fMRI and electroencephalographic evaluation of sleep deprivation in epilepsy patients: An observational study

Background: Sleep deprivation (SD) is considered an important activation test to facilitate the visualization of electroencephalogram (EEG) epileptic abnormalities, in order to perform a correct diagnosis. Objective: The aim of this study was to evaluate the local functional activity in healthy controls (HC) subjects and left mesial temporal lobe epilepsy-hippocampal sclerosis patients, after a SD, by using functional Magnetic Resonance Imaging (fMRI) and EEG. Materials and methods: We enrolled 22 healthy controls and 34 patients with a diagnosis of left mesial temporal lobe epilepsy-hippocampal sclerosis. Each participant underwent two examinations separately: an fMRI study using 3 T MRI to detect spontaneous activity during the RS-fMRI and an EEG. Results: The SD-EEG results showed the presence of epileptiform discharges predominantly in left fronto-centro-temporal areas. fMRI findings if compared to HC showed an increase of functional activity in some areas. Discussion: We showed that SD-EEG study confirmed a high specificity to assess a specific diagnosis. Therefore, the decrease of activity observed in DMN could be explain by a different amount of sleep/awake time during fMRI recording in the two groups or the interictal activity during fMRI acquisition. Our study highlighted alterated functional activity in SD cortical areas of epileptic patients if compared to HC.