Long-term prognosis of patients with Lennox--Gastaut syndrome in recent decades

We investigated long term prognosis of Lennox-Gastaut syndrome (LGS) with active application of recent advanced treatment modalities such as ketogenic diet (KD) or epilepsy surgery (ES).

We retrospectively evaluated 68 patients with LGS, aged 18-35 years. We assessed seizure outcomes for a range of therapeutic modalities. Evolution of seizure types, EEG characteristics, cognition, ambulation, social outcomes and other clinical data were also evaluated.

For a mean follow-up duration of 19.3 years (range 8.3-32.5 years), finally sixteen patients (23.5%) were seizure-free. Of the 68 patients, 26 (38.2%) were treated solely with AEDs and six became seizure-free. The KD was administered to 19 patients, five patients maintained a seizure free state during the KD but only one patient was able to maintain a seizure free state by continuing on a modified Atkins diet. Focal resective surgery was performed in 15 patients, ten out of the 15 patients had Engel class I outcomes, but only three patients maintained seizure freedom to adults. CC was performed in 17 patients, and VNS was performed in 14 patients. These palliative procedures were also effective but had limitations to obtain and maintain seizure freedom to adults. Characteristic EEG features of diffuse slow spike-wave and generalized paroxysmal fast activity ceased in half of the patients. In cognitive terms, 94.7% of patients exhibited moderate to profound mental retardation. Only 39.7% of patients had intact independent daily living skills, and 25.4% could not walk, even with support.

KD and epilepsy surgery were effective for seizure control, but they did not necessarily lead to the maintenance of a seizure-free state. LGS remains a form of intractable epilepsy despite the application of recent advanced treatment modalities.