Parametric And Non-parametric Analysis Of Carotid Sinus Baroreflex System Using Electrically Induced Muscle Contraction

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Title: Parametric And Non-parametric Analysis Of Carotid Sinus Baroreflex System Using Electrically Induced Muscle Contraction
Author: Deshmukh, Sheetal D
Abstract: The arterial pressure is an important physiological parameter which if not maintained at desired level may lead to fatal disorders or in worst situations even death . The physiological feedback control mechanism in order to regulate the arterial pressure is performed by the baroreceptors . In this study the dynamic characteristics of carotid sinus baroreceptor are identified to obtain the open -loop characteristics of the carotid sinus pressure (CSP , mmHg ) to the renal sympathetic nerve activity (RSNA , Arbitrary unit ) , RSNA to systemic arterial pressure (SAP , mmHg ) , CSP to SAP and CSP to heart rate (HR , bpm ) .The purpose of this study was to know if resetting of baroreflex resetting takes place during exercise . The assumption that the baroreflex afferents interact with the somatic afferents in NTS affects the baroreflex functioning was evaluated by studying the baroreflex transfer functions for two different measurement conditions . Data for this study was recorded from 6 dogs for two experimental conditions , control and the electrically induced muscle contraction . The control measurement condition was assumed to be the rest condition and the electrical stimulation mimicked exercise . Non -parametric (NP ) estimation technique was applied to the measured data and the baroreflex transfer functions were estimated . The gain and the phase was analyzed in the frequency range of 0 .1 to 1Hz . Comparison of CSP -RSNA , RSNA -SAP , CSP - SAP and the CSP -HR transfer functions was made between the electrical stimulation and the control measurement conditions to see if the transfer characteristics differ due to stimulation . It was observed that the DC gain for the two measurement conditions , control and electrical stimulation differed . The slope and the coherence were analyzed in the frequency range of 0 .2 to 0 .4Hz . Parametric models were estimated employing ARX and OE methods for all four transfer functions , for two measurement conditions to obtain a best possible fit of the model output to the measured output . MSE value from the measured and estimated output was used as the criterion for order selection . Higher order models were estimated along with lower order models . The parametric models were also obtained for the shorter ensembles of the data selected by visual inspection from data of 15 min . Comparison of the nonparametric estimated transfer function and the parametric estimated transfer function was made . The parameters estimated from the control data and the electrical stimulation data were compared for each transfer function by their pole -zero positions . It is seen that the models obtained from the basic linear model structures doesn't fit well to the measured output . The stationarity of the data and the linearity of the system analyzed is an important issue in parametric modeling
URI: http : / /hdl .handle .net /10106 /132
Date: 2007-08-23

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Parametric And Non-parametric Analysis Of Carotid Sinus Baroreflex System Using Electrically Induced Muscle Contraction. Available electronically from http : / /hdl .handle .net /10106 /132 .

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