Pub Date : 1995-09-20DOI: 10.1109/IEMBS.1995.579708
A. Ali, D. Stashuk, M. Tvrdon
Based on the line source model, simulated concentric-needle-detected motor unit action potentials (MUAPs) were transformed into compound weight functions using inverse-average-current filtering. The numbers of significant individual muscle fiber contributions to the compound weight functions were estimated using acceleration thresholds. The ability of the technique to detect the contribution of single fibers to a MUAP was evaluated. For fibers that contributed muscle fiber action potentials (MFAPs) with maximum slopes larger than 2.4 V/s to a MUAP, the correlation between the expected number of contributing fibers and the number measured was 0.95 and no significant bias existed. The spatial distribution of fibers that could be detected was found to be approximately semicircular with a radius of 300 /spl mu/m. This capacity to detect the activity of single fibers will allow the concentric needle electrode to be used in ways comparable to that of the single fiber electrode.
{"title":"Detecting single muscle fiber activity using a concentric needle electrode: a simulation study","authors":"A. Ali, D. Stashuk, M. Tvrdon","doi":"10.1109/IEMBS.1995.579708","DOIUrl":"https://doi.org/10.1109/IEMBS.1995.579708","url":null,"abstract":"Based on the line source model, simulated concentric-needle-detected motor unit action potentials (MUAPs) were transformed into compound weight functions using inverse-average-current filtering. The numbers of significant individual muscle fiber contributions to the compound weight functions were estimated using acceleration thresholds. The ability of the technique to detect the contribution of single fibers to a MUAP was evaluated. For fibers that contributed muscle fiber action potentials (MFAPs) with maximum slopes larger than 2.4 V/s to a MUAP, the correlation between the expected number of contributing fibers and the number measured was 0.95 and no significant bias existed. The spatial distribution of fibers that could be detected was found to be approximately semicircular with a radius of 300 /spl mu/m. This capacity to detect the activity of single fibers will allow the concentric needle electrode to be used in ways comparable to that of the single fiber electrode.","PeriodicalId":20509,"journal":{"name":"Proceedings of 17th International Conference of the Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1995-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77970065","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 : 1995-09-20DOI: 10.1109/IEMBS.1995.579765
S.S. Ghosh, W. Funnell
An existing finite-element model of the cat middle ear was modified to include a shell representation of the incudostapedial joint. Joint stiffness was varied from very small to very large and the results show that both out-of-plane and in-plane displacements become smaller as the joint becomes more flexible. In-plane rotations remain significant at all stiffness values and tilting varies considerably in magnitude and direction as a function of stiffness.
{"title":"On the effects of incudostapedial joint flexibility in a finite-element model of the cat middle ear","authors":"S.S. Ghosh, W. Funnell","doi":"10.1109/IEMBS.1995.579765","DOIUrl":"https://doi.org/10.1109/IEMBS.1995.579765","url":null,"abstract":"An existing finite-element model of the cat middle ear was modified to include a shell representation of the incudostapedial joint. Joint stiffness was varied from very small to very large and the results show that both out-of-plane and in-plane displacements become smaller as the joint becomes more flexible. In-plane rotations remain significant at all stiffness values and tilting varies considerably in magnitude and direction as a function of stiffness.","PeriodicalId":20509,"journal":{"name":"Proceedings of 17th International Conference of the Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1995-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74915120","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 : 1995-09-20DOI: 10.1109/IEMBS.1995.574993
A. Feldman, Y. Chernyak, R. Cohen
The authors derived a general eikonal equation describing the evolution of a wavefront propagating in an excitable medium this equation implements the relation between the propagation speed and the wavefront curvature known from a more detailed theory. The authors used an approximate solution to obtain equations linking the excitation time scale /spl tau/ and diffusion constant D of a continuous reaction rate model with the excitation parameters of a discrete cellular automaton model on a randomized lattice.
{"title":"Relations between continuous and discrete models of excitable media","authors":"A. Feldman, Y. Chernyak, R. Cohen","doi":"10.1109/IEMBS.1995.574993","DOIUrl":"https://doi.org/10.1109/IEMBS.1995.574993","url":null,"abstract":"The authors derived a general eikonal equation describing the evolution of a wavefront propagating in an excitable medium this equation implements the relation between the propagation speed and the wavefront curvature known from a more detailed theory. The authors used an approximate solution to obtain equations linking the excitation time scale /spl tau/ and diffusion constant D of a continuous reaction rate model with the excitation parameters of a discrete cellular automaton model on a randomized lattice.","PeriodicalId":20509,"journal":{"name":"Proceedings of 17th International Conference of the Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1995-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75229055","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 : 1995-09-20DOI: 10.1109/IEMBS.1995.579394
Yan Yongsheng, Kang Nansheng
The fetal heart signal obtained using ultrasonic Doppler effect measurements is generally quasi-periodic. Its autocorrelation function (ACF) has been successfully applied in the estimation of fetal heart rate (FHR). To overcome the massive computations incurred in the estimation, the authors developed a fast strategy involving two-pass process to estimate FHR via normalized ACF. The algorithm has enabled up to four-channel simultaneous FHR measurement based on a general purpose PC.
{"title":"Fast fetal heart rate estimation for multi-channel FHR measurement","authors":"Yan Yongsheng, Kang Nansheng","doi":"10.1109/IEMBS.1995.579394","DOIUrl":"https://doi.org/10.1109/IEMBS.1995.579394","url":null,"abstract":"The fetal heart signal obtained using ultrasonic Doppler effect measurements is generally quasi-periodic. Its autocorrelation function (ACF) has been successfully applied in the estimation of fetal heart rate (FHR). To overcome the massive computations incurred in the estimation, the authors developed a fast strategy involving two-pass process to estimate FHR via normalized ACF. The algorithm has enabled up to four-channel simultaneous FHR measurement based on a general purpose PC.","PeriodicalId":20509,"journal":{"name":"Proceedings of 17th International Conference of the Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1995-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76266029","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 : 1995-09-20DOI: 10.1109/IEMBS.1995.579258
R. Atarius, L. Sornmo
An "instantaneous" optimal filter is presented for improvement of the signal-to-noise ratio in averaged ECGs. The filter is designed for the case when the noise level varies from beat to beat. Simulation results indicate that a better performance is achieved by the new filter when compared to a similar filter designed for processing of beats with identical noise levels. An example is presented in which the filter is applied to the detection of cardiac late potentials.
{"title":"Late potentials and the improvement of signal-to-noise ratio in nonstationary noise","authors":"R. Atarius, L. Sornmo","doi":"10.1109/IEMBS.1995.579258","DOIUrl":"https://doi.org/10.1109/IEMBS.1995.579258","url":null,"abstract":"An \"instantaneous\" optimal filter is presented for improvement of the signal-to-noise ratio in averaged ECGs. The filter is designed for the case when the noise level varies from beat to beat. Simulation results indicate that a better performance is achieved by the new filter when compared to a similar filter designed for processing of beats with identical noise levels. An example is presented in which the filter is applied to the detection of cardiac late potentials.","PeriodicalId":20509,"journal":{"name":"Proceedings of 17th International Conference of the Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1995-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76286045","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 : 1995-09-20DOI: 10.1109/IEMBS.1995.575278
V. Shyam, Huang Rao
In medical ultrasound imaging, the axial resolution is limited by the bandwidth of the transducer. In a linear frequency modulation (chirp) pulse coding technique for imaging, it is possible to inverse modulate the chirp amplitude by a function adaptively derived from the transducer frequency response. The transducer output then becomes an equalized chirp with a wider effective bandwidth. Subsequent pulse compression processing consequently improves the resolution. This concept has been evaluated experimentally in this paper.
{"title":"Adaptive inverse filtering with chirp for medical ultrasound","authors":"V. Shyam, Huang Rao","doi":"10.1109/IEMBS.1995.575278","DOIUrl":"https://doi.org/10.1109/IEMBS.1995.575278","url":null,"abstract":"In medical ultrasound imaging, the axial resolution is limited by the bandwidth of the transducer. In a linear frequency modulation (chirp) pulse coding technique for imaging, it is possible to inverse modulate the chirp amplitude by a function adaptively derived from the transducer frequency response. The transducer output then becomes an equalized chirp with a wider effective bandwidth. Subsequent pulse compression processing consequently improves the resolution. This concept has been evaluated experimentally in this paper.","PeriodicalId":20509,"journal":{"name":"Proceedings of 17th International Conference of the Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1995-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74667592","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 : 1995-09-20DOI: 10.1109/IEMBS.1995.579914
J. Corey, B. Wheeler, G. Brewer
The authors have developed a new photoresist based technique for micrometer resolution patterning of covalently bound silanes on glassy substrates in order to pattern the growth of primary hippocampal neurons in low density culture. The technique is named Selective Silane Removal because the substrate is initially reacted with a cytophilic aminosilane (trimethoxy-silylpropyl-diethylenetriamine or DETA), which, is then aggressively removed by plasma etching through a masking layer of patterned photoresist. The process is completed by reacting the cleaned surface areas with a cytophobic arylsilane (phenyltrichlorosilane or PTCS) followed by removal of the photoresist, rinsing and sterilization. Embryonic rat hippocampal neurons are cultured on the substrates at very low density (20000 cells/cm/sup 2/) using serum free B27/Neurobasal(TM) defined medium. Up to 90% of cell bodies grown on these substrates complied to a grid pattern of 3, 5 or 10 /spl mu/m wide lines. An average of 76% of the background squares were free of stray neurites or cells connected to the pattern.
{"title":"Selective silane removal: a technique for micropatterning of neurons in culture","authors":"J. Corey, B. Wheeler, G. Brewer","doi":"10.1109/IEMBS.1995.579914","DOIUrl":"https://doi.org/10.1109/IEMBS.1995.579914","url":null,"abstract":"The authors have developed a new photoresist based technique for micrometer resolution patterning of covalently bound silanes on glassy substrates in order to pattern the growth of primary hippocampal neurons in low density culture. The technique is named Selective Silane Removal because the substrate is initially reacted with a cytophilic aminosilane (trimethoxy-silylpropyl-diethylenetriamine or DETA), which, is then aggressively removed by plasma etching through a masking layer of patterned photoresist. The process is completed by reacting the cleaned surface areas with a cytophobic arylsilane (phenyltrichlorosilane or PTCS) followed by removal of the photoresist, rinsing and sterilization. Embryonic rat hippocampal neurons are cultured on the substrates at very low density (20000 cells/cm/sup 2/) using serum free B27/Neurobasal(TM) defined medium. Up to 90% of cell bodies grown on these substrates complied to a grid pattern of 3, 5 or 10 /spl mu/m wide lines. An average of 76% of the background squares were free of stray neurites or cells connected to the pattern.","PeriodicalId":20509,"journal":{"name":"Proceedings of 17th International Conference of the Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1995-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74669618","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 : 1995-09-20DOI: 10.1109/IEMBS.1995.579240
B. Hochwald, A. Nehorai
Modern magnetoencephalographic (MEG) instruments estimate the location of endocranial current sources with an array of magnetometers. The authors provide a technique for computing the magnetometer orientations that achieve minimum mean-square localization error. They thereby show that the radial orientations in a commonly-used array are non-optimal, and suggest a simple modification that significantly improves the array's performance.
{"title":"Optimizing an array of sensors for magnetoencephalography","authors":"B. Hochwald, A. Nehorai","doi":"10.1109/IEMBS.1995.579240","DOIUrl":"https://doi.org/10.1109/IEMBS.1995.579240","url":null,"abstract":"Modern magnetoencephalographic (MEG) instruments estimate the location of endocranial current sources with an array of magnetometers. The authors provide a technique for computing the magnetometer orientations that achieve minimum mean-square localization error. They thereby show that the radial orientations in a commonly-used array are non-optimal, and suggest a simple modification that significantly improves the array's performance.","PeriodicalId":20509,"journal":{"name":"Proceedings of 17th International Conference of the Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1995-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73024220","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 : 1995-09-20DOI: 10.1109/IEMBS.1995.575331
L. Kalakutsky, G. Kuraev, É. Manelis
An anaesthesiological heart rate monitor was developed for estimation of the adaptation degree of a person to the stress factor in anaesthesiology and reanimatology. This device allows one to estimate the activity of sympathetic and parasympathetic departments of VNS with the help of computer analysis of ECG R-R intervals. Information is displayed on the screen in real-time. AHRM was applied to research of the influence of analgesia means and methods on patients' vegetal status in the postoperative period.
{"title":"Anaesthesiological heart rate monitor","authors":"L. Kalakutsky, G. Kuraev, É. Manelis","doi":"10.1109/IEMBS.1995.575331","DOIUrl":"https://doi.org/10.1109/IEMBS.1995.575331","url":null,"abstract":"An anaesthesiological heart rate monitor was developed for estimation of the adaptation degree of a person to the stress factor in anaesthesiology and reanimatology. This device allows one to estimate the activity of sympathetic and parasympathetic departments of VNS with the help of computer analysis of ECG R-R intervals. Information is displayed on the screen in real-time. AHRM was applied to research of the influence of analgesia means and methods on patients' vegetal status in the postoperative period.","PeriodicalId":20509,"journal":{"name":"Proceedings of 17th International Conference of the Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1995-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74214870","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 : 1995-09-20DOI: 10.1109/IEMBS.1995.575056
Y. Bensadoun, E. Novakov, K. Raoof
Electrocardiographic signals (ECG) are corrupted with a certain number of noisy signals like baseline drift, mains interference (50 Hz or 60 Hz) due to electric sources, and electromyographic signals (EMG). This interference usually disturbs long periods of the useful signal and normally overlaps its spectrum. Till now, an adaptive approach remains difficult, because requires the acquisition of a noise reference channel (Xu, 1987; Thakor, 1991), or an "a priori" information based on detected QRS complexes and RR intervals (Provaznik 1993, 1994). Here, the authors show a new multidimensional adaptive method without an electromyographic noise reference, and without any "a priori" information. This technique was evaluated by using real cardiac signals recorded on three channels.
{"title":"Multidimensional adaptive method for cancelling EMG signal from the ECG signal","authors":"Y. Bensadoun, E. Novakov, K. Raoof","doi":"10.1109/IEMBS.1995.575056","DOIUrl":"https://doi.org/10.1109/IEMBS.1995.575056","url":null,"abstract":"Electrocardiographic signals (ECG) are corrupted with a certain number of noisy signals like baseline drift, mains interference (50 Hz or 60 Hz) due to electric sources, and electromyographic signals (EMG). This interference usually disturbs long periods of the useful signal and normally overlaps its spectrum. Till now, an adaptive approach remains difficult, because requires the acquisition of a noise reference channel (Xu, 1987; Thakor, 1991), or an \"a priori\" information based on detected QRS complexes and RR intervals (Provaznik 1993, 1994). Here, the authors show a new multidimensional adaptive method without an electromyographic noise reference, and without any \"a priori\" information. This technique was evaluated by using real cardiac signals recorded on three channels.","PeriodicalId":20509,"journal":{"name":"Proceedings of 17th International Conference of the Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1995-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74488654","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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