Bioimpedance and chronoamperometry as an adjunct to prostate-specific antigen screening for prostate cancer

The clinical application of electrical impedance technology in the detection of malignant neoplasms: a systematic review

BACKGROUND

Electrical impedance technology has been well established for the last 20 years. Recently research has begun to emerge into its potential uses in the detection and diagnosis of pre-malignant and malignant conditions. The aim of this study was to systematically review the clinical application of electrical impedance technology in the detection of malignant neoplasms.

METHODS

A search of Embase Classic, Embase and Medline databases was conducted from 1980 to 22/02/2018 to identify studies reporting on the use of bioimpedance technology in the detection of pre-malignant and malignant conditions. The ability to distinguish between tissue types was defined as the primary endpoint, and other points of interest were also reported.

RESULTS

731 articles were identified, of which 51 reported sufficient data for analysis. These studies covered 16 different cancer subtypes in a total of 7035 patients. As the studies took various formats, a qualitative analysis of each cancer subtype's data was undertaken. All the studies were able to show differences in electrical impedance and/or related metrics between malignant and normal tissue.

CONCLUSIONS

Electrical impedance technology provides a novel method for the detection of malignant tissue, with large studies of cervical, prostate, skin and breast cancers showing encouraging results. Whilst these studies provide promising insights into the potential of this technology as an adjunct in screening, diagnosis and intra-operative margin assessment, customised development as well as multi-centre clinical trials need to be conducted before it can be reliably employed in the clinical detection of malignant tissue.

The value of bioelectrical impedance analysis and phase angle in the evaluation of malnutrition and quality of life in cancer patients--a comprehensive review

Bioelectrical impedance analysis (BIA) and especially its derived parameter phase angle have been widely used in different populations. The variability of BIA measures has often been cited as a major limitation for its clinical use in evaluating nutritional status and overall health of patients. Cancer patients often present with malnourishment and cachexia, which complicate the course of treatment and affect outcomes. PubMed, CINAHL, EBSCO and Cochrane Library have been searched for relevant publications in English for BIA in cancer patients. Out of 197 total results, 27 original research articles related to BIA measures in cancer patients were included in this review. Studies indicate that the use of BIA and phase angle measures can benefit in the clinical management of cancer patients in multiple ways: in the prevention; diagnosis; prognosis; and outcomes related to treatments that affect nutritional and overall health status. Phase angle and fat-free mass measures were most commonly evaluated and correlated with nutritional status and survival rate. One limitation of BIA measures is the high interpatient variability which requires careful interpretation of results in the context of the individual patient rather than comparison with population data. The BIA and phase angle provide practitioners for the evaluation of nutritional and overall health status in cancer patients with a convenient and non-invasive technique and should be encouraged.

Electro interstitial scan system: assessment of 10 years of research and development

BACKGROUND

Ten years of research and development have allowed an understanding of how the electro interstitial scan (EIS) works and what its clinical applications may be.

MATERIALS AND METHODS

The EIS is a galvanic skin response device. The measurements are performed by electrical stimulation of the post sympathetic cholinergic fiber with weak DC current and voltage 1.28V applied during 2 minutes and in bipolar mode. CURRENT SCIENTIFIC KNOWLEDGE: EIS ELECTRICAL MEASUREMENTS ARE RELATED TO: (1) the concentration of free chloride ions in the interstitial fluid, which affects the transfer of electrical current and the ratio intensity/voltage; (2) the morphology of the interstitial fluid, which is related to the electrical dispersion calculated from the Cole equation (α parameter); (3) electrical stimulation, which causes a change in sweat rate at the passive electrodes - post sympathetic cholinergic fiber electrical stimulation appears to be responsible for activating M2 receptors, which regulate nitric oxide (NO) production in the endothelial cell and cause vasodilation and a released sweat response; and (4) the electrochemical redox reactions (electrolysis) of the released sweat on electrodes, which are different on the bulk of the metal electrodes (O2 + [4H(+)] + [4e(-)]) and on the Ag/AgCl disposable electrodes (AgCl precipitation).

RESULTS

FOR EACH OF THE EIS CLINICAL RESULTS, VARIOUS EXPLANATIONS WERE POSITED, SUCH AS: (1) electrical stimulation of the postsympathetic cholinergic fiber-activating NO production in the endothelial cell, which causes vasodilation and a released sweat response (diabetes detection); (2) estimation of interstitial fluid's acid-base balance, which is reflected in an electrochemical reaction on the bulk of the electrodes through the released sweat (prostate cancer detection); (3) estimation of cerebral interstitial fluid chloride ions (detection of ADHD in children); and (4) estimation of the morphology of the interstitial fluid (selective serotonin reuptake inhibitor treatment response).

CONCLUSION

After 10 years of development, the analysis of current scientific knowledge and results of clinical investigations have allowed a better understanding of EIS electrical measurements.

Bioimpedance in monitoring of effects of selective serotonin reuptake inhibitor treatment

Background

Bioimpedance has been shown to be a safe technique when used in a number of biomedical applications. In this study, we used the Electro Interstitial Scan (EIS) to perform bioimpedance measurements to follow up the efficacy of selective serotonin reuptake inhibitor (SSRI) treatment in subjects diagnosed to have major depressive disorder.

Methods

We recruited 59 subjects (38 women, 21 men) aged 17–76 (mean 47) years diagnosed with major depressive disorder by psychiatric assessment at the Botkin Hospital according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Baseline Clinical Global Impression scores and EIS (electrical conductivity and dispersion α parameter) measurements were done before starting SSRI therapy. Treatment follow-up was undertaken using EIS bioimpedance measurements and by treatment response based on the Hamilton Depression Scale and Clinical Global Impression, every 15 days for 60 days. At day 45, we classified the patients into two groups, ie, Group 1, including treatment responders, and Group 2, including nonresponders. At day 60, patients were classified into two further groups, ie, Group 3, comprising treatment responders, and Group 4, comprising nonresponders.

Results

Comparing Group 1 and Group 2, electrical conductivity measurement of the pathway between the two forehead electrodes had a specificity of 72% and a sensitivity of 85.3% (P < 0.0001), with a cutoff >4.32. Comparing Group 3 and Group 4, electrical conductivity measurements in the same pathway had a specificity of 47.6% and a sensitivity of 76.3% (P < 0.16), with a cutoff >5.92. Comparing Group 1 and Group 2, the electrical dispersion α parameter of the pathway between the two disposable forehead electrodes had a specificity of 80% and a sensitivity of 85.2% (P < 0.0001) with a cutoff >0.678. Comparing Group 3 and Group 4, the electrical dispersion α parameter of the same pathway had a specificity of 100%, a sensitivity of 89.5% (P < 0.0001), and a cutoff >0.692.

Conclusion

Electrical conductivity measurement of the forehead pathway using EIS has a high specificity and sensitivity at day 45 when comparing treatment responders and nonresponders, but decreases at day 60. The EIS electrical dispersion α parameter of the forehead pathway has a high specificity and sensitivity at day 45 when comparing treatment responders and nonresponders, and increases at day 60. The EIS system may be a noninvasive, easily administered, low-cost technique that could be used as an adjunct to DSM-IV and Clinical Global Impression scores for monitoring of efficacy of treatment in patients with major depressive disorder.

New marker using bioimpedance technology in screening for attention deficit/hyperactivity disorder (ADHD) in children as an adjunct to conventional diagnostic methods

Background

Diagnosis of attention deficit/hyperactivity disorder (ADHD) in children is not straightforward and misdiagnosis may occur, which leads to the possibility of errors in treatment, with numerous possible side effects that could be especially damaging in view of the age of the population. For this reason, a tool that is easy to use, fast, and cost-effective, which provides an addition to conventional diagnosis and treatment monitoring of ADHD children, is needed. In this study, electro interstitial scans (EIS) were used to perform bioimpedance measurements. The results of conductivity measurements taken using forehead electrodes in a group of children conventionally diagnosed with ADHD and in a control group not showing any symptoms of ADHD were compared.

Method

Sixty children without any ADHD symptoms (group 1) and 52 children diagnosed with ADHD following psychiatric examination (group 2) underwent an examination with the EIS system. Statistical analysis was performed to compare the conductivity measurements at the level of the forehead electrodes, using independent t-tests and a receiver-operating characteristic curve (ROC) to determine the specificity and sensitivity of the test.

Results

The mean of the conductivity measurements of two pathways between the forehead electrodes (from left forehead to right forehead and from right forehead to left forehead) in the ADHD group was 33.11 micro Siemens (mS) (range 2–113 mS). This was significantly higher (P < 0.001) than mean of the conductivity measurements of two pathways between the forehead electrodes of the control group (2.75 mS, range 1.75–27.4 mS). In terms of the ROC results, comparing the two groups using the reference of the mean of conductivity measurements of the two pathways between the forehead electrodes, the test showed a specificity of 98% and sensitivity of 80% and P = 0.0001 (95% confidence interval) with a cutoff value at 7.4 mS.

Conclusion

The EIS marker related to the conductivity measurements of the forehead pathway has a high specificity and high sensitivity and use of this could provide practitioners with a noninvasive, low-cost system that is easy to use in the office and could offer an adjunct to the conventional diagnosis of ADHD children. It could also assist in treatment monitoring, and allow for earlier intervention.

Comparing the accuracy of ES-BC, EIS-GS, and ES Oxi on body composition, autonomic nervous system activity, and cardiac output to standardized assessments

BACKGROUND AND PURPOSE

THE ELECTRO SENSOR COMPLEX (ESC) IS SOFTWARE THAT COMBINES THREE DEVICES USING BIOELECTRICAL IMPEDANCE, GALVANIC SKIN RESPONSE, AND SPECTROPHOTOMETRY: (1) ES-BC (Electro Sensor-Body Composition; LD Technology, Miami, FL) to assess body composition, (2) EIS-GS (Electro Interstitial Scan-Galvanic Skin; LD Technology) to predict autonomic nervous system activity, and (3) ES Oxi (Electro Sensor Oxi; LD Technology) to assess cardiac output. The objective of this study was to compare each to a standardized assessment: ES-BC to dual-energy X-ray absorptiometry (DXA), EIS-GS to heart rate variability, and ES Oxi to BioZ Dx Diagnostic System (BioZ Dx; SonoSite Inc, Bothell, WA).

PATIENTS AND METHODS

The study was conducted in two waves. Fifty subjects were assessed for body composition and autonomic nervous system activity. Fifty-one subjects were assessed for cardiac output.

RESULTS

We found adequate relative and absolute agreement between ES-BC and DXA for fat mass (r = 0.97, P < 0.001) with ES-BC overestimating fat mass by 0.1 kg and for body fat percentage (r = 0.92, P < 0.001) with overestimation of fat percentage by 0.4%. For autonomic nervous system activity, we found marginal relative agreement between EIS-GS and heart rate variability by using EIS-GS as the predictor in a linear regression equation (adjusted R(2) = 0.56, P = 0.03). For cardiac output, adequate relative and absolute agreement was found between ES Oxi and BioZ Dx at baseline (r = 0.60, P < 0.001), after the first exercise stage (r = 0.79, P < 0.001), and after the second exercise stage (r = 0.86, P < 0.001). Absolute agreement was found at baseline and after both bouts of exercise; ES Oxi overestimated baseline and stage 1 exercise cardiac output by 0.3 L/minute and 0.1 L/minute, respectively, but exactly estimated stage 2 exercise cardiac output.

CONCLUSION

ES-BC and ES Oxi accurately assessed body composition and cardiac output compared to standardized instruments, whereas EIS-GS showed marginal predictive ability for autonomic nervous system activity. The ESC software managing the three devices would be useful to help detect complications related to metabolic syndrome, diabetes, and cardiovascular disease and to noninvasively and rapidly manage treatment follow-up.