PMC8636682_01
(A) T2-weighted axial MRI of bilateral posterior band heterotopia (white arrows), (B) T1-weighted coronal MRI, and (C) scalp interictal EEG with left posterior temporal spikes (black arrow).
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F1
We present a 32 year old patient with posterior SBH (Figures 1A,B) and a pathogenic somatic mosaicism duplication variant of the PAFAH1B1 gene (c. 162dupA; p. Interictal scalp EEG showed frequent spike and slow wave complexes in the left posterior temporal region, maximal at the T5 (P7) electrode as shown in Figure 1C. Based on the highly focal and concordant interictal and ictal EEG findings, and frequency of the discrete interictal spikes every 1-5 s (Figure 1C), the clinical epilepsy team concluded that intraoperative electrocorticography was adequate to localize the epileptogenic region.
(A) Typical seizure recorded from chronic intracortical electrodes prior to activating stimulation and (B) The typical shortened seizure with less propagation following optimization of stimulation parameters.
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F2
This clinical improvement was associated with decreased electrographic seizure duration from a mean of 25-18 s (median 23 and 17 s; Wilcoxon two-sample test p-value <0.001) and less propagation, as shown in Figures 2A,B.