to two or more electrodes; impedance detection means configured to detect, from each of the electrodes, an impedance of the living organism disposed in quasi-electrostatic fields generated individually from the electrodes in response to the outputs; and colloid detection means configured to detect presence or absence of colloid in the inside of the living organism in response to the differences between the detected impedances.

Abstract: A medical device monitors a level of fluid accumulation, e.g., pulmonary edema, and one or more respiratory parameters of the patient to detect worsening heart failure. The medical device may use intrathoracic impedance measurements to monitor both the fluid accumulation and the one or more respiratory parameters. Respiration rate and volume, also referred to as the tidal volume, are examples of respiratory parameters. The medical device examines the one or more respiratory parameters after determining that the fluid accumulation indicates worsening heart failure. In this manner, the medical device uses the one or more respiratory parameters to confirm a determination of worsening heart failure that was made based on the fluid accumulation.

Abstract: System and method of applying electric fields to a patient's lung(s) to reduce pulmonary edema. The system includes a first electrode and a second electrode, at least one of which is associated with the lung. The electric field can be controlled so as to modulate a level of fluid in the lung.

Abstract: The system and method may measure and monitor physiological changes in a body. In some embodiments, the system and method may measure the impedance at a site in the body. In some embodiments, the system and method identify, quantify, and localize leaks from a site following surgery, measure cardiac contractility, or lung compliance. In an embodiment, the system includes a measuring device with one or more sensors embedded in a porous matrix. Changes in the electrical properties of one or more sensors may be used to determine the presence of leaks from a site following surgery, measure cardiac contractility, or lung compliance, depending on the position of the device.

Abstract: In an implantable heart monitoring device and a monitoring method, an impedance is measured across at least part of an atrium, such that variation of the impedance is related to the volume change of the atrium. Values are stored at different occasions that indicate the rate of change of the measured impedance. The stored values are determined such that, when the device is used in a living being, the variation of the stored values will be related to the variation of the speed with which the atrium is filled with blood during the atrial diastole.

Abstract: Systems and Methods for predicting patient health and patient relative well-being within a patient management system are disclosed. A preferred embodiment utilizes an implantable medical device comprising an analysis component and a sensing component further comprising a three-dimensional accelerometer, a transthoracic impedance sensor, a cardio-activity sensor, an oxygen saturation sensor and a blood glucose sensor. Some embodiments of a system disclosed herein also can be configured as an Advanced Patient Management System that helps better monitor, predict and manage chronic diseases.

Abstract: Methods and systems to collect a sample of bodily fluid from a patient using an integrated needle and test strip assembly are provided. In this novel assembly, the test strip and needle form one unit that captures the sample of blood or interstitial fluid from the patient once the apparatus is pressed to the skin. The hollow aspiration needle includes more than one opening at a distal end, each opening coming into contact with the bodily fluid when disposed within a cutaneous or subcutaneous layer of the patient's skin. The disclosed test strip includes at least one reaction site for testing analyte concentrations and a means for linking to many commercially available test strip meters to provide readout of the analyte concentration. The sample may be captured by capillary flow, by an integrated aspirator, or by a differential vacuum device resident on the test strip meter.

Abstract: The brassiere may include at least one accommodation disposed on a portion of the brassiere with the at least one accommodation configured to carry at least a pair of sensors. The pair of sensors may be detachably carried by the at least one accommodation. The accommodation may be a pocket, slit, or pouch. The accommodation may be a pair of pockets that support a garment accessory. The garment accessory may include a member having first and second ends that fit within the pair of pockets. The pair of sensors may be carried by the member, which holds the sensors against the skin of a subject wearing the brassiere. The garment accessory may further include a wireless transmitter carried by the member.

Abstract: A device to measure tissue impedance comprises drive circuitry coupled to calibration circuitry, such that a calibration signal from the calibration circuitry corresponds to the current delivered through the tissue. Measurement circuitry can be coupled to measurement electrodes and the calibration circuitry, such that the tissue impedance can be determined in response to the measured calibration signal from the calibration circuitry and the measured tissue impedance signal from the measurement electrodes. Processor circuitry comprising a tangible medium can be configured to determine a complex tissue impedance in response to the calibration signal and the tissue impedance signal. The processor can be configured to select a frequency for the drive current, and the amount of drive current at increased frequencies may exceed a safety threshold for the drive current at lower frequencies.

Abstract: The disclosure relates to a method for determining a body composition parameter by applying a bioimpedance measurement on a subject, the overall body size and an impedance value of the body of the subject entering into the calculation of the body composition parameter. It is provided that when calculating the body composition parameter a term is additionally entered which constitutes a product of a previously determined coefficient and of a ratio of measured impedance values of different body segments of the subject. During the calculation of the ratio of impedance values of different body segments the ratio of the real parts of the impedances preferably takes the form of x R ? ? Trunk / Extremities = R Trunk ( R Right ? ? arm + R Left ? ? arm + R Right ? ? leg + R Left ? ? leg ) / 4 .

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: An impedance spectroscopy system for monitoring ischemic mucosal damage in hollow viscous organs comprises a sensor catheter and an impedance spectrometer for electrically driving the catheter to obtain a complex tissue impedance spectrum. Once the catheter is in place in one of a patient's hollow viscous organs, the impedance spectrometer obtains the complex impedance spectrum by causing two electrodes in the tip of the catheter to inject a current into the mucosal tissue at different frequencies, while two other electrodes measure the resulting voltages. A pattern recognition system is then used to analyze the complex impedance spectrum and to quantify the severity of the mucosal injury. Alternatively, the complex impedance spectrum can be appropriately plotted against the spectrum of normal tissue, allowing for a visual comparison by trained personnel.