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The diagnosis of nonconvulsive status epilepticus (NCSE) relies largely on electroencephalography (EEG) findings. The lack of a unified EEG terminology, and of evidence-based EEG criteria, leads to varying criteria for and ability to diagnose NCSE. We propose a unified terminology and classification system for NCSE, using, as a template, the Standardised Computer-based Organised Reporting of EEG (SCORE). This approach integrates the terminology recently proposed for the rhythmic and periodic patterns in critically ill patients, the electroclinical classification of NCSE (type of NCSE) and the context for the pathologic conditions and age-related epilepsy syndromes. We propose flexible EEG criteria that employ the SCORE system to assemble a database for determining evidence-based EEG criteria for NCSE., (Wiley Periodicals, Inc. © 2013 International League Against Epilepsy.)

Objective: To determine the duration of epileptic seizure types in patients who did not undergo withdrawal of antiseizure medication. Methods: From a large, structured database of 11 919 consecutive, routine video‐electroencephalograpy (EEG) recordings, labeled using the SCORE (Standardized Computer‐Based Organized Reporting of EEG) system, we extracted and analyzed 2742 seizures. For each seizure type we determined median duration and range after removal of outliers (2.5–97.5 percentile). We used surface electromyography (EMG) for accurate measurement of short motor seizures. Results: Myoclonic seizures last <150 ms, epileptic spasms 0.4–2 s, tonic seizures 1.5–36 s, atonic seizures 0.1–12,5 s, when measured using surface EMG. Generalized clonic seizures last 1–24 s. Typical absence seizures are rarely longer than 30 s (2.75–26.5 s) and atypical absences last 2–100 s. In our patients, the duration of focal aware (median: 27 s; 1.25–166 s) and impaired awareness seizures (median: 42.5 s; 9.5–271 s) was shorter than reported previously in patients undergoing withdrawal of antiseizure medication. All focal seizures terminated within 10 min. Median duration of generalized tonic–clonic seizures was 79.5 s (57–102 s) and of focal‐to‐bilateral tonic–clonic seizures was 103.5 (77.5–237 s). All tonic–clonic seizures terminated within 5 min. Significance: This comprehensive list of seizure durations provides important information for characterizing seizures and diagnosing patients with epilepsy. The upper limits of seizure durations are helpful in early recognition of imminent status epilepticus. [ABSTRACT FROM AUTHOR]