Neurology & clinical neurophysiology : NCN最新文献_第7页

MEG and EEG show different sensitivity to myogenic artifacts. MEG和EEG对肌源性伪影的敏感性不同。

Neurology & clinical neurophysiology : NCN Pub Date : 2004-11-30

R Zimmermann, E Scharein

引用次数: 0

Magnetocardiographic differences of ventricular repolarization parameters between Wistar rats and guinea pigs. Wistar大鼠与豚鼠心室复极参数的心磁图差异。

Neurology & clinical neurophysiology : NCN Pub Date : 2004-11-30

D Brisinda, A M Meloni, R Fenici

{"title":"Magnetocardiographic differences of ventricular repolarization parameters between Wistar rats and guinea pigs.","authors":"D Brisinda, A M Meloni, R Fenici","doi":"","DOIUrl":"","url":null,"abstract":"Unlabelled: The morphology and range of duration of the action potential (AP) in normal Wistar rat's (WR) myocyte markedly differ from those of guinea pigs (GP), whose plateau (phase 2) duration is longer. Thus a clear-cut T wave can be easy defined in GP but not in WR. Aim of this study was to differentiate magnetocardiographic (MCG) ventricular repolarization (VR) parameters of healthy adult WR and GP.Methods: 10 female animals (5 Guinea pigs and 5 Wistar rats) were studied with a 36-channel MCG system (sensitivity of 20 fT/square root of Hz1/2) and with one ECG lead, in an unshielded hospital room. To assess VR, HR-corrected, JTpeak, JTend, Tpeak-end and QTend, intervals were measured from both MCG waveforms. Timing was improved by MCG maps analysis. Magnetic field orientation (MFO), its dynamics (MFD) and stability (JTS) during the JT interval, were also automatically computed from MCG maps.Results: All repolarization intervals were significantly shorter in WR than in GP, except the Tpeak-end, which was longer. MFO and MFD also differed.Conclusions: MCG estimate of VR parameters, in adult WR and GP, is precise enough to evidence breed-related differences, consistent with physiological heterogeneity of duration during phases 2 and 3 of the AP, and with an higher degree of transmural dispersion of repolarization in WR.","PeriodicalId":83814,"journal":{"name":"Neurology & clinical neurophysiology : NCN","volume":"2004 ","pages":"9"},"PeriodicalIF":0.0,"publicationDate":"2004-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24895555","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}

引用次数: 0

Spatial-temporal analysis of non-stationary fMEG data. 非平稳fMEG数据的时空分析。

Neurology & clinical neurophysiology : NCN Pub Date : 2004-11-30

P Soni, Y Chan, H Preissl, H Eswaran, J Wilson, P Murphy, C L Lowery

{"title":"Spatial-temporal analysis of non-stationary fMEG data.","authors":"P Soni, Y Chan, H Preissl, H Eswaran, J Wilson, P Murphy, C L Lowery","doi":"","DOIUrl":"","url":null,"abstract":"Magnetoencephalography (MEG) is a technique used to non-invasively record neuromagnetic fields generated by the human brain. Our new SARA (SQUID Array for Reproductive Assessment) is a unique MEG device designed specifically for the study of the fetal neurophysiology. During the acquistion of fetal magnetoencephalography (fMEG), many other interfering bio-magnetic signals are collected as well. Examples include the movement of fetus or muscle contraction of the mother. As a result, the recorded signals may show unexpected patterns, other than the target signal of interest. These interventions makes it difficult for a physician to assess the exact fetal condition, including its response to various stimuli. We propose using intervention analysis and spatial-temporal autoregressive moving average (STARMA) modeling to address the problem. STARMA is a statistical method that examines the relationship between the current observations as a linear combination of past observations, as well as observations at neighboring sites. Through intervention analysis, the change in pattern due to interfering signals can be well accounted for. When these interferences are removed, the end product is a template time series, or a typical signal from the target of interest thus providing a more reliable means to monitor the actual signals generated by the fetal brain and other organs of interest.","PeriodicalId":83814,"journal":{"name":"Neurology & clinical neurophysiology : NCN","volume":"2004 ","pages":"100"},"PeriodicalIF":0.0,"publicationDate":"2004-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25185574","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}

引用次数: 0

SAM(g2) analysis for detecting spike localization: a comparison with clinical symptoms and ECD analysis in an epileptic patient. SAM(g2)分析检测尖峰定位:与癫痫患者临床症状和ECD分析的比较。

Neurology & clinical neurophysiology : NCN Pub Date : 2004-11-30

S Ukai, S Kawaguchi, R Ishii, M Yamamoto, A Ogawa, Y Mizuno-Matsumoto, S E Robinson, N Fujita, T Yoshimine, K Shinosaki, M Takeda

{"title":"SAM(g2) analysis for detecting spike localization: a comparison with clinical symptoms and ECD analysis in an epileptic patient.","authors":"S Ukai, S Kawaguchi, R Ishii, M Yamamoto, A Ogawa, Y Mizuno-Matsumoto, S E Robinson, N Fujita, T Yoshimine, K Shinosaki, M Takeda","doi":"","DOIUrl":"","url":null,"abstract":"SAM(g2) analysis, a combination of synthetic aperture magnetometry (SAM) and excess kurtosis (g2) method, is a novel epilepsy analysis procedure based on a spatial filtering technique. By producing a three-dimensional image of the g2 values and superimposing them onto a patient's MR images, this analysis can automatically estimate spike localization from raw MEG epilepsy signals including spikes. The aim of this study is to examine SAM(g2) analysis using MEG signals of an epileptic patient, whose clinical symptoms of colored elementary visual auras had ceased in accordance with the changes of the estimated localizations of the equivalent current dipoles (ECDs) of the interictal spikes. His visual auras were experienced in 1997, while they ceased in 1999 with effective medication. The patient provided written informed consent for the experimental procedures. The MEG signals were recorded in 1997 and 1999, and were analyzed using both ECD and SAM(g2) analyses. For the MEG signals of 1997, ECD analysis estimated most of the interictal spikes in the right fusiform and inferior temporal gyri, which subserve human color processing. SAM(g2) analysis also estimated them in the same areas. For those of 1999, both ECD and SAM(g2) analyses estimated them in the right transverse gyrus of Heschl. As well as ECD analysis, SAM(g2) analysis successfully estimated the changes of the localizations of the interictal spikes in accordance with the changes of the patient's clinical symptoms, indicating that SAM(g2) analysis is useful for detection of interictal spike localization in epileptic patients.","PeriodicalId":83814,"journal":{"name":"Neurology & clinical neurophysiology : NCN","volume":"2004 ","pages":"57"},"PeriodicalIF":0.0,"publicationDate":"2004-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25185578","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}

引用次数: 0

Rejection of stimulus-related MEG artifacts using independent component analysis. 使用独立分量分析拒绝刺激相关的MEG伪影。

Neurology & clinical neurophysiology : NCN Pub Date : 2004-11-30

S Iwaki, C Yamamoto, M Tonoike, T Yamamoto

{"title":"Rejection of stimulus-related MEG artifacts using independent component analysis.","authors":"S Iwaki, C Yamamoto, M Tonoike, T Yamamoto","doi":"","DOIUrl":"","url":null,"abstract":"Electro-gustatory (EG) stimuli have been used to investigate the gustatory information processing in the human brain with precise temporal and spatial accuracy. But this technique was not widely applicable to magnetoencephalographic measurements due to the difficulty in eliminating huge stimulus-related artifact. In this study, we used independent component decomposition of the measured signal to reject the stimulus-related artifact from other brain activities based on information maximization (infomax) approach. Infomax ICA was applied to raw MEG data measured by 122 magnetometer channels producing 122 temporally independent components, and the trials for each component were averaged separately. Each independent component was visually inspected and the components obviously representing the EG stimulus-related artifacts were excluded from remixing and the signal projection onto the original MEG signal space to reconstruct the artifact-free MEG signals. Results showed that large EG stimulus-related artifacts were clearly removed from MEG waveforms. We were also able to separate blink-related components and magnetocardiographic components as well as the components representing alpha-band (8-13 Hz) spontaneous brain activity.","PeriodicalId":83814,"journal":{"name":"Neurology & clinical neurophysiology : NCN","volume":"2004 ","pages":"17"},"PeriodicalIF":0.0,"publicationDate":"2004-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25185579","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}

引用次数: 0

Changes in magnetocardiogram patterns of infarcted-reperfused myocardium after injection of superparamagnetic contrast media. 注射超顺磁造影剂后梗死再灌注心肌的心磁图变化。

Neurology & clinical neurophysiology : NCN Pub Date : 2004-11-30

A Brazdeikis, C W Chu, P Cherukuri, S Litovsky, M Naghavi

{"title":"Changes in magnetocardiogram patterns of infarcted-reperfused myocardium after injection of superparamagnetic contrast media.","authors":"A Brazdeikis, C W Chu, P Cherukuri, S Litovsky, M Naghavi","doi":"","DOIUrl":"","url":null,"abstract":"The changes in spatio-temporal patterns of magnetocardiograms were investigated following injection of superparamagnetic iron-oxide (SPIO) nanoparticles using a dog model of ischemia/reperfusion. Acute myocardial infarction was induced by ligation of the left anterior descending coronary in two anesthetized open-chest dogs. Following 60 min coronary occlusion and 30 min reperfusion, dogs were subjected to injections of SPIO at a dose of 0.56 mg Fe/kg using a catheter inserted into the left atrium. Magnetocardiograms were measured before coronary occlusion, 15 min after reperfusion and immediately after administration of the SPIO. Magnetic field maps of early reperfused myocardium showed spatio-temporal field distributions consistent with anterior myocardial infarction. Magnetic field distribution measured after injection of SPIO revealed additional spatio-temporal features most prominent during ventricular repolarization due to augmentation/fragmentation of the ST-segment detected at several sensor locations. No significant differences in MCG patterns were noted following contrast agent injections in a dog without coronary occlusion. In conclusion, preliminary experimental evidence appears to support the notion that superparamagnetic contrast agents increase the sensitivity of standard MCG and may have an important implication for magnetocardiography in the assessment of regional myocardial ischemia, infarction and perfusion.","PeriodicalId":83814,"journal":{"name":"Neurology & clinical neurophysiology : NCN","volume":"2004 ","pages":"16"},"PeriodicalIF":0.0,"publicationDate":"2004-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25185585","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}

引用次数: 0

Magnetic noise rejection in the MCG using independent component analysis. 用独立分量分析抑制MCG中的磁噪声。

Neurology & clinical neurophysiology : NCN Pub Date : 2004-11-30

K Kobayashi, K Yamazaki, Y Uchikawa, T Simizu, K Nakai, K Kawazoe, H Izumoto, M Yoshizawa

引用次数: 0

Clinical multichannel MCG in unshielded hospital environment. 非屏蔽医院环境下临床多通道MCG研究

Neurology & clinical neurophysiology : NCN Pub Date : 2004-11-30

D Brisinda, A M Meloni, R Fenici

{"title":"Clinical multichannel MCG in unshielded hospital environment.","authors":"D Brisinda, A M Meloni, R Fenici","doi":"","DOIUrl":"","url":null,"abstract":"Unlabelled: From November 5th, 2001 to May 19th, 2004, 545 patients (177 with arrhythmias, 67 with WPW syndrome, 60 with Ischemic Heart Disease (IHD), 129 with different kinds of cardiomyopathy, 106 normals, 6 FMCG) have been consecutively investigated at the Catholic University of Rome, with unshielded Multichannel Magnetocardiographic Mapping (MMCG): 20 with the 9-channel system only and 525 with the 36-channel system (207 of them with both systems). 107 patients were investigated also after physical stress, carried out with a standard bicycle ergometer. In all patients MMCG was recorded at least three times, to check for reproducibility and/or for clinical follow-up, for a total of more than 1600 recordings.Method: MMCG was performed, with both the 9-channel and the 36-channel systems, at 1 kHz in the bandwidth DC-100 Hz. In the last 200 pts, 12-lead ECG was simultaneously recorded with amagnetic electrodes. On each patient file, post-processing and signal analysis for the quantitative assessment of ventricular repolarization and for 3D localization and electroanatomical imaging of cardiac arrhythmias, were carried out independently with two different approaches and software programs developed by CMI and by Neuromag (Finland).Results: The results with the two methods have been compared. For 3D electroanatomical integration of MMCG localization results, 3D cardiac models have been used, constructed from patient MRI and/or from orthogonal fluoroscopic images taken at the moment of MCG recording.Conclusions: Qualitative reproducibility of MMCG was satisfactory. However the estimate of quantitative parameters has shown a certain degree of variability, which deserves further evaluation.","PeriodicalId":83814,"journal":{"name":"Neurology & clinical neurophysiology : NCN","volume":"2004 ","pages":"8"},"PeriodicalIF":0.0,"publicationDate":"2004-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25188027","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}

引用次数: 0

Maximum likelihood dipole fitting in spatially colored noise. 空间彩色噪声中的最大似然偶极子拟合。

Neurology & clinical neurophysiology : NCN Pub Date : 2004-11-30

B V Baryshnikov, B D Van Veen, R T Wakai

引用次数: 0

Study on optimization for current distribution in magnetic stimulation therapy for urinary incontinence. 磁刺激治疗尿失禁的电流分布优化研究。

Neurology & clinical neurophysiology : NCN Pub Date : 2004-11-30

M Odagaki, K Suga, T Sasaki, H Hosaka

引用次数: 0