Giampiccolo Davide, Howells Henrietta, Bährend Ina, Schneider Heike, Raffa Giovanni, Rosenstock Tizian, Vergani Francesco, Vajkoczy Peter, Picht Thomas
Department of Neurosurgery, Verona University Hospital, University of Verona, Verona, Italy.
MoCa Laboratory, University of Milan, Milan, Italy.
Brain Commun. 2020 Sep 29;2(2):fcaa158. doi: 10.1093/braincomms/fcaa158. eCollection 2020.
In preoperative planning for neurosurgery, both anatomical (diffusion imaging tractography) and functional tools (MR-navigated transcranial magnetic stimulation) are increasingly used to identify and preserve eloquent language structures specific to individuals. Using these tools in healthy adults shows that speech production errors occur mainly in perisylvian cortical sites that correspond to subject-specific terminations of the major language pathway, the arcuate fasciculus. It is not clear whether this correspondence remains in oncological patients with altered tissue. We studied a heterogeneous cohort of 30 patients (fourteen male, mean age 44), undergoing a first or second surgery for a left hemisphere brain tumour in a language-eloquent region, to test whether speech production errors induced by preoperative transcranial magnetic stimulation had consistent anatomical correspondence to the arcuate fasciculus. We used navigated repetitive transcranial magnetic stimulation during picture naming and recorded different perisylvian sites where transient interference to speech production occurred. Spherical deconvolution diffusion imaging tractography was performed to map the direct fronto-temporal and indirect (fronto-parietal and parieto-temporal) segments of the arcuate fasciculus in each patient. Speech production errors were reported in all patients when stimulating the frontal lobe, and in over 90% of patients in the parietal lobe. Errors were less frequent in the temporal lobe (54%). In all patients, at least one error site corresponded to a termination of the arcuate fasciculus, particularly in the frontal and parietal lobes, despite distorted anatomy due to a lesion and/or previous resection. Our results indicate that there is strong correspondence between terminations of the arcuate fasciculus and speech errors. This indicates that white matter anatomy may be a robust marker for identifying functionally eloquent cortex, particularly in the frontal and parietal lobe. This knowledge may improve targets for preoperative mapping of language in the neurosurgical setting.
在神经外科手术的术前规划中，解剖学工具（扩散成像纤维束成像）和功能工具（磁共振导航经颅磁刺激）越来越多地用于识别和保留个体特有的明确语言结构。在健康成年人中使用这些工具表明，言语产生错误主要发生在与主要语言通路（弓状束）的个体特异性终末相对应的外侧裂周围皮质部位。目前尚不清楚在组织改变的肿瘤患者中这种对应关系是否仍然存在。我们研究了30名患者（14名男性，平均年龄44岁）组成的异质性队列，这些患者因左侧半球语言功能区脑肿瘤接受首次或二次手术，以测试术前经颅磁刺激诱发的言语产生错误是否与弓状束存在一致的解剖学对应关系。我们在图片命名过程中使用导航重复经颅磁刺激，并记录发生言语产生短暂干扰的不同外侧裂周围部位。对每位患者进行了球形反卷积扩散成像纤维束成像，以绘制弓状束的直接额颞段和间接（额顶段和顶颞段）。刺激额叶时，所有患者均出现言语产生错误，刺激顶叶时，超过90%的患者出现错误。颞叶出现错误的频率较低（54%）。在所有患者中，至少有一个错误部位对应于弓状束的终末，特别是在额叶和顶叶，尽管由于病变和/或先前的切除导致解剖结构变形。我们的结果表明，弓状束终末与言语错误之间存在很强的对应关系。这表明白质解剖结构可能是识别功能明确皮质的可靠标志物，尤其是在额叶和顶叶。这一认识可能会改善神经外科手术中语言术前定位的靶点。
