Signal analysis of auditory evoked cortical fields in fetal magnetoencephalography

被引:50
作者
Schneider, U
Schleussner, E
Haueisen, J
Nowak, H
Seewald, HJ
机构
[1] Univ Hosp, Dept Obstet, D-07740 Jena, Germany
[2] Univ Jena, Dept Neurol, Biomagnet Ctr, D-6900 Jena, Germany
关键词
fetal magnetoencephalography; fetal magnetocardiography; auditory evoked cortical fields; functional brain maturation; signal-to-noise ratio; signal analysis;
D O I
10.1023/A:1012519923583
中图分类号
R74 [神经病学与精神病学];
学科分类号
摘要
Magnetoencephalography (MEG) using auditory evoked cortical fields (AEF) is an absolutely non-invasive method of passive measurement which utilizes magnetic fields caused by specific cortical activity. By applying the exceptionally sensitive SQUID technology to record these fields of dipolar configuration produced by the fetal brain, MEG as an investigational tool could provide new insights into the development of the human brain in utero. The major constraint to this application is a very low signal-to-noise ratio (SNR) that has to be attributed to a variety of factors including the magnetic signals generated by the fetal and maternal hearts which inevitably obscure a straightforward signal analysis. By applying a new algorithm of specific heart artefact reduction based on the relative regularity of the heart signals, we were able to increase the chance of extracting a fetal AEF from the raw data by the means of averaging techniques and principle component analysis. Results from 27 pregnant, healthy women (third trimester of their uncomplicated pregnancy) indicate an improved detection rate and the reproducibility of the fetal MEG. We evaluate and discuss a-priori criteria for signal analyses which will enable us to systematically analyze additional limiting factors, to further enhance the efficiency of this method and to promote the assessment of its possible clinical value in the future.
引用
收藏
页码:69 / 80
页数:12
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