Aström Mattias, Johansson Johannes D, Hariz Marwan I, Eriksson Ola, Wårdell Karin
Department of Biomedical Engineering, Linköping University, Sweden.
J Neural Eng. 2006 Jun;3(2):132-8. doi: 10.1088/1741-2560/3/2/007. Epub 2006 May 16.
Although the therapeutic effect of deep brain stimulation (DBS) is well recognized, a fundamental understanding of the mechanisms responsible is still not known. In this study finite element method (FEM) modelling and simulation was used in order to study relative changes of the electrical field extension surrounding a monopolar DBS electrode positioned in grey matter. Due to the frequently appearing cystic cavities in the DBS-target globus pallidus internus, a nucleus of grey matter with and without a cerebrospinal fluid filled cystic cavity was modelled. The position, size and shape of the cyst were altered in relation to the electrode. The simulations demonstrated an electrical field around the active element with decreasing values in the radial direction. A stepwise change was present at the edge between grey and white matters. The cyst increased the radial extension and changed the shape of the electrical field substantially. The position, size and shape of the cyst were the main influencing factors. We suggest that cystic cavities in the DBS-target may result in closely related unexpected structures or neural fibre bundles being stimulated and could be one of the reasons for suboptimal clinical effects or stimulation-induced side effects.
尽管深部脑刺激（DBS）的治疗效果已得到充分认可，但对其作用机制的基本认识仍不清楚。在本研究中，采用有限元方法（FEM）建模和模拟来研究位于灰质中的单极DBS电极周围电场扩展的相对变化。由于DBS靶点内侧苍白球中经常出现囊性空洞，因此对有和没有充满脑脊液的囊性空洞的灰质核进行了建模。囊肿的位置、大小和形状相对于电极发生了改变。模拟结果表明，有源元件周围存在电场，其值在径向方向上逐渐减小。在灰质和白质之间的边缘处存在逐步变化。囊肿增加了径向扩展并显著改变了电场的形状。囊肿的位置、大小和形状是主要影响因素。我们认为，DBS靶点中的囊性空洞可能导致密切相关的意外结构或神经纤维束受到刺激，这可能是临床效果欠佳或刺激引起副作用的原因之一。
