Abstract: Apparatus and methods for detecting lead migration through the use of measured artifactual data about the tissue in the vicinity of the lead.

Abstract: System and methods for adjusting electrical therapy based on impedance changes are disclosed herein. A method in accordance with a particular embodiment includes applying a therapeutic electrical signal to a patient via an implanted portion of a patient stimulation system that includes a signal delivery device in electrical communication with a target neural population of the patient. The electrical signal is delivered in accordance with a signal delivery parameter having a first value. Using the implanted portion of the patient stimulation system, a change in an impedance of an electrical circuit that includes the signal delivery device is detected. Based at least in part on the detected impedance change, the method can further include automatically adjusting the value of the signal delivery parameter from the first value to a second value different from the first, without human intervention.

Abstract: Systems that sense the volume, activity or other parameters of the urinary bladder are described. The systems include at least two electrodes that are implanted at respective locations proximate the wall of the bladder, and may be located substantially opposite each other with respect to a center of the bladder. At least one of the electrodes receives an electrical signal emitted by another of the electrodes. Systems according to the invention detect an impedance through the bladder based on the signal, e.g., based on one or both of the current or voltage of the signal. Based on the detected impedance, the systems sense one or more parameters of the bladder, such as volume, activity, or the like, which influence the impedance. The detected impedance, or bladder parameter information derived from the impedance, may be stored for short- or long-term monitoring, or used to control delivery of a therapy to a patient.

Abstract: A system for heart performance characterization receives an electrical signal indicating heart electrical activity of a patient over a heart beat cycle. The electrical signal is acquired at a particular anatomical location. A gating signal generator generates a gating signal for use in identifying a particular portion of the heart beat cycle. An acquisition device, responsive to the gating signal, derives first and second voltage potentials from the received electrical signal. The first voltage potential comprises a voltage potential derived over a time period comprising a heart beat cycle and the second voltage potential comprises a voltage potential derived over a time period comprising a particular portion of the heart beat cycle. A computation processor derives a dynamic impedance representative value by adjusting a baseline impedance value by a ratio of the first and second voltage potentials.

Abstract: An impedance analyzer includes: a control voltage generating unit for generating a control voltage that has a predetermined amplitude value; a measuring unit operable to provide an output current, which has an amplitude value corresponding to that of the control voltage, for flowing through first and second body portions of a biological target, and to generate a measurement voltage that has an amplitude value corresponding to a difference between voltages at the first and second body portions attributed to flow of the output current therethrough; and a calculating module operable to determine an electrical impedance between the first and second body portions according to a predetermined adjustment value and the amplitude value of the measurement voltage.

Abstract: A method of assessing the likelihood that an infected subject develops sepsis, using an input radiofrequency signal received from the subject responsively to an output radiofrequency signal transmitted to the subject. The method comprises: processing the input signal to provide a processed signal, analyzing the processed signal to determine a characteristic pulse morphology of the processed signal, and using the characteristic pulse morphology for assessing the likelihood that the subject develops sepsis.

Abstract: Disclosed are methods, systems, and devices for generating sleep predicators to avoid preventable mental episodes from breaking through, thereby averting an irreversible brain damage to a patient, that may be caused by such future mental episodes. In one embodiment, the present invention is a method comprising: acquiring biomedical data from a patient by using a means of signal acquisition; forming a database of the biomedical records in which the database further comprises a sleep prediction algorithm, psychiatric records, and a statistical engine to compute the data and the psychiatric records using the algorithm; mapping the acquired data in reference to the sleep prediction algorithm; validating the sleep predictors; and providing an output of the sleep predicators to a patient or caretaker. The present invention can be used to treat mania, depression, bipolar disorder, schizophrenia, PTSD, anxiety, and other chronic mental health conditions.

Abstract: A device for electroimpedance tomography with an electrode belt (2), which has electrodes (E1 . . . E16), wherein at least two groups (5, 6) of electrodes located next to each other are formed and the electrodes of one group are contacted with at least one, multiwire feed cable (7, 8). For a reduced noise level during data acquisition, provisions are made for at least one electrode (E9) of two mutually adjacently located electrodes (E8, E9) of two different groups (5, 6) to have an additional electrode feed line (15), which is led over the feed cable (7) of the adjacent group (5).

Abstract: A method and system are provided for determining a condition of a selected region of epithelial and stromal tissue in the human breast. A plurality of measuring electrodes are used to measure the tissue and transepithelial electropotential of breast tissue. Surface electropotential and impedance are also measured at one or more locations. An agent may be introduced into the region of tissue to enhance electrophysiological characteristics. The condition of the tissue is determined based on the electropotential and impedance profile at different depths of the epithelium, stroma, tissue, or organ, together with an estimate of the functional changes in the epithelium due to altered ion transport and electrophysiological properties of the tissue. Devices for practicing the disclosed methods are also provided.

Abstract: A device and method for accurately characterizing tissue impedance employs multiple electrodes at a plurality of separation distances to cancel the effects of front end loading leakage currents and electrode polarization to improve the accuracy of sensitive impedance measurements used to identify cancerous tissues. These measurements may be automated over a range of frequencies.

Abstract: A device is described for measuring electrical characteristics of biological tissues with one or a plurality of electrodes and a processor controlling the stimulation and measurement in order to detect the presence of abnormal tissue masses in the breast and determine probability of tumors containing malignant cancer cells being present in a breast. The device has the capability of providing the location of the abnormality, at least to the quadrant. Either single or multiple source electrodes can be used. Either palpable lumps can be evaluated or screening or breasts, whether with palpable masses or not, can be accomplished. The method for measuring electrical characteristics includes placing electrodes and applying a voltage waveform in conjunction with a current detector. A mathematical analysis method is then applied to the collected data, which computes spectrum of frequencies and correlates magnitudes and phases with given algebraic conditions to determine mass presence and type.

Abstract: Devices and systems to measure luminal organ parameters using impedance. In at least one embodiment of an impedance device of the present disclosure, the impedance device comprises an elongated body having a distal body end and a pair of detection electrodes positioned in between a pair of excitation electrodes located at or near the distal body end, the pair of detection electrodes configured to obtain one or more conductance values within a mammalian luminal organ within a field generated by the pair of excitation electrodes, wherein a measured parameter of the mammalian luminal organ can be calculated based in part upon the one or more conductance values obtained by the device and a known distance between the pair of detection electrodes.

Abstract: Provided are devices and methods capable of interfacing with biological tissues, such as organs like the heart, in real-time and using techniques which provide the ability to monitor and control complex physical, chemical, biochemical and thermal properties of the tissues as a function of time. The described devices and methods utilize micro scale sensors and actuators to spatially monitor and control a variety of physical, chemical and biological tissue parameters, such as temperature, pH, spatial position, force, pressure, electrophysiology and to spatially provide a variety of stimuli, such as heat, light, voltage and current.

Abstract: A device is described for measuring electrical characteristics of biological tissues with plurality of electrodes and a processor controlling the stimulation and measurement in order to detect the presence of abnormal tissue masses in the breast and determine probability of tumors containing malignant cancer cells being present in a breast. The device has the capability of providing the location of the abnormality, at least to the quadrant. The method for measuring electrical characteristics includes placing electrodes and applying a voltage waveform in conjunction with a current detector. A mathematical analysis method is then applied to the collected data, which computes spectrum of frequencies and correlates magnitudes and phases with given algebraic conditions to determine mass presence and type.

Abstract: Methods and systems for determining a condition of a selected region of epithelial tissue and/or an organ in a body as well as to diagnose disease, susceptibility, premalignancy or cancer and measure response to therapy, introduction of a drug and to assess the margins of a tumor or resection. The methods utilize through the tissue or organ electrical measurements with alternating current using one or more surface or internal electrodes and measuring the electrical response using one or more surface electrodes, preferably in combination with one or more electrodes in direct or indirect contact with epithelium comprising the organ or tissue under test. The methods are also useful in combination with DC measurements on the surface of the organ or tissue under test. Measurement of impedance, admittance, electropotential and dielectric properties is particularly useful, particularly as a function of frequency and position on and in the tissue or organ.

Abstract: A sheath includes an elongate tube, which has an outer wall that surrounds an inner lumen and has multiple holes along the tube penetrating the outer wall. Multiple electrically-conducting elements are inserted in the respective holes, so as to allow transmission of electrical current between the inner lumen and an exterior of the outer wall.

Abstract: Embodiments relate to devices and methods for monitoring, identifying, and determining risk of congestive heart failure (CHF) hospitalization. Methods include determining physiological values of a patient by electrocardiogram (ECG), bioimpedance, and 3-axis accelerometer, filtering the physiological values, comparing physiological values to baseline parameters and determining CHF risk. Devices include a 3-axis accelerometers, bioimpedance sensors, and an electrocardiogram, each capable of measuring patient physiological values, and one or more processors to receive the measured physiological values.

Abstract: Disclosed techniques include monitoring a physiological characteristic of a patient with a sensor that is mounted to an inner wall of a thoracic cavity of the patient, and sending a signal based on the monitored physiological characteristic from the sensor to a remote device.

Abstract: A system for the acquisition of biopotential signals, comprising at least a first electrode configured for detecting a biopotential signal within a signal bandwidth of interest and being connected to an impedance detection module that provides a first electrode voltage. The impedance detection module comprises a current generation circuit connected in parallel to an amplifier. The current generation circuit comprises an AC current generator configured to generate a first current signal through the first electrode. The first current signal has a frequency outside of the signal bandwidth of interest. The current generation circuit also comprising a capacitor connected between the input of the amplifier and the AC current generator so as to isolate the AC current generator from the amplifier input at the signal bandwidth of interest.

Abstract: Apparatus and methods for the diagnostics of biological conditions using impedance measurements.

Abstract: An apparatus for processing signals, in particular physiological measuring signals, is provided with a number of channels with main signal inputs for receiving input signals. Each of the input signals has a specific signal component and a signal component common to all input signals. Each channel is provided with an impedance transforming input amplifier. The apparatus supplies a respective input signal to the first input of each input amplifier and an analog reference signal, which is equal for all channels, to the second input. The apparatus includes a digital signal processor and one or more analog-digital converters for supplying the signals provided by the input amplifiers to the digital signal processor. The signal processor converts signals received from the one or more analog-digital converters at least into one or more output signals.

Abstract: A body composition analyzer for animals is provided. A movement of an animal may be restrained by controlling a physical motion of a plurality of electrode units that come into contact with feet of the animal and thus, it is possible to effectively restrict the movement of the animal during measuring of a body composition of the animal, thereby more accurately measuring the body composition.

Abstract: The activity monitor (100) includes a basic information acquisition unit (20) that accepts input of basic physical information (BA) of the user's body, a target information acquisition unit (30) that accepts input of the user's target physical expenditure (CS), an activity pattern acquisition unit (40) that acquires pattern information indicating the user's intent on the activity amount (AM), and a target activity calculation unit (50) that determines a target activity amount (TA) on the basis of the basic physical information (BA), the target physical expenditure (CS), and the pattern information acquired by the activity pattern acquisition unit (40).

Abstract: A sweat sensing device includes a plurality of sweat collection pads communicating with a sensor. Each of the pads is activated by a timing circuit which allows one or more of the pads to be activated at a selected time and subsequent deactivated after a defined period of time. This allows for selective collection of sweat from a plurality of pads over a prolonged period of time. An impedance measuring circuit can be employed to determine if one or more of the pads becomes disconnected, in order to avoid irritation. Further, the devices can use a common microfluidic device which both transports sweat activating substance, such as pilocarpine, to the surface of the skin and directs sweat away from the skin to a sensing device.

Abstract: An patch and sensor assembly for use in an EP mapping system has two portions: a reusable portion and a disposable portion. The reusable portion houses the biosensors used in magnetic based location and mapping systems and the electrical lead necessary to communicate between the biosensor and the mapping system. The reusable portion may also contain a portion of the electrode necessary to receive electrical signals from the body of the patient. The disposable portion of the patch and sensor assembly contains an adhesive covered flexible patch having at least a portion of the electrode used to receive electrical signals form the body of the patient and may contain the electrical lead necessary to communicate such an electrical signal to the mapping system. The disposable portion contains a receptacle adapted to receive and mechanically secure the reusable portion to the disposable portion of the assembly.

Abstract: A method for the automated removal of a stimulus artifact from an electrophysiological signal waveform, wherein the novel method comprises: providing a model of the stimulus artifact that is physically derived and is based on known properties of the electrophysiological signal waveform acquisition hardware and stimulator; and filtering the stimulus artifact out of the electrophysiological signal waveform using the model.

Abstract: Electrical impedance myography (EIM) can be used for the assessment and diagnosis of muscular disorders. EIM includes applying an electrical signal to a region of tissue and measuring a resulting signal. A characteristic of the region of tissue is determined based on the measurement. Performing EIM at different frequencies and/or different angular orientations with respect to a muscle can aid in the assessment and diagnosis. Devices are described that facilitate assessment and diagnosis using EIM.

Abstract: A human body support, such as a chair, has a plurality of support segments that are arranged in an array. Each support segment has a protrusion elevation that is independently variable and controllable in its distance of protrusion elevation against the supported human body. A sensor is connected to a human body on the support and senses a human body parameter that can indicate the presence of drowsiness. A controller analyzes the sensed parameter to detect whether the sensed parameter is within a range indicating the presence of drowsiness. The controller applies a wave of varying segment protrusion elevation against the human body in response to the detection of drowsiness. The wave progresses in a direction from an inferior location on the human body toward a more superior location. Alternatively, a wave of electrical stimuli is applied by similarly positioned electrodes and causes periodic tightening and relaxing of proximate muscles.

Abstract: An electrode assembly includes a retainer, a flexible sheath, and an electrode. The retainer may include a plurality of clasping arms. The retainer is movable to an open position and a closed position. The flexible Sheath is positioned below a lower surface of the retainer. The flexible sheath is at least partially surrounded by the clasping arms of the retainer. The retainer is able to hold the flexible sheath around a target tissue when the retainer is in the closed position. The electrode is configured for conducting electrical signals to or from the target tissue. The electrode is connected to at least one of the retainer and the flexible sheath. The retainer is able to hold the electrode in electrical communication with the target tissue when the retainer is disposed around the target tissue in the closed position.

Abstract: The present invention relates to a method for detecting contact between an injection needle of a medication delivery device and a body of a patient. The method comprises the step of generating a contact signal in response to closure of an electrical signal path comprising an exterior surface part of the injection needle, an exterior surface part of a handle of the medication delivery device and at least part of the body of the patient. The present invention further relates to a method for determining the position of insertion of the injection needle, and to the insertion depth of the injection needle.

Abstract: A wearable physiological sensing device with optical pathways is described. The wearable physiological sensing device may include at least one light source; a first light pipe coupled with the at least one light source, the first light pipe at least partially circumscribing an extremity of a patient, and including at least one aperture for radiating light from the light source into the extremity. The wearable physiological sensing device may also include a second light pipe including at least one aperture for receiving the light radiated through the extremity, the second light pipe at least partially circumscribing the extremity of the patient, and an optical receiver coupled with the second light pipe configured to receive the light and output one or more signals representative of the received light.

Abstract: A method of measuring skin moisture content, the method including: measuring a differential rate of a skin impedance of a predetermined skin area of a user for a predetermined period of time; and determining that the skin area is a moist area when the differential rate of skin impedance is greater than or equal to a predetermined value for a predetermined period of time, and determining that the skin area is a dry area when the differential rate of skin impedance is less than the predetermined value for the predetermined period of time.

Abstract: An electrode catheter and a method for assessing electrode-tissue contact and coupling are disclosed. An exemplary electrode catheter comprises an electrode adapted to apply electrical energy. A measurement circuit is adapted to measure impedance between the electrode and ground as the electrode approaches a target tissue. A processor determines a contact and coupling condition for the target tissue based at least in part on reactance of the impedance measured by the measurement circuit. In another exemplary embodiment, the electrode catheter determines the contact and coupling condition based at least in part on a phase angle of the impedance.

Abstract: A system and method is provided that allows for determining the local impedance of one or more electrodes of an electrode catheter. Such local impedance may be utilized to identify the relative position of an electrode catheter to a sheath of a guiding introducer. In another arrangement, local impedance of a catheter electrode can be utilized to calibrate a catheter electrode to provide improved contact sensing.

Abstract: An exemplary embodiment includes acquiring an electroneurogram of the right carotid sinus nerve or the left carotid sinus nerve, analyzing the electroneurogram for at least one of chemosensory information and barosensory information and calling for one or more therapeutic actions based at least in part on the analyzing. Therapeutic actions may aim to treat conditions such as sleep apnea, an increase in metabolic demand, hypoglycemia, hypertension, renal failure, and congestive heart failure. Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: A system and method for providing dietary guidance is provided. The method includes receiving a selection of a health program for an individual, the health program including a dietary regimen, measuring the individual's caloric expenditure and change in body composition or body mass during the individual's participation in the health program, determining adherence to the health program based on the measured caloric expenditure or the measured change in body composition or body mass, identifying a modification to the health program, and informing the individual of the modification. The modification can include nutritional supplements, meals or recipes having a nutritional and/or caloric content tailored to assist the individual in meeting his or her health goals. The method can further include predicting an expected change in body composition or body mass based on the health program and based on the individual's gender, age, height, weight, and other factors.

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: An apparatus for testing of electrical or physical properties of a material include a single coil sensor mounted adjacent to a sample of the material. Sheet conductance of a wide variety of materials may be measured using the single coil to determine if the material conforms to generally accepted standards for the use to which the material will be put. In some examples, the material is a semiconductor wafer or flat panel. In other examples, the material is the body tissue of a patient. A non-invasive technique using the apparatus is also disclosed for monitoring the health of patient tissue such as musculature, and/or to determine whether healthy circulation is present, by measuring the conductance of the patient tissue in response to a magnetic field applied by the single coil. The single coil may be hand held, or it may be movable using an automated positioning system under computer control.

Abstract: Devices and methods for detecting physiological target event such as events indicative of HF decompensation status are described. An ambulatory medical device (AMD) can measure bio-impedance, such as thoracic impedance, from a patient. The AMD can receive a specified threshold within a range or a distribution of impedance measurement, or a specified percentile such as less than 50th percentile, and calculate a representative impedance value (ZRep) corresponding to the specified threshold or percentile using a plurality of thoracic impedance measurements. The representative impedance value can be calculated using an adaptation process, or using an estimated distribution of the impedance measurements. The AMD can include a physiologic event detector circuit that can generate a trend of representative impedance values over a specified time period, and to detect a target physiologic event such as indicative of HF decompensation using the trend of representative impedance values.

Abstract: The present disclosure introduces systems and methods to measure fluid in a body segment. In one embodiment, a computer system used to measure fluid in a body segment is described. A current generation module may be used to emit an electrical through at least one body segment. The electrical current may be used to measure fluid-volume content of the at least one body segment. An electrode module having a plurality of electrodes may be attached to the current generation module. A signal-processing module may be used to measure changes in the electrical current through at least one body segment. Further, an impedance module may be used to calculate fluid-volume change in at least one body segment and determine the flow of fluid through the at least one body segment. Other embodiments also are described.

Abstract: Loosing the ability to interact with one's environment can be devastating. The invention enables a person to control the real or virtual action or movement of an output device in from one to three dimensions through the use of at least one electrical sensor implanted beneath the skin or as a part of a headset on either one side or on both sides of the person's head in electrical communication with a vestigial periauricular nerve or muscle. Each sensor communicates through a selected channel to transmit information preferably in digital form to an output device designating an action to be taken or the position of a target location for enabling the output device to perform the action or to move toward or to a target location through real or virtual space. At least one and preferably up to four sensors are located on each side of the head.

Abstract: A soft-field tomography system includes a plurality of transducers configured for positioning at a surface of an object. An excitation driver is configured to generate a precomputed default excitation pattern for the plurality of transducers. A processor stores the precomputed default excitation pattern and a corresponding predicted response for the precomputed excitation pattern. The processor further stores one or more precomputed fault excitation patterns and corresponding predicted response for the fault excitation patterns corresponding to one or more fault conditions of the plurality of transducers. A response measurement device is configured to measure a response at one or more of the transducers to determine if a fault condition exists. If a fault condition exists, the processor at least one of instructs the excitation driver to generate a precomputed fault excitation pattern or uses a predicted response that corresponds to the fault condition for a soft field tomography process.

Abstract: A method includes monitoring an indicator of fluid volume of a patient via a sensor device, and setting an initial fluid volume removal prescription for a blood fluid removal session based on the monitored indicator of fluid volume. The method may further include transmitting data regarding the indicator of fluid volume from the implantable sensor device to fluid removal device. The system includes a blood fluid removal device and control electronics configured to set the initial fluid removal volume and rate prescription. In some embodiments, the fluid removal device sets or calculated the initial fluid volume removal prescription based on the data received from the implantable sensor. The indicator of fluid volume may be an indicator of tissue fluid volume or an indicator of blood fluid volume.

Abstract: An amount of fluid in a thoracic or other region of a subject may be monitored by internally injecting an electrical energy stimulus (e.g., constant voltage source) through the region, detecting voltage resulting from the electrical energy stimulus, and calculating a fluid volume indicative signal. The injected energy stimulus creates a first lead field. The responsive voltage is detected using an electrode configuration that defines a second lead field, which is arranged in a negative sensitivity configuration with respect to the first lead field at the region being monitored.

Abstract: Techniques are provided for use by implantable medical devices such as cardiac resynchronization therapy (CRT) devices for detecting pulmonary edema based on transthoracic impedance sensed using cardiac pacing/sensing leads, wherein detection can be performed while lead maturation occurs. Briefly, the implantable device determines whether the leads are within an initial post-implant interval following implant during which lead maturation generally occurs. The device then detects pulmonary edema or related medical conditions within the patient based on transthoracic impedance using a set of detection parameters adjusted for use during the post-implant interval. Thus, rather than “blanking” impedance data during lead maturation, the device instead detects and processes impedance during this period to identify possible episodes of pulmonary edema so that appropriate measures can be undertaken, such as delivery of warnings or titration of appropriate medications.

Abstract: A method of determining a change in nerve function attributable to a surgical procedure includes assessing the nerve function via a first, induced mechanomyographic muscle response prior to the surgical procedure, and reassessing the nerve function via a second, induced mechanomyographic muscle response after the surgical procedure. Each mechanomyographic muscle response may be induced through an electrical stimulus provided directly to the nerve of the subject.

Abstract: A medical device and associated method acquire a biopotential signal from a pair of electrodes at a first sampling rate and a bioimpedance signal from the pair of electrodes at a second sampling rate. An onset and/or offset of the drive signal delivered to the pair of electrodes for acquiring the bioimpedance signal is synchronized to the first sampling rate.

Abstract: A shape-imparting mechanism for a catheter that includes an elongate element dimensioned to fit within a lumen of an electrode sheath of a catheter. An insertion facilitating arrangement is carried at a distal end of the elongate element for facilitating insertion of the distal end of the elongate element into the lumen of the electrode sheath of the catheter.

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: A reconfigurable measuring apparatus includes a first chopper configured to modulate an input signal, and an amplifier configured to amplify an output signal of the first chopper. The reconfigurable measuring apparatus further includes a second chopper configured to demodulate an output signal of the amplifier, and a controller configured to control the first chopper and the second chopper based on a measurement mode.