PMC9987853_01
Structural and functional brain imaging in Case 1. Interictal cerebral MRI scan:axial (A) and coronal (B) sections:showing right amygdala and hippocampus FLAIR hyperintensities. Interictal functional imaging using 18FDG-PET:axial (C) and coronal (D) sections:showing extensive right temporal lobe hypometabolism: the temporal pole, mesial and basal areas, and superior temporal and Heschl gyri.
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T2-weighted/FLAIR hyperintensities. The interictal cerebral FDG-PET scan revealed extensive right temporal lobe hypometabolism: temporal pole, mesial and basal areas, and superior temporal and Heschl gyri (Figure 1). To better characterize the electrical seizure onset and the early propagation network, we performed independent component analysis (ICA) of scalp EEG signals (Figure 2A) using the infomax algorithm as implemented in EEGLAB.
EEG data displaying rhythmic ictal discharge over the right temporal leads spreading toward the suprasylvian and contralateral regions after the clinical onset (A); independent component analysis identified a theta discharge represented in the time domain (B) and frequency domain (C); the dipole was represented in the right temporal region of the patient's cerebral MRI (3D view) (D); and cortical surface reconstruction:coronal (E) and sagittal (F) sections.
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T2-weighted/FLAIR hyperintensities. The interictal cerebral FDG-PET scan revealed extensive right temporal lobe hypometabolism: temporal pole, mesial and basal areas, and superior temporal and Heschl gyri (Figure 1). To better characterize the electrical seizure onset and the early propagation network, we performed independent component analysis (ICA) of scalp EEG signals (Figure 2A) using the infomax algorithm as implemented in EEGLAB. One independent component (IC) was visually selected by an expert epileptologist based on the IC activation pattern (Figure 2B) and its time-frequency decomposition (Figure 2C). Afterward, an equivalent current dipole (ECD) model was fitted to the component (Figures 2D-F). In this case, the dipole was located in the right anterior temporal basal region (Figures 2D-F).
PMC9987853_02
Structural brain imaging in Case 2. Interictal cerebral MRI scan:coronal sections:showing the enlargement of the left amygdala (A) and hippocampus (B) on T1-inversion recovery pulse sequence, as well as FLAIR hyperintensities in the same regions [(C) amygdala; (D) hippocampus].
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The interictal brain MRI scan revealed an increase in the volume of the left amygdala and the hippocampus and FLAIR hyperintensities in the same regions (Figure 3).
EEG data displaying rhythmic ictal discharge over the left temporal leads spreading toward the suprasylvian and contralateral regions after the clinical onset (A); independent component analysis identified a theta discharge represented in the time domain (B) and the frequency domain (C); the dipole was localized in the left temporal neocortical region of patient's cerebral MRI (3D view) (D); and cortical surface reconstruction:coronal (E) and sagittal (F) sections.
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Electrically, the seizures started in the left frontal-temporal leads with theta discharge over the temporoparietal region at the clinical onset (Figure 4A). The independent component analysis as described in the case before [with the exception that the SOBI algorithm worked better than infomax for this patient] highlighted one component encoding a sustained ictal theta discharge (Figures 4B, C), with dipoles localized in the left superior temporal gyrus (Figures 4D-F).