PMC7286251_01
First EEG findings. 20 s of 19-channel EEG, referenced to bipolar (upper window) and average (lower window) reference, showing intermittent 4 Hz activity in the bilateral parasagittal region (as shown). Background posterior activity at 8 Hz is unstable but symmetric. Black lines: recordings from the right hemisphere. Blue lines: recordings from the left hemisphere. Green lines: midlines traces. Distance between orange vertical bars: 1 s. Patient was awake during this period of recording (exploring the space, not speaking, not answering to simple verbal orders). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
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A first routine video-EEG on day 18 was performed, which revealed an intermittent onset of 4 Hz rhythms over the bilateral parasagittal regions (Fig. 1), lasting from 5 s to maximum 25 s.
EEG findings at day 19 (second EEG): 20 s per page, 19-channel EEG referenced to bipolar (upper window) and average (lower window) reference, showing intermittent, 4 Hz theta activity in the central-frontal region here with right more than left predominance. Background activity showing symmetric synchronous 10 Hz. Black lines: recordings from the right hemisphere. Blue lines: recordings from the left hemisphere. Green lines: midlines traces. Distance between orange vertical bars: 1 s. Electrical bridge artifact between Cz-Pz. Patient was awake during this period of recording but unresponsive (eyes open, exploring the space, not speaking, not following simple verbal orders). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
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It showed the same pattern with preserved background rhythms, suggesting focal injury in the absence of encephalopathy (Fig. 2).
MRI findings. Upper row: Transverse SWI/T*showing diffuse microbleeds in bilateral juxtacortical white matter, corpus callosum, and internal capsule. Lower row from left to right: Diffusion weighted imaging, T2-weighted and T1-weighted, not showing any parenchymal lesion. 3D angiogram reconstruction not showing any focal stenosis of the extracranial and intracranial vessels. Right hemisphere is on the left side of the image.
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Cervical and cerebral-MRI angiography was normal with no sign of stenosis or vasculitis (Fig. 3).