Liu Aoxuan, Ge Qianqian, Jiao Liqin, Peng Hao, Sun Yuhang, Han Shuai, Zhang Qin, Si Juanning, He Jianghong
Beijing Tiantan Hospital, Capital Medical University, Department of Neurosurgery, Beijing, China.
Capital Medical University, Beijing, China.
Neurophotonics. 2025 Jul;12(3):035003. doi: 10.1117/1.NPh.12.3.035003. Epub 2025 Aug 7.
Disorders of consciousness (DOCs) pose significant challenges for therapeutic intervention. Spinal cord stimulation (SCS) has emerged as a promising neuromodulation technique for treating DOC patients. However, the selection of optimal SCS stimulation parameters, particularly intensity, lacks objective standards, and considerable variations in the configuration of stimulation intensity are evident among different research groups in previous studies.
We aim to systematically evaluate the effects of different stimulation intensities of SCS using functional near-infrared spectroscopy (fNIRS) to further optimize the efficacy of SCS.
Eleven DOC patients with implanted SCS devices were recruited. Four different stimulation intensities based on individual motor thresholds were used: low (50%), threshold (100%), medium (125%), and high (150%). Hemodynamic responses were recorded using fNIRS, and the mean, peak, and net area under the curve values of hemodynamics, as well as the activated channel count, were analyzed, mainly focusing on two regions of interest: the prefrontal cortex (PFC) and the temporo-parietal junction (TPJ).
An inverted U-shaped dose-response curve was observed. The medium-intensity group triggered the most significant hemodynamic responses. The high-intensity group evoked less pronounced responses and showed negative responses post-stimulation. The threshold-intensity group exhibited positive responses but less pronounced than the medium- and high-intensity groups. Conversely, the low-intensity SCS evoked a decreased response. The medium-intensity SCS also resulted in the highest number of activated channels and maintained the highest total hemoglobin concentration level during the inter-stimulus interval. Differences in brain region responses to SCS intensity were observed, with the PFC tolerating higher intensities and the TPJ having a narrower therapeutic window.
Our findings illustrate that the medium-intensity SCS provides the optimal hemodynamic effect. The observed inverted U-shaped dose-response curve underscores the importance of precise parameter adjustments in SCS for DOC patients to maximize efficacy and to avoid overstimulation or insufficient activation.
意识障碍（DOCs）给治疗干预带来了重大挑战。脊髓刺激（SCS）已成为治疗DOC患者的一种有前景的神经调节技术。然而，最佳SCS刺激参数的选择，尤其是强度，缺乏客观标准，并且在先前研究中不同研究组之间刺激强度配置存在明显差异。
我们旨在使用功能近红外光谱（fNIRS）系统评估不同刺激强度的SCS的效果，以进一步优化SCS的疗效。
招募了11名植入SCS设备的DOC患者。使用基于个体运动阈值的四种不同刺激强度：低（50%）、阈值（100%）、中（125%）和高（150%）。使用fNIRS记录血流动力学反应，并分析血流动力学的平均值、峰值和曲线下净面积值以及激活通道数，主要关注两个感兴趣区域：前额叶皮层（PFC）和颞顶叶交界处（TPJ）。
观察到倒U形剂量反应曲线。中等强度组引发了最显著的血流动力学反应。高强度组引发的反应较不明显，且在刺激后显示出负反应。阈值强度组表现出阳性反应，但不如中等强度组和高强度组明显。相反，低强度SCS引发反应降低。中等强度SCS还导致激活通道数量最多，并在刺激间隔期间保持最高的总血红蛋白浓度水平。观察到脑区对SCS强度的反应存在差异，PFC能耐受更高强度，而TPJ的治疗窗口较窄。
我们的研究结果表明，中等强度SCS提供了最佳的血流动力学效果。观察到的倒U形剂量反应曲线强调了在SCS中精确调整参数对于DOC患者最大化疗效以及避免过度刺激或激活不足的重要性。
