Background

Head and brain anatomy have been related to e-field strength induced by transcranial electrical stimulation (tES). Individualization based on anatomic factors require high-quality structural magnetic resonance images, which are not always available. Head circumference (HC) can serve as an alternative means, but its linkage to electric field strength has not yet been established.

Methods

We simulated electric fields induced by tES based on individual T1w- and T2w-images of 47 healthy adults, for four conventional (“standard”) and four corresponding focal (”4x1”) electrode montages. Associations of electric field strength with individual HC were calculated using linear mixed models.

Results

Larger HC was associated with lower electric field strength across montages. We provide mathematical equations to estimate individual electric field strength based on the HC.

Conclusion

HC can be used as an alternative to estimate interindividual differences of the tES-induced electric field strength and to prospectively individualize stimulation dose, e.g., in the clinical context.

中文翻译：

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使用头围估计经颅电刺激过程中的个体感应电场强度

背景

头部和大脑解剖结构与经颅电刺激 (tES) 引起的电场强度有关。基于解剖因素的个体化需要高质量的结构磁共振图像，而这些图像并不总是可用的。头围 (HC) 可以作为替代方法，但其与电场强度的联系尚未确定。

方法

我们基于 47 名健康成年人的个人 T1w 和 T2w 图像模拟了 tES 感应的电场，用于四个常规（“标准”）和四个相应的焦点（“4x1”）电极蒙太奇。使用线性混合模型计算电场强度与单个 HC 的关联。

结果

较大的 HC 与跨蒙太奇的较低电场强度相关。我们提供数学方程来估计基于 HC 的个体电场强度。

结论

HC 可用作估计 tES 诱导电场强度的个体差异和前瞻性个体化刺激剂量的替代方法，例如，在临床环境中。