Objective: Epileptic predisposition means genetically determined, increased seizure susceptibility. Neurophysiological evaluation of this condition is still lacking. In order to investigate " pure epileptic predisposition" (without epilepsy) in this pilot study the authors prospectively recruited ten persons who displayed generalized tonic-clonic seizures precipitated by 24 or more hours of sleep deprivation but were healthy in any other respects. Methods: 21-channel EEGs were recorded in the morning, in the waking state, after a night of sufficient sleep in the interictal period. For each person, a total of 120. s artifact-free EEG was processed to low resolution electromagnetic tomography (LORETA) analysis. LORETA activity (Ampers/meters squared) was computed for 2394 voxels, 19 active electrodes and 1. Hz very narrow bands from 1 to 25. Hz. The data were compressed into four frequency bands (δ: 0.5-4.0. Hz, θ: 4.5-8.0. Hz, α: 8.5-12.0. Hz, β: 12.5-25.0. Hz) and projected onto the MRI figures of a digitized standard brain atlas. The band-related LORETA results were compared to those of ten, age- and sex-matched healthy persons using independent t-tests. p<0.01 differences were accepted as statistically significant. Results: Statistically significant decrease of α activity was found in widespread, medial and lateral parts of the cortex above the level of the basal ganglia. Maximum α decrease and statistically significant β decrease were found in the left precuneus. Statistically not significant differences were δ increase in the medial-basal frontal area and θ increase in the same area and in the basal temporal area. Discussion: The significance of α decrease in the patient group remains enigmatic β decrease presumably reflects non-specific dysfunction of the cortex. Prefrontal δ and θ increase might have biological meaning despite the lack of statistical significance: these findings are topographically similar to those reported in idiopathic generalized epilepsy in previous investigations. Significance: Quantitative EEG characteristics of the genetically determined epilepsy predisposition were given in terms of frequency bands and anatomical distribution.
ASJC Scopus subject areas
- Clinical Neurology