Abstract: Objective To evaluate brain plasticity by resting-state fMRI (rs-fMRI), and to explore the potential neuroendocrine mechanism of repetitive transcranial magnetic stimulation (rTMS) in improving post-stroke cognitive impairment (PSCI) in patients with low thyroid hormone (TH) level.Methods A total of 28 patients with PSCI with low TH level who received rehabilitation treatment in Shijiazhuang People's Hospital from August 2020 to December 2021 were randomly divided into rTMS group (n = 15) and control group (n = 13). Cognitive function was assessed by Montreal Cognitive Scale (MoCA) before and 4 weeks after rTMS, and serum levels of tri-iodothyronine (T₃), thyroxine (T₄) and thyroid stimulating hormone (TSH) were measured by double antibody sandwich method. rs-fMRI was used to calculate the fractional amplitude of low-frequency fluctuation (fALFF) and observe the activated brain regions after stimulation. Pearson correlation analysis was used to obtain the distribution of synchronous changes of activated brain areas based on whole-brain functional connection strength of hypothalamus and serum TH level in 2 groups.Results After 4 weeks of intervention, compared with control group, MoCA score (F = 1163.054, P=0.000), and serum T₃ (F = 1111.685, P=0.000), T₄ (F = 847.333, P=0.000), TSH (F = 251.316, P=0.000) in rTMS group was increased. In rTMS group, fALFF value increased mainly in posterior cerebellar lobe (t=4.699, P<0.05), middle frontal gyrus (t=4.356, P<0.05) and superior frontal gyrus (t=5.675, P<0.05), while fALFF value decreased in superior temporal gyrus (t=-7.874, P<0.05) and middle temporal gyrus (t=-5.776, P<0.05). The enhanced functional connectivity of the whole brain with bilateral hypothalamus as the region of interest (ROI) and the simultaneous increase of serum T₃ and TSH levels were mainly concentrated in the cerebellum, frontal lobe and parahippocampal gyrus.Conclusions rTMS can indirectly affect hypothalamic function through cerebral cortex, increase serum TH level and improve cognitive function in PSCI patients.

Key words: Stroke, Cognition disorders, Transcranial magnetic stimulation, Thyroid hormons, Neurological rehabilitation, Magnetic resonance imaging

摘要： 目的 采用静息态fMRI（rs-fMRI）评价大脑可塑性，探讨重复经颅磁刺激（rTMS）改善低甲状腺素水平脑卒中后认知障碍患者的潜在神经内分泌机制。方法 选择2020年8月至2021年12月在河北省石家庄市人民医院进行康复治疗的低甲状腺激素水平脑卒中后认知障碍患者共28例，随机分为rTMS组（15例）和对照组（13例），重复经颅磁刺激干预前及干预4周后，采用蒙特利尔认知评价量表（MoCA）评价认知功能，双抗体夹心法检测血清三碘甲状腺原氨酸（T₃）、甲状腺素（T₄）和促甲状腺激素（TSH）水平，通过rs-fMRI计算分数低频振幅（fALFF）并观察刺激后激活脑区，Pearson相关分析获得两组激活脑区基于下丘脑的全脑功能连接强度与血清甲状腺激素水平同步变化的分布图。结果 干预4周后，与对照组相比，rTMS组患者MoCA评分增加（F=1163.054，P=0.000），血清T₃（F=1111.685，P=0.000）、T（4F=847.333，P=0.000）、TSH（F=251.316，P=0.000）水平升高；rTMS组fALFF值增高脑区主要分布于小脑后叶（t=4.699，P<0.05）、额中回（t=4.356，P<0.05）和额上回（t=5.675，P<0.05），fALFF值降低脑区以颞上回（t=-7.874，P<0.05）和颞中回（t=-5.776，P<0.05）为主。以双侧下丘脑为兴趣区的全脑功能连接增强与血清T₃和TSH水平同步升高存在相关性的脑区主要集中于小脑、额叶及海马旁回。结论 重复经颅磁刺激可以通过大脑皮质间接影响下丘脑功能，提高脑卒中认知障碍患者血清甲状腺激素水平，继而改善认知功能。

关键词: 卒中, 认知障碍, 经颅磁刺激, 甲状腺激素类, 神经康复, 磁共振成像