f-MRI in Epilepsy with Spike and Wave Activity Evoked by Eye Closure: Different Bold Activation in a Patient with Idiopathic Partial Epilepsy with Occipital Spikes and a Control Group

Abstract

We performed functional magnetic resonance imaging (fMRI) in a 30-year-old man with idiopathic partial epilepsy with occipital spikes whose scalp EEG activity was characterized by persistent epileptiform discharges on eye closure, ceasing upon eye opening. We compared BOLD activation in the patient and in a control group of three normal volunteers. f-MRI showed that occipital cortex and frontal areas were activated in relation to eye movement in normal subjects during eye opening but not during eye closing. While persistent interictal spike and wave activity was present over the posterior and anterior scalp in the patient upon eye closing, f-MRI showed bilateral activation of the parietal and temporal regions. This fMRI study documents the activation of posterior and temporal areas related to continuous intercritical spikes evoked by eye closure, which are diffuse over the scalp. This activation was absent in the control group during eye closure.

Reproducibility of EEG–fMRI Results in a Patient With Fixation-Off Sensitivity

“…EEG–fMRI activations indicated a BOLD signal decrease related to epileptiform activity in the parietal areas. Our results partially agree with previous fMRI studies, 3,5-7 which reported activation in the parieto-occipital areas, whereas our analysis, based on the construction of an EEG regressor representing the epileptic activity of the patient, produced a reproducible deactivation in the same areas. Control experiments conducted in two subjects under the same blocked design protocol and using EEG-regressor analysis 18 showed significant deactivation in the visual cortex (Brodmann area 18), similar to Bittar et al, 9 in which only a negative activation was observed in the occipital cortex.…”

“…Neuroimaging studies have sought to glean more precise information on the cerebral areas generating epileptiform discharges in such patients. 3-7 Iannetti et al 5 described activations in the extrastriate cortex (Brodmann areas 19 and 37) in three patients. When they repeated the EEG–fMRI study using the same experimental setting and paradigm in the same patients 3 years later, the fMRI data showed a main activation cluster in the temporo-occipital regions (bilateral in one patient and monolateral in another), but no changes in the remaining third patient in which the FOS phenomenon had disappeared.…”

Cognitive tasks as provocation methods in routine EEG: a multicentre field study

“…observed when just recording the resting period with eyes open. Extended, mostly inhibitory brain responses to eye opening have already been described both in EEG and connectivity studies [26][27][28][29], favouring the hypothesis of a major role of attention.…”

Neuroimaging of Epilepsy: EEG-fMRI in the Presurgical Evaluation of Focal Epilepsy

“…In up to 20-30% of such patients, who are candidates for surgical treatment, the MRI exam is negative (Duncan, 1997) because microscopic structural malformations, identifiable only by histological study, are not detectable with conventional MRI (Kuzniecky, 1991). Using [11C]flumazenil positron-emission tomography ([11C]FMZ-PET), Hammers studied 18 patients with TLE and normal MRI: 16 demonstrated abnormalities in the binding of 11 C-FMZ in the temporal lobe; 7 of these were concordant with clinical and standard EEG data; 3 patients underwent surgical treatment of the anterior temporal lobe, with marked clinical improvement. The neuropathological data revealed microdysgenesis not detected by MRI (Hammers, 2002).…”