Associations between peripheral cytokines, perceived fatigue and event-related potentials during a sustained attention task in depressive episodes: a case-control study

Abstract

This case-control study investigated the associations between peripheral inflammation, perceived fatigue, and event-related potentials (ERP) during a sustained attention test (SAT) in depression. Participants included 25 individuals with depressive episodes (DE) and 31 healthy controls (HC). A 15-minute SAT (subtest of the Test Battery for Attention, version 2.3.1) was administered with concurrent EEG recordings. Peripheral inflammation was assessed by measuring IL-6, IL-1β, and TNF-α cytokines. Linear mixed models and generalized linear models were utilized for data analysis. Our results showed that the DE group exhibited lower P300 amplitudes than HC (estimate = -0.98, CI95 [-1.60; -0.35], p = 0.004). Furthermore, P300 amplitudes were inversely associated with IL-6 (estimate = -1.73, CI95 [-3.27; -0.19], p = 0.03), regardless of group status. Surprisingly, higher perceived fatigue correlated with increased P300 amplitudes, irrespective of group status (estimate = 0.009, CI95 [0.0004; 0.02], p = 0.05). Finally, accuracy, measured as the total number of correct answers in the SAT, correlated negatively with TNF-α (OR = 0.44, CI95 [0.27; 0.70]). However, no significant effects were found for P300 latency or reaction time in the SAT when comparing DE and HC. The study highlights the potential role of peripheral inflammation on sustained attention in cognitive performance. Due to the low interaction effect, fatigue and P300 amplitude results must be interpreted cautiously. Although P300 amplitudes were lower in DE, no significant association was observed between DE and inflammation in ERP and cognitive performance. Further research is required to confirm these findings.