Analysis of rehabilitation effect of repetitive transcranial magnetic stimulation based on resting⁃state fMRI in post⁃stroke cognitive impairment patients with low thyroid hormone levels

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.

doi：10.3969/j.issn.1672⁃6731.2022.11.004