Reality Is in the Posterior Hippocampus: Who Knew?

Research output: Contribution to journalArticlepeer-review

Abstract

Bilateral Volume Reduction in Posterior Hippocampus in Psychosis of Epilepsy Allebone J, Kanaan R, Maller J, et al. J Neurol Neurosurg Psychiatry. 2019. pii: jnnp-2018-319396. doi:10.1136/jnnp-2018-319396. [Epub ahead of print]. PMID: 30796132. Objective: Psychosis of epilepsy (POE) occurs more frequently in temporal lobe epilepsy, raising the question as to whether abnormalities of the hippocampus are etiologically important. Despite decades of investigation, it is unclear whether hippocampal volume is reduced in POE, perhaps due to small sample sizes and methodological limitations of past research. Methods: In this study, we examined the volume of the total hippocampus, and the hippocampal head, body, and tail, in a large cohort of patients with POE and patients with epilepsy without psychosis (EC). One hundred adults participated: 50 with POE and 50 EC. Total and subregional hippocampal volumes were manually traced and compared between (1) POE and EC; (2) POE with temporal lobe epilepsy, extratemporal lobe epilepsy, and generalized epilepsy; and (3) patients with POE with postictal psychosis (PIP) and interictal psychosis (IP). Results: Compared to EC, the POE group had smaller total left hippocampus volume (13.5% decrease, P <.001), and smaller left hippocampal body (13.3% decrease, P =.002), and left (41.5% decrease, P <.001) and right (36.4% decrease, P <.001) hippocampal tail volumes. Hippocampal head volumes did not differ between groups. Conclusion: Posterior hippocampal volumes are bilaterally reduced in POE. Volume loss was observed on a posteroanterior gradient, with severe decreases in the tail and moderate volume decreases in the body, with no difference in the hippocampal head. Posterior hippocampal atrophy is evident to a similar degree in PIP and IP. Our findings converge with those reported for the paradigmatic psychotic disorder and schizophrenia and suggest that posterior hippocampal atrophy may serve as a biomarker of the risk for psychosis, including in patients with epilepsy.

Original languageEnglish (US)
Pages (from-to)305-306
Number of pages2
JournalEpilepsy Currents
Volume19
Issue number5
DOIs
StatePublished - Sep 1 2019

ASJC Scopus subject areas

  • Clinical Neurology

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