Objectives: We aimed to characterize the effect of electroconvulsive therapy (ECT) on mismatch negativity (MMN), an event-related potential suggested as a biomarker of cortical dysfunction and illness progression in psychosis, and its association with improvement in positive symptoms. Methods: MMN was calculated from electroencephalogram recorded during a passive auditory oddball paradigm before and after ECT in psychosis patients receiving both ECT and medication, at matched intervals in patients receiving medication only, and at baseline in healthy controls (HCs). In patient groups, group-time interaction on MMN amplitudes was analyzed using mixed models for repeated measures. In the ECT group, correlations between MMN amplitude and Positive and Negative Syndrome Scale (PANSS) subscales were assessed. Results: Data from 26 ECT-treated patients, 23 medication-only patients, and 50 HCs were analyzed. At baseline, MMN amplitude and latency differed among groups. A significant group-time interaction indicated differential MMN amplitude change between the ECT group and the medication-only group. In the ECT group, a positive repeated-measure correlation was observed between MMN amplitude and PANSS positive score. Conclusion Our results demonstrate a normalizing effect of ECT on MMN amplitude and its relationship with improvement of positive symptoms. They imply that ECT modulates neurophysiological mechanisms underlying MMN generation.

This report presents a case of fourth ventricle neurenteric cyst (NE cyst) mimicking hemangioblastoma, which developed in a 50-year-old woman. A tiny enhancing mural portion of the fourth ventricle in MRI suggested that the cyst was hemangioblastoma, but pathological evidence showed that the cyst was in fact NE cyst in the fourth ventricle. In order to make proper decision on to what extent of surgical resection should be done, considering every possibility in differential diagnosis might be helpful. This case reports an unusual pathology in 4th ventricle, considering the patient's age, and demonstrates that a rarer disease may share radiological features of a common disease.
Diagnosis, Differential ; Female ; Fourth Ventricle* ; Hemangioblastoma* ; Humans ; Magnetic Resonance Imaging ; Middle Aged ; Neural Tube Defects* ; Pathology