Reproducible localization of interictal epileptiform discharges using EEG-triggered fMRI

We report preliminary experiences using fMRI triggered by EEG to localize t he site of interictal epileptiform activity. EEG was recorded in the scanne r and monitored on-line; the recording quality was good enough to allow the clear identification of spikes in the EEG. Snap-shot EPI was performed 2-4 s after an epileptiform discharge ('spike') or after at least 10 s of back ground activity ('rest') was observed. A pixel-by-pixel t-test was performe d between the 'rest' and the 'spike' images to determine areas of significa nt activation. Significant activation was obtained in a patient with epilep sy. To assess the reliability and reproducibility of the technique, the pat ient was scanned on four separate occasions with similar areas being activa ted in all the studies, confirming the validity of the result.