PMC6403409_01
MRI showing bilateral symmetric periventricular nodular heterotopia and bilateral hippocampal atrophy more pronounced on the left. In A) T2-weighted and B) T1-weighted images of the nodules that are isointense to cortical gray matter, adjacent enlarged perivascular spaces showing a T2-hyperintense cystic appearance. C) Coronal orientated T2-weighted images revealing hippocampal atrophy and disruption of the internal hippocampal structure on both sides. D) FLAIR-images supplementing these findings with hyperintense signals present in both hippocampi.
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The MRI showed bilateral symmetric periventricular nodular heterotopia (PVNH) and bilateral hippocampal atrophy more pronounced on the left (Fig. 1).
A) Interictal EEG showing repetitive sharp waves, maximum left frontal (F3). B) Ictal EEG during the onset of a generalized tonic-clonic seizure showing low amplitude fast activity over both central regions.
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The interictal EEG showed sharp waves over the left hemisphere, most frequently with a maximum over F3 and rarely with a bifrontal distribution (Fig. 2A). We recorded two right versive seizures evolving into bilateral tonic-clonic seizures associated with severe cyanosis and postictal apnoea as well as three subclinical seizures which were associated with a left frontal ictal onset zone (maximum Fz/F3, Fig. 2B).