Real time impedance plots with arbitrary frequency components.


:Temporal changes in the impedance spectra of bioelectrodes in contact with skin provide useful data for comparisons between differing electrode materials and skin preparation methods. Traditional impedance measuring systems employ swept frequency methods which will distort results in the impedance spectra of a sample which has nonstationary electrical characteristics. The system reported here obtains impedance spectra by applying a digitally constructed waveform consisting of many frequency components. This allows impedance values to be measured at a number of frequencies simultaneously. Sample data are provided and compared with data obtained using similar square wave techniques.


Physiol Meas


Searle A,Kirkup L




Has Abstract


1999-02-01 00:00:00












  • Tracking boundary movement and exterior shape modelling in lung EIT imaging.

    abstract::Electrical impedance tomography (EIT) has shown significant promise for lung imaging. One key challenge for EIT in this application is the movement of electrodes during breathing, which introduces artefacts in reconstructed images. Various approaches have been proposed to compensate for electrode movement, but no comp...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Biguri A,Grychtol B,Adler A,Soleimani M

    更新日期:2015-06-01 00:00:00

  • Eye-tracker algorithms to detect saccades during static and dynamic tasks: a structured review.

    abstract:OBJECTIVE:Eye-tracking devices have become widely used as clinical assessment tools in a variety of applied-scientific fields to measure saccadic eye movements. With the emergence of multiple static and dynamic devices, the concurrent need for algorithm development and validation is paramount. APPROACH:This review ass...

    journal_title:Physiological measurement

    pub_type: 杂志文章,评审


    authors: Stuart S,Hickey A,Vitorio R,Welman K,Foo S,Keen D,Godfrey A

    更新日期:2019-02-26 00:00:00

  • Dynamic data monitoring improves predictive analytics for failed extubation in the ICU.

    abstract:OBJECTIVE:Predictive analytics monitoring that informs clinicians of the risk for failed extubation would help minimize both the duration of mechanical ventilation and the risk of emergency re-intubation in ICU patients. We hypothesized that dynamic monitoring of cardiorespiratory data, vital signs, and lab test result...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Keim-Malpass J,Enfield KB,Calland JF,Lake DE,Clark MT

    更新日期:2018-07-16 00:00:00

  • Gastric activity studies using a magnetic tracer.

    abstract::A magnetic pulse generator has been set up in order to study gastric activity. Two coils 1.05 m in diameter, arranged in a Helmholtz configuration, were used. The system generated magnetic field pulses higher than 15 mT, of duration 17.3+/-1.2 ms. Measurements were performed in 11 male volunteers, with average age 29....

    journal_title:Physiological measurement

    pub_type: 临床试验,杂志文章


    authors: Cordova-Fraga T,Bernal-Alvarado JJ,Gutierrez-Juarez G,Sosa M,Vargas-Luna M

    更新日期:2004-10-01 00:00:00

  • Triple-frequency method for measuring blood impedance.

    abstract::A method was developed for simultaneously measuring plasma resistance, cell interior resistance and cell membrane capacitance of blood. A three-element circuit model for simulating the impedance of blood was evaluated by comparing measured and calculated impedance frequency curves and was found feasible. The values of...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Zhao TX,Jacobson B,Ribbe T

    更新日期:1993-05-01 00:00:00

  • Recognition of elementary arm movements using orientation of a tri-axial accelerometer located near the wrist.

    abstract::In this paper we present a method for recognising three fundamental movements of the human arm (reach and retrieve, lift cup to mouth, rotation of the arm) by determining the orientation of a tri-axial accelerometer located near the wrist. Our objective is to detect the occurrence of such movements performed with the ...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Biswas D,Corda D,Baldus G,Cranny A,Maharatna K,Achner J,Klemke J,Jöbges M,Ortmann S

    更新日期:2014-09-01 00:00:00

  • Auditory magnetic fields in cochlear-implant patients.

    abstract::Neuromagnetic recordings were used to check if electrical stimulation of the auditory nerve in cochlear-implant patients activates cortical auditory areas in a similar manner as acoustic stimulation in normal hearing subjects or whether the excitation processes are different. The waveform of the evoked magnetic field ...

    journal_title:Physiological measurement

    pub_type: 杂志文章,评审


    authors: Pelizzone M

    更新日期:1993-11-01 00:00:00

  • False alarms during patient monitoring in clinical intensive care units are highly related to poor quality of the monitored electrocardiogram signals.

    abstract::Electrocardiograms (ECGs) recorded from patients in intensive care were investigated to quantify any relationship between ECG signal quality and false monitoring alarms. False alarms are a considerable problem for nursing and medical staff as they distract from clinical care, and are also a problem for patients as the...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Tsimenidis C,Murray A

    更新日期:2016-08-01 00:00:00

  • Assessing the validity and reliability and determining cut-points of the Actiwatch 2 in measuring physical activity.

    abstract:OBJECTIVE:The Actiwatch 2 (AW2) is a wrist-worn accelerometer typically used to measure sleep. Although it can measure physical activity, there is limited evidence supporting its validity. We assessed the validity and reliability of the AW2 to measure sedentary behavior and physical activity (light, moderate, vigorous ...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Kemp C,Pienaar PR,Henst RHP,Roden LC,Kolbe-Alexander TL,Rae DE

    更新日期:2020-09-04 00:00:00

  • Fractal analysis of foetal heart rate variability.

    abstract::Current methods for analysing foetal heart rate (FHR) patterns have yet to meet their full potential in the recognition of hypoxia in the foetus. Following the recent suggestion that fractal analysis can be applied to FHR recordings, the current paper describes a method for distinguishing two simultaneous fractal dime...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Gough NA

    更新日期:1993-08-01 00:00:00

  • The influence of cardiac preload and positive end-expiratory pressure on the pre-ejection period.

    abstract::The pre-ejection period (PEP) has recently been described as a potential parameter for monitoring cardiac preload. This study further investigated the influence of changes in intravascular volume status and the application of positive end-expiratory pressure (PEEP) on the pre-ejection period. In ten pigs, ECG, arteria...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Kubitz JC,Kemming GI,Schultheib G,Starke J,Podtschaske A,Goetz AE,Reuter DA

    更新日期:2005-12-01 00:00:00

  • Different approaches for quantifying ventilation distribution and lung tissue properties by functional EIT.

    abstract::We investigated five different methods which can be applied to quantitatively construct functional tomograms of the lungs. The focus was on the sensitivity of functional tomograms to errors in acquired data. To quantify this sensitivity, theoretical, error-free data sets of well-known properties were artificially gene...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Hahn G,Dittmar J,Just A,Quintel M,Hellige G

    更新日期:2010-08-01 00:00:00

  • Localization of sources of brain alpha/theta/delta activity and the influence of the mode of spontaneous mentation.

    abstract::A method is described that accounts for multichannel brain field data (EEG) epochs, after transformation into the frequency domain, by a single oscillating dipole source in terms of phase angles. The method produces a potential distribution for each frequency point ('FFT dipole approximation'). These maps can be subje...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Michel CM,Henggeler B,Brandeis D,Lehmann D

    更新日期:1993-11-01 00:00:00

  • Limited agreement between two noninvasive measurements of blood volume during fluid removal: ultrasound of inferior vena cava and finger-clip spectrophotometry of hemoglobin concentration.

    abstract:OBJECTIVE:Plots of blood volume measurements over time (profiles) may identify euvolemia during fluid removal for acute heart failure. We assessed agreement between two noninvasive measurements of blood volume profiles during mechanical fluid removal, which exemplifies the interstitial fluid shifts that occur during di...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Lucas BP,D'Addio A,Block C,Manning H,Remillard B,Leiter JC

    更新日期:2019-07-01 00:00:00

  • Multi-frequency imaging and modelling of respiratory related electrical impedance changes.

    abstract::Two studies concerning multi-frequency impedance measurements are presented. The first uses tetrapolar measurements made on the thorax and the second electrical impedance tomography images, also made from the thorax. The way in which the impedance and the changes in impedance with ventilation depend upon frequency are...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Brown BH,Barber DC,Wang W,Lu L,Leathard AD,Smallwood RH,Hampshire AR,Mackay R,Hatzigalanis K

    更新日期:1994-05-01 00:00:00

  • Electrical biopsy of irradiated intestinal tissue with a simple electrical impedance spectroscopy system for radiation enteropathy in rats--a pilot study.

    abstract::Electrical impedance is one of the most often used parameters for characterizing material properties, especially in biomedical applications. Electrical impedance spectroscopy (EIS), used for revealing both resistive and capacitive characteristics, is good for use in tissue characterization. In this study, a portable a...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Huang YJ,Huang EY,Lu YY,Chen CY,Cheng KS

    更新日期:2011-09-01 00:00:00

  • Development of a novel method for assessing balance: the quantitative posturography system.

    abstract::Balance is the ability to maintain equilibrium while sitting or standing. There are a number of different methods which are used to assess balance: technical methods such as sway magnetometry, ataxia meter and force platforms, and clinical methods such as the functional reach test, Berg balance test and fall risk inde...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Browne J,O'Hare N

    更新日期:2000-11-01 00:00:00

  • Empirically derived cut-points for sedentary behaviour: are we sitting differently?

    abstract::Sedentary behaviour (SB) is associated with a number of adverse health outcomes. Studies that have used ActiGraph monitors to define sedentary time tend to use a threshold of  <100 counts per minute (cpm) for classifying SB; however, this cut-point was not empirically derived for adults. It is not known whether ActiGr...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Clarke-Cornwell AM,Farragher TM,Cook PA,Granat MH

    更新日期:2016-10-01 00:00:00

  • Permutation Lempel-Ziv complexity measure of electroencephalogram in GABAergic anaesthetics.

    abstract::Monitoring the brain state in anaesthesia is crucial for clinical doctors. In this study, we propose a novel nonlinear method, the permutation Lempel-Ziv complexity (PLZC) index, which describes the complexity in the electroencephalographic (EEG) signal to quantify the effect of GABAergic anaesthetics on brain activit...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Bai Y,Liang Z,Li X,Voss LJ,Sleigh JW

    更新日期:2015-12-01 00:00:00

  • Daily physical activity patterns from hip- and wrist-worn accelerometers.

    abstract::Accelerometer wear location may influence physical activity estimates. This study investigates this relationship through the examination of activity patterns throughout the day. Participants from the aging research evaluating accelerometry (AREA) study (n men  =  37, n women  =  47, mean age (SD)  =  78.9 (5.5) years)...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Shiroma EJ,Schepps MA,Harezlak J,Chen KY,Matthews CE,Koster A,Caserotti P,Glynn NW,Harris TB

    更新日期:2016-10-01 00:00:00

  • A comparison of methods for measurement of spatial resolution in two-dimensional circular EIT images.

    abstract::The literature concerning measurement of spatial resolution in electrical impedance tomography (EIT) is vague. Different groups often use their own method or a modified version of a better known method, thus hindering a generalized resolution measurement which could be useful for gauging the performance of one system ...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Wheeler JL,Wang W,Tang M

    更新日期:2002-02-01 00:00:00

  • The possible role of the vagal nervous system in the recovery of the blood pressure control after cardiac arrest: a porcine model study.

    abstract::Previous studies have proved that the baroreceptor reflex (baroreflex) control of heart rate can be used for stratification of post-infarction population and, in general, cardiovascular disease populations. Many methods have been proposed to estimate the so-called baroreflex sensitivity (BRS) expressed as ms mmhg-1. M...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Lavanga M,Baselli G,Fumagalli F,Ristagno G,Ferrario M

    更新日期:2017-01-01 00:00:00

  • Validation of a finite-element solution for electrical impedance tomography in an anisotropic medium.

    abstract::Electrical impedance tomography is an imaging method, with which volumetric images of conductivity are produced by injecting electrical current and measuring boundary voltages. It has the potential to become a portable non-invasive medical imaging technique. Until now, implementations have neglected anisotropy even th...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Abascal JF,Arridge SR,Lionheart WR,Bayford RH,Holder DS

    更新日期:2007-07-01 00:00:00

  • Reference intervals for the evoked tympanic membrane displacement measurement: a non-invasive measure of intracranial pressure.

    abstract:OBJECTIVE:Evoked tympanic membrane displacement (TMD) is a non-invasive technique for assessing intracranial pressure (ICP). The aim of this study was to define reference intervals (RIs) in the healthy population. APPROACH:Measurements were made in 154 healthy adults. Results were quantified by V m, which is the most ...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Campbell-Bell CM,Birch AA,Vignali D,Bulters D,Marchbanks RJ

    更新日期:2018-01-31 00:00:00

  • Measuring dissimilarity between respiratory effort signals based on uniform scaling for sleep staging.

    abstract::Polysomnography (PSG) has been extensively studied for sleep staging, where sleep stages are usually classified as wake, rapid-eye-movement (REM) sleep, or non-REM (NREM) sleep (including light and deep sleep). Respiratory information has been proven to correlate with autonomic nervous activity that is related to slee...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Long X,Yang J,Weysen T,Haakma R,Foussier J,Fonseca P,Aarts RM

    更新日期:2014-12-01 00:00:00

  • In vivo neutron activation analysis of bone manganese in workers.

    abstract:OBJECTIVE:Manganese (Mn) is a neurotoxin. However, the impact of elevated, chronic Mn exposure is not well understood, partially due to the lack of a cumulative exposure biomarker. To address this gap, our group developed a compact in vivo neutron activation analysis (IVNAA) system to quantify Mn concentration in bone ...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Liu Y,Rolle-McFarland D,Mostafaei F,Zhou Y,Li Y,Zheng W,Wells E,Nie LH

    更新日期:2018-03-23 00:00:00

  • Quantifying agitation in sedated ICU patients using heart rate and blood pressure.

    abstract::Agitation is a significant problem in the intensive care unit (ICU), affecting 71% of sedated adult patients during 58% of ICU patient-days (Fraser and Riker 2001 NY Health-Syst. Pharm. 20 17-24). Subjective scale-based assessment methods are currently used to assess the level of patient agitation, but are limited in ...

    journal_title:Physiological measurement

    pub_type: 临床试验,杂志文章


    authors: Chase JG,Starfinger C,Lam Z,Agogue F,Shaw GM

    更新日期:2004-08-01 00:00:00

  • Trabecular thickness measurement in cancellous bones: postmortem rat studies with the zoom-in micro-tomography technique.

    abstract::Using the cross-sectional images taken with the zoom-in micro-tomography technique, we measured trabecular thicknesses of femur bones in postmortem rats. Since the zoom-in micro-tomography technique is capable of high resolution imaging of a small local region inside a large subject, we were able to measure the trabec...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Cho MH,Chun IK,Lee SC,Cho MH,Lee SY

    更新日期:2005-10-01 00:00:00

  • EITS changes following oleic acid induced lung water.

    abstract::We present the results of using electrical impedance tomographic spectroscopy (EITS) to follow the changes in lung water induced by oleic acid. Measurements were made on three goats before and after the injection of oleic acid. In addition to the EITs measurements, lung water was also measured using a double-indicator...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Brown BH,Flewelling R,Griffiths H,Harris ND,Leathard AD,Lu L,Morice AH,Neufeld GR,Nopp P,Wang W

    更新日期:1996-11-01 00:00:00

  • Within-breath measurement of respiratory impedance.

    abstract::The measurement of the complex respiratory impedance at a high temporal resolution is described. The measurement of impedance is correlated with the breathing cycle using electrical transthoracic impedance. This allows the determination of the complex impedance at any fixed point in the respiratory cycle, which result...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: van der Putten WJ,MacLeod D,Prichard JS

    更新日期:1993-08-01 00:00:00