Long-term follow-up of childhood epilepsy associated with tuberous sclerosis

Abstract

Purpose: To study the clinical and electroencephalographic (EEG) characteristics of patients whose epilepsy is associated with tuberous sclerosis, with special reference to their clinical course. Methods: We investigated the electroclinical and radiologic features of 38 patients with epilepsy associated with tuberous sclerosis. Results: Eleven patients showed only generalized epilepsy, and 10 showed only localization-related epilepsy throughout their clinical course. Among the other 17 cases, the nature of the epilepsy changed between generalized and localization-related epilepsies during the clinical course. A shift from generalized to localization-related epilepsies was more common than the reverse. Seventeen had West syndrome (WS), three had Lennox-Gastaut syndrome (LGS), and eight had epilepsies that evolved from WS to LGS. Tonic spasms, mostly in series, were seen in all 28 patients with generalized epilepsy. Eleven of the 28 patients had partial seizures and tonic spasms in the same period. Six of them showed 'simultaneous seizures,' consisting of tonic spasms in series and a partial seizure. Partial seizures were the main seizure type in 27 patients with localization-related epilepsy, but three of them also showed tonic spasms that included 'simultaneous seizures.' Ictal EEGs revealed multiple active foci in the same period that could shift during the clinical course. Neither the location nor number of tubers was related to the clinical course. As for seizure outcome, 12 (32%) of 38 patients were free from seizures at follow- up. Conclusions: In epilepsies associated with tuberous sclerosis, there may be an interrelation between generalized and localization-related epilepsies, as well as one between generalized and partial seizures.