#7208 Changes in heart-brain integration precede psychogenic pseudosyncope

<h3></h3> Psychogenic pseudosyncope (PPS) is a condition characterized by transient subjective loss of consciousness that mimics syncope, but without the associated drop in blood pressure. Recent work from our group has explored changes in heart-brain integration in the context of functional seizures using the heartbeat-evoked potential. The present study aimed to explore this in the context of PPS. PPS is routinely diagnosed based on history and examination but can be confirmed with simultaneous ECG and electroencephalography (EEG) recordings during a tilt-table test. We used EEG and ECG data recorded from patients with PPS during a tilt-table investigation. There is currently no positive EEG marker of these events. Previous work from our group has shown changes in the heartbeat-evoked potential (HEP, which can be considered a measure of heart-brain integration) precede functional seizures. The present study examined this in the PPS group. In both the global HEP and at C4 (right frontocentral region) we identified a significant decrement from baseline after the tilt-table procedure begins. This is a comparable distribution to that identified in our previous work with patients with functional seizures. This may represent a change in interoception during these events. Interoception can be defined as the moment-by-moment mapping of bodily signals at conscious and preconscious levels. Considering these changes alongside the semiological similarities and differences with functional seizures may help us understand the pathophysiology of paroxysmal functional neurological disorders. Furthermore, identifying interoception as a process involved in the pathophysiology of these conditions potentially identifies novel therapeutic and diagnostic methods.