Neurofeedback (NF), a training tool aimed at enhancing neural self-regulation, has been suggested as a complementary treatment option for neuropsychiatric disorders. Despite its potential as a neurobiological intervention directly targeting neural alterations underlying clinical symptoms, the efficacy of NF for the treatment of mental disorders has been questioned recently by negative findings obtained in randomized controlled trials (e.g., Cortese et al., 2016). A possible reason for insufficient group effects of NF trainings vs. placebo could be related to the high rate of participants who fail to self-regulate brain activity by NF (“non-learners”). Another reason could be the application of standardized NF protocols not adjusted to individual differences in pathophysiology. Against this background, we have summarized information on factors determining training and treatment success to provide a basis for the development of individualized training protocols and/or clinical indications.

The present systematic review included 25 reports investigating predictors for the outcome of NF trainings in healthy individuals as well as patients affected by mental disorders or epilepsy. We selected these studies based on searches in EBSCOhost using combinations of the keywords “neurofeedback” and “predictor/predictors”. As “NF training” we defined all NF applications with at least two sessions.

The best available evidence exists for neurophysiological baseline parameters. Among them, the target parameters of the respective training seem to be of particular importance. However, particularities of the different experimental designs and outcome criteria restrict the interpretability of some of the information we extracted. Therefore, further research is needed to gain more profound knowledge about predictors of NF outcome.

神经反馈（NF），一种旨在增强神经自我调节的训练工具，已被建议作为神经精神疾病的补充治疗选择。尽管其作为直接针对潜在临床症状的神经改变的神经生物学干预的潜力，但近来在随机对照试验中获得的阴性结果对NF治疗精神障碍的功效提出了质疑（例如，Cortese等，2016）。与安慰剂相比，NF训练对小组的影响不足的可能原因可能是由于无法通过NF自我调节大脑活动的参与者比例较高（“非学习者”）。另一个原因可能是标准NF协议的应用未针对病理生理学的个体差异进行调整。在这种背景下，

本系统综述包括25份报告，这些报告调查了健康个体以及患有精神疾病或癫痫病患者的NF训练结果。我们根据在EBSCOhost中使用关键字“ neurofeedback”和“ predictor / predictors”的组合进行搜索来选择这些研究。作为“ NF培训”，我们定义了至少两个疗程的所有NF应用程序。

神经生理学基线参数存在最佳的可用证据。其中，各个训练的目标参数似乎特别重要。但是，不同实验设计和结果标准的特殊性限制了我们提取的某些信息的可解释性。因此，需要进一步的研究来获得有关NF结局预测因子的更深入的知识。