BioMag Laboratory, HUSLAB, Hospital District of Helsinki and Uusimaa, Helsinki University Central Hospital, PO Box 340, FI-00029 HUS, Helsinki, Finland.
Brain Stimul. 2013 May;6(3):286-91. doi: 10.1016/j.brs.2012.04.012. Epub 2012 May 23.
Recently, navigated transcranial magnetic stimulation (nTMS) has been suggested to be useful in preoperative functional localization of motor cortex in patients having tumors close to the somatomotor cortex. Resection of tumors in anatomically predicted eloquent areas without adverse effects have emphasized functional plasticity elicited by intracranial pathology.
To describe functional plasticity of motor cortex indicated by nTMS in two patients with epilepsy.
nTMS, functional MRI (fMRI), diffusion-tensor (DT)-tractography and magnetoencephalography (MEG) were utilized to preoperatively localize motor cortical areas in the workup for epilepsy surgery. The localizations were compared with each other, with the cortical anatomical landmarks, and in one patient with invasive electrical cortical stimulation (ECS).
In two out of 19 studied patients, nTMS identified motor cortical sites that differed from those indicated by anatomical landmarks. In one patient, nTMS activated preferentially premotor cortex rather than pathways originating from the precentral gyrus. MEG and fMRI localizations conformed with nTMS whereas ECS localized finger motor function into the precentral gyrus. Resection of the area producing motor responses in biphasic nTMS did not produce a motor deficit. In the other patient, nTMS indicated abnormal ipsilateral hand motor cortex localization and confirmed the functionality of aberrant motor cortical representations of the left foot also indicated by fMRI and DT-tractography.
nTMS may reveal the functional plasticity and shifts of motor cortical function. Epileptic foci may modify cortical inhibition and the nTMS results. Therefore, in some patients with epilepsy, the nTMS results need to be interpreted with caution with regard to surgical planning.
最近，经颅磁刺激导航（nTMS）被认为在靠近运动皮质的肿瘤患者的术前运动皮质功能定位中有用。在解剖学上预测的语言区切除肿瘤而没有不良影响，强调了颅内病变引起的功能可塑性。
描述 2 例癫痫患者的 nTMS 所示运动皮质的功能可塑性。
nTMS、功能磁共振成像（fMRI）、弥散张量（DT）-追踪和脑磁图（MEG）用于癫痫手术的术前定位运动皮质区。将定位与彼此、皮质解剖标志和 1 例有侵袭性皮质电刺激（ECS）的患者进行比较。
在 19 例研究患者中的 2 例中，nTMS 确定了与解剖标志指示的不同的运动皮质部位。在 1 例患者中，nTMS 优先激活运动前皮质，而不是起源于中央前回的通路。MEG 和 fMRI 定位与 nTMS 一致，而 ECS 将手指运动功能定位到中央前回。在双相 nTMS 中产生运动反应的区域的切除并未产生运动缺陷。在另一位患者中，nTMS 表明异常同侧手部运动皮质定位，并证实了 fMRI 和 DT 追踪所示左足异常运动皮质代表的功能。
nTMS 可揭示运动皮质功能的可塑性和转移。癫痫灶可能改变皮质抑制和 nTMS 结果。因此，在一些癫痫患者中，需要谨慎解释 nTMS 结果以进行手术规划。
