Nakasato N, Yoshimoto T
Department of Neurosurgery, Tohoku University School of Medicine, Sendai, Japan.
J Clin Neurophysiol. 2000 Mar;17(2):201-11. doi: 10.1097/00004691-200003000-00009.
The features of somatosensory (SEFs), auditory (AEFs), and visual evoked fields (VEFs) in healthy subjects and patients with brain diseases provide the basis for clinical investigations using magnetoencephalography (MEG). The SEFs provide clinically useful information to identify the central sulcus and somatotopic organization of the primary somatosensory cortex. Localization accuracy of the SEFs can be tested by cortical stimulation during surgery. Functional reorganization suggested by SEF studies must be verified by other modalities. The AEFs can localize the auditory cortex in the bilateral temporal lobes. Separation of bilateral activities is much clearer in AEFs than in auditory evoked potentials. Modulation of the interhemispheric differences of latency, amplitude, and source localization of AEFs can be used to evaluate auditory function in patients with intracranial lesions. Pattern reversal VEFs provide stable localization of the primary visual function. Separation of bihemispherical activities is the advantage of VEFs over visual evoked potentials. Investigation of VEFs provides objective evaluation of visual field deficits such as homonymous or bitemporal hemianopsia in patients with intracranial lesions. Evoked magnetic fields can provide useful diagnostic information. Such clinical findings, in turn, provides the opportunity to test the source estimation accuracy of MEG.
健康受试者和脑部疾病患者的体感诱发电场（SEFs）、听觉诱发电场（AEFs）和视觉诱发电场（VEFs）的特征为使用脑磁图（MEG）进行临床研究提供了基础。SEFs为识别中央沟和初级体感皮层的躯体定位组织提供了临床上有用的信息。SEFs的定位准确性可在手术期间通过皮层刺激进行测试。SEF研究表明的功能重组必须通过其他方式进行验证。AEFs可将听觉皮层定位在双侧颞叶。与听觉诱发电位相比，双侧活动在AEFs中的分离更为清晰。AEFs潜伏期、振幅和源定位的半球间差异的调制可用于评估颅内病变患者的听觉功能。模式翻转VEFs可对初级视觉功能进行稳定定位。与视觉诱发电位相比，双侧半球活动的分离是VEFs的优势。对VEFs的研究可为颅内病变患者的视野缺损（如同侧偏盲或双颞侧偏盲）提供客观评估。诱发磁场可提供有用的诊断信息。反过来，这些临床发现为测试MEG的源估计准确性提供了机会。
