Insights into Postictal Psychosis, from functional imaging and EEG: A systematic review

Multiple hypotheses exist about the pathophysiology of Postictal Psychosis (PIP). As the clinical manifestations of PIP are roughly stereotyped, we assumed the existence of a common neurological pathway. This study aimed to determine if a specific brain network sustained the psychotic episode, regardless of the localization of the epileptogenic zone. We conducted a systematic review following the PRISMA guidelines. We included a total of 24 studies providing electrophysiological results(n=22) and metabolic imaging performed during the PIP(n=5). Temporal and frontal lobes seemed frequently involved, without clear evidence for lateralization. The EEG patterns were heterogenous, varying from unchanged to diffuse slowing. Metabolic pattern showed an increased perfusion within temporal and frontal lobes during PIP. These results correspond to the patterns described during postictal state, but they persisted throughout PIP, within regions larger than the epileptogenic zone and resolved with the recovery. PIP symptoms are associated with an excessive persistence of postictal changes within extended frontotemporal networks. A hypothesis could be that PIP results from an abnormally prolonged and diffuse post-ictal dysregulation.