Consensus over Individualism: Validation of the ILAE Definition for Drug Resistant Epilepsy

Abstract

In Clinical Science Commentary Consensus in Merriam-Webster's dictionary is defined as "a general agreement about something." However, since the introduction of classifications of seizures, epilepsy syndromes, and surgical outcome scales, there seems to be an inability to reach agreement in the epilepsy community about details and wording. To alleviate some of the controversial items, the International League Against Epilepsy (ILAE) has called task forces and published statements to standardize classifications and definitions (1-3). One such statement is the definition for drug-resistant epilepsy (2). However, definitions are of value only if they are practical, usable, and generally accepted. A possible way to assess whether a published medical definition is valid is to evaluate the definition for repeatability, consistency, and practicability in daily medical care. The above study by Tellez-Zenteno et al. attempts to validate the ILAE definition for drug-resistant epilepsy and compares the ILAE definition to previously published definitions by individual authors. In short, the ILAE defines drug-resistant as "failure of adequate trials of two tolerated and appropriately chosen AED schedules (whether as monotherapies or in combination) to achieve seizure freedom" (2). The authors find that the ILAE

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“…Although, the terms “refractory”, “intractable”, and “pharmaco-resistant” epilepsy are used interchangeably. The ILAE defines “drug-resistant epilepsy” as a failure to achieve and maintain seizure freedom despite trialling two AEDs that are well tolerated, in terms of side effects, whether as a monotherapy or polytherapy [ 88 ].…”

Nucleic Acid Aptamers for Molecular Therapy of Epilepsy and Blood-Brain Barrier Damages

“…Epilepsy is considered to be resolved for individuals past the applicable age of an age-dependent epilepsy syndrome or those who have remained seizure-free for the past 10 years, with no use of seizure medicines for the past 5 years 40 . Unfortunately, 6% to 69% of patients fail to respond to standard medical and surgical therapies and continue to experience debilitating refractory seizures 41 .…”

Neural Fragility as an EEG Marker of the Seizure Onset Zone

“…Since there is no biomarker for the EZ and it is never observed directly, the network mechanisms that cause seizures are complex. Case clinical complexity ordered by increasing localization difficulty: lesional (1), focal temporal (2), focal extratemporal (3), and multi-focal (4) that are present in the dataset. These four categories simplify the possible epilepsy presentations, but provide a broad categorization of simple to complex cases observed in the clinic.…”

“…Over 15 million epilepsy patients worldwide and 1 million in the US suffer from drug-resistant epilepsy (DRE) [1, 2, 3, 4, 5]. DRE is defined as continued seizures despite adequate trials of two tolerated appropriately chosen anti-epileptic drugs [6]. DRE patients have an increased risk of sudden death and are frequently hospitalized, burdened by epilepsy-related disabilities, and the cost of their care is a significant contributor to the $16 billion dollars spent annually in the US treating epilepsy patients [7, 8].…”