Department of Human Neurosciences, Sapienza University of Rome, Viale Dell'Università 30, 00185, Rome, Italy; IRCCS Neuromed, Via Atinense 18, 86077, Pozzilli, IS, Italy.
IRCCS Neuromed, Via Atinense 18, 86077, Pozzilli, IS, Italy.
Brain Stimul. 2020 May-Jun;13(3):765-773. doi: 10.1016/j.brs.2020.02.029. Epub 2020 Feb 26.
In healthy subjects (HS), transcranial magnetic stimulation (TMS) demonstrated an increase in motor-evoked potential (MEP) amplitudes during specific linguistic tasks. This finding indicates functional connections between speech-related cortical areas and the dominant primary motor cortex (M1).
To investigate M1 function with TMS and the speech-related cortical network with neuroimaging measures in frontotemporal dementia (FTD), including the non-fluent variant of primary progressive aphasia (nfv-PPA) and the behavioral variant of FTD (bv-FTD).
M1 excitability changes during specific linguistc tasks were examined using TMS in 24 patients (15 with nfv-PPA and 9 with bv-FTD) and in 18 age-matched HS. In the same patients neuroimaging was used to assess changes in specific white matter (WM) bundles and grey matter (GM) regions involved in language processing, with diffusion tensor imaging (DTI) and voxel-based morphometry (VBM).
During the linguistic task, M1 excitability increased in HS, whereas in FTD patients it did not. M1 excitability changes were comparable in nfv-PPA and bv-FTD. DTI revealed decreased fractional anisotropy in the superior and inferior longitudinal and uncinate fasciculi. Moreover, VBM disclosed GM volume loss in the left frontal operculum though not in the parietal operculum or precentral gyrus. Furthermore, WM and GM changes were comparable in nfv-PPA and bv-FTD. There was no correlation between neurophysiological and neuroimaging changes in FTD. Atrophy in the left frontal operculum correlated with linguistic dysfunction, assessed by semantic and phonemic fluency tests.
We provide converging neurophysiological and neuroimaging evidence of abnormal speech-related cortical network activation in FTD.
在健康受试者（HS）中，经颅磁刺激（TMS）在特定语言任务中显示运动诱发电位（MEP）幅度增加。这一发现表明与言语相关的皮质区域与优势初级运动皮质（M1）之间存在功能连接。
用 TMS 研究额颞叶痴呆（FTD）中的 M1 功能以及与言语相关的皮质网络，包括非流利型原发性进行性失语（nfv-PPA）和行为变异型 FTD（bv-FTD）。
使用 TMS 检查 24 例患者（15 例 nfv-PPA 和 9 例 bv-FTD）和 18 例年龄匹配的 HS 患者在特定语言任务期间 M1 兴奋性变化。在相同的患者中，使用扩散张量成像（DTI）和基于体素的形态测量学（VBM）评估参与语言处理的特定白质（WM）束和灰质（GM）区域的变化。
在语言任务中，HS 中的 M1 兴奋性增加，而 FTD 患者则没有。nfv-PPA 和 bv-FTD 患者的 M1 兴奋性变化相当。DTI 显示上纵束、下纵束和钩束的各向异性分数降低。此外，VBM 显示左额下回 GM 体积减少，但不包括顶下回或中央前回。此外，nfv-PPA 和 bv-FTD 患者的 WM 和 GM 变化相当。FTD 患者的神经生理学和神经影像学变化之间没有相关性。左额下回的萎缩与语义和语音流畅性测试评估的语言功能障碍相关。
我们提供了额颞叶痴呆患者言语相关皮质网络激活异常的神经生理学和神经影像学证据。
