Adriana Ma Goicoechea Astencio, René Andrade Machado, Yudith Merayo, Andrés Rodrigo Solarte Mila, Martha Jiménez Jaramillo and Juan Felipe Alvarez Restrepo
Introduction: Lennox- Gastaut Syndrome (LGS) is characterized by seizures which may have inconspicuous semiological features so they may be unrecognized while patients are continuously deteriorating. To confirm its clinical and electrographic characteristics is mandatory, which has therapeutic and prognostic implications. Those features have not been completely elucidated in LGS in adulthood.
Purpose: We performed a descriptive study to investigate seizure types, interictal and ictal EEG characteristics and cognitive outcome in adult LGS subjects.
Methods: We evaluated 28 cases with development impairment and several refractory seizure types, which included tonic seizures, in order to make a screening of LGS. We confirm LGS diagnosis in 24 patients older than 12 years who were assessed by video-EEG, particularly to record seizure types and EEG findings as well as cognitive outcome.
Results: During this stage of the disease, all patients presented tonic seizures (TS) during wakefulness and sleep, 12/24 had atypical absences, more rarely other seizure types. Some cases (5/24) have evolved from West syndrome and in 62.5% aetiology was cryptogenic. Interictal EEG showed normal background activity in 13/24 patients, slow spike-wave discharges during wakefulness was diffuse just in 4/24; bursts of diffuse fast rhythms (DFR) in sleep were seen in all patients. A moderate to severe cognitive impairment was observed in 18/24 patients, but all of them experience deterioration after the epilepsy had begun.
Conclusions: In adult LGS patients a standard waking EEG may be normal. TS during sleep and the presence of DFR are paramount to confirm the diagnosis.