[Electroencephalography in acute stroke]. / Elektroentsefalografiya v ostrom periode insul'ta.

OBJECTIVE: To determine the incidence of non-convulsive status epilepticus, epileptiform activity, rhythmic and periodic patterns in patients with acute stroke. MATERIAL AND METHOD: An analysis of electroencephalography (EEG) in 86 stroke patients in the neurointensive care unit of the tertiary medical center was performed. Criteria for starting EEG recording were epileptic seizures or clinical suspicion of uncontrolled epileptic status. The ictal-interictal continuum biomarkers and the diagnostic value of EEG for prediction of survival and recovery were assessed. RESULTS: Pathological changes on EEG were recorded in 84% of patients. These patients showed the absence of the dominant occipital rhythm (66%) and hemispheric slowing (42%). Diffuse slowing below the theta range was observed in 41% of patients. EEG reactivity was absent in 20%. Sporadic epileptiform discharges were recorded in 36% of patients and rhythmic and periodic patterns in 26%. Reliable predictors of the unfavorable outcome were the absence of dominant occipital rhythm, lack of reactivity, and low amplitude of the background EEG. No association between the recording of epileptiform activity and the probability of death was shown. CONCLUSION: The most useful EEG biomarkers for predicting survival are amplitude, dominant frequency of background EEG activity and reactivity to external stimulus. Sporadic epileptiform discharges, rhythmic, and periodic patterns are not mandatory associated with a negative prognosis in stroke patients.

[Acute period in a rat model of brain trauma: immediate seizures, damage to functional neocortical zones and behavioral disturbances]. / Ostryi period pri modelirovanii cherepno-mozgovoi travmy u krys: nemedlennye sudorogi, povrezhdenie funktsional'nykh zon novoi kory i narusheniia povedeniia.

BACKGROUND: Establishing the relationship between the damage in the neocortex and the functional manifestations of these lesions is important to understand the mechanisms of acute seizures and their consequences. An analysis of immediate seizures in patients with a traumatic brain injury (TBI) in practice is difficult, however it can be performed in animal models. AIM: To compare the damage to functional neocortical areas with the semiology of immediate seizures and behavioral disturbances in the acute period after lateral fluid percussion (TBI model) in rats. MATERIAL AND METHODS: The study was performed on 48 Wistar rats. TBI was modelled using lateral fluid-percussion injury to the right sensory-motor cortex. To study the semiology of immediate seizures, video recording was performed at the moment of the injury and 5 min after it. After that, a number of behavioral tests were employed. RESULTS AND CONCLUSION: This study presents the first detailed evaluation of damage to the functional neocortical areas in the acute period of TBI using the 'unfolded maps' approach. The focus of damage in the cortex increased from 3rd to 7th day and demonstrated a complex shape, extending far beyond the area of the direct impact. TBI induced immediate seizures with a variability which cannot be explained by the involvement of certain areas of the neocortex alone, as well as behavioral disturbances suggested to reflect developing necrosis predominantly in the sensory area of the neocortex.

[Early electrophysiological consequences of dosed traumatic-brain injury in rats]. / Rannie élektrofiziologicheskie posledstviia dozirovannoi cherepno-mozgovoi travmy u krys.

AIM: To analyze the pathological electrical activity during the acute period after traumatic brain injury (TBI) and to search for potential morphological correlates of this activity in the neocortex and hippocampus. MATERIAL AND METHODS: The study was performed on male Sprague Dawley rats. TBI was modeled using a lateral hydrodynamic impact in the sensorimotor cortex area. ECoG was continuously recorded one week before and one week after TBI. A histological analysis was performed one week after TBI. Brain slices were Nissl stained as well as immunohistochemically stained for astrocytes (GFAP) and microglia (Isolectin B4). The damage to the neocortex and hippocampus was evaluated. RESULTS AND CONCLUSION: The slowdown of the background activity one and six hours after TBI and appearance of epileptiform activity in a half of animals one week after TBI were shown. The number of discharges was correlated with the area of astrocyte gliosis in the neocortex and with the number of dark (ischemic-like) neurons in the hippocampus. Microglial activation did not correlate with the epileptiform activity. These data are important to understanding early mechanisms of post-trauma epileptogenesis.