Impact of Electrodes Separation Distance on Bio-Impedance Diagnosis

Bio-impedance diagnosis depends mainly on two factors first being the location of electrode placement and second being the distance between electrodes. To minimize the errors caused during bio impedance measurement at variable frequencies, it is required to study the electrodes used for the measurement and its exact location where the electrodes are placed. This paper analyses various electrode separations used for bioimpedance measurement for cardiac signal. The electrode system is used based on the type of tissue under consideration for measurement. It is found that the errors are dependent on the frequencies at which the measurement is carried out and it also depends on the intensity of current applied. Thus, selection of current and frequency is very important for measurements. In this paper, the impact of size, distance and location of the electrodes that can be used for bio-impedance cardiograph.

Lung Diffusion Capacity Affects Stroke Volume in Systemic Sclerosis

Objective: In our previous cross-sectional study, we reported impaired stroke volume in patients with systemic sclerosis; however, no cardiac parameter using echocardiography was found to be related to stroke volume reduction. As few studies have focused on the hemodynamic clinical course, the patients were re-evaluated in a median interval of 18 months, and correlations between stroke volume and cardiopulmonary parameters were analyzed.Results: Seventeen patients who were able to complete the 6-minute walk test wearing a non-invasive impedance cardiograph device were assigned for re-evaluation, and individual changes in the stroke volume were noted. The stroke volume was not related to cardiac parameters, but it was significantly related to the diffusion capacity of the lung for carbon monoxide after walking in the first evaluation (r = 0.63, p = 0.006), and at rest in the re-evaluation (r = 0.72, p = 0.001). Significant relation was also found between the distance walked and the stroke volume after walking in the first evaluation and re-evaluation, and at rest in the re-evaluation. Thus, a limited lung diffusion capacity may affect stroke volume due to the exercise intolerance in systemic sclerosis without pathological heart involvement.

Social and Physiological Context Affects the Meaning of Physiological Synchrony

This protocol describes procedures for conducting a dyadic, psychophysiological study. The key goal of this study is to continuously and simultaneously measure electrocardiograph and impedance cardiograph data from two participants engaged in a social interaction. The social interaction was framed as competitive or cooperative but the task partners engaged in was identical across conditions. The entire protocol takes 2 hours to complete.

Markov chain for heart failure diagnostic decision model with irregular Thoracic Fluid Content measurements

Properties of results obtained on Markov processes analysis in medical applications have been illustrated. Calculation was done for measurement of Thoracic Fluid Content by means of impedance cardiograph for chosen medical patients population. Main medical aspect of Markov chain calculation has been underlined to exhibit some constraints in decision making with such math models. Markov chain analysis was done as optimization task. Effective algorithm for irregular data in continuous time has been proposed.

Physiological Responses to Virtual Exergame Feedback for Individuals with Different Levels of Exercise Self-Efficacy

OBJECTIVE: Exercise videogames are increasingly popular as individuals seek to increase their activity. This study assessed the interaction of exercise self-efficacy (ESE) levels and perceived task demands of a virtual game on exercise and physiological reactions. Perceived task demands were manipulated by changing parameters of the participant's avatar in the exergame. METHODOLOGY: An experimental design was used with 89 female undergraduate students (Mean age=18.74+1.05, 18 to 21 years) who were randomly assigned to the high task demand condition (avatar weight remaining constant) or low task demand condition (avatar losing weight). Prior to the biking task, the Exercise Self-Efficacy scale was used to measure ESE. Participants biked on a stationary bike while immersed in a virtual environment with an avatar and were told the avatar would slim if they cycled fast enough. Only half of participants' avatars actually slimmed (high task demand manipulation). During biking, cardiovascular measures were assessed using a Biopac MP150 system with an Impedance Cardiograph and CNAP Monitor 500. One week after completion of the study, participants reported amount of exercise completed in the last week (in 15 minute increments) via the Physical Activity Questionnaire. Moderated regressions and moderated mediation models were used to examine the interaction of ESE levels, experimental condition and cardiovascular reactivity on amount of strenuous physical activity. RESULTS: Individuals with high ESE showed similar results in both task demand conditions with physiological reactivity patterns indicative of threat. Individuals with low ESE with a static avatar completed less exercise than those with low ESE with a slimming avatar. CONCLUSION: Results confirm that individuals with low ESE are particularly vulnerable to exercise demands.