Inter-Subject Variability of Skull Conductivity and Thickness in Calibrated Realistic Head Models
Inter-Subject Variability of Skull Conductivity and Thickness in Calibrated Realistic Head Models
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DOI：
10.1016/j.neuroimage.2020.117353
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发表时间：
2020-12-01
期刊：
影响因子：
5.7
通讯作者：
Wolters, Carsten H.
中科院分区：
文献类型：
--
作者：
Antonakakis, Marios;Schrader, Sophie;Wolters, Carsten H.
颅骨电导率对脑电图、脑电图和脑磁图联合源分析以及优化经颅电刺激有重大影响。为了克服标准文献值的使用，我们提出了一种无创两级校准程序，在对 20 名健康成年人进行的小组研究中单独估计颅骨电导率。我们的程序仅需要额外运行组合体感诱发电位和现场数据，这些数据可以轻松集成到脑电图/脑磁图实验中。校准过程使用 P20/N20 地形和来自 MRI 的特定主题的真实头部模型。我们研究了颅骨电导率的受试者间变异性，并将其与受试者的颅骨厚度、年龄和性别、P20 电位峰值和 N20 电位谷之间的个体头皮 P20/N20 表面距离以及 P20/N20 源的个体源深度相关联。我们发现（校准的）颅骨电导率 (8.44 +/- 4.84 mS/m) 和颅骨厚度 (5.97 +/- 1.19 mm) 存在相当大的受试者间差异，并且它们之间具有统计上显着的相关性 (rho = 0.52)。年龄与颅骨电导率呈统计显着负相关 (rho = - 0.5)。此外，P20/N20 表面距离和源深度显示出较大的受试者间变异，分别为 12.08 +/- 3.21 cm 和 15.45 +/- 4.54 mm，但它们之间没有显着相关性。我们还发现，所调查的指标在性别亚组之间没有显着差异。因此，通过使用特定于受试者的校准真实头部模型来考虑颅骨电导率和厚度的受试者间变异性非常重要。
Skull conductivity has a substantial influence on EEG and combined EEG and MEG source analysis as well as on optimized transcranial electric stimulation. To overcome the use of standard literature values, we propose a noninvasive two-level calibration procedure to estimate skull conductivity individually in a group study with twenty healthy adults. Our procedure requires only an additional run of combined somatosensory evoked potential and field data, which can be easily integrated in EEG/MEG experiments. The calibration procedure uses the P20/N20 topographies and subject-specific realistic head models from MRI. We investigate the inter-subject variability of skull conductivity and relate it to skull thickness, age and gender of the subjects, to the individual scalp P20/N20 surface distance between the P20 potential peak and the N20 potential trough as well as to the individual source depth of the P20/N20 source. We found a considerable inter-subject variability for (calibrated) skull conductivity (8.44 +/- 4.84 mS/m) and skull thickness (5.97 +/- 1.19 mm) with a statistically significant correlation between them (rho = 0.52). Age showed a statistically significant negative correlation with skull conductivity (rho = - 0.5). Furthermore, P20/N20 surface distance and source depth showed large inter-subject variability of 12.08 +/- 3.21 cm and 15.45 +/- 4.54 mm, respectively, but there was no significant correlation between them. We also found no significant differences among gender subgroups for the investigated measures. It is thus important to take the inter-subject variability of skull conductivity and thickness into account by means of using subject-specific calibrated realistic head modeling.