TOPOGRAPHICAL EEG OSCILLATION PATTERNS DURING COGNITIVE BIAS MODIFICATION TRAINING

Objective: Patients with Major Depressive Disorder (MDD) display attentional negative bias and specific EEG oscillation patterns (alpha asymmetry, increased frontal alpha, and reduced parietal alpha1 and beta2 activities). This study investigates oscillatory changes in a sample of MDD patients and healthy control subjects (HCS) during cognitive bias modification (CBM) training, focusing on positive materials, exploring potential effects of medication, depression severity, age, and gender.
Methods: 240 participants, matched for age and gender (M_Age = 34.7 years, ± 12.2 years; 67.1% female), participated in two clinical assessments and resting-state EEGs with eyes open (114 MDD; 111 HCS) and closed (114 MDD; 113 HCS), administered two weeks apart, utilizing 64 Ag/AgCl ActiCap electrodes. Oscillations were assessed regarding alpha (7-13 Hz), alpha1 (7-9.5 Hz), and beta2 (20-30 Hz) frequency band powers (FBP in µV²). Between measurements, participants underwent ten CBM sessions, consisting of a Dot-Probe Task with positive and neutral images. Participants were randomized to positivity-focused training (PT) or control training (CT).
Results : Analysis revealed a significant interaction between time and training group and age in alpha1 FBP over all areas. Specifically, 32–45-year-olds exhibited a larger reduction in alpha1 FBP over time after PT than CT.
Conclusions: Alpha1 FBP decreased significantly more after PT than CT, albeit only in middle-aged participants. Results suggest positivity-focused CBM training can improve neurophysiological functions among this age group. Depression severity and medication intake seem secondary, indicating potential benefits of CBM across varying levels of depression and a complementary approach to pharmacological treatments.