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

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.