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Phenomenological models of NaV1.5. A side by side, procedural, hands-on comparison between Hodgkin-Huxley and kinetic formalisms
No full textComputational models of ion channels represent the building blocks of conductance-based, biologically inspired models of neurons and neural networks. Ion channels are still widely modelled by means of the formalism developed by the seminal work of Hodgkin and Huxley (HH), although the electrophysiological features of the channels are currently known to be better fitted by means of kinetic Markov-type models. The present study is aimed at showing why simplified Markov-type kinetic models are more suitable for ion channels modelling as compared to HH ones, and how a manual optimization process can be rationally carried out for both. Previously published experimental data of an illustrative ion channel (NaV1.5) are exploited to develop a step by step optimization of the two models in close comparison. A conflicting practical limitation is recognized for the HH model, which only supplies one parameter to model two distinct electrophysiological behaviours. In addition, a step by step procedure is provided to correctly optimize the kinetic Markov-type model. Simplified Markov-type kinetic models are currently the best option to closely approximate the known complexity of the macroscopic currents of ion channels. Their optimization can be achieved through a rationally guided procedure, and allows to obtain models with a computational burden that is comparable with HH models one
Indices of symbolic dynamic distribution in cardiac patients
No full textAlthough symbolic dynamics analysis (SDA) has been proposed for encoding words of different length and symbols, the resulting rapidly growing number of patterns has limited its clinical use. Aim of this study is to propose new SDA indices tested on a clinical data-set. We studied 40 ECG Holter of normal (NR), post-MI (MI), heart failure (HF) and transplanted (TR) subjects. RR differences were encoded into 5 symbols, deriving 3, 5 and 7 length words classified by a dominance's criterion in pattern words with a predominant vagal content (V), decelerating content (D), accelerating content (A), sympathetic content (S) and without variability content (0). Their distributions were then quantified by Kurtosis an Chi-square indexes. Results showed an optimum word-length of 3, where both Kurtosis (2.2±0.6; 2.2±0.9; 3.1±0.9; 4.0±0.4) and Chi-square (7±5; 8±5; 26±17; 106±42, respectively for N, MI, HF and TR) showed very significant p<0,0001 values at the ANOVA test among groups, mainly discriminating HF and TR subject by Tukey's post-test. SDA is an helpful technique in interpreting the encoded HRV information. The pattern words distributions clearly tend to lose their tails to the worsening of the autonomic impairment as immediately described by Kurtosy or chi-square index, especially for risk stratification of HF patients
An application of symbolic dynamics for FHRV assessment
No full textFetal heart rate variability is surely one of the most important parameters to monitor fetal wellbeing. Linear studies, widely employed to study fetal heart variability and its correlations with the development of the autonomous nervous system, have shown some limitations in highlight dynamics potentially relevant. During the last decades, therefore, nonlinear analysis methods have gained a growing interest to analyze the chaotic nature of cardiac activity. Techniques investigating nonlinear dynamics have been already successfully employed in adults, to analyze different physiological and pathological states. Concerning fetal monitoring, instead, a smaller number of papers is available in the literature; even if symbolic dynamics was recently employed to quantify fetal heart rate regularity, demonstrating that the use of this technique may lead to a better and more differentiated understanding of normal fetal physiological development. In this work, we applied the symbolic dynamics to analyze fetal heart rate variability in healthy fetuses at the end of a physiological pregnancy. Our results confirmed the potentiality of the technique to highlight differences between signals characterized by more or less variabilit
Prognostic decision support using symbolic dynamics in CTG monitoring
No full textFoetal heart rate variability is one of the most important parameters to monitor foetal wellbeing. Linear parameters, widely employed to study foetal heart variability, have shown some limitations in highlight dynamics potentially relevant. During the last decades, therefore, nonlinear analysis methods have gained a growing interest to analyze the chaotic nature of cardiac activity. Parameters derived by techniques investigating nonlinear can be included in computerised systems of cardiotocographic monitoring. In this work, we described an application of symbolic dynamics to analyze foetal heart rate variability in healthy foetuses and a concise index, introduced for its classification in antepartum CTG monitoring. The introduced index demonstrated to be capable to highlight differences in heart rate variability and resulted correlated with the Apgar score at birth, in particular, higher variability indexes values are associated to early greater vitality at birth. These preliminary results confirm that SD can be a helpful tool in CTG monitoring, supporting medical decisions in order to assure the maximum well-being of newborn
Improved Splines Fitting of Intervertebral Motion by Local Smoothing Variation
No full textKnowledge of intervertebral motion provides important information about the level of stabilization of a single spine segment. By using X-ray fluoroscopy it is possible to screen spinal motion during spontaneous patient???s movement. Discrete-time experimental measurements can be interpolated by smoothing splines, which provide both noise reduction and continuous-time representation of joint motion. A patient, albeit trained, is unable to perform a spontaneous movement with such regularity to keep constant certain parameters such as the speed. Therefore, spontaneous motion can include different tracts performed at different speed. The use of a single smoothing parameter to fit the entire motion for spline fitting requires a compromise. Alternatively, smaller differences with the experimental data and more stable motion parameters can be obtained by appropriately varying the smoothing parameter: less smoothing is applied in higher velocity tracts. This concept has been applied to the analysis of cervical intervertebral motion as obtained by processing sequences of fluoroscopic images. Preliminary results showed more close representation of the experimental data without missing the regular progression of the joint movement
A low-cost force sensor-based posturographic plate for home care telerehabilitation exergaming
No full textComputerised simulation of fetal heart rate signals
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2017 E-Health and Bioengineering Conference, EHB 2017
28 July 2017, Article number 7995392, Pages 185-188
6th IEEE International Conference on E-Health and Bioengineering, EHB 2017; Grigore T. Popa University of Medicine and PharmacySinaia; Romania; 22 June 2017 through 24 June 2017; Category numberCFP1703P-ART; Code 129704
Computerised simulation of fetal heart rate signals(Conference Paper)
Romano, M.abEmail Author, Iuppariello, L.bcEmail Author, D'Addio, G.bEmail Author, Clemente, F.dEmail Author, Amato, F.aEmail Author, Cesarelli, M.bcEmail Author
aDMSC, University Magna Graecia, Cǎtanzaro, Italy
bFondazione S. Maugeri, Clinica Del Lavoro e della Riabilitazione, Telese Terme (BN), Italy
cDIETI, University Federico II, Napoli, Italy
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Abstract View references (24)
Computerized systems employed for the analysis of cardiotocographic signals have become almost indispensable tools in fetal monitoring, for which evaluation of fetal heart rate signals plays a key role. Consequently to the diffusion of these systems, new software and complex signal processing methodologies are spreading and are gaining more and more interest. For testing the performances of new software and/or techniques, the availability of synthetic signals with a-priori known characteristics can be very helpful. In this paper we describe an updating of a procedure previously published for the computerized simulation of fetal heart rate signals, realized in order to obtain more realistic signals. Obtained results, analyzed by a team of experts, are satisfying, in that new simulated signals appear less regular and more complex, and hence more similar to real signals. Nevertheless, further research is necessary for obtaining very realistic signals. The future research will be initially focused on the study of floatingline and uterine contractions simulation
In-time prognosis based on swarm intelligence for home-care monitoring: A case study on pulmonary disease
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