A clinical and magnetoencephalography study of MRI-negative startle epilepsy

OBJECTIVE: The goal of this study was to investigate clinical findings, ictal semiology, and results of video/electroencephalography (video/EEG), and magnetoencephalography (MEG) in patients with startle epilepsy and normal brain MRI.

METHODS: Four patients (mean age 12.5 years) with startle epilepsy were investigated with MRI, video/EEG, and MEG.

RESULTS: Epilepsy diagnosis was established in childhood, and all had spontaneous and reflex seizures. Reflex seizures were triggered by sudden, unexpected sounds and tactile stimuli. The neurological examinations and MRIs were normal. MEG recordings showed focal epileptiform activity. An ictal MEG was obtained in one patient. Source modeling yielded dipole sources in right central frontal region.

CONCLUSION: The present study demonstrates that the origin of epileptiform activity in startle epilepsy can be localized in brain areas associated with supplementary motor seizures, even in patients with normal brain MRI. MEG adds complementary information to the localization of epileptiform activity and can be useful in planning invasive studies in cases evaluated for epilepsy surgery.