Abstracts

Rationale: 'Musicogenic epilepsy' is a rare reflex epilepsy syndrome. Seizures elicited by musical stimuli have been shown to involve temporal lobe structures. Only a few cases have been investigated using functional imaging, in which activity in frontal areas seemed to precede seizure onset in temporal regions. We used multimodal imaging with simultaneous high-density EEG- (hd-EEG) and MEG as well as parallel hd-EEG-fMRI to investigate seizure onset and propagation in high temporal and spatial resolution in a case with musicogenic epilepsy.Methods: We examined a 22 year old patient with musicogenic seizures in the form of d j vu aurae triggered by rap music using EEG-fMRI and simultaneous 256 channel hd-EEG-MEG. We were able to record 1 seizure during EEG-fMRI and 4 aurae during hd-EEG-MEG.Results: SPM-analysis of EEG-fMRI data revealed activations in left medial frontal gyrus, right mesio-temporal region, left middle temporal gyrus, right pre-/postcentral gyrus and left anterior cerebellar lobe during the seizure as compared to listening to epileptogenic music before seizure onset (p<0.001, uncorrected). Source analysis of hd-EEG data using BESA Research 5.3.7 and a distributed source model (CLARA algorithm = iterative LORETA analysis) showed sources in the left medial frontal, right mesio-temporal and bilateral cerebellar regions at seizure onset (onset of initial spike). During further propagation (maximum negativity of initial spike) the frontal source disappeared and a source in the left mesio-temporal region evolved. Analysis of seizure onset in MEG data revealed multiple sources in bilateral medial frontal, right mesio-temporal, left insular, parietal and bioccipital areas, with the parietal and bioccipital sources disappearing during propagation. Analysis of power spectra revealed peaks at 3 Hz in the right temporal region at seizure onset. Throughout the whole seizure a peak at 1.9 Hz was visible in the right temporal region corresponding to the visually identified seizure pattern.Conclusions: Consistent across all modalities we detected foci in the left medial frontal and right mesio-temporal region at seizure onset with the frontal focus disappearing during propagation. This supports the hypothesis of activity in deep medial frontal areas, for which scalp EEG is often blind, playing a decisive role or even triggering the activation in temporal regions visible as seizure pattern in scalp EEG (M rocz IA, Karni A, Haut S, Lantos G, Liu G (2003). fMRI of triggerable aurae in musicogenic epilepsy. Neurology; 60:705-9). The cerebellar activity seen in both fMRI and hd-EEG is probably due to the rhythmic nature of the epileptogenic rap music, as it has been shown that the cerebellum is one of the core structures for the analysis of rhythm and metre. Our results show good concordance of all three functional imaging methods. Taking advantage of their complementary nature, we were able to precisely determine onset and propagation of epileptic activity and found evidence for the hypothesis that frontal lobe activity precedes seizure activity in the right mesio-temporal region.