Speech Neuroscience Lab, Department of Communication Sciences and Disorders, Arnold School of Public Health, University of South Carolina, Columbia, United States.
Speech Neuroscience Lab, Department of Communication Sciences and Disorders, Arnold School of Public Health, University of South Carolina, Columbia, United States.
Cortex. 2022 Oct;155:75-89. doi: 10.1016/j.cortex.2022.07.001. Epub 2022 Jul 29.
Impairments in speech production can have devastating effects on the overall quality of life in left-hemisphere stroke survivors with aphasia; however, there is a paucity of research focusing on neural deficits in speech motor planning networks that are activated prior to the onset of speech production in this clinical population. In the present study, we examined directional brain connectivity correlates of speech preparation and planning in low-β (13-20 Hz) and high-β (21-30 Hz) band neural oscillations in participants aphasia compared with controls prior to the onset of speech. Electroencephalographic (EEG) data were concurrently recorded from 33 participants with post-stroke aphasia and 22 neurologically intact controls while they engaged in speech production tasks. Using Granger causality, brain connectivity was calculated between electrode pairs that fell within fronto-frontal, fronto-central, and fronto-parietal networks implicated in sensorimotor integration and speech planning. Clinical assessment was further conducted in post-stroke participants to measure the severity of language impairment associated with aphasia. Increased intra-hemispheric connectivity was found within low- and high-β bands in the left parieto-central and parieto-frontal as well as the right fronto-frontal and fronto-central electrodes in post-stroke participants compared with controls prior to the onset of speech production. In addition, we found that decreased inter-hemispheric centro-central connectivity within high-β band was negatively correlated with aphasia severity whereas increased parieto-frontal connectivity within high-β band was positively correlated with aphasia severity. These findings suggest that participants with left-hemisphere stroke express aberrant brain connectivity within low- and high-β bands in both left and right hemispheres during the planning phase of speech production, and that these deficits are associated with specific aspects of their language impairment, as indicated by their clinical symptoms due to aphasia.
言语产生障碍会对左半球卒中后失语症患者的整体生活质量造成严重影响；然而，目前针对该临床人群在言语产生之前激活的言语运动规划网络的神经缺陷的研究很少。在本研究中，我们在言语产生之前，检测了低-β（13-20 Hz）和高-β（21-30 Hz）频段神经振荡中言语准备和规划的方向脑连接与对照组的相关性。在进行言语产生任务时，同时记录了 33 名卒中后失语症患者和 22 名神经功能正常的对照组参与者的脑电（EEG）数据。使用格兰杰因果关系，计算了在涉及感觉运动整合和言语规划的额-额、额-中央和额-顶网络内的电极对之间的脑连接。在卒中后参与者中进一步进行临床评估，以测量与失语症相关的语言损伤严重程度。与对照组相比，在言语产生之前，卒中后参与者的左顶-中央和顶-额以及右额-额和额-中央电极的低-β和高-β频段内，发现了半球内连接的增加。此外，我们发现高-β 频段内的半球间中央-中央连接的减少与失语症严重程度呈负相关，而高-β 频段内的顶-额连接的增加与失语症严重程度呈正相关。这些发现表明，左半球卒中患者在言语产生的规划阶段表现出左、右半球内低-β 和高-β 频段内的异常脑连接，并且这些缺陷与他们的语言损伤的特定方面相关，如他们的失语症临床症状所表明的那样。
