Brain-computer interface-assisted motor imagery (MI-BCI) or transcranial direct current stimulation (tDCS) has been proven effective in post-stroke motor function enhancement, yet whether the combination of MI-BCI and tDCS may further benefit the rehabilitation of motor functions remains unknown. This study investigated brain functional activity and connectivity changes after a two-week MI-BCI and tDCS combined intervention in 19 chronic subcortical stroke patients. Patients were randomized into MI-BCI with tDCS group and MI-BCI only group who underwent ten sessions of 20-minute real or sham tDCS followed by 1-hour MI-BCI training with robotic feedback. We derived amplitude of low-frequency fluctuation (ALFF), regional homogeneity (ReHo), and functional connectivity (FC) from resting-state functional magnetic resonance imaging (fMRI) data pre- and post-intervention. At baseline, stroke patients had lower ALFF in the ipsilesional somatomotor network (SMN), lower ReHo in the contralesional insula, and higher ALFF/Reho in the bilateral posterior default mode network (DMN) compared to age-matched healthy controls. After the intervention, the MI-BCI only group showed increased ALFF in contralesional SMN and decreased ALFF/Reho in the posterior DMN. In contrast, no post-intervention changes were detected in the MI-BCI+tDCS group. Furthermore, higher increases in ALFF/ReHo/FC measures were related to better motor function recovery (measured by the Fugl-Meyer Assessment scores) in the MI-BCI group while the opposite association was detected in the MI-BCI+tDCS group. Taken together, our findings suggest that brain functional re-normalization and network-specific compensation were found in the MI-BCI only group but not in the MI-BCI+tDCS group although both groups gained significant motor function improvement post-intervention with no group difference. MI-BCI and tDCS may exert differential or even oppsite impact on brain functional reorganization during post-stroke motor rehabilitation; therefore, the integration of the two strategies requires further refinement to improve efficacy and effectiveness.

中文翻译：

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使用有和没有 tDCS 的脑机接口辅助运动图像进行康复后中风的脑功能变化：一项初步研究

脑机接口辅助运动想象（MI-BCI）或经颅直流电刺激（tDCS）已被证明可有效增强卒中后运动功能，但 MI-BCI 和 tDCS 的结合是否可能进一步有益于运动的康复？功能仍然未知。本研究调查了 19 名慢性皮层下中风患者在为期两周的 MI-BCI 和 tDCS 联合干预后的大脑功能活动和连接变化。患者被随机分为带有 tDCS 的 MI-BCI 组和仅 MI-BCI 组，他们接受了 10 次 20 分钟的真实或假 tDCS 训练，然后是 1 小时的带有机器人反馈的 MI-BCI 训练。我们推导出低频波动幅度 (ALFF)、区域同质性 (ReHo)、和功能连通性 (FC) 来自干预前后静息状态功能磁共振成像 (fMRI) 数据。在基线时，与年龄匹配的健康对照相比，卒中患者的同侧躯体运动网络 (SMN) 中的 ALFF 较低，对侧岛叶中的 ReHo 较低，双侧后部默认模式网络 (DMN) 中的 ALFF/Reho 较高。干预后，仅 MI-BCI 组显示对侧 SMN 的 ALFF 增加，后部 DMN 的 ALFF/Reho 降低。相比之下，在 MI-BCI+tDCS 组中没有检测到干预后的变化。此外，在 MI-BCI 组中，ALFF/ReHo/FC 测量值的更高增加与更好的运动功能恢复（通过 Fugl-Meyer 评估分数测量）相关，而在 MI-BCI+tDCS 组中检测到相反的关联。综合起来，我们的研究结果表明，仅在 MI-BCI 组中发现了脑功能重新正常化和网络特异性补偿，但在 MI-BCI+tDCS 组中没有发现，尽管两组在干预后都获得了显着的运动功能改善，没有组间差异。MI-BCI 和 tDCS 可能对卒中后运动康复过程中的脑功能重组产生不同甚至相反的影响；因此，两种战略的整合需要进一步完善，以提高效力和效力。MI-BCI 和 tDCS 可能对卒中后运动康复过程中的脑功能重组产生不同甚至相反的影响；因此，两种战略的整合需要进一步完善，以提高效力和效力。MI-BCI 和 tDCS 可能对卒中后运动康复过程中的脑功能重组产生不同甚至相反的影响；因此，两种战略的整合需要进一步完善，以提高效力和效力。