Abstracts

Rationale: Autosomal dominant partial epilepsy with auditory features (ADPEAF) is a benign form of epilepsy associated with mutations in LGI1, and brain magnetic resonance imaging (MRI) usually normal or with minor abnormalities. The objective of this study was to identify areas with abnormal volume and cortical thickness in individuals of the same family with ADPEAF and mutation in LGI1. Methods: We performed volumetric and cortical thickness analysis in 15 subjects (7 men) with point mutation in LGI1. Ten individuals had normal MRI on visual analyses, and five had enlargement of the left temporal lobe. Ten patients had clinical diagnosis of ADPEAF and the others were asymptomatic carriers of LGI1 mutation. T1-volumetric images (1mm) were obtained in a 2T MRI. Optimized voxel based-morphometry (VBM) with modulation was performed for volume investigation. Images were pre-processed with the program MRIcro and the software SPM8/DARTEL was used in a Matlab7.5 platform. For this analysis, eighty-five healthy subjects were included for statistical comparison (t-test) in order to identify possible areas of growth or atrophy of gray (GM) and white (WM) matter (minimum of 30 voxels, p <0.05, T> 4.84). Cortical thickness analysis was performed with Freesurfer , with 20 healthy subjects as control group (t-test, FDR, p <0.05, T> 2.5). Results: Individuals with mutation in LGI1 showed areas of GM atrophy in frontal lobes, more significant in left pre-central gyri, and WM atrophy in fronto-temporal regions and cerebellum, more significant in left temporal lobe and right cerebellum (Figure 1). There were no significant areas of GM or WM volume increase in the group of individuals with mutation in LGI. Surface analysis demonstrated reduction of cortical thickness in the transition of left pre-central and post-central region and increased cortical thickness in right posterior temporal lobe and parietal lobe (Figure 2). Conclusions: In agreement with previous studies showing minor imaging abnormalities predominantly in the left hemisphere in ADPEAF, we found areas of reduced GM and WM concentration mainly in left frontal and left temporal lobes, respectively, and reduced cortical thickness in the transition of left pre- and post-central areas. Right hemisphere abnormalities had not been previously described in ADPEAF, and we also found increased cortical thickness in right posterior temporal and parietal regions in these individuals.