Pathological emotionalism following limbic encephalitis: the neural foundations of a novel disorder

Abstract

ObjectiveWe investigated pathological emotionalism in a large cohort of patients that had presented with autoimmune limbic encephalitis(a-LE).Methods38 patients in the post-acute phase of a-LE completed questionnaires probing emotion regula- tion. They all underwent structural/functional MRI post-acutely, along with age- and sex-matched healthy controls. We investigated correlations of questionnaire scores with demographic, clinical, neuropsycho- logical and brain MRI data across patients. We also compared patients with pathological emotionalism and those without, along with healthy controls, on grey matter volume, resting-state functional connec- tivity and activity.ResultsPathological emotionalism was reported by 50% of the patients. It was not associated with depres- sion, impulsiveness, or memory impairment. However, it correlated with abnormalities in specific emotional brain networks: volume reduction in the anterior hippocampus, fusiform gyrus and cerebellum, abnormal hippocampal resting-state functional connectivity with the posteromedial cortex and middle frontal gyrus, and abnormal hemodynamic activity in the fusiform gyrus, inferior parietal lobule, and ventral pons.ConclusionsPathological emotionalism is common following a-LE, is not a manifestation of other neu- ropsychiatric disorders, and reflects abnormalities in networks of emotion regulation including, but not limited to the acute hippocampal focus. This condition provides novel insights into the neural basis of emotion regulation and its dysfunction in disease.christopher.butler@imperial.ac.uk