What is the role of EEG in the workup of Lennox-Gastaut syndrome (LGS)?

Updated: Nov 09, 2018
  • Author: Koshi A Cherian, MD; Chief Editor: Amy Kao, MD  more...
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Always perform an EEG in patients with suspected LGS, since the diagnosis depends on the presence of specific EEG findings. A routine 20-minute EEG may not capture the patient both awake and asleep and thus may miss specific important EEG findings. Instead, obtain prolonged video/EEG telemetry, if possible. Record both waking and sleep EEG, to assist in confirming a suspected diagnosis and to capture and classify each of the patient's multiple seizure types.

Video recordings can also be used to educate the parents on which of the patient's "events" are seizures and which are nonepileptic behavioral events. Parental ability to correctly recognize and identify atypical absences is poor. In one study using video/EEG monitoring in a cohort of children with LGS, parental recognition was 27% for atypical absences, while the sensitivity was as high as 80% for myoclonic seizures and 100% for tonic, atonic, tonic-clonic, clonic, and complex partial seizures. [8]

Go to EEG in Common Epilepsy Syndromes, Epileptiform Normal Variants on EEG, and Generalized Epilepsies on EEG for more information on these topics.

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