The learning effects and curves during high beta down-training neurofeedback for patients with major depressive disorder.

BACKGROUND:Electroencephalography (EEG) has revealed increased beta activity in patients with comorbid major depressive disorder (MDD) and anxiety symptoms. Negative emotions and high beta activity could be decreased by a high beta down-training neurofeedback (NFB) protocol. The present study utilized three objective parameters - trainability, independence, and interpretability - to validate the effects of high beta down-training sessions. METHODS:EEG data were collected from 23 patients with comorbid MDD and anxiety symptoms during high beta down-training sessions. Participants received five weeks of training, two sessions per week, to down-train high beta amplitude (20-32 Hz) at EEG sites P3 and P4. Three efficacy parameters were examined by comparing pre-training and post-training EEG. RESULTS:The trainability index revealed the learning curves of reduced high beta activity at P3 and P4, confirming training effects across and within sessions. The independence index revealed only beta band activity decreased. The interpretability index revealed the decreased high beta activity was positively correlated with decreased severity of depression, especially for cognitive depression. LIMITATIONS:With only ten sessions in this study, it is unknown whether the NFB training caused extended and stable learning effects. Additionally, combining high beta down-training protocol with enhancing another target band could better ensure the desired changes in brain activity. Finally, the effect of medication on EEG cannot be excluded in present study. CONCLUSIONS:The trainability, independence and interpretability of the high beta down-training NFB protocol were confirmed, supporting the protocol's use in future research and clinical applications.