Electroencephalographic evidence of unconscious and conscious attentional bias in people with functional gastrointestinal disorders: A pilot study

Abstract

Debate continues as to whether an attentional bias towards threat displayed by sufferers of functional gastrointestinal disorders (FGIDs) is conscious and, thus, more amenable to change through psychological therapy. We compared the amplitudes of early (unconscious) and later (conscious) electroencephalographic (EEG) event-related potentials following silent reading of symptom-related, emotionally neutral, and emotionally negative nouns across two participant groups: 30 FGID-sufferers who met diagnostic criteria for irritable bowel syndrome or functional dyspepsia, and 30 healthy controls. Analogous indices based on alpha desynchronisation were also examined, as were correlations between the EEG-based indices and a range of psychosocial variables. FGID-sufferers displayed marginally significantly higher occipital EPN amplitudes for all nouns, indicating marginally higher levels of unconscious attention in the task. FGID-sufferers also displayed, for negative as compared to neutral nouns, significantly lower central N400 amplitudes indicative of higher conscious attention. The result was only apparent in post-hoc pairwise comparisons, however. Uniquely among FGID-sufferers, occipital EPN and central N400 were strongly correlated with psychosocial problems. The findings provide preliminary evidence of hypervigilance to general (as opposed to symptom-specific) threat among FGID-sufferers. Amidst concerns over Type I error, recommendations are made for fine-tuning the operationalisation of unconscious and conscious attentional bias in this population.