A Neurophysiological Model based on Resting-State EEG Functional Connectivity Features for Assessing Semantic Long-term Memory Performance

Existing methods for assessing long-term memory (LTM) rely predominantly on
psychometric tests or clinical expert observations. In this study, we propose an
objective method for evaluating semantic LTM ability using resting-state
electroencephalography (EEG) functional connectivity. Data from 68 participants were analysed, deriving functional connectivity from the phase information of EEG theta (4-8Hz), alpha (8-13Hz) and gamma (30-45Hz) frequency bands across the entire scalp at resting state. Participants’ responses were recorded during a memory recall task over four sessions. Multiple linear regression was used to model the LTM score. The proposed method successfully predicted LTM retention after 30 minutes, with performance metrics of F(18,49)=2.216, p=0.014, R=0.670; 2 months retention, F(18,45)=3.057, p<0.001, R=0.742; 4 months retention, F(18,42)=2.237, p=0.016, R=0.700; and 6 months retention, F(18,36)=1.988, p=0.039, R=0.706, respectively. Additionally, this method achieved at least 27 points lower in the Bayesian Information Criterion (BIC) compared to the standard psychometric RAPM test across all retention periods. These findings suggest that the semantic LTM ability of healthy young individuals can be objectively quantified using resting-state EEG functional connectivity. This approach holds promise for future applications in understanding and addressing below standard performance in students learning.