Exploring cardiac, gastric and urinary interoception in women with Endometriosis

Endometriosis is a condition characterised by chronic pelvic pain and visceral hypersensitivity which, like other chronic pain conditions, may lead to altered levels of interoception. The main aim of the present study is to probe interoceptive differences between patients with endometriosis (EP) and healthy women (HC). 30 EP (age: 32.93 ± 6.58) and 30 HC (age: 31.6 ± 6.88) underwent three interoceptive tasks: the Heartbeat Counting Task (HCT) to assess the cardiac domain, the Water Load Test-II (WLT-II) to assess the gastric domain, and a novel Urinary Interoceptive Task (UIT) for the bladder domain. Participants also completed measures of interoceptive bladder sensibility and subjective ratings of pain for each endometriosis symptom (i.e., dysmenorrhea, dyspareunia, dyschezia, chronic pain). Results showed a positive correlation between the WLT-II and the UIT in all participants (R=0.47, p<0.001), indicating that the higher the gastric interoceptive alteration, the higher the urinary one. 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), but higher scores in subjective bladder sensibility questions (t(57.346)= -4.0304, p < 0.001), suggesting a dissociation between EP’s poor objective performance on interoceptive tasks and their high subjective belief to focus on physiological signals. UIT scores were associated with pain symptoms (Estimate: -0.00440 (SE = 0.00228, Z= -1.93, p = 0.054), suggesting that patients, probably due to habituation to chronic pain, struggle to ignore discomfort sensations, resulting in reduced accuracy in detecting physiological signals coming from the pelvic area.