Understanding Lennox–Gastaut syndrome: insights from focal epilepsy patients with Lennox–Gastaut features
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To delineate the clinical and EEG features of adults with focal epilepsy associated with a generalized paroxysmal fast activity (GPFA) pattern on EEG who developed refractory seizures, notably drop attacks, but do not fulfill the classical triad for the diagnosis of Lennox–Gastaut syndrome (LGS) and provide further insight into LGS mechanisms. Among 957 patients admitted to video-EEG monitoring between 2002 and 2015, we retrospectively research adult patients with refractory focal epilepsy, drop attacks and GPFA on EEG. We collected demographic, anamnestic, and clinical data from medical records. We reviewed for all patients the interictal and ictal video-EEG recordings. We identified ten patients with focal epilepsy and electro-clinical features of LGS. As compared to classical LGS patients, our patients: (1) began epilepsy later (15.4 ± 8 years); (2) exhibited exclusively focal onset seizures, including drop attacks seizures linked to focal asymmetrical tonic posturing seizures; (3) had a stable cognition over time and (4) evolved favourably with a good secondary response to treatments in 80% of cases. Interestingly, all patients exhibited apparent diffuse interictal and ictal EEG abnormalities but a detailed analysis revealed that 50% had asymmetrical GPFA and 70% secondary bilateral synchrony processes. We may hypothesize here that a process of “secondary LGS” occurred which produced a worsening of seizures with the apparition of drop attacks and GPFA on EEG. This study brings arguments to consider that some cases of LGS could be linked to the development of a “secondary epileptic network” driven by a primary focal epileptic zone.
KeywordsFocal epilepsy Drop attacks Generalized paroxysmal fast activity Secondary Lennox–Gastaut
Compliance with ethical standards
Conflicts of interest
The authors have nothing to declare.
The study has been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki.
- 6.Archer JS, Warren AEL, Jackson GD, Abbott DF (2014) Conceptualizing Lennox–Gastaut syndrome as a secondary network epilepsy. Font Neurol 5:1–11Google Scholar
- 19.Gastaut H, Zifkin BG (1992) The Lennox–Gastaut syndrome. In: Roger J, Bureau M, Dravet Ch et al (eds) Epileptic syndromes in infancy, childhood and adolescence, 4th edn. John Libbey, LondonGoogle Scholar
- 20.Beaumanoir A (1982) The Lennox–Gastaut syndrome: a personal study. Electroencephalogr Clin Neurophysiol 35:85–99Google Scholar
- 26.Ohtahara S, Ohtsuka Y, Tyoshinga H, Iyoda K, Amano R, Yamatogi Y et al (1988) Lennox–Gastaut syndrome: etiological considerations. In: Niedermeyer E, Degen R (eds) The Lennox–Gastaut syndrome. Alan R. Lissp, New York, pp 47–63Google Scholar