Open Access

S. A. Groppa, V. Chiosa, D. Ciolac, Muthuraman Muthuraman, N. Koirala, A. Vataman, Y. Winter, M. Moldovanu, G. Gonzales-Escamilla, S. Groppa

• Purpose: Investigating the daytime‐related patterns of sei-zure presentation might provide important insights into theinvolved epileptogenic networks. However, the alterationsof brain structural integrity linked to different profiles ofseizure occurrence are still not clear. In this study weaddressed the structural magnetic resonance imaging(MRI)‐derived features of the involved cortical and subcor-tical substrates. Method: In 13 patients (mean age ± standard deviation:28±9 years; 9 male) with nocturnal seizures (NS), 12patients (26±9; 3 male) with diurnal seizures (DS) and 10healthy controls (HC) (28±4; 6 male) 3D 3T MRI was per-formed. Cortical and subcortical volumes (hippocampus,amygdala, thalamus) were extracted with the FreeSurferprocessing stream and the between‐group differencesassessed with analysis of variance (ANOVA) and Bonfer-roni post hoc tests. There was no difference between thegroups regarding age (F2,32= 0.26, p = 0.77) and gender(χ†= 5.103, df = 2, p =Purpose: Investigating the daytime‐related patterns of sei-zure presentation might provide important insights into theinvolved epileptogenic networks. However, the alterationsof brain structural integrity linked to different profiles ofseizure occurrence are still not clear. In this study weaddressed the structural magnetic resonance imaging(MRI)‐derived features of the involved cortical and subcor-tical substrates. Method: In 13 patients (mean age ± standard deviation:28±9 years; 9 male) with nocturnal seizures (NS), 12patients (26±9; 3 male) with diurnal seizures (DS) and 10healthy controls (HC) (28±4; 6 male) 3D 3T MRI was per-formed. Cortical and subcortical volumes (hippocampus,amygdala, thalamus) were extracted with the FreeSurferprocessing stream and the between‐group differencesassessed with analysis of variance (ANOVA) and Bonfer-roni post hoc tests. There was no difference between thegroups regarding age (F2,32= 0.26, p = 0.77) and gender(χ†= 5.103, df = 2, p = 0.08). Results: NS group in contrast to DS group showed largervolumes of bilateral insula, superior temporal and orbito-frontal cortices (p = 0.05, corrected). In patients with NScortical volumes of left postcentral and right middle tempo-ral cortices were smaller in comparison to HC. Patientswith DS in comparison to HC displayed reduced corticalvolumes mainly in frontal, temporal and parietal lobes ofthe right hemisphere. Hippocampus analysis showed a sig-nificant group difference (F2,32= 3.643, p = 0.03) withpost hoc test indicating larger volumes in NS group(8208.6±1006.1) vs DS group (3859.1±508.1 mm‡,p = 0.02). For amygdala, ANOVA showed a similar signif-icant group difference (F2,32= 4.341, p = 0.02) with largervolumes in NS group (1797.3±323.2 mm‡) vs DS group(1500.5±246.2 mm‡, p = 0.03). There were no differencesin thalamic volumes between the studied groups. Conclusion: Despite epileptogenesis daytime‐related sei-zures have distinct structural correlates. These alterationscan assign protective or susceptibility properties linked tovigilance or sleep states that could be useful for therapeuticdecisions.…