Multimodal Psychophysiological Assessment Reveals Gastric but Not Cardiac Interoception Deficits in Disorders of...

Disorders of Gut-Brain Interaction (DGBI) are characterized by persistent digestive symptoms in the absence of objectively detectable abnormalities. Visceral hypersensitivity and interoceptive dysfunction are central features of DGBI, yet the specific interoceptive impairments associated with these conditions remain underexplored. This study aimed to characterize interoceptive processing in patients with DGBI by comparing gastric and cardiac interoceptive accuracy, interoceptive beliefs, and related affective responses with those of healthy controls. Thirty patients with DGBIs and 30 matched healthy controls completed the Water Load Test-II (WLT-II) and the Heartbeat Counting Task (HCT) to assess gastric and cardiac interoception, respectively. Participants completed self-report measures of interoceptive beliefs (MAIA-II), visceral sensitivity (VSI), and somatic symptom burden (SSD-12). Resting electrogastrographic signal (EGG) was also recorded. Results revealed that patients suffering from DGBIs exhibited significantly reduced gastric interoception compared to controls (p < 0.001), despite no differences in cardiac interoception (p = 0.893), supporting a modality-specific impairment. Patients also showed altered drinking behavior during WLT-II, requiring less water to reach satiety but more to reach fullness. Despite interoceptive beliefs not differing between groups, patients reported greater visceral sensitivity and somatic distress. Notably, WLT interoceptive measure in patients correlated positively with the "Trusting" MAIA-II subscale (r = 0.423, p = 0.020), and EGG peak frequency correlated with affective symptom distress (r = 0.496, p = 0.024). These findings suggest that impaired gastric interoception in DGBIs is associated with dysregulated physiological and affective responses, independent of subjective interoceptive beliefs. Our results highlight the importance of using modality-specific interoceptive assessments and suggest the potential for interoceptive training interventions to improve symptom management in DGBI populations.