No 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.

Parameters dynamics of brain bioelectric activity of 50 patients in alcoholic coma are  considered. Patients underwent continuous EEG monitoring from the end of the basic resuscitation to the apparent recovery of consciousness (awakening). The average registration time was 4.5 hours. EEG was recorded in standard derivations using the 10–20 system. The amplitude-frequency indices of spontaneous activity and reactivity are analyzed. Electroencephalographic correlates of cerebral insufficiency in comatose states are distinguished by pronounced polymorphism and high individual variability. Considering these features, “dynamic” parameters should be used as prognostic criteria: spontaneity and variability of the pattern, reactivity during stimulation. The increase in the frequency of bioelectric activity, desynchronization with external stimuli may indicate the beginning of the process of recovery of consciousness. Electrophysiological criteria for awakening, developed in this work on the example of alcoholic coma, can be mostly applicable to unconscious states caused by other etiological factors: trauma, hypoxia, vascular failure.