Antiepileptic drug reduction and increased risk of stimulation-evoked focal to bilateral tonic-clonic seizure during cortical stimulation in patients with focal epilepsy

Autores de IIS La Fe

• Kevin Gill Hampel

  Autor

• Asier Gomez Ibañez

  Autor

• Mercedes Garcés Sánchez

  Autor

• David Hervás Marín

  Autor

• Rebeca Conde Sarrión

  Autor

• Antonio Joaquín Gutiérrez Martín

  Autor

• Vicente Enrique Villanueva Haba

  Autor

Participantes ajenos a IIS La Fe

• Cano-Lopez, Irene
• Gonzalez-Bono, Esperanza

Abstract

Introduction: Stimulation-evoked focal to bilateral tonic-clonic seizure (FBTCS) can be a stressful and possibly harmful adverse event for patients during cortical stimulation (CS). We evaluated if drug load reduction of anti epileptic drugs (AEDs) during CS increases the risk of stimulation-evoked FBTCS. Material and methods: In this retrospective cohort study, we searched our local database for patients with drug resistant epilepsy who underwent invasive video-EEG monitoring and CS in the University Hospital la Fe Valencia from January 2006 to November 2016. The AED drug load was calculated with the defined daily dose. We applied a uni- and multivariate logistic regression model to estimate the risk of stimulation-evoked FBTCS and evaluate possible influencing factors. Furthermore, we compared patients whose AEDs were completely withdrawn with those whose AEDs were not. Results: Fifty-eight patients met the inclusion criteria and were included in the analysis. Stimulating 3806 electrode contact pairs, 152 seizures were evoked in 28 patients (48.3%). Ten seizures (6.6%) in seven patients (12.1%) evolved to FBTCS. In the univariate and multivariate analysis, a 10% reduction in drug load was associated with an increase of the odds ratio (OR) of stimulation-evoked FBTCS by 1.9 (95%-CI 1.2, 4.0, p-value = 0.04) and 1.9 CI 1.2, 4.6, p-value = 0.04), respectively. In patients, whose AEDs were completely withdrawn he OR of FBTCS increased by 9.1 (95%CI 1.7, 69.9, p-value = 0.01) compared with patients whose AEDs were not completely withdrawn. No other factor (implantation type, maximum stimulus intensity, number of stimulated contacts, history of FBTCS, age, gender, or epilepsy type) appears to have a significant effect on the risk of stimulation-evoked FBTCS. Conclusions: The overall risk of stimulation-evoked FBTCS during CS is relatively low. However, a stronger reduction and, especially, a complete withdrawal of AEDs are associated with an increased risk of stimulation-evoked FBTCS. (C) 2017 Elsevier Inc. All rights reserved.

Keywords

• Epilepsy surgery; Electrical stimulation; Generalized tonic-clonic seizure; Safety; Withdrawal; Defined daily dose