Neuroradiology, Foundation IRCCS Neurological Institute Carlo Besta, Milan, Italy.
Cortex. 2012 Feb;48(2):255-72. doi: 10.1016/j.cortex.2011.11.015. Epub 2011 Dec 7.
Lesions in the ventrolateral region of the dominant frontal lobe have been historically associated with aphasia. Recent imaging results suggest that frontal language regions extend beyond classically defined Broca's area to include the ventral precentral gyrus (VPCG) and the arcuate fasciculus (AF). Frontal gliomas offer a unique opportunity to identify structures that are essential for speech production. The aim of this prospective study was to investigate the correlation between language deficits and lesion location in patients with gliomas.
Nineteen patients with glioma and 10 healthy subjects were evaluated with diffusion tensor imaging magnetic resonance (MR) tractography, functional MR (verb generation task) and the Aachener Aphasie Test. Patients were divided into two groups according to lesion location with respect to the ventral precentral sulcus: (i) anterior (n=8) with glioma growing in the inferior frontal gyrus (IFG) and underlying white matter; (ii) posterior (n=11) with glioma growing in the VPCG and underlying white matter. Virtual dissection of the AF, frontal intralobar tract, uncinate fasciculus (UF) and inferior frontal occipital fasciculus (IFOF) was performed with a deterministic approach.
Seven posterior patients showed aphasia classified as conduction (4), Broca (1), transcortical motor (1) and an isolated deficit of semantic fluency; one anterior patient had transcortical mixed aphasia. All posterior patients had invasion of the VPCG, however only patients with aphasia had also lesion extension to the AF as demonstrated by tractography dissections. All patients with language deficits had high grade glioma. Groups did not differ regarding tumour volume. A functional pars opercularis was identified with functional MR imaging (fMRI) in 17 patients.
Gliomas growing in the left VPCG are much more likely to cause speech deficits than gliomas infiltrating the IFG, including Broca's area. Lesion extension to the AF connecting frontal to parietal and temporal regions is an important mechanism for the appearance of aphasia.
历史上，优势侧额下回腹外侧区的病变与失语症有关。最近的影像学结果表明，额语言区不仅包括经典的布罗卡区（Broca's area），还包括腹侧中央前回（VPCG）和弓状束（AF）。额叶胶质瘤为确定与言语产生相关的关键结构提供了独特的机会。本前瞻性研究旨在探讨胶质瘤患者语言缺陷与病变位置的相关性。
19 名胶质瘤患者和 10 名健康受试者接受了弥散张量成像磁共振（MR）示踪、功能磁共振（动词生成任务）和亚琛失语症测试。根据病变相对于腹侧中央前沟的位置将患者分为两组：（i）前组（n=8），肿瘤生长于额下回（IFG）及其下方的白质；（ii）后组（n=11），肿瘤生长于 VPCG 及其下方的白质。采用确定性方法对 AF、额内束、钩束（UF）和下额枕束（IFOF）进行虚拟解剖。
7 名后组患者表现出失语症，分类为传导性（4 例）、布罗卡氏（1 例）、皮质下运动性（1 例）和孤立的语义流畅性障碍；1 名前组患者表现为皮质下混合性失语症。所有后组患者均存在 VPCG 侵犯，但只有出现失语症的患者，其病变延伸至 AF，这通过示踪分析得到证实。所有存在语言缺陷的患者均为高级别胶质瘤。两组患者的肿瘤体积无差异。17 名患者通过功能磁共振成像（fMRI）识别出功能性额下回岛盖部。
与浸润 Broca's area 的 IFG 相比，生长于左侧 VPCG 的胶质瘤更有可能导致言语缺陷。病变延伸至连接额、顶、颞叶的 AF 是导致失语症的重要机制。
