[Visual and computer evaluation of diazepam-induced EEG changes in epilepsy for localization of epileptogenic lesion]

Diazepam-induced EEG changes were analyzed both visually and by computer in epilepsy for localization of epileptogenic lesion. The results demonstrated that changes in beta spectral were diminished in 11/24 or 15/25 cases, but regionally increased in 3/24 or 3/25 patients overlying the epileptogenic lesion or area of EEG abnormalities. Diazepam-induced delta spectral power was usually increased (9/24), but occasionally focally reduced (3/24) over the lesion. The percentage of positive findings for localization was 38% with visual analysis and 46% with spectral analysis in beta spectral power, 38% in delta spectral power, and 67% with the analysis in combined beta with delta, and 83% with four independent tests. Spectral analysis was more sensitive than visual analysis, and it was a useful supplement to visual analysis, to general EEG evaluation, and to CT. Finally, the study emphasized that a localizing diagnosis to define the epileptogenic lesion should be based on the combination of a multitude of independent tests.