EEG dynamical correlates of focal and diffuse causes of coma

Background: Rapidly determining the causes of a depressed level of consciousness (DLOC) including coma is a common clinical challenge. Quantitative analysis of the electroencephalogram (EEG) has the potential to improve DLOC assessment by providing readily deployable, temporally detailed characterization of brain activity in such patients. While used commonly for seizure detection, EEG-based assessment of DLOC etiology is less well-established. As a first step towards etiological diagnosis, we sought to distinguish focal and diffuse causes of DLOC through assessment of temporal dynamics within EEG signals. Methods: We retrospectively analyzed EEG recordings from 40 patients with DLOC with consensus focal or diffuse culprit pathology. For each recording, we performed a suite of time-series analyses, then used a statistical framework to identify which analyses (features) could be used to distinguish between focal and diffuse cases. Results: Using cross-validation approaches, we identified several spectral and non-spectral EEG features that were significantly different between DLOC patients with focal vs. diffuse etiologies, enabling EEG-based classification with an accuracy of 76%. Conclusions: Our findings suggest that DLOC due to focal vs. diffuse injuries differ along several electrophysiological parameters. These results may form the basis of future classification strategies for DLOC and coma that are more etiologically-specific and therefore therapeutically-relevant. Electronic supplementary material The online version of this article (doi: 10.1186/s12883-017-0977-0) contains supplementary material, which is available to authorized users

Effects of interleukin-1β on spinal cord nociceptive transmission in intact and propentofylline-treated rats

To investigate the contribution of glial cells in the spinal cord nociceptive transmission, the effect of intrathecally administered interleukin-1β (IL-1β) was studied in rats treated with the glial cell inactivator propentofylline and submitted to a C-fiber-mediated reflex paradigm evoked by single and repetitive (wind-up) electric stimulation. Intrathecal IL-1β did not modify the C reflex integrated activity in either group of animals, while producing increased wind-up in intact and decreased wind-up in propentofylline pre-treated rats. Results suggest that the excitatory effect of IL-1β on spinal wind-up activity in healthy rats is produced by a glial mediator, whereas the inhibitory effect resulted from a direct effect of the cytokine on dorsal horn neurons. Copyright © 2007 Informa Healthcare

Additional file 1: Table S1. of EEG dynamical correlates of focal and diffuse causes of coma

Additional details regarding study population. (DOCX 12 kb