Neurofeedback (NF) training based on alpha upregulation has been widely used on patient and healthy populations. However, active voluntary modulation of central or widespread posterior alpha in response to central alpha feedback is still ambiguous. The objective of this study is to confirm whether patients learn to truly increase alpha power and to determine if patients modulate central or widespread alpha power when alpha feedback is provided from central brain region. This EEG-based NF study was conducted on seven paraplegic patients with same injury type, pain location, and sensitization to ensure homogeneity. In addition to routine NF training sessions, various experiments were performed to compare alpha NF modulation received from C4 with alpha shift during cognitive tasks, occipital or parieto-occipital cortex, and Laplacian montage which is expected to separate localized alpha from widespread alpha, to attain objectives. Moreover, imaginary coherence analysis in alpha band was also performed to check whether C4 training site is coupled with other brain regions and to confirm whether activity at training site leads/lags the activity of other brain regions. The results indicate widespread alpha modulation in patients during regular NF sessions (p < 0.05) with large effect size (> 0.8), sufficiently high statistical power (> 80%), and a narrower confidence interval (CI) in response to NF provided from the central brain region reflecting less uncertainty and higher precision. However, small effect size obtained with Laplacian montage require patients to be trained with Laplacian feedback to achieve a reliable conclusion regarding localized alpha modulation. The outcomes of this study are not only limited to validate true alpha modulation in response to central alpha feedback but also to explore the mechanism of central alpha NF training.

基于 alpha 上调的神经反馈 (NF) 训练已广泛用于患者和健康人群。然而，响应中央 alpha 反馈的中央或广泛的后部 alpha 的主动自愿调制仍然不明确。本研究的目的是确认患者是否学会真正增加 alpha 功率，并确定当从中央大脑区域提供 alpha 反馈时，患者是否调节中央或广泛的 alpha 功率。这项基于 EEG 的 NF 研究是对 7 名具有相同损伤类型、疼痛部位和敏感性的截瘫患者进行的，以确保均匀性。除了常规的 NF 训练课程外，还进行了各种实验，以比较从 C4 接收到的 alpha NF 调制与认知任务、枕叶或顶枕叶皮层中的 alpha 移位，和拉普拉斯蒙太奇，它有望将局部 alpha 与广泛的 alpha 分开，以实现目标。此外，还进行了α波段的假想相干分析，以检查C4训练部位是否与其他大脑区域耦合，并确认训练部位的活动是否领先/滞后于其他大脑区域的活动。结果表明，患者在常规 NF 会话期间广泛存在 α 调制（p < 0.05），具有大的效应量（> 0.8）、足够高的统计功效（> 80%）和更窄的置信区间（CI），以响应来自提供的 NF大脑中央区域反映了更少的不确定性和更高的精度。然而，使用拉普拉斯蒙太奇获得的小效应量要求患者接受拉普拉斯反馈训练，以获得关于局部 α 调制的可靠结论。这项研究的结果不仅限于验证响应中央 alpha 反馈的真实 alpha 调制，而且还探索中央 alpha NF 训练的机制。