ERROR-BOUNDS FOR EEG AND MEG DIPOLE SOURCE LOCALIZATION
ERROR-BOUNDS FOR EEG AND MEG DIPOLE SOURCE LOCALIZATION
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DOI：
10.1016/0013-4694(93)90043-u
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发表时间：
1993-05-01
期刊：
影响因子：
--
通讯作者：
LEWIS, PS
中科院分区：
文献类型：
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作者：
MOSHER, JC;SPENCER, ME;LEWIS, PS
本文给出了任意传感器阵列几何形状的脑电（EEG）或脑磁图（MEG）电流源偶极子模型的定位和矩误差下界的一般计算公式。给出了四球壳头部模型中多偶极子的脑电和脑磁图的具体计算公式。定位误差界的EEG和MEG几种不同的传感器配置。覆盖上半球的127个传感器，覆盖较小区域的37个传感器和127个传感器，以及标准的10-20 EEG传感器布置的图形误差轮廓。1-和2-偶极子的情况下，检查所有可能的偶极子方向和位置内的头部象限。结果表明，强烈的依赖于绝对偶极子的位置和方向。结果还表明，融合的EEG和MEG测量到一个组合的模型降低了下限。进行蒙特卡罗模拟以检查所选情况的界限的紧密性。在这项研究中，简单的头部模型，低功率噪声和几个强偶极子都被选为乐观的条件，建立可能的基本分辨率限制的任何定位工作。在这些有利的假设下，结果显示EEG和MEG模型之间具有可比性的分辨率，但在任何一种情况下，单个偶极子的精度对于单个时间片似乎仅限于几毫米。仅用2个偶极子时，下限显著增加。观测支持需要完整的时空建模，以提高这些下限。所有的模拟结果可以很容易地扩展到其他情况下的噪声功率和偶极子强度。
General formulas are presented for computing a lower bound on localization and moment error for electroencephalographic (EEG) or magnetoencephalographic (MEG) current source dipole models with arbitrary sensor array geometry. Specific EEG and MEG formulas are presented for multiple dipoles in a head model with 4 spherical shells. Localization error bounds are presented for both EEG and MEG for several different sensor configurations. Graphical error contours are presented for 127 sensors covering the upper hemisphere, for both 37 sensors and 127 sensors covering a smaller region, and for the standard 10-20 EEG sensor arrangement. Both 1- and 2-dipole cases were examined for all possible dipole orientations and locations within a head quadrant. The results show a strong dependence on absolute dipole location and orientation. The results also show that fusion of the EEG and MEG measurements into a combined model reduces the lower bound. A Monte Carlo simulation was performed to check the tightness of the bounds for a selected case. The simple head model, the low power noise and the few strong dipoles were all selected in this study as optimistic conditions to establish possibly fundamental resolution limits for any localization effort. Results, under these favorable assumptions, show comparable resolutions between the EEG and the MEG models, but accuracy for a single dipole, in either case, appears limited to several millimeters for a single time slice. The lower bounds increase markedly with just 2 dipoles. Observations are given to support the need for full spatiotemporal modeling to improve these lower bounds. All of the simulation results presented can easily be scaled to other instances of noise power and dipole intensity.