Dimensions of interoception in people with epilepsy and people with functional non- epileptic seizures

<h3>Background</h3> Interoception describes the predictive representation and control of internal bodily states. We compared dimensions of interoception across three groups: functional seizures (FS), epileptic seizures (ES) and healthy controls (HC). We hypothesised that people with ES would display deficits in interoception, given neuroanatomical correlates of interoception are frequently implicated in epilepsy. <h3>Methods</h3> 37 participants with FS, 48 with ES and 34 HC completed measures of (1)interoceptive accuracy – objective performance on a heartbeat tracking task (HTT) and heartbeat discrimination task (HDT); (2)trait interoceptive sensibility – subjective sensitivity to internal sensations and (3)state interoceptive sensibility – subjective trial-by-trial measures of confidence in heartbeat detection. Interoceptive awareness and interoceptive prediction errors were computed. <h3>Results</h3> Both ES and FS groups demonstrated significantly reduced interoceptive accuracy and increased interoceptive sensibility compared to HC. Interoceptive awareness on the HDT differed significantly between ES and FS groups (t=3.214, <i>p</i>=0.005). HDT awareness significantly predicted FS diagnosis (OR=0.009, <i>p</i>=0.009). Both ES and FS groups had higher interoceptive trait prediction errors compared to HC. <h3>Conclusions</h3> Interoceptive deficits in ES could be related to structural effects of epilepsy on interoceptive networks and bottom-up processing of interoceptive information. This has implications for understanding interoception in epilepsy, and how interoceptive awareness differs between ES and FS.