Various skin impedance models based on physiological stratification

Bora, Dhruba Jyoti; Dasgupta, Rajdeep

doi:10.1049/iet-syb.2019.0013

Cited by 23 publications

(17 citation statements)

References 41 publications

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“…In the use case of interest, the stimulation is performed by symmetric biphasic pulses, with a current-controlled square shape. [3] Therefore, a frequency sweep, often used to characterize the electrode skin models, [17,18] is not the optimal method to ascertain the relevant parameters for the impedance model with the most approximate response to the targeted stimulus. Instead, the system's step response was analyzed, with the excitation signal formed as a rectangular biphasic current-controlled pulse with 4 ms pulse width and 1 mA amplitude.…”

Section: Human Model Equivalent Circuit Parameters Identificationmentioning

confidence: 99%

“…[16] While its impedance is a complex function of tissue and stimuli properties, for electrical stimulation, it exhibits largely resistive and capacitive properties, [17] which vary according to the type and thickness of skin, where the inductive property is negligible. [18] There are numerous electrical models of human skin proposed in the literature, composed of resistancecapacitor (RC) combinations according to the characteristics stratified by skin layers. The most common models are the Montague model, [19] Tregear model, and Lykken model.…”

Section: Introductionmentioning

confidence: 99%

“…The most common models are the Montague model, [19] Tregear model, and Lykken model. [20] The proposed HMEC device is based on the Montague model.…”

Section: Introductionmentioning

confidence: 99%

“…The Montague model, widely used in the area of transcutaneous electrical stimulation due to its simplicity, [21] is composed of only three elements: two resistors and a capacitor. [18] Here, the skin can be abstracted into two layers: the outer layer called the epidermis and the deeper structures called the dermis. [22] As depicted in Figure 1, the resistive and capacitive properties of the epidermis and the electrode-skin interface are represented by a parallel resistance R d and a dielectric capacitance C d .…”

Section: Introductionmentioning

confidence: 99%

“…Human skin morphology and the Montague model. [18] approach allows simple testing of each batch of electrodes to assess the performance of logic components, as well as to evaluate how the design adaptation or fabrication methods will affect the stimulation signals in the human tissue, prior to the actual validation of newly developed electrodes in human trials.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Design and Fabrication of Printed Human Skin Model Equivalent Circuit: A Tool for Testing Biomedical Electrodes without Human Trials

Peřinka

Štrbac²,

Kostić³

et al. 2021

Adv Eng Mater

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Within the efforts of developing a new generation of biomedical electrodes with embedded switching logics, developing safe and simple procedures for testing these novel systems is tackled. The development and demonstration of an all‐printed flexible testbed for automated validation and testing of multi pad systems is presented. The system is based on a Human model equivalent circuit (HMEC), which, when connected to the electrical stimulation system, mirrors the electrical behavior of biomedical electrodes and their specific interface material as if they are placed on a human subject. A simulation model of the electrical stimulation system components was developed based on the experimental data, in order to optimize printed electronic components’ characteristics and design. The testbed is composed of five layers of different conductive and dielectric materials screen‐printed on a flexible poly(ethylene terephthalate) (PET) substrate. The system was prototyped with the characteristic values of the HMEC matching the average experimental data acquired from human subjects. Thus, it is demonstrated that an all printed flexible HMEC is a feasible approach to enabling the functional testing of transcutaneous electrical stimulation devices required for their fabrication, evaluation and optimization, reducing the need for tests on human subjects in the development phase of new systems.

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Section: Human Model Equivalent Circuit Parameters Identificationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…The most common models are the Montague model, [19] Tregear model, and Lykken model. [20] The proposed HMEC device is based on the Montague model.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Design and Fabrication of Printed Human Skin Model Equivalent Circuit: A Tool for Testing Biomedical Electrodes without Human Trials

Peřinka

Štrbac²,

Kostić³

et al. 2021

Adv Eng Mater

View full text Add to dashboard Cite

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Silk Fibroin Hydrogel for Pulse Waveform Precise and Continuous Perception

Yan,

Deng,

Xie

et al. 2024

Adv Healthcare Materials

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Precise and continuous monitoring of blood pressure and cardiac function is of great importance for early diagnosis and timely treatment of cardiovascular diseases. The common tests rely on on‐site diagnosis and bulky equipments, hindering early diagnosis. The emerging hydrogels have gained considerable attention in skin bioelectronics by virtue of the similarities to biological tissues and versatility in mechanical, electrical, and biofunctional engineering. However, hydrogels should overcome intrinsic issues such as poor mechanical strength, easy dehydration and freezing, weak adhesiveness and self‐recovery, severely limiting their precision and reliability in practical applications. Here, silk fibroin hydrogels are developed as resistive sensors for pulse waveform monitoring. The silk fibroin hydrogel is simultaneously transparent, extremely stretchable, extra tough, adhesive, printable, and environmentally endurable. The silk fibroin hydrogel is also conductive with high sensitivity, short self‐healing time, highly repeatable and reliable response, meeting the requirements for wearable sensors for continuous monitoring. The sensors with silk fibroin hydrogel present high‐quality and stable waveforms of radical and brachial pulses with high precision and rich features, providing physiological signals of blood pressure and cardiac function. The sensors are promising for personalized health management, daily monitoring and timely diagnosis.

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Using electrocardiogram electrodes to monitor skin impedance spectroscopic response when skin is subjected to sustained static pressure

Owen

Hathaway

Lafferty

et al. 2023

Skin Health and Disease

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Background Impedance spectroscopy is a non‐invasive technique which can be used to monitor skin barrier function, with potential applications in early‐stage pressure ulcer detection. This paper describes how changes in skin impedance, due to mechanical damage of the stratum corneum by tape stripping or applied pressure, can be straightforwardly measured using commercial electrocardiogram electrodes and a relatively low‐cost impedance analyser. Two models of pressure injury were studied, an ex vivo porcine and in vivo human skin model. Objectives Determine whether impedance spectroscopy may have potential utility in measuring the effect on skin of applied pressure on early‐stage pressure injury. Methods Two models were utilized to measure the effect of pressure. Porcine model: 0, 7.5, 15 or 22.5 mmHg of pressure was applied for up to 24 h (N = 4) and monitored at various time intervals. Human Model: 88 mmHg of pressure was applied for four sets of three‐minute intervals (N = 13) and post‐pressure recovery was monitored for 4 h. For each model, skin impedance was monitored at 0.1 Hz–50 kHz using disposable Ag/AgCl electrodes. The data was analysed using Ordinary One‐Way Analysis of Variance. Results Porcine model: after 24 h, the impedance of pressure‐loaded skin was significantly reduced compared to the non‐loaded control group (p ≤ 0.0001); this reduction in impedance was proportional to the degree of mechanical loading. Histology images of skin cross‐sections provided qualitative evidence that the epidermis was structurally compromised by pressure. Human Model: the response of healthy skin to applied pressure displayed inter‐variation. Participants with a significant change in skin impedance (p ≤ 0.01) also demonstrated signs of erythema. Conclusions This study suggests that using impedance spectroscopy to measure skin (stratum corneum) resistance may have utility in giving early warning of skin pressure injury prior to clinical symptoms, with a good correlation between observed erythema and reduction in skin resistance. Further work should be initiated on patients at risk of pressure injury to improve intervention strategies, including in darker skin tones where early‐stage pressure injuries may not be visually distinct.

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Various skin impedance models based on physiological stratification

Cited by 23 publications

References 41 publications

Design and Fabrication of Printed Human Skin Model Equivalent Circuit: A Tool for Testing Biomedical Electrodes without Human Trials

Design and Fabrication of Printed Human Skin Model Equivalent Circuit: A Tool for Testing Biomedical Electrodes without Human Trials

Silk Fibroin Hydrogel for Pulse Waveform Precise and Continuous Perception

Using electrocardiogram electrodes to monitor skin impedance spectroscopic response when skin is subjected to sustained static pressure

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