{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,20]],"date-time":"2026-10-20T05:40:25Z","timestamp":1792474825514,"version":"4.5.0"},"reference-count":34,"publisher":"Wiley","license":[{"start":{"date-parts":[[2026,10,19]],"date-time":"2026-10-19T00:00:00Z","timestamp":1792368000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,10,19]],"date-time":"2026-10-19T00:00:00Z","timestamp":1792368000000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Epilepsia"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>Lennox\u2013Gastaut Syndrome (LGS) is a severe developmental and epileptic encephalopathy characterized by multiple seizure types, cognitive impairment, and distinct electroencephalographic (EEG) findings. However, evolving diagnostic criteria, heterogeneous clinical features, and inconsistent electronic health record (EHR) documentation complicate accurate diagnosis and cohort identification. As part of a Patient\u2010Centered Outcomes Research Institute\u2010sponsored study developing EHR\u2010based computable phenotypes for LGS, we established a reference standard through retrospective chart review and epileptologist classification.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>A multicenter retrospective chart review was conducted across seven pediatric epilepsy centers. Stratified sampling using PCORnet data selected patients based on the International Classification of Diseases, 10th Revision diagnosis code for LGS or other intractable epilepsy diagnoses between 2016 and 2022. Clinical teams abstracted seizure history, EEG findings, developmental status, and treatment history. Two epileptologists independently reviewed each case as classic LGS, pragmatic LGS, or not LGS. Discordant cases underwent adjudication by a senior epileptologist. Cases with incomplete or unclear data underwent repeat abstraction and review.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Of 997 identified patients, 935 underwent classification after exclusions. Initial epileptologist disagreement occurred in 105 cases (11%, unweighted Cohen kappa\u2009=\u200982%). Following adjudication, 130 cases underwent reabstraction to retrieve additional EEG reports and clinical details. Rereview reclassified 67 cases initially considered \u201cnot LGS\u201d: 33 classic LGS, 12 pragmatic LGS, and 22 excluded for insufficient data. Key EHR challenges included inconsistent EEG reporting, incomplete seizure type characterization, fragmented documentation of cognitive impairment, unclear age at onset, and variable terminology across institutions and providers. Slow spike\u2010and\u2010wave EEG findings were the most frequently missing diagnostic element.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Significance<\/jats:title>\n                    <jats:p>Validating LGS diagnoses using EHR data is complex and resource intensive. Standardized terminology, structured documentation, and rigorous multicenter validation may improve diagnostic accuracy, research cohort identification, computable phenotype development, and longitudinal care for individuals with LGS. Our results highlight important operational lessons for multicenter rare epilepsy studies and underscore the need for improved diagnosis pathways and longitudinal care systems for those with LGS and their families.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1002\/epi.70551","type":"journal-article","created":{"date-parts":[[2026,10,20]],"date-time":"2026-10-20T05:21:45Z","timestamp":1792473705000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Validation of the diagnosis of Lennox\u2013Gastaut syndrome: Challenges and lessons learned"],"prefix":"10.1002","author":[{"ORCID":"https:\/\/orcid.org\/0009-0001-0430-2669","authenticated-orcid":false,"given":"Nicole","family":"Villalba","sequence":"first","affiliation":[{"name":"Division of Pediatric Neurosurgery, Department of Surgery Ann &amp; Robert H. Lurie Children's Hospital  Chicago Illinois USA"},{"name":"Department of Neurological Surgery Northwestern University Feinberg School of Medicine  Chicago Illinois USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9403-345X","authenticated-orcid":false,"given":"Marc","family":"Rosenman","sequence":"additional","affiliation":[{"name":"Mary Ann &amp; J. Millburn Smith Child Health Outcomes, Research, and Evaluation Center Ann &amp; Robert H. Lurie Children's Hospital of Chicago  Chicago Illinois USA"},{"name":"Department of Pediatrics Northwestern University Feinberg School of Medicine  Chicago Illinois USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3294-6637","authenticated-orcid":false,"given":"Sandi","family":"Lam","sequence":"additional","affiliation":[{"name":"Division of Pediatric Neurosurgery, Department of Surgery Ann &amp; Robert H. Lurie Children's Hospital  Chicago Illinois USA"},{"name":"Department of Neurological Surgery Northwestern University Feinberg School of Medicine  Chicago Illinois USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1967-0827","authenticated-orcid":false,"given":"Kelly G.","family":"Knupp","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, Division of Neurology University of Colorado School of Medicine Anschutz Medical Campus  Aurora Colorado USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9779-7903","authenticated-orcid":false,"given":"Liu Lin","family":"Thio","sequence":"additional","affiliation":[{"name":"Department of Neurology Washington University School of Medicine  St. Louis Missouri USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"William P.","family":"Welch","sequence":"additional","affiliation":[{"name":"Division of Neurology, Department of Pediatrics University of Pittsburgh School of Medicine  Pittsburgh Pennsylvania USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stephanie C.","family":"Randle","sequence":"additional","affiliation":[{"name":"Division of Pediatric Neurology, Department of Neurology University of Washington  Seattle Washington USA"},{"name":"Division of Pediatric Neurology and Epilepsy, Department of Pediatrics Seattle Children's Hospital  Seattle Washington USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5991-7070","authenticated-orcid":false,"given":"Rebecca","family":"Garcia\u2010Sosa","sequence":"additional","affiliation":[{"name":"Division of Neurology, Department of Pediatrics Northwestern University Feinberg School of Medicine  Chicago Illinois USA"},{"name":"Division of Pediatric Neurology Ann &amp; Robert H. Lurie Children's Hospital of Chicago  Chicago Illinois USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Laurel","family":"Reed","sequence":"additional","affiliation":[{"name":"Division of Pediatric Neurology, Department of Pediatrics Michigan Medicine, University of Michigan  Ann Arbor Michigan USA"},{"name":"Pediatric Neurology Department C. S. Mott Children's Hospital  Ann Arbor Michigan USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tracy","family":"Dixon\u2010Salazar","sequence":"additional","affiliation":[{"name":"Lennox\u2010Gastaut Syndrome Foundation  San Diego California USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maura","family":"Carroll","sequence":"additional","affiliation":[{"name":"Division of Pediatric Neurosurgery, Department of Surgery Ann &amp; Robert H. 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