EEG-fMRI coregistration of absence seizures in patients with juvenile absence epilepsy | [Coregistrazione EEG-fMRI delle crisi di assenza in pazienti con juvenile absence epilepsy]

Simultaneous coregistration of EEG and fMRI (EEG-fMRI) is a new methodology which enables to identify changes in cerebral blood oxygenation level-dependent (BOLD) signal related to specific EEG events. Our objective is to describe BOLD dynamics during absence seizures in patients with Juvenile Absence Epilepsy (JAE). Methods: we studied two patients with JAE, without antiepileptic drug at the time of scanning. Scalp EEG was recorded by means of a 32 channels MRI-compatible EEG recording system. Functional data were acquired with a 3T Philips Achieva system. Event-related analysis was performed on functional data with SPM2 software. Results: seven and 13 absence seizures were recorded in the two patients. BOLD temporal dynamics showed activations in thalamus, medial temporal regions and pre-frontal cortex. Furthermore we observed deactivations in brainstem, caudate nuclei and widespread cortical regions, including precuneus, posterior parietal areas and pre-frontal cortex. Conclusion: We found cortical-subcortical BOLD network mostly overlapping of what previously described in GSWD of IGE. In addition we observed BOLD variations in brainstem and medial temporal regions not previously reported. We speculate that these data could be in relation to occurrence of absence seizures rather than GSWD and/or to the presence of complex absences with post-ictal oral automatisms.