Quantitative assessment of seizure severity for clinical trials: A review of approaches to seizure components

Quantitative assessment of seizure severity has been approached using a var iety of systems. This review describes currently available methods and poss ible new approaches to seizure assessment fur clinical trials. A review of the literature on methods of seizure assessments resulted in tabulation of the seizure rating scales known as VA, Chalfont-National Hospital, Liverpoo l, Hague. and the Occupational Hazard Scale. Seizures have been evaluated b y simply counting all events, counting events by type, by clinician ratings , patient ratings, and combinations. Each of the scales has advantages and disadvantages. Most scales share core components: seizure frequency, seizur e type, seizure duration, postictal events, post ictal duration, automatism s; seizure clusters, known patterns, warnings, tongue biting, incontinence, injuries, and functional impairment. This review revealed a partial consen sus about aspects of seizures that are important markers for severity. Howe ver, usefulness of the existing scales is limited by lack of data on respon siveness. New approaches are needed to assess changes in seizure severity a s a result of an intervention in a clinical trial.