■言语失用症(AOS)是一种运动性言语障碍,会损害产生言语所需的复杂关节运动的协调性。AOS通常与非流利性失语症同时发生,或者语言障碍,这使得确定导致AOS的特定大脑结构具有挑战性。没有失语症的纯AOS病例很少见,但为支持关节规划的神经相关性提供了最佳窗口。当前研究的目标是在纯AOS的情况下探索无氧言语错误的模式及其潜在的神经相关性。
■一名67岁的惯用右手的男子因缺血性中风引起的前岛病变而出现严重的AOS。参与者的言语和语言在1-,发病后3个月和12个月。高分辨率结构MRI,包括弥散加权成像,在发病后12个月获得。
■在第一次评估时,参与者在综合失语症测试中犯了小错误,在写作上表现出轻微的缺陷,听觉理解,和重复。通过第二次评估,他不再失语了。关于运动言语评价,他的AOS的严重程度最初被评为5分(满分7分),并在第二次访问时提高到4分,可能是由于当时他的SLP训练来减缓他的演讲。结构MRI数据显示,额-岛叶病变包括脑岛的上中央前回以及下中和中额回和中央前回的部分。从扩散MRI得出的纤维束成像显示,沿着白质向脑岛的投影,额叶倾斜束和弓形束受到部分损伤。
■这种没有失语症的严重AOS的纯病例为这种运动性言语障碍的行为和神经机制提供了独特的窗口。当前的发现支持先前的观察结果,即AOS和失语症是可分离的,并证实了脑岛和BA44的中央前回以及潜在的白质在支持复杂的关节运动协调中的作用。此外,其他区域,包括中央前回,布罗卡区,和第55b区讨论了它们在成功的语音制作中的潜在作用。
UNASSIGNED: Apraxia of speech (AOS) is a motor speech disorder impairing the coordination of complex articulatory movements needed to produce speech. AOS typically co-occurs with a non-fluent aphasia, or language disorder, making it challenging to determine the specific brain structures that cause AOS. Cases of pure AOS without aphasia are rare but offer the best window into the neural correlates that support articulatory planning. The goal of the current study was to explore patterns of apraxic speech errors and their underlying neural correlates in a
case of pure AOS.
UNASSIGNED: A 67-year-old right-handed man presented with severe AOS resulting from a fronto-insular lesion caused by an ischemic stroke. The participant\'s speech and language were evaluated at 1-, 3- and 12-months post-onset. High resolution structural MRI, including diffusion weighted imaging, was acquired at 12 months post-onset.
UNASSIGNED: At the first assessment, the participant made minor errors on the Comprehensive Aphasia Test, demonstrating mild deficits in writing, auditory comprehension, and repetition. By the second assessment, he no longer had aphasia. On the Motor Speech Evaluation, the severity of his AOS was initially rated as 5 (out of 7) and improved to a score of 4 by the second visit, likely due to training by his SLP at the time to slow his speech. Structural MRI data showed a fronto-insular lesion encompassing the superior precentral gyrus of the insula and portions of the inferior and middle frontal gyri and precentral gyrus. Tractography derived from diffusion MRI showed partial damage to the frontal aslant tract and arcuate fasciculus along the white matter projections to the insula.
UNASSIGNED: This pure
case of severe AOS without aphasia affords a unique window into the behavioral and neural mechanisms of this motor speech disorder. The current findings support previous observations that AOS and aphasia are dissociable and confirm a role for the precentral gyrus of the insula and BA44, as well as underlying white matter in supporting the coordination of complex articulatory movements. Additionally, other regions including the precentral gyrus, Broca\'s area, and Area 55b are discussed regarding their potential role in successful speech production.