Quantitative EEG Analysis Based on PSD and eLORETA-Source Localization Approach in Spatial Auditory Process

The advancement of spatial audio technology has been driven by the human capacity for spatial auditory, enabling immersive auditory experiences that replicate real-life sound environments. Understanding how the brain encodes spatial auditory processes has emerged as a growing area of research. Electroencephalography (EEG), a non-invasive modality with high temporal resolution, offers an ideal means to study brain responses to moving sound stimuli. This study aims to compare quantitative EEG methods derived from direct EEG recordings, focusing on EEG temporal features such as Power Spectral Density (PSD), as well as EEG source localization using eLORETA. Two types of audio stimuli, stereo audio and spatial audio, delivered through headsets attached directly to both ears, were investigated. When exposed to the spatial audio stimulus, there was a notable increase in the mean PSD within the Theta, Alpha, and Beta frequency bands in the auditory cortex (channel T3, T4, T5, and T6). The most significant increase was observed in the Beta frequency band of 145.601 µV
²
/Hz in T4, indicating heightened focus experienced by the subjects compared to the stereo audio stimulus. Furthermore, EEG source localization using eLORETA revealed distinct activation in the frontal area during the second experiment involving the spatial audio stimulus. Specifically, there was a significant increase (p>0.05) in current density within the frontal regions of the brain, including Brodmann Area (BA) 6 and 9, which are associated with selective attention and spatial orientation. These findings highlight the practicality of the employed methods and their potential to shed light on brain activity during spatial auditory processes.