High alpha oscillations in portable prefrontal EEG indicate gender-sensitive biomarkers for emotional disorders.

Major depressive disorder (MDD) is a prevalent mental health condition associated with substantial emotional and functional impairment. While interest in neurophysiological markers is growing, gender-specific neural oscillatory patterns measured by portable electroencephalogram (EEG) devices remain underexplored. This study examined whether relative spectral power in the high alpha band (11-13 Hz), recorded by a three-channel prefrontal EEG device during eyes-closed resting state, is associated with emotional states and clinical diagnosis, with attention to gender differences. Forty participants from the MODMA dataset were included, comprising 18 patients with MDD (8 females, 10 males; mean age = 30.39 ± 10.91 years) and 22 healthy controls (8 females, 14 males; mean age = 30.86 ± 9.40 years). All participants completed EEG recordings using both a 128-channel laboratory system and a portable three-channel device (Fp1, Fpz, Fp2). Emotional status was assessed using the Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), and Childhood Trauma Questionnaire-Short Form (CTQ-SF). Pearson correlations between relative spectral power and emotional scale scores were computed separately for males and females, with false discovery rate (FDR) correction applied to multiple comparisons. Spectral features from the portable EEG closely matched those of the lab system (r = 0.975). High alpha power was positively correlated with PHQ-9 and GAD-7 scores, with stronger and more extended correlations observed in females, sometimes reaching into the low beta range. After FDR correction, significant correlations were observed primarily at 11-14 Hz. At 11.9 Hz, PHQ-9 correlations were significant for both males (r = 0.40, p = 0.011) and females (r = 0.33, p = 0.037). High alpha power also distinguished MDD from controls (r = 0.32, p = 0.042), independent of age and education. Frontal high alpha activity measured by a portable EEG device is a promising neural marker of emotional dysregulation, with stronger and broader associations observed in females. These findings support gender-sensitive EEG-based screening approaches for mood disorders in community and clinical settings.