Neurofeedback for post-traumatic stress disorder: systematic review and meta-analysis of clinical and neurophysiological outcomes

Extrahippocampal Contributions to Social Memory: The Role of Septal Nuclei

Social memory, the ability to recognize and remember individuals within a social group, is crucial for social interactions and relationships. Deficits in social memory have been linked to several neuropsychiatric and neurodegenerative disorders. The hippocampus, especially the circuit that links dorsal CA2 and ventral CA1 neurons, is considered a neural substrate for social memory formation. Recent studies have provided compelling evidence of extrahippocampal contributions to social memory. The septal nuclei, including the medial and lateral septum, make up a basal forebrain region that shares bidirectional neuronal connections with the hippocampus and has recently been identified as critical for social memory. The focus of our review is the neural circuit mechanisms that underlie social memory, with a special emphasis on the septum. We also discuss the social memory dysfunction associated with neuropsychiatric and neurodegenerative disorders.

Systematic review and meta-analysis of neurofeedback and its effect on posttraumatic stress disorder

Background

To date, only one systematic review and meta-analysis of randomized controlled trials (RCTs) has evaluated the effect of neurofeedback in PTSD, which included only four studies and found an uncertainty of the effect of EEG-NF on PTSD symptoms. This meta-analysis is an update considering that numerous studies have since been published. Additionally, more recent studies have included fMRI-NF as well as fMRI-guided or -inspired EEG NF.

Methods

Systematic literature searches for RCTs were conducted in three online databases. Additional hand searches of each study identified and of systematic reviews and meta-analyses published were also undertaken. Outcomes evaluated the effect of neurofeedback vs. a control (active, sham, and waiting list) on their effects in reducing PTSD symptoms using various health instruments. Meta-analytical methods used were inverse variance random-effects models measuring both mean and standardized mean differences. Quality and certainty of the evidence were assessed using GRADE. Adverse events were also evaluated.

Results

A total of 17 studies were identified evaluating a total of 628 patients. There were 10 studies used in the meta-analysis. Results from all studies identified favored neurofeedback's effect on reducing PTSD symptoms including BDI pretest-posttest [mean difference (MD): 8.30 (95% CI: 3.09 to 13.52; P = 0.002; I 2 = 0%)]; BDI pretest-follow-up (MD: 8.75 (95% CI: 3.53 to 13.97; P < 0.00001; I 2 = 0%); CAPS-5 pretest-posttest [MD: 7.01 (95% CI: 1.36 to 12.66; P = 0.02; I 2 = 86%)]; CAPS-5 pretest-follow-up (MD: 10 (95% CI: 1.29 to 21.29; P = 0.006; I 2 = 77%); PCL-5 pretest-posttest (MD: 7.14 (95% CI: 3.08 to 11.2; P = 0.0006; I 2 = 0%); PCL-5 pretest-follow-up (MD: 14.95 (95% CI: 7.95 to 21.96; P < 0.0001; I 2 = 0%). Other studies reported improvements using various other instruments. GRADE assessments of CAPS, PCL, and BDI demonstrated a moderate/high level in the quality of the evidence that NF has a positive clinical effect.

Conclusion

Based on newer published studies and the outcomes measured, NF has demonstrated a clinically meaningful effect size, with an increased effect size at follow-up. This clinically meaningful effect appears to be driven by newer fMRI-guided NF and deeper brain derivates of it.

Increasing Value and Reducing Waste of Research on Neurofeedback Effects in Post-traumatic Stress Disorder: A State-of-the-Art-Review

Post-Traumatic Stress Disorder (PTSD) is often considered challenging to treat due to factors that contribute to its complexity. In the last decade, more attention has been paid to non-pharmacological or non-psychological therapies for PTSD, including neurofeedback (NFB). NFB is a promising non-invasive technique targeting specific brainwave patterns associated with psychiatric symptomatology. By learning to regulate brain activity in a closed-loop paradigm, individuals can improve their functionality while reducing symptom severity. However, owing to its lax regulation and heterogeneous legal status across different countries, the degree to which it has scientific support as a psychiatric treatment remains controversial. In this state-of-the-art review, we searched PubMed, Cochrane Central, Web of Science, Scopus, and MEDLINE and identified meta-analyses and systematic reviews exploring the efficacy of NFB for PTSD. We included seven systematic reviews, out of which three included meta-analyses (32 studies and 669 participants) that targeted NFB as an intervention while addressing a single condition-PTSD. We used the MeaSurement Tool to Assess systematic Reviews (AMSTAR) 2 and the criteria described by Cristea and Naudet (Behav Res Therapy 123:103479, 2019, https://doi.org/10.1016/j.brat.2019.103479 ) to identify sources of research waste and increasing value in biomedical research. The seven assessed reviews had an overall extremely poor quality score (5 critically low, one low, one moderate, and none high) and multiple sources of waste while opening opportunities for increasing value in the NFB literature. Our research shows that it remains unclear whether NFB training is significantly beneficial in treating PTSD. The quality of the investigated literature is low and maintains a persistent uncertainty over numerous points, which are highly important for deciding whether an intervention has clinical efficacy. Just as importantly, none of the reviews we appraised explored the statistical power, referred to open data of the included studies, or adjusted their pooled effect sizes for publication bias and risk of bias. Based on the obtained results, we identified some recurrent sources of waste (such as a lack of research decisions based on sound questions or using an appropriate methodology in a fully transparent, unbiased, and useable manner) and proposed some directions for increasing value (homogeneity and consensus) in designing and reporting research on NFB interventions in PTSD.