Pub Date : 1997-05-21DOI: 10.1109/NEBC.1997.594932
B. Ristic, S. Kun, R. Peura
Impedance spectroscopy is a promising method for tissue ischemia monitoring. Ischemia causes changes in tissue impedance that can be detected by impedance spectroscopic measurements. This technique has numerous advantages over existing ischemia monitoring methods: it is non-invasive and suitable for long term and continuous use. To fully develop this method, we experimentally investigated the relationships between ischemia and tissue impedance. For this purpose, in-vivo animal experiments were conducted, Results show complex, nonlinear relationships between tissue impedance and ischemia. Previous studies identified R/sub 0/ (DC impedance) as the parameter most sensitive to ischemia. However, R/sub 0/ variations are quite non-specific, therefore R/sub 0/ cannot be quantitatively correlated to ischemia. In this paper, we present an analysis which indicates that ischemia induced variations of the tissue time constant /spl tau/ are well correlated to R/sub 0/ and pH variations. /spl tau/ has a better sensitivity and a higher level of specificity to ischemia variations, compared to R/sub 0/. This is evidence that /spl tau/ is a powerful indicator of tissue ischemia.
{"title":"Muscle tissue ischemia monitoring using impedance spectroscopy: analysis of R/sub 0/ and /spl tau/ variations with ischemia","authors":"B. Ristic, S. Kun, R. Peura","doi":"10.1109/NEBC.1997.594932","DOIUrl":"https://doi.org/10.1109/NEBC.1997.594932","url":null,"abstract":"Impedance spectroscopy is a promising method for tissue ischemia monitoring. Ischemia causes changes in tissue impedance that can be detected by impedance spectroscopic measurements. This technique has numerous advantages over existing ischemia monitoring methods: it is non-invasive and suitable for long term and continuous use. To fully develop this method, we experimentally investigated the relationships between ischemia and tissue impedance. For this purpose, in-vivo animal experiments were conducted, Results show complex, nonlinear relationships between tissue impedance and ischemia. Previous studies identified R/sub 0/ (DC impedance) as the parameter most sensitive to ischemia. However, R/sub 0/ variations are quite non-specific, therefore R/sub 0/ cannot be quantitatively correlated to ischemia. In this paper, we present an analysis which indicates that ischemia induced variations of the tissue time constant /spl tau/ are well correlated to R/sub 0/ and pH variations. /spl tau/ has a better sensitivity and a higher level of specificity to ischemia variations, compared to R/sub 0/. This is evidence that /spl tau/ is a powerful indicator of tissue ischemia.","PeriodicalId":393788,"journal":{"name":"Proceedings of the IEEE 23rd Northeast Bioengineering Conference","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124062624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-05-21DOI: 10.1109/NEBC.1997.594934
Sunghoon Jang, M. D. Fox
A new approach to non-invasive closed loop optical glucose sensing has been proposed. Incident light on the cornea travels into the eye and reflects from the retina. The reflected light contains information about glucose concentration in the aqueous humor which can potentially be used to measure long term and instantaneous blood glucose concentration. Previous designs have utilized two Faraday rotators to create a closed loop system. The data reported here indicates that only one Faraday rotator is actually needed for this system. The modifications not only cut the system cost substantially, but also improve sensitivity by 143%, over a two Faraday rotator implementation.
{"title":"Optical glucose sensor using a single Faraday rotator","authors":"Sunghoon Jang, M. D. Fox","doi":"10.1109/NEBC.1997.594934","DOIUrl":"https://doi.org/10.1109/NEBC.1997.594934","url":null,"abstract":"A new approach to non-invasive closed loop optical glucose sensing has been proposed. Incident light on the cornea travels into the eye and reflects from the retina. The reflected light contains information about glucose concentration in the aqueous humor which can potentially be used to measure long term and instantaneous blood glucose concentration. Previous designs have utilized two Faraday rotators to create a closed loop system. The data reported here indicates that only one Faraday rotator is actually needed for this system. The modifications not only cut the system cost substantially, but also improve sensitivity by 143%, over a two Faraday rotator implementation.","PeriodicalId":393788,"journal":{"name":"Proceedings of the IEEE 23rd Northeast Bioengineering Conference","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125772510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-05-21DOI: 10.1109/NEBC.1997.594937
J. Canfield, M. Carter
A network of realistic neuron models interconnected by Hebbian synapses is shown to be capable of autoassociative recall. However, a collective network property, the robust entrainment of activity between neurons, leads to several interesting network level phenomena not seen in attractor networks with conventional neuron models. These include phase-locked bursting patterns of neural activity, the temporal segmentation of mixed pattern input cues, and the functionality to serve as a subunit for the storage of temporal sequences. Given the previously established accuracy of the utilized single neuron model as a reduced order approximation of the Hodgkin-Huxley equations, these findings are well suited for comparison with their biological correlates.
{"title":"Effects of neural entrainment within a biologically realistic network","authors":"J. Canfield, M. Carter","doi":"10.1109/NEBC.1997.594937","DOIUrl":"https://doi.org/10.1109/NEBC.1997.594937","url":null,"abstract":"A network of realistic neuron models interconnected by Hebbian synapses is shown to be capable of autoassociative recall. However, a collective network property, the robust entrainment of activity between neurons, leads to several interesting network level phenomena not seen in attractor networks with conventional neuron models. These include phase-locked bursting patterns of neural activity, the temporal segmentation of mixed pattern input cues, and the functionality to serve as a subunit for the storage of temporal sequences. Given the previously established accuracy of the utilized single neuron model as a reduced order approximation of the Hodgkin-Huxley equations, these findings are well suited for comparison with their biological correlates.","PeriodicalId":393788,"journal":{"name":"Proceedings of the IEEE 23rd Northeast Bioengineering Conference","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133866550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-05-21DOI: 10.1109/NEBC.1997.594927
D. Raunig, M. Fox
The authors describe preliminary efforts to measure the human microcirculation with conventional CW Doppler ultrasound equipment. The results suggest that it may be possible to detect and measure capillary flow in this way. The broad spectrum expected from capillary returns, rather than a single-point capillary velocity, could potentially provide information of the statistics of the flow. Overall, the preliminary results obtained thus far are encouraging in terms of the potential for developing methodologies for utilizing Doppler ultrasound to assess general end organ tissue perfusion.
{"title":"Doppler ultrasound determination of capillary blood flow","authors":"D. Raunig, M. Fox","doi":"10.1109/NEBC.1997.594927","DOIUrl":"https://doi.org/10.1109/NEBC.1997.594927","url":null,"abstract":"The authors describe preliminary efforts to measure the human microcirculation with conventional CW Doppler ultrasound equipment. The results suggest that it may be possible to detect and measure capillary flow in this way. The broad spectrum expected from capillary returns, rather than a single-point capillary velocity, could potentially provide information of the statistics of the flow. Overall, the preliminary results obtained thus far are encouraging in terms of the potential for developing methodologies for utilizing Doppler ultrasound to assess general end organ tissue perfusion.","PeriodicalId":393788,"journal":{"name":"Proceedings of the IEEE 23rd Northeast Bioengineering Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126787088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-05-21DOI: 10.1109/NEBC.1997.594944
S. Jo, R. Gaumond
We examined the effectiveness of two-microphone acoustic reflection pharyngometry in determining the changes in the human upper airway collapsible segment during steady inspiratory flow conditions. Differences in oral airway dimensions of a male subject, at 3 flow levels, were analyzed. The physiological data, then, was applied to a mathematical model of airway collapse, and the coefficient of collapse (C/sub c/) was calculated. The collapsible segment was approximately 10 cm in length, and was located between the oro-pharyngeal junction (OPJ), and the glottis; the entire segment was susceptible to area decrease at a flow rate of 500 ml/s. C/sub c/ calculation indicated that full collapse would not occur during our experimental conditions, which was validated by pharyngometry.
{"title":"Measurement of upper airway dimensions during inspiratory flow","authors":"S. Jo, R. Gaumond","doi":"10.1109/NEBC.1997.594944","DOIUrl":"https://doi.org/10.1109/NEBC.1997.594944","url":null,"abstract":"We examined the effectiveness of two-microphone acoustic reflection pharyngometry in determining the changes in the human upper airway collapsible segment during steady inspiratory flow conditions. Differences in oral airway dimensions of a male subject, at 3 flow levels, were analyzed. The physiological data, then, was applied to a mathematical model of airway collapse, and the coefficient of collapse (C/sub c/) was calculated. The collapsible segment was approximately 10 cm in length, and was located between the oro-pharyngeal junction (OPJ), and the glottis; the entire segment was susceptible to area decrease at a flow rate of 500 ml/s. C/sub c/ calculation indicated that full collapse would not occur during our experimental conditions, which was validated by pharyngometry.","PeriodicalId":393788,"journal":{"name":"Proceedings of the IEEE 23rd Northeast Bioengineering Conference","volume":"175 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125938426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-05-21DOI: 10.1109/NEBC.1997.594969
G.D. Gaebe, R. Peura
Mechanical ventilation is an important lifesaving tool in the modern ICU, but just as critical as its use is knowing when to wean a patient from it. This study used the new technology of the continuous metabolic monitor coupled with auto and cross correlation analyses to discern differences between pass and fail patient groups during weaning trials. These dynamic analyses were compared to the mean values of respiratory parameters commonly used by clinicians. It was found that the cross correlation function differences were more significant than differences in all parameters examined, except ventilatory equivalent.
{"title":"Continuous monitoring of patients being weaned from mechanical ventilation","authors":"G.D. Gaebe, R. Peura","doi":"10.1109/NEBC.1997.594969","DOIUrl":"https://doi.org/10.1109/NEBC.1997.594969","url":null,"abstract":"Mechanical ventilation is an important lifesaving tool in the modern ICU, but just as critical as its use is knowing when to wean a patient from it. This study used the new technology of the continuous metabolic monitor coupled with auto and cross correlation analyses to discern differences between pass and fail patient groups during weaning trials. These dynamic analyses were compared to the mean values of respiratory parameters commonly used by clinicians. It was found that the cross correlation function differences were more significant than differences in all parameters examined, except ventilatory equivalent.","PeriodicalId":393788,"journal":{"name":"Proceedings of the IEEE 23rd Northeast Bioengineering Conference","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116359620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-05-21DOI: 10.1109/NEBC.1997.594938
B.P. Kirk, J. LaCourse
Length of vigilance is a major obstacle in jobs associated with low levels of arousal. To provide the highest levels of safety, the level of attention, particularly visual awareness, has to be monitored. A system has been designed, offline, as a precedent to a real-time awareness predictor. The electroencephalograph (EEG) is used as the major predictive data with a radial basis function network classifying the attention level.
{"title":"Performance monitoring from the EEG power spectrum with a radial basis function neural network","authors":"B.P. Kirk, J. LaCourse","doi":"10.1109/NEBC.1997.594938","DOIUrl":"https://doi.org/10.1109/NEBC.1997.594938","url":null,"abstract":"Length of vigilance is a major obstacle in jobs associated with low levels of arousal. To provide the highest levels of safety, the level of attention, particularly visual awareness, has to be monitored. A system has been designed, offline, as a precedent to a real-time awareness predictor. The electroencephalograph (EEG) is used as the major predictive data with a radial basis function network classifying the attention level.","PeriodicalId":393788,"journal":{"name":"Proceedings of the IEEE 23rd Northeast Bioengineering Conference","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128266658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-05-21DOI: 10.1109/NEBC.1997.594946
M. Bergen, S.A. Soldan, S. Reisman, J. Ottenweller
Chronic fatigue syndrome (CFS) is a condition that results in moderate to severe disability. A leading symptom of CFS is that patients report critical reductions in their levels of physical activity due to fatigue related symptoms. We have developed a rodent model, using rats, hamsters, and mice, that enables us to investigate fatigue and physiological rhythms in an integrated framework. The animal's activity is one measure of great importance in the study of these rhythms and chronic fatigue. To monitor a free-ranging rodent's activity we utilize two complementing methods: first, is an infra-red photo beam to detect and count turns of a running wheel, and second, is a force sensor located under the housing tub to detect general motion. Both methods are used in the animal's home cage and are made to be low cost, compared to commercial units, for implementation on many animals.
{"title":"Low cost rodent activity monitoring instrumentation","authors":"M. Bergen, S.A. Soldan, S. Reisman, J. Ottenweller","doi":"10.1109/NEBC.1997.594946","DOIUrl":"https://doi.org/10.1109/NEBC.1997.594946","url":null,"abstract":"Chronic fatigue syndrome (CFS) is a condition that results in moderate to severe disability. A leading symptom of CFS is that patients report critical reductions in their levels of physical activity due to fatigue related symptoms. We have developed a rodent model, using rats, hamsters, and mice, that enables us to investigate fatigue and physiological rhythms in an integrated framework. The animal's activity is one measure of great importance in the study of these rhythms and chronic fatigue. To monitor a free-ranging rodent's activity we utilize two complementing methods: first, is an infra-red photo beam to detect and count turns of a running wheel, and second, is a force sensor located under the housing tub to detect general motion. Both methods are used in the animal's home cage and are made to be low cost, compared to commercial units, for implementation on many animals.","PeriodicalId":393788,"journal":{"name":"Proceedings of the IEEE 23rd Northeast Bioengineering Conference","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114690147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-05-21DOI: 10.1109/NEBC.1997.594945
L. Hendrickson, P. Engler
Paced breathing devices are designed and used for exactly that - paced breathing. Often when a researcher is conducting an experiment that requires biological signals to be analyzed, the number of variables are reduced by keeping all of the subject's rate of breaths per minute (BPM) the same. Presently there exists both software and hardware that serves the purpose for this task. This project has combined both of these to build a new apparatus using the latest technology. Instead of a hardware device which is difficult to manipulate once constructed, the software package LabVIEW (Laboratory Virtual Instrument Engineering Workbench) Is used to construct this device. LabVIEW is a icon driven package which parallels actual electrical components. If the situation arises in which changes need to be made, they can be performed relatively easily assuming there is some knowledge of the software at hand. The convenience of this arises because manipulations can be made without the use of a soldering iron or any other tool with the exception of a mouse.
{"title":"Paced breathing controller using LabView","authors":"L. Hendrickson, P. Engler","doi":"10.1109/NEBC.1997.594945","DOIUrl":"https://doi.org/10.1109/NEBC.1997.594945","url":null,"abstract":"Paced breathing devices are designed and used for exactly that - paced breathing. Often when a researcher is conducting an experiment that requires biological signals to be analyzed, the number of variables are reduced by keeping all of the subject's rate of breaths per minute (BPM) the same. Presently there exists both software and hardware that serves the purpose for this task. This project has combined both of these to build a new apparatus using the latest technology. Instead of a hardware device which is difficult to manipulate once constructed, the software package LabVIEW (Laboratory Virtual Instrument Engineering Workbench) Is used to construct this device. LabVIEW is a icon driven package which parallels actual electrical components. If the situation arises in which changes need to be made, they can be performed relatively easily assuming there is some knowledge of the software at hand. The convenience of this arises because manipulations can be made without the use of a soldering iron or any other tool with the exception of a mouse.","PeriodicalId":393788,"journal":{"name":"Proceedings of the IEEE 23rd Northeast Bioengineering Conference","volume":"196 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115977871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-05-21DOI: 10.1109/NEBC.1997.594949
Martin D. Fox, W. Pruehsner
Ultrasound tissue characterization has generally been carried out in the 1-5 MHz frequency range. In the present research, we looked into methodologies to extend tissue characterization to the 10-50 MHz domain. Preliminary experiments were carried out using transducers constructed from PVDF. Initial results suggested that frequencies from 8-20 MHz could readily be detected through tissue samples in a 3.5 cm test cell. Spectrum analysis of averaged and digitized transmitted bursts revealed differences in the transmission spectra for different tissue samples placed in the test cell.
{"title":"High frequency ultrasound tissue characterization","authors":"Martin D. Fox, W. Pruehsner","doi":"10.1109/NEBC.1997.594949","DOIUrl":"https://doi.org/10.1109/NEBC.1997.594949","url":null,"abstract":"Ultrasound tissue characterization has generally been carried out in the 1-5 MHz frequency range. In the present research, we looked into methodologies to extend tissue characterization to the 10-50 MHz domain. Preliminary experiments were carried out using transducers constructed from PVDF. Initial results suggested that frequencies from 8-20 MHz could readily be detected through tissue samples in a 3.5 cm test cell. Spectrum analysis of averaged and digitized transmitted bursts revealed differences in the transmission spectra for different tissue samples placed in the test cell.","PeriodicalId":393788,"journal":{"name":"Proceedings of the IEEE 23rd Northeast Bioengineering Conference","volume":"295 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133165742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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