Frontal Power Spectrum Density in Emotional Video Viewing: Associations with Depression in Healthy Elderly and Mild Cognitive Impairment.

In neurodegenerative conditions, such as Mild cognitive impairment (MCI), emotional processing is often impaired, but analogous impairments are linked to depressive symptoms, which are particularly relevant in the elderly and could represent an independent risk factor for development of dementia. This study examined frontal Power Spectral Density (PSD) in alpha, beta, and theta frequency bands in MCI and healthy participants (HP) at rest and during emotional video-viewing (positive vs negative, as compared to neutral). Moreover, the relationships between PSD and depressive symptoms were also assessed separately within each group. The results revealed significant group differences in PSD across resting-state and video-viewing conditions. MCI patients exhibited higher beta power compared to HP, above all in Right hemisphere. HP, but not MCI patients, showed significant hemispheric asymmetries (Left > Right). Notably, EEG power, specifically in theta band and particularly during emotional processing, positively correlated with depressive symptomatology in HP and MCI groups. These findings suggest a relationship between PSD and depressive symptoms in healthy ageing and neurodegenerative conditions. They also support the study of EEG biomarkers for early identification and monitoring of treatment of late-life depression and cognitive decline.