Non-convulsive status epilepticus diagnostics in severe brain injury: dynamics of clinical-electroencephalographic criteria

Abstract

Non-convulsive status epilepticus (NCSE) in case of severe traumatic brain injury is the reason for the persistence of a long unconscious state in the postcomatose period. Currently, there are no unified EEG-criteria for the diagnosis of non-convulsive status epilepticus. The proposed diagnostic criteria do not provide the neurodynamics of the damaged brain. The results, obtained in this work, allow us to clarify the relationship between the duration of the postcomatose period and the severity of pathological changes on the EEG. Diagnostic criteria for NCSE are proposed for the different periods of the acute period of traumatic brain damage. In the first 3–5 days of a postcomatose unconscious state, NCSE is diagnosed with an epileptiform activity index of at least 50 %. When the unconscious state lasts more than 7–10 days, the registration of epileptiform activity with an index of more than 25–30 % is a sufficient criterion for the diagnosis of NCSE. It has been shown that the formation of non-convulsive epileptic status can occur “delayed”, after more than 10–14 days from the moment of restoration of spontaneous respiration, which necessitates EEG monitoring throughout the entire period of the unconscious state in patients with severe brain injury.