卒中后水和唾液吞咽过程中外周与中枢神经调控的任务依赖性皮层反应：一项探索性fNIRS初步研究

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中文摘要

背景： 卒中后吞咽困难是一种常见且严重的并发症。神经康复策略包括外周神经肌肉电刺激（NMES）和中枢经颅直流电刺激（tDCS），分别通过不同的自下而上和自上而下的机制发挥作用。然而，它们在功能不同的吞咽任务中对皮层血流动力学反应的差异效应仍知之甚少。本初步研究旨在利用功能性近红外光谱（fNIRS）探讨NMES和tDCS对卒中后患者不同吞咽任务中皮层血流动力学的即时调控效应。
方法： 11名卒中后吞咽困难患者参与了这项探索性、受试者内、重复测量初步研究。各次访视之间保持至少24小时的洗脱期，并使用计算机生成的序列对干预条件的顺序进行随机化。使用56通道fNIRS系统监测皮层血流动力学反应，以氧合血红蛋白变化（ΔHbO₂）衡量。每位参与者在三种随机条件下均执行水吞咽和唾液吞咽任务：无刺激基线、外周刺激（对舌骨上肌群施加NMES）和中枢刺激（对初级运动皮层施加双侧阳极tDCS）。对关键感兴趣区的任务相关皮层血流动力学反应和半球偏侧化进行了分析。
结果： 主要分析发现双侧额极皮层（FPC）存在显著的刺激×任务交互作用，包括同侧病灶FPC，F(2, 20) = 8.44，原始p = 0.002，q = 0.031，偏η2 = 0.458，以及对侧病灶FPC，F(2, 20) = 7.42，原始p = 0.004，q = 0.031，偏η2 = 0.426。Bonferroni校正的简单效应分析显示，在tDCS下，水吞咽在同侧病灶（p_adj = 0.020）和对侧病灶（p_adj = 0.008）FPC中均比唾液吞咽引起更大的FPC反应。在水吞咽期间，tDCS比无刺激产生更大的对侧病灶FPC反应（p_adj = 0.006），而在唾液吞咽期间，无刺激比tDCS产生更大的双侧FPC反应（I-FPC：p_adj = 0.008；C-FPC：p_adj = 0.034），并且比NMES产生更大的同侧病灶FPC反应（p_adj = 0.043）。探索性配对比较，在每个比较家族内应用FDR校正，进一步显示在无刺激条件下，唾液吞咽比水吞咽引起更大的双侧FPC反应（I-FPC：q = 0.018；C-FPC：q = 0.024）。在NMES下，水吞咽比唾液吞咽引起更大的同侧病灶FPC反应（q = 0.002）。在唾液吞咽期间，tDCS与比NMES更大的同侧病灶SMA/PMC反应相关（q = 0.014）。
结论： 急性皮层血流动力学反应因刺激条件和吞咽任务的组合而异，最强的证据来自双侧FPC的刺激×任务交互作用。这些发现表明存在任务依赖性的前额叶血流动力学反应，但并未确立刺激特异性疗效、半球重组、神经可塑性或治疗优越性。需要更大规模的假对照研究来确定这些急性fNIRS发现的可重复性和临床相关性。
临床试验注册： 该试验已在国际传统医学临床试验注册中心（ITMCTR）注册，网址：https://itmctr.ccebtcm.org.cn/en/index.html，注册号ITMCTR2025001814。

英文摘要

BACKGROUND: Post-stroke dysphagia is a common and serious complication. Neurorehabilitation strategies include peripheral neuromuscular electrical stimulation (NMES) and central transcranial direct current stimulation (tDCS), which operate via distinct bottom-up and top-down mechanisms, respectively. However, their differential effects on cortical hemodynamic responses during functionally distinct swallowing tasks remain poorly understood. This pilot study aimed to investigate the immediate modulatory effects of NMES and tDCS on cortical hemodynamics during different swallowing tasks in post-stroke patients using functional near-infrared spectroscopy (fNIRS).
METHODS: Eleven patients with post-stroke dysphagia participated in this exploratory, within-subject, repeated-measures pilot study. A minimum 24-h washout period was maintained between sessions, and the order of intervention conditions was randomized using a computer-generated sequence. Cortical hemodynamic responses, measured by changes in oxygenated hemoglobin (ΔHbO₂), were monitored using a 56-channel fNIRS system. Each participant performed both water swallowing and saliva swallowing tasks under three randomized conditions: a no-stimulation baseline, peripheral stimulation (NMES applied to suprahyoid muscles), and central stimulation (bilateral anodal tDCS over the primary motor cortex). Task-related cortical hemodynamic responses and hemispheric lateralization were analyzed for key regions of interest.
RESULTS: The primary analysis identified significant Stimulation × Task interactions in the bilateral frontopolar cortex (FPC), including the ipsilesional FPC, F(2, 20) = 8.44, raw p = 0.002, q = 0.031, partial η2 = 0.458, and the contralesional FPC, F(2, 20) = 7.42, raw p = 0.004, q = 0.031, partial η2 = 0.426. Bonferroni-adjusted simple-effects analyses showed that, under tDCS, water swallowing elicited greater FPC responses than saliva swallowing in both the ipsilesional (p_adj = 0.020) and contralesional (p_adj = 0.008) FPC. During water swallowing, tDCS produced greater contralesional FPC responses than no stimulation (p_adj = 0.006), whereas during saliva swallowing, no stimulation produced greater bilateral FPC responses than tDCS (I-FPC: p_adj = 0.008; C-FPC: p_adj = 0.034) and greater ipsilesional FPC responses than NMES (p_adj = 0.043). Exploratory paired comparisons, with FDR correction applied within each comparison family, further showed that under the no-stimulation condition, saliva swallowing elicited greater bilateral FPC responses than water swallowing (I-FPC: q = 0.018; C-FPC: q = 0.024). Under NMES, water swallowing elicited greater ipsilesional FPC responses than saliva swallowing (q = 0.002). During saliva swallowing, tDCS was associated with greater ipsilesional SMA/PMC responses than NMES (q = 0.014).
CONCLUSION: Acute cortical hemodynamic responses varied according to the combination of stimulation condition and swallowing task, with the strongest evidence arising from the bilateral FPC Stimulation × Task interaction. These findings indicate task-dependent prefrontal hemodynamic responses but do not establish stimulation-specific efficacy, hemispheric reorganization, neuroplasticity, or therapeutic superiority. Larger sham-controlled studies are required to determine the reproducibility and clinical relevance of these acute fNIRS findings.
CLINICAL TRIAL REGISTRATION: The trial is registered at the International Traditional Medicine Clinical Trial Registry (ITMCTR), Available at: https://itmctr.ccebtcm.org.cn/en/index.html, Identifier ITMCTR2025001814.