The refractory epilepsy screening tool for Lennox-Gastaut syndrome (REST-LGS)

Abstract

Background: The complex clinical presentation and progression of Lennox-Gastaut syndrome (LGS) can complicate the accurate diagnosis of this severe, lifelong, childhood-onset epilepsy, often resulting in suboptimal treatment. The Refractory Epilepsy Screening Tool for LGS (REST-LGS) was developed to improve the identification of patients with LGS.

Methods: Using the Modified Delphi Consensus, a group of experts developed and tested the REST-LGS Case Report Form (CRF) comprising 8 criteria (4 major, 4 minor) considered potentially indicative of LGS. Diagnosis-blinded specialist and nonspecialist raters at 2 epilepsy centers applied the CRF to deidentified patient records, including 1:1 records of patients with drug-resistant epilepsy or confirmed LGS. Interrater reliability was measured by Cohen's κ. Diagnosis was then unblinded to reveal common criteria for LGS or drug-resistant epilepsy. Cronbach's α was used to measure internal consistency between raters for all criteria combined.

Results: Of 200 patients, 81% to 85% met 1 to 3 major criteria. At both sites, moderate (κ, 0.41-0.60) to good (κ, 0.61-0.80) agreement on most criteria was reached between expert and nonexpert raters. Unblinding revealed that most patients with LGS met 3 major and 2 to 3 minor criteria, while patients with drug-resistant epilepsy met ≤1 major and only 1 to 2 minor criteria. Cronbach's α of raters at both sites was 0.64.

Conclusions: The combined number of major/minor criteria on the CRF may be particularly indicative of LGS. Therefore, the REST-LGS may be a valuable clinical tool in identifying patients requiring further diagnostic evaluation for LGS.

Keywords: Diagnosis; Epilepsy; LGS; Lennox–Gastaut syndrome; Screening tool.