Abstracts

Rationale: LGS is characterized by multiple seizure types including tonic, atonic, and atypical absence seizures; abnormal electroencephalogram (EEG) patterns such as the classical slow spike and wave activity; and intellectual disability. As patients mature, the transition of care from pediatric to adult neurologist is particularly relevant in the context of LGS, as disconnects in treatment may arise. LGS may not be readily recognized in adult patients, and many of them may carry the diagnosis of symptomatic generalized epilepsy. Further, the classical characteristics of LGS evolve over time and may not present in adult patients, and neurologists might not consider a diagnosis of LGS especially when typical EEG findings are absent. The underdiagnosis of LGS in adults needs to be addressed to prevent patients receiving ineffective and unsuitable medications. Thus, a new diagnostic algorithm with a broader definition of LGS is needed to allow reliable and effective LGS diagnosis in adults. Methods: The LGS Transitions of Care Advisory Board met in November 2017 to discuss the development of a new diagnostic algorithm for LGS in adult patients. A rudimentary diagnostic framework was created to facilitate discussions around the core criteria that are essential for making a clinical diagnosis of LGS in adults. Results: The primary focus of discussion was on identifying readily available assessments to facilitate the adult LGS diagnosis in a community setting, including past medical history, physical examination, and review of medical records. It was proposed that in equivocal cases, a routine EEG should be used to distinguish abnormal activity. Board members recognized that the typical finding of slow spike and wave discharges may no longer present in adult patients and is often replaced by background slowing, focal epileptiform discharges or slowing, or multifocal spike and wave discharges. When diagnosis remains uncertain after EEG, a longer duration of EEG monitoring with sleep features should be considered. The proposed diagnostic algorithm is shown in Figure 1. Conclusions: The criteria used for the diagnosis of LGS in adult patients need to be widened to minimize missed diagnoses. Diagnostic criteria should consider: childhood-onset seizures (typically <8); cognitive impairment of varying severity; presence of =2 seizure types that are often resistant to medical treatment, commonly including, but not limited to, atonic, atypical and tonic-clonic seizures; and EEG findings that may be nonspecific. Further, absence of slow spike and wave discharges should not preclude the possible diagnosis of LGS. Funding: The advisory board was convened and funded by Eisai Inc. All authors were participants of the advisory board and were responsible for the decision to develop and submit this abstract. Medical writing support, under the direction of the authors, was funded by Eisai Inc., in accordance with GPP3 guidelines.