Facial Emotion Recognition Deficits and EEG Alterations in Mild Behavioral Impairment

Background: Mild Behavioral Impairment (MBI) is a late-life neurobehavioral syndrome associated with increased risk of incident cognitive decline and dementia. Facial emotion recognition (FER), a core component of social cognition, is impaired across neurodegenerative disorders, yet its association with MBI remains underexplored. We examined cognitive/socio-emotional profiles and resting-state electroencephalogram (EEG) in individuals with MBI. Methods: A total of 120 older adults with subjective cognitive decline (SCD) or mild cognitive impairment (MCI) were classified into MBI (n = 57) and non-MBI (n = 63) using the MBI-Checklist. Participants underwent comprehensive clinical and neuropsychological evaluation and neuropsychological assessments including Mini-Mental State Examination (MMSE), and the Korean Facial Affect Battery (K-FAB subtests 1–5). Resting-state EEG was analyzed using an automated platform to derive sensor-level spectral power and source-level connectivity measures. Group comparisons used appropriate tests; K-FAB analyses were adjusted for age, education, MMSE, and Geriatric Depression Scale (GDS). Results: The MBI group showed greater functional impairment (higher CDR-SOB, p = 0.019) and higher depressive symptom severity (GDS, p = 0.004), with a trend toward fewer years of education (p = 0.090). Neuropsychological domain scores were broadly comparable, although the MBI group showed a trend toward lower frontal executive composite performance after covariate adjustment (p = 0.076). On K-FAB, the MBI group demonstrated significantly poorer affect selection performance (FAB4; adjusted p = 0.031), with additional trend-level differences in affect naming (FAB3; adjusted p = 0.084) and in negative emotion recognition (fear and sadness). Resting-state EEG findings indicated elevated Beta1–3 and Gamma absolute power in the MBI group across multiple scalp regions (p < 0.05), as well as frequency-specific source connectivity differences, including widespread Delta-band hyperconnectivity, relatively stronger Alpha1 connectivity in the non-MBI group, and increased Beta1 connectivity within fronto-parietal and fronto-temporal circuits in the MBI group. Conclusion: In this clinic-based SCD/MCI cohort, MBI was associated with greater functional impairment and depressive symptom burden, selective FER deficits—particularly in affect selection—and distinct resting-state EEG spectral and connectivity patterns. These findings suggest that socio-emotional measures and EEG markers may provide complementary information for characterizing neurobehavioral alterations associated with MBI, although interpretations should remain cautious given the cross-sectional design and methodological constraints of automated EEG analyses.