Impaired Gastric and Urinary but Preserved Cardiac Interoception in Women with Endometriosis

Abstract

Endometriosis is a chronic inflammatory gynaecological condition frequently associated with chronic pelvic pain. Visceral hypersensitivity could be present, like in other chronic pain conditions, causing altered levels of interoception. So far, studies have explored interoceptive deficits in chronic pain individuals exclusively using questionnaires or cardiac interoceptive tasks. Here, we explore cardiac, gastric, and urinary domains to probe interoceptive differences between patients with endometriosis and healthy women. 30 patients and 30 controls underwent three interoceptive tasks for assessing cardiac (through Heartbeat Counting Task, HCT), gastric (through Water Load Test-II, WLT-II) domains and bladder (through a novel Urinary Interoceptive Task, UIT) domain, which has been neglected so far. Participants also completed bladder interoceptive sensibility measures and subjective pain ratings for each endometriosis symptom (i.e., dysmenorrhea, dyspareunia, dyschezia, chronic pain). A positive correlation between WLT-II and UIT emerged in all participants (R=0.47, p<0.001), indicating that the lower the gastric interoceptive abilities, the lower the urinary ones. Moreover, compared to healthy controls, women with endometriosis exhibited lower scores in WLT-II (t(58) = 4.6814, p<0.001) and UIT (t(39.931)= 5.1462, p<0.001), as well as higher scores in subjective bladder sensibility questions (t(57.346)= -4.0304, p<0.001). UIT scores were associated with pain symptoms. Results indicate a dissociation between patients’ poor objective performance on interoceptive tasks and their high bladder interoceptive sensibility. UIT scores were associated with pain symptoms, suggesting that patients, probably due to sensitisation, struggle to ignore painful sensations, resulting in reduced accuracy in detecting physiological signals from the pelvic area.