June 24, 2020

Whose Seizures Last Longest? Impact of Clinical and Demographic Factors

Abstract, published in Epilepsia

Objective: To investigate the impact of clinical and demographic parameters on the duration of seizures starting at a single place in the brain (focal onset), with and without secondary spread, using precise duration measurements from intracranial electroencephalographic (iEEG) recordings. These recordings are made with electrodes placed directly on the brain.

Methods: Patients with focal epilepsy syndromes and iEEG recordings were retrospectively identified from the database of the local epilepsy center (2006-2016). Seizure duration was defined as the time between seizure onset and end, according to the iEEG. The specific seizure symptoms were classified based on video recordings. Clinical and demographic data were extracted from patient reports.

Results: In total, 69 adults were included, and 654 focal onset seizures were analyzed. Those that spread throughout the brain and involved violent convulsing (98/654 [~15%]) were significantly longer than without secondary spread (556/654 [~85%]). Most focal seizures (545/654 [83.3%]) ended within 2 minutes. The duration of focal seizures was prolonged with increasing age of the patients and was significantly shortened by secondary spread. Furthermore, seizures with secondary spread that were also preceded by an aura, began at the front of the brain, or occurred during sleep were shorter.

Significance: The identified modifiers of seizure duration are of great relevance for clinical risk evaluation, especially in the aging epilepsy patient suffering from epilepsy with secondary generalized seizures.

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