Interictal SPECT in patients with mesial temporal lobe epilepsy and psychosis: a case-control study

Psychosis is commonly observed in patients with mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS). Interictal single photon emission computed tomography (SPECT) was performed to compare regional cerebral blood flow (rCBF) pattern of MTLE-HS patients with psychosis of epilepsy (POE) comorbidity and MTLE-HS patients without any psychiatric disorders (Control group). For this, 21 patients with POE and 23 Control patients were matched by educational level, clinical, demographic, electrophysiological, and MRI data. SPECT scans were acquired using (99m)Tc and interpreted with a semiquantitative method. We analyzed brain regions of interest (ROI) of frontal, temporal, and parietal cortex, in addition to subcortical structures. There were no significant statistical differences of ROI between the POE group and the Control group after Bonferroni adjustment. However, we observed a trend for rCBF increase of right posterior cingulate in the POE Group. This increase would be in accordance with recent findings of cingulate abnormalities in schizophrenia, suggesting that abnormal function in this region might be associated with the psychotic phenomena.