Figure 4

Scalp HFO rates of skull defect channels and their contralateral channels in presurgical and postsurgical EEG recordings. The patients for whom postsurgical seizure freedom was achieved (Engel I) are indicated by blue (full) circles, while patients with postsurgical seizure recurrence (Engel II–IV) are indicated by white (empty) circles. Of the 11 patients with skull defect channels, seven achieved postsurgical seizure freedom and four had postsurgical seizure recurrence. (a) Mean scalp HFO rates of skull defect channels within the HFO area significantly decreased (Wilcoxon signed-rank: p = 0.043, z = 2.023) from the presurgical (median 0.280 HFO/min, iqr 0.491) to the postsurgical EEG (median of 0.000 HFO/min, iqr 0.025) in the five patients for whom postsurgical seizure freedom was achieved. (b) Mean scalp HFO rates of skull defect channels outside the HFO area did not differ significantly (Wilcoxon signed-rank: p = 0.091, z = 1.690) between the presurgical (median 0.042 HFO/min, iqr 0.118) and postsurgical EEG (median 0.000 HFO/min, iqr 0.005) in the seven patients for whom postsurgical seizure freedom was achieved. (c) Mean HFO rates of skull defect channels outside the HFO area (median 0.003 HFO/min, iqr 0.063) did not differ significantly (Wilcoxon signed-rank: p = 0.726, z = 0.350) from their contralateral channels (median 0.003 HFO/min, iqr 0.011) in the postsurgical EEG of all patients, regardless of postsurgical seizure outcome.