Pain-Related Fear Modulates Attentional Bias for Threat Processing in Chronic Pain: An ERP Study.

Purpose: Pain-related fear (PRF) is increasingly recognized as a clinically relevant psychological factor in chronic pain, yet its role in attentional processing across varying threat levels remains unclear, particularly in functional visceral pain conditions such as epigastric pain syndrome (EPS). Using event-related potentials (ERPs), this study examined how PRF is associated with the attentional processing of emotional faces in patients with EPS. Methods: Twenty-nine patients with EPS were categorized into high- and low-PRF groups based on a composite index derived from validated questionnaires. A three-stimulus oddball paradigm was used to assess neural responses to emotional faces (fearful, sad, and happy). Results: PRF-related group differences emerged selectively for high-threat (fearful) faces. Compared with the low-PRF group, the high-PRF group exhibited reduced P2 amplitudes and attenuated P3 amplitudes specifically for fearful faces, while no group differences were observed for sad or happy faces. The N1 interaction, though significant, did not yield significant pairwise effects, and the N2 showed no PRF-related modulation. Conclusion: These findings provide preliminary evidence that elevated PRF in chronic pain is associated with threat-specific alterations in attentional processing, rather than a generalized hypervigilance or global processing deficit. The selective reduction of perceptual and late-stage resource mobilization for high-threat signals suggests that PRF may disrupt the adaptive allocation of cognitive resources specifically when individuals confront the most salient threat cues. However, given the cross-sectional ERP design and modest sample size, these interpretations should be regarded as preliminary.