Electrical Bioimpedance Research Articles

Diagnostic Assessment of Respiratory and Hemodynamic Changes Related to Prone Position in COVID-19 Patients.

To study the respiratory patterns and the hemodynamic variations related to postural changes in inpatients with coronavirus disease (COVID-19). This report is a prospective study in a cohort of inpatients admitted with COVID-19. We recruited 10 patients admitted to the hospital with moderate or severe COVID-19 who showed improvement in oxygen saturation with prone positioning. We performed cardiorespiratory polygraphy and hemodynamic evaluations by thoracic electrical bioimpedance. We observed a median minimum oxygen saturation of 85.00% (IQR: 7.00) in the supine position versus 91.00% (IQR: 8.00) (P = 0.173) in the prone position. The airflow restriction in the supine position was 2.70% (IQR: 6.55) versus 1.55% (IQR: 2.80) (P = 0.383) in the prone position. A total of 36.4% of patients were classified as having a normo-hemodynamic state in the supine position, whereas 54.5% were classified in this group in the prone position (P = 0.668). A decrease in vascular resistance was observed in the prone position (18.2% of vasoconstriction) compared to the supine position (36.4% of vasoconstriction) (P = 0.871). This brief report describes the effects of prone positioning on respiratory and hemodynamic variables in 10 patients with moderate or severe COVID-19.

Body Composition Assessment of University Athletes: Comparison Between the Data Obtained by Bioelectrical Impedance and by Anthropometry

Introduction: To compare the values obtained of the most used practical methods in clinical practice, by bioelectrical impedance and by anthropometry of the body composition of university athletes. Methods: Observational analytical study whose sample included 26 athletes of a Portuguese university football team. The assessment of individuals’ body composition was executed through bioelectrical impedance and anthropometry by an ISAK level one anthropometrist accredited completing the inherent protocol. For the data analysis was considered a critical significance level of 5% for a confidence level of 95% to test the hypotheses between the variables under study and their correlations, Pearson's parametric test of linear correlation coefficient was applied. Results: The variability of body composition assessed in the sample is highlighted. Significant correlations were found for fat mass and skinfolds sum (r=0,782; p=<0,001) as well as for individual skinfolds. Respectively through the elaboration of the scatter diagram, the following linear r2= 0.612 was obtained, representing the correlation between the variables. Similar correlations were found in the context of fat free mass and circumferences. However, in the case of the waist-to-hip ratio assessed by electrical bioimpedance and the waist-to-hip ratio assessed by anthropometry, there were lower correlations compared to the other parameters evaluated (r=0,441; p=0,036). Conclusion: It is intended to make it easier for interested sports professionals to select practical methods for assessing the body composition of their athletes, while eliminating the risk of selecting inappropriate methods. It is noted the possibility of replacing or complementing the bioelectrical impedance analysis with an accessible and viable anthropometric method such as the skinfolds sum, especially in teams with lower budgets like the university teams.

Prediction of respiratory distress severity and bronchopulmonary dysplasia by lung ultrasounds and transthoracic electrical bioimpedance.

This study aims to evaluate whether the assessment of a lung ultrasound score (LUS) by lung ultrasonography and of thoracic fluid contents (TFC) by electrical cardiometry may predict RDS severity and the development of bronchopulmonary dysplasia (BPD) in preterm infants with respiratory distress (RDS). Infants ≤ 34weeks' gestation admitted with RDS to two neonatal intensive care units were prospectively enrolled in this observational study. A simultaneous evaluation of LUS and TFC was performed during the first 72h. The predictivity of LUS and TFC towards mechanical ventilation (MV) need after 24h and BPD development was evaluated using receiver operating characteristic analysis. Sixty-four infants were included. The area under the curve (AUC) for the prediction of MV need was 0.851 (95%CI, 0.776-0.925, p < 0.001) for LUS and 0.793 (95%CI, 0.724-0.862, p < 0.001) for TFC, while an AUC of 0.876 (95%CI, 0.807-0.946, p < 0.001) was obtained for combined LUS and TFC evaluation. LUS and TFC AUC for BPD prediction were 0.769 (95%CI, 0.697-0.842, p < 0.001) and 0.836 (95%CI, 0.778-0.894, p < 0.001), respectively, whereas their combined assessment yielded an AUC of 0.867 (95%CI, 0.814-0.919, p < 0.001). LUS ≥ 11 and TFC ≥ 40 were identified as cut-off values for MV need prediction, whereas LUS ≥ 9 and TFC ≥ 41.4 best predicted BPD development. Conclusion: A combined evaluation of LUS and TFC by lung ultrasonography and EC during the first 72h may represent a useful predictive tool towards short- and medium-term pulmonary outcomes in preterm infants with RDS. What is Known: •Lung ultrasonography is largely used in neonatal intensive care and can contribute to RDS diagnosis in preterm infants. •Little is known on the diagnostic and predictive role of TFC, measured by transthoracic electrical bioimpedance, in neonatal RDS. What is New: •Combining lung ultrasonography and TFC evaluation during the first 72 h can improve the prediction of RDS severity and BPD development in preterm infants with RDS and may aid to establish tailored respiratory approaches to improve these outcomes.

A Closed-Loop Automated Craniotomy System With Real-Time Bio-Impedance Feedback

Cranial microsurgery is a prerequisite for neuroscience research, which provides an accessible brain for neural recording and optogenetic stimulation. As the scale of electrode implantation increases, massive delicate craniotomies are required to perform on the submillimeter-thick skull of small animals (e.g., mice). Automated craniotomy (AMC) is ideal for improving surgery efficiency and ensuring consistent results. However, due to the lack of effective feedback, the current AMC platforms are prone to over-drilling and injuring brain tissues. Fragile and ultrathin skulls of small objects also make it hard to integrate suitable sensors into the end-effector for accurate perception. Thus, this article proposes an integrated electrical bioimpedance measurement (EBIM) solution for the closed-loop AMC. A sensing drill and a custom EBIM device are implemented to form reliable electrical contact with the object and accurately measure the impedance. After evaluating the EBIM device’s accuracy (< 2% relative error) and stability, we provide a modified judgment signal for breakthrough detection and further simulate closed-loop craniotomies on an equivalent model. The experimental results demonstrate that the proposed system can achieve sensitive breakthrough detection (< 0.1 s delay at 100 Hz excitation) and consistent drilling depth ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10.3 \mu \text{m}$ </tex-math></inline-formula> deviation with a 10-mm/min feed rate) in contrast to the gold standard (LCR meter).

Anthropometric characteristics of young elite sailors based on performance level

Background/ObjectivesThe aim of the present study was to analyse possible differences in anthropometric characteristics of elite sailors based on categories and performance level. MethodsA total of 42 young (aged 12–18 years) elite sailors (men = 31; women = 11) of the Monohull (n = 21) and Windsurfing (n = 21) categories composed the study sample. Testing was per-formed in one session the day before the start of an official and international competition. Body composition was measured using an octopolar and multi-frequency electrical bioimpedance analyser, and height was recorded using a telescopic measuring instrument. Cross-sectional study. The total sample was divided into two groups based on their performance level (ranking), 50th percentile (P1), and 100th percentile (P2). ResultsP1 presented a lower BMI, total body fat mass, and body fat mass in the trunk, arms, and legs (p < 0.05). Similarly, P1 reported a higher total body muscle mass and body muscle mass on the trunk, arms, and legs compared to the less level performance group (p < 0.05). In addition, P2 sailors were taller and heavier (p < 0.05). Regarding categories, the Windsurf sailors presented statistically significantly lower arm fat mass than the Monohull (p < 0.05). The Windsurf sailors showed differences between the two performance-level groups (p < 0.05). Additionally, comparing the high-level performance group in both categories, higher arm muscle mass on the Windsurfing sailors was detected (p < 0.05). ConclusionsThese findings could help to differentiate the anthropometric variables that determine sport performance in young elite sailors and could be used to differentiate the anthropometric variables in each category.

The Severity of Obesity Promotes Greater Dehydration in Children: Preliminary Results.

The state of hydration of the body depends on the balance between the amount of water and salt consumed and excreted (the urinary extraction of excess sodium requires water). Inappropriate nutrition, particularly consuming too much processed food, causes obesity in children and additionally causes excessive sodium consumption, thus increasing the risk of excessive water loss. The aim of this study was to assess the hydration status of children with obesity and the relation between hydration, body composition, urinary sodium extraction, and nutrient intake. The study group consisted of 27 patients with obesity, with a mean age of 12.89 ± SD 2.79. Each patient's height, weight, body composition (electrical bioimpedance (BIA)), diet (7-day record), and biochemical tests were assessed. The hydration status was assessed using 24-hour urine collection, 24-hour urine osmolality, and an ultrasound of the vena cava (IVC/Ao index). Overall, 55% of children (n = 15) had urine osmolality values above 800 mOsm/kgH2O, which indicates significant dehydration, and 53% (n = 14) were dehydrated, based on the IVC/Ao index. Children with obesity and dehydration had a significantly higher BMI (31.79 vs. 27.32; p = 0.0228), fat mass percentage (37.23% vs. 30.07% p = 0.0051), and fat mass in kg (30.89 vs. 20.55; p = 0.0158), and significantly higher sodium intake from their diet (3390.0 mg vs. 2921.0 mg; p = 0.0230), as well as their sodium/potassium ratio (2.4 vs. 2.0; p = 0.0043). The 24-hour urinary sodium excretion and osmolality values were directly related to fat-mass percentage and fat-mass (in kg) in a simple linear correlation analysis. Our preliminary results confirm that obesity is related to dehydration. The overall high sodium excretion in children with obesity indicates an excessive salt intake along with low potassium intake, which is a significant predictor of dehydration, regardless of the total water intake (TWI).

Quantifying Rheumatoid Arthritis Disease Activity Using a Multimodal Sensing Knee Brace.

Rheumatoid arthritis (RA) is a chronic inflammatory syndrome that features painful and destructive joint disease. Aggressive disease-modifying treatment can result in reduced symptoms and protection from irreversible joint damage; however, assessment of treatment efficacy is currently based largely on subjective measures of patient and physician impressions. In this work, we address this compelling need to provide an accurate and quantitative capability for monitoring joint health in patients with RA. Joint acoustic emissions (JAEs), electrical bioimpedance (EBI), and kinematics were measured noninvasively from 11 patients with RA over the course of three weeks using a custom multimodal sensing brace, resulting in 49 visits with JAE recordings and 43 with EBI recordings. Features derived from all sensing modalities were fed into a linear discriminant analysis (LDA) model to predict disease activity according to the validated disease activity index (the DAS28-ESR). Erythrocyte sedimentation rate (ESR) was predicted using ridge regression and classified into a high or low class using LDA. DAS28-ESR level was predicted with an area under the receiver operating characteristic curve (AUC) of 0.82. With JAEs alone, we were able to track intrasubject differences in the disease activity score as well as classify ESR level with an AUC of 0.93. The majority of patients reported both an interest and ability to use the brace at home for longitudinal monitoring. This work demonstrates the ability to detect RA disease activity using noninvasive sensing. This system has the potential to improve RA disease activity monitoring by giving treating clinicians objective data that can be acquired independent of a face-to-face clinic visit.

Nutritional Status of Slovene Adults in the Post-COVID-19 Epidemic Period.

Background: Monitoring nutritional status data in the adult population is extremely important to mediate their health status. Unfortunately, for Slovenia (2.1 million European Union citizens), data on the body composition status of the general adult population are currently rare or nonexistent in scientific journals. Furthermore, dietary intake was last assessed several years before the COVID-19 epidemic period. Methods: We randomly recruited 844 adult Slovenes from all regions of Slovenia. The primary aim of the cross-sectional study was to examine body composition status (using a medically approved electrical bioimpedance monitor) during the post-COVID-19 epidemic period. In addition, we assessed dietary intake (using a standardized food frequency questionnaire) and compared the obesity propensity for both sexes separately using the body mass index (BMI) and body fat percentage (FAT%) obesity classification of the World Health Organization. Results: Regarding BMI classification, 43% of the whole sample was overweight (28%) or obese (15%), and there were more older adults than adults (64% vs. 42%, p < 0.001). The average FAT% of adult females and males was 26.9% and 19.5% (p < 0.001), respectively, while for older adult females and males, it was 32.7% and 23% (p < 0.001). In addition, a comparison of the proportions of obese people between the two cut-off obesity classifications (BMI vs. FAT%) showed a significantly underestimated proportion of obese female participants based on BMI classification (13% vs. 17%, p = 0.005). In terms of the dietary intake of the assessed nutrients in comparison with the national dietary reference values for energy and nutrient intake, the participants, on average, had lower intake than the recommended values for carbohydrates, fiber, vitamins C, D and E (for males) and calcium, and higher intake than the recommended values for total fat, saturated fatty acids, cholesterol, sodium and chloride (for males). Conclusions: The results urgently call for the need to not only improve the overall national nutritional status but also for regular national monitoring of body composition and dietary intake statuses.

SELECTED ANTHROPOMETRIC CHARACTERISTICS AND BODY COMPOSITION OF FEMALE VOLLEYBALL PLAYERS IN CADET, JUNIOR AND SENIOR NATIONAL TEAMS OF SLOVENIA

Certain morphological characteristics and motor abilities are systematically monitored in Slovenian volleyball teams of different age categories. The study aimed to determine selected anthropometric dimensions and the body composition of 46 members of the cadet, junior and senior women’s volleyball national teams. Anthropometric characteristics were measured using the NX-16 [TC]2 3D-technology for body scanning. Body height was measured using an anthropometer, body mass was weighed using scales, and the body mass index (BMI) was calculated. By using an electrical bioimpedance (EBI) Inbody 720 tetrapolar, 8-point electrode system (Biospace Co., Ltd.), we established percentages of skeletal muscle mass and fat mass as well as body water percentage. The differences among the results for female volleyball players of various categories in terms of body height and body mass are small. Likewise, the body composition results are similar in all three age categories. We also investigated whether the results of anthropometric variables of the upper body differ statistically significantly among individual categories. We identified statistically significant differences between cadet women and senior women in terms of right forearm circumference (p = 0.04). Cadet women (24,62 cm) have a smaller forearm circumference than senior women (25,08 cm). Statistically significant differences were also established between cadet women and junior women in terms of right upper arm circumference (p = 0.03). Junior women have a statistically significantly larger left upper arm circumference. No statistical significance was recorded with respect to other variables. The results obtained are generally similar to those from studies by other authors.

PHASE ANGLE AS A POTENTIAL MARKER OF NUTRITIONAL STATUS OF INTENSIVE CARE PATIENTS

Objective: to verify the association of phase angle with nutritional status, length of hospitalization and death in critically ill patients. Methods: longitudinal study with 57 critically ill patients evaluated upon admission to an intensive care unit during the year 2019, in the countryside of São Paulo - BR. The phase angle was obtained by electrical bioimpedance, and nutritional assessment, by the global subjective assessment instrument and anthropometry. The data were associated with the time of hospitalization and death. For the analysis, Mann-Whitney and Pearson's chi-square tests were used. Results: in the global subjective evaluation, 59.6% of the patients presented nutritional risk, and in 91.2% the phase angle was low. Malnutrition was associated with longer hospital stay (p=0.001) in intensive care unit (p=0.023). There was a tendency to death in the group with nutritional risk (p=0.054). Conclusion: The phase angle can contribute to a better accuracy in nutritional assessment, especially when combined with other assessment methods.

Phase Angle as a Predictor for Physical Function in Institutionalized Independent Older Adults.

The aim of this study was to investigate the relationship between phase angle (PhA) and physical function in institutionalized, independent older adults. Physical function was evaluated using the Senior Fitness Test Battery. PhA was measured by electrical bioimpedance at 50 khz, and body composition parameters were also registered. Results showed that PhA significantly correlated with all physical fitness tests, except for arm curls. Regarding the results of the multivariate analysis, three models were created: Model 1, formed by a dependent variable "PhA" and two predictor variables "8 ft up-and-go" and "6 min walk"; Model 2, formed by a dependent variable "PhA" and three predictor variables "8 ft up-and-go", "6 min walk" and "30-s chair stand"; and Model 3, formed by a dependent variable "PhA" and four predictor variables "8 ft up-and-go", "6 min walk", "30-s chair stand" and "arm curl". Results showed that predictor variables had a significant influence on the PhA for all three models (Model 1: p = 0.001, 12.5%; Model 2: p = 0.002, 12.9%; and Model 3: p = 0.005, 13.1%). For women, Model 1 showed a significant influence of predictor variables on the PhA (p = 0.030, 9.3%). The results for men in Models 1, 2 and 3 showed significant influences on the PhA (p = 0.002, 31.2%; p = 0.006, 31.6%; and p = 0.016, 31.6%; respectively). This study confirmed previous studies regarding to the relationship between PhA and physical function. It also indicates that PhA could be an excellent predictor of physical function.

Efficacy of neuromuscular electrical stimulation with combined low and high frequencies on body composition, peripheral muscle function and exercise tolerance in patients with chronic kidney disease undergoing haemodialysis: a protocol for a randomised, double-blind clinical trial

IntroductionNeuromuscular electrical stimulation (NMES) as an adjunctive strategy to increase isolated muscular strength or endurance has been widely investigated in patients with chronic kidney disease (CKD) undergoing haemodialysis (HD). However,...

Differences in Body Composition Analysis by DEXA, Skinfold and BIA Methods in Young Football Players.

The most widely used method in professional sports for fat percentage assessment is the skinfold method. However, there is the chance of bias and human error. For this reason, other more precise methods are used, such as single-frequency bioelectrical impedance analysis (BIA) or dual energy X-ray absorptiometry (DEXA). However, there are limited data that demonstrate the methodological shortcomings or congruences in fat and fat-free mass estimates including gender differences and differences in athlete populations. Thus, the aim of the present study was to compare total body fat (%BF) estimated by six skinfold thickness measurement (SKF) and single-frequency bioelectrical impedance analysis (BIA) methods, using three different sets of equations, to that assessed by the dual energy X-ray absorptiometry (DEXA) method using a DEXA Hologic Serie Discovery QDR. For this aim, 76 males and 70 females belonging to the professional Spanish football federation were evaluated. We found significant differences between the three measures. BIA significantly underestimates the fat percentage, followed by skinfolds. With DEXA being the more objective or accurate method, an equation is established by means of linear regression analysis that allows the percentage of adipose tissue to be obtained either through anthropometry or electrical bioimpedance and adjusted to that which would be obtained by the DEXA system.

Can passive leg raise predict the response to fluid resuscitation in ED?

ObjectivePassive leg raise (PLR) can be used as a reversible preload challenge to stratify patients according to preload response. We aim to evaluate the accuracy of PLR, monitored by a non-invasive cardiac output monitor in predicting to response to fluid resuscitation in emergency department (ED).MethodsWe recruited adult patients planned to receive a resuscitation fluid bolus. Patients were monitored using a thoracic electrical bioimpedance (TEB) cardiac output monitor (Niccomo, Medis, Germany). A 3-min PLR was carried out before and after fluid infusion. Stroke volume changes (ΔSV) were calculated and a positive response was defined as ≥ 15% increase.ResultsWe recruited 39 patients, of which 37 were included into the analysis. The median age was 63 (50–77) years and 19 patients were females. 17 patients (46%) were fluid responders compared to 11 (30%) with positive response to PLR1. ΔSV with PLR1 and fluid bolus showed moderate correlation (r = 0.47, 95% confidence interval, CI 0.17–0.69) and 62% concordance rate. For the prediction of the response to a fluid bolus the PLR test had a sensitivity of 41% (95% CI 22–64) and specificity of 80% (95% CI 58–92) with an area under the curve of 0.59 (95% CI 0.41–0.78). None of the standard parameters showed a better predictive ability compared to PLR.ConclusionUsing TEB, ΔSV with PLR showed a moderate correlation with fluid bolus, with a limited accuracy to predict fluid responsiveness. The PLR test was a better predictor of fluid responsiveness than the parameters commonly used in emergency care (such as heart rate and blood pressure). These data suggest the potential for a clinical trial in sepsis comparing TEB monitored, PLR directed fluid management with standard care.

CD36 polymorphism, sugary drinks, and sedentarism are associated with hypertriglyceridemic waist phenotype.

Background: The hypertriglyceridemic waist (HTGW) phenotype is characterized by concomitant increases in waist circumference (WC) and blood triglyceride levels (TG), which have been identified as a predictor of metabolic disorders. This study aimed to analyze associations between food consumption, exercise, and the CD36 gene rs1761667 G>A polymorphism with the HTGW phenotype in adult Mexicans. Methods: This cross-sectional study included a total of 255 participants (both genders, between 18-64 years of age). The HTGW phenotype was defined as WC >88 cm in women, WC >102 cm in men, and TG >150 mg/dL. Body composition was analyzed by electrical bioimpedance. Dietary intakes (macro and micronutrients) were evaluated through a validated 64-item food frequency questionnaire and a 24-h recall. Physical exercise was subjectively recorded asking the participants if they regularly performed some systematic exercise or sport of moderate intensity at least 150-300 minutes a week. Biochemical tests were determined by an automated system. A Taqman real-time assay was used to detect the rs1761667 (G>A) polymorphism of the CD36 gene. A multivariate logistic regression model was performed to analyze the variables potentially associated with the HTGW phenotype (adjusted for age, energy intake, and total fat mass). Results: Overall, 21.6% of the population presented the HTGW phenotype; compared to the HTGW-, also, they were older, had more body fat, higher glucose, cholesterol and insulin levels, and high blood pressure. Female sex (OR=2.92, 95% CI: 1.12-7.60, p=0.028), body mass index (OR=1.19, 95% CI: 1.07-1.32, p=0.001), total cholesterol (OR=1.01, 95% CI:1.00-1.02, p=0.039), daily consumption of sugary drinks (OR=6.94, 95% CI: 1.80-26.8, p=0.005), and the CD36 AG genotype (OR=3.81, 95% CI: 1.08-13.4, p=0.037) were positively associated with the HTGW phenotype, while performing exercise played a protective role (OR=0.23, 95% CI: 0.08-0.62, p=0.004). Overall, the model predicted the HTGW phenotype in 47% (R2=0.47, p≤0.001). Conclusion: The CD36 AG genotype, daily consumption of sugary drinks and sedentarism are risk factors for the HTGW phenotype in Mexicans.

GRU Neural Network Improved Bioimpedance Based Stroke Volume Estimation during Ergometry Stress Test.

Cardiovascular diseases (CVDs) are one of the leading members of non-communicable diseases. An early diagnosis is essential for effective treatment, to reduce hospitalization time and health care costs. Nowadays, an exercise stress test on an ergometer is used to identify CVDs. To improve the accuracy of diagnostics, the hemodynamic status and parameters of a person can be investigated. For hemodynamic management, thoracic electrical bioimpedance has recently been used. This technique offers beat-to-beat stroke volume calculation but suffers from an artifact-sensitive signal that makes such measurements difficult during movement. We propose a new method based on a gated recurrent unit (GRU) neural network and the ECG signal to improve the measurement of bioimpedance signals, reduce artifacts and calculate hemodynamic parameters. We conducted a study with 23 subjects. The new approach is compared to ensemble averaging, scaled Fourier linear combiner, adaptive filter, and simple neural networks. The GRU neural network performs better with single artifact events than shallow neural networks (mean error −0.0244, mean square error 0.0181 for normalized stroke volume). The GRU network is superior to other algorithms using time-correlated data for the exercise stress test.

Different factors are associated with changing body composition in people living with HIV

ABSTRACT Introduction: Antiretroviral Therapy (ART) gives people living with HIV/AIDS (PLWHA) a new perspective of life, although some develop changes in impaired body composition. This study aimed to assess the factors associated with changes in body composition in PLWHA using ART, depending food consumption. Material and methods: It was a cross-sectional study and took place through interviews with patients treated at an University Hospital. Secondary data: CD4+ T cells, ART time and age. The level of physical activity and smoking were self-reported. For the assessment of body composition, electrical bioimpedance and measurements of weight, height and waist circumference were used. Results: The highest percentages of fat mass and fat-free mass, in treatment for more than 5 years, were in the female group (p <0.01), aged> 50 years (p = 0.02) and in the male group (p <0.01), young adult (p <0.01), respectively. The final linear regression model for both free fat mass and fat mass had sex, age, smoking and nutritional diagnosis as relevant factors. The frequency of food consumption was inadequate for calories, carbohydrates, proteins and lipids was high, however it did not significantly influence body composition. Conclusions: Gender, age, smoking and nutritional diagnosis by BMI significantly influence body composition.

P.205 Utility of electrical bioimpedance as a biomarker in myotonic dystrophy type I

Myotonic dystrophy type 1 (DM1) is frequently associated with endocrinopathies. Body composition analysis by electrical bioimpedance study is useful in the nutritional assessment of these patients. The aim of this study is to investigate its usefulness as a biomarker of clinical progression/severity in DM1. We carried out a cross-sectional study of 47 patients with DM1 attended in the last year who underwent impedancemetry with the InBody S10 device for segmental multifrequency analysis. Muscle weakness was classified according to severity using the muscular impairment rating scale (MIRS). 18 men and 29 women were evaluated. Mean age was 46.11 years. By means of Spearman's Rho correlation, a highly statistically significant concordance was identified between the MIRS scale and the global phase angle (PA) at 50 kHz (p 0.000 and R -0.717) and also with the skeletal muscle mass index (SMMI) (p 0.000 and R -0.549). However, no relationship was observed between MIRS with classical nutritional indicators such as BMI or percentage weight loss. In logistic regression models, PA and SMMI adjusted by age and sex decrease statistically significantly as muscle weakness progresses with high explanatory value. There is a highly significant correlation between clinical severity measured by the MIRS scale and PA and SMMI. PA and SMMI are more sensitive, early and constant as a marker of muscle deterioration than any of the GLIM phenotypic criteria for the diagnosis of malnutrition that are usually related to muscle weakness, thus postulating themselves as a possible useful biomarker of progression in DM1.

S31 Cole Relaxation Frequency: A Parameter for Pancreatic Cancer Detection

Introduction: Pancreatic cancer (PC) accounts for half a million new cases and 4.7% of the world's cancer-related deaths in 2020. It is considered one of the most lethal malignancies with a global survival rate of only 5%. Innovative imaging and endoscopic techniques are being studied to improve the accuracy of PC detection. Endoscopic ultrasound (EUS) guided tissue acquisition is currently the gold standard for sampling pancreatic masses. EUS guided fine needle biopsy has been considered superior to fine needle aspiration, but both are limited by the subjectivity of endoscopists and invasiveness of the procedure. Nonetheless, at present, there is no standard procedure for PC detection. The Cole Relaxation Frequency (CRF) – a derived electrical bioimpedance signature for cancer detection proposed by NovaScan – has been proven to quantitatively detect cancer in breast, skin, and lung tissues. The aim of this pilot study was to determine if the CRF based NovaScan technology can detect cancer in pancreatic tissues. Methods: CRF was measured with NovaScan technology in multiple locations (Figure A) on the pancreas samples in a cohort of n=26 mice, of which 15 were KPC (model of pancreatic ductal adenocarcinoma), 2 were KC (model of pancreatic neoplasia), and 9 were wild type controls. NovaScan determined cancer presence when the CRF parameter was measured above 1 MHz (Figure:B,C). Outcomes were compared to histopathology results for each of these samples to determine the specificity and sensitivity of the NovaScan device. Results: From histology, 12 KPC pancreases were confirmed as cancerous, 9 controls were confirmed as noncancerous, while 5 pancreases (3 KPC and 2 KC) presented with pancreatic intraepithelial neoplasia (PanIN), a precancerous condition. NovaScan technology identified 4 out of 5 PanIN samples as cancerous. Considering the entire cohort (n=26), specificity and sensitivity were 100% and 94%, respectively. If PanIN samples were excluded, specificity and sensitivity were both 100% (n=21). Conclusion: Future development of NovaScan CRF based technology into a rapid onsite evaluation or an endoscopic device would provide an affordable means for accurate and quantitative PC detection that guides or substitutes pancreatic biopsy acquisition. Identification of malignant precursors indicates the technological capability of NovaScan’s device to detect early stage PCs. Further technology development could allow for the distinction between cancerous and precancerous lesions.Figure 1.: (A) KPC pancreas sample placed on Novascan’s electrode array for a series of spectral bioimpedance measurements. A zoom in of the electrode with a pancreas sample is also shown. White rectangles indicate multiple locations measured across the sample. Spectral impedance scans for a control mouse (B) and a KPC mouse (C). The examination of CRF peak properties was used for cancer identification in pancreas samples. For the control mouse the CRF peaks fall below the threshold of 1 MHz, determining no cancer. For the KPC mouse several scans have CRF peaks above the threshold of 1 MHz, determining cancer presence.

Derivation of Bioimpedance Model Data Utilizing a Compact Analyzer and Two Capacitive Electrodes: A Forearm Example.

The paper investigates the impacts of the selected electrical equivalent circuit model, measurement setup, and surrounding environment on the trustworthiness of electrical bioimpedance measurement and obtained model data in the human body. The influence of these constitutive components of the system on finding the model parameters is analyzed and illustrated with examples. The results based on experimental measurements on a forearm near the wrist are provided by employing the model, measurement setup, and novel 16-bit compact wireless impedance analyzer (CIA) according to the outcome of the analysis. The area near the wrist is of interest because of attempts to get cardiac-activity-related impedance changes. It is concluded that a two-electrode system with voltage excitation suits better for determining bioimpedance model parameters in the β dispersion area. The results obtained with the CIA and two capacitive bracelet electrodes on a left forearm were used for the fitting model parameters. Despite the small dimensions of 60 × 60 × 25 mm of the CIA reducing stray capacitance to 8 pF, it provides relative impedance magnitude measurement error below 0.3% and phase error below 0.2 ° in the 10 MHz range. Analysis of the model parameters allowed separation of the electrodes, skin, and internal tissue spectra and revealed the relative significance of model components at different frequencies.