Spherical splines and average referencing in scalp electroencephalography
Spherical splines and average referencing in scalp electroencephalography
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DOI：
10.1007/s10548-006-0011-0
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发表时间：
2006-12-01
期刊：
影响因子：
2.7
通讯作者：
Ferree, Thomas C.
中科院分区：
文献类型：
--
作者：
Ferree, Thomas C.
参考电极影响着脑电图的分析和解释。平均参考电位被广泛用于近似相对于无穷大的电位，但由于头皮表面采样不完整，平均表面电位的估计容易出现误差。即使电极密度很高，这也是由于没有对头皮下表面取样造成的。本文用解析的方法说明了球面样条如何表示平均表面势。它还表明，对于样条阶m >= 3，插值函数可以很好地近似于它的大m极限，赋予近电极和远电极相反的符号。综上所述，球面样条可以比在优越的头皮电极上计算的离散平均值更好地估计相对于无穷远的电位。它使用数值模拟在一个四球头模型与单和多偶极子源，并在样条顺序，电极数和头模型参数的变化。结果证实，如果电极采样密度足够，球面样条可以更好地估计相对于无穷远的电位。
EEG analysis and interpretation are affected by the reference electrode. Average referenced potentials are used widely to approximate the potentials relative to infinity, but estimates of the average surface potential are prone to errors due to incomplete sampling of the scalp surface. Even if the electrode density is high, this arises by not sampling the inferior scalp surface. This paper shows analytically how the spherical splines represent the average surface potential. It also shows that, for spline orders m >= 3, the interpolating function is well approximated by its large-m limit, weighting near and distant electrodes with opposite signs. Together these motivate the hypothesis that spherical splines permit a better estimate of the potentials relative to infinity than the discrete average computed over superior scalp electrodes. it tests this hypothesis using numerical simulations in a four-sphere head model with single- and many-dipole sources, and variations in spline order, electrode number and head model parameters. The results confirm that the spherical splines yield a better estimate of the potentials relative to infinity, provided the electrode sampling density is adequate.