Facilitating the timely diagnosis of Lennox–Gastaut syndrome: A checklist to support clinical practice

OBJECTIVE: To develop and evaluate a simple-to-use checklist to support physicians with the timely diagnosis of Lennox-Gastaut syndrome (LGS). METHODS: A panel of 10 pediatric and adult epileptologists used the International League Against Epilepsy (ILAE) criteria for LGS classification and definition to develop seven questions for the checklist, through an iterative process. A scoring system formulated for the checklist yielded four distinct outcomes: likely LGS, possible LGS, unlikely LGS, and insufficient data. The checklist was then tested for reliability. Firstly, each expert selected LGS and non-LGS cases from their patient medical records and, for each case, provided the original diagnosis and answers to the checklist questions to an independent third party, who subsequently compared the outcome with the original diagnosis. The checklist questions were then refined based on the initial assessment. All cases were re-evaluated by the panel, and the results were collected as previously. Correct outcomes were defined as a perfect level of agreement with the original diagnosis provided by the expert (both LGS and non-LGS cases) or "possible LGS" outcome matching an original LGS diagnosis. RESULTS: Of the 120 cases evaluated (LGS, n = 64; non-LGS, n = 56), the outcome was correct for 95% (n = 114): 66.7% (n = 80) had a perfect level of agreement with the original diagnosis, and 28.3% (n = 34) were "possible LGS" matching an original LGS diagnosis. Incorrect matches, where the checklist outcome did not match the original LGS diagnosis, were due to the absence of documented characteristic EEG features and, related to young age, lack of cognitive/behavioral impairment. SIGNIFICANCE: The checklist offers a simple-to-use resource for treating physicians to support earlier LGS diagnosis, using the ILAE criteria as the framework. The findings also highlight the importance of EEG data for LGS diagnosis, that mandatory ILAE diagnostic features are not always initially present and may evolve over time, and the need to re-evaluate patients during follow-up.