A New Index of Coordinated Posterior and Anterior Evoked EEG to Detect Recall Under Sedation - A Pilot Study

• Published in: Scientific reports Vol. 9; no. 1; pp. 17859 - 11
• Main Authors: Baron Shahaf, Dana, Hare, Gregory M T, Baker, Andrew J, Chenosia, Violina, Priven, Leonid, Mistry, Nikhil, Shahaf, Goded
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 28.11.2019; Nature Publishing Group UK
• Subjects: Adult; Anesthesia; Anesthesia, General - adverse effects; Anesthesia, General - methods; Awareness - drug effects; Cerebral Cortex - drug effects; Cerebral Cortex - physiology; Conscious Sedation - adverse effects; Conscious Sedation - methods; EEG; Electroencephalography - instrumentation; Electroencephalography - methods; Evoked Potentials; Female; Humans; Male; Memory - drug effects; Midazolam; Midazolam - adverse effects; Middle Aged; Monitoring, Physiologic - instrumentation; Monitoring, Physiologic - methods; Propofol; Propofol - adverse effects
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-019-54270-3

EEG-based technologies may be limited in identifying recall under sedation (RUS). We developed a novel index, posteriorization/anteriorization (P/A) index, based on auditory evoked EEG signal and assessed whether it could differentiate between patients with or without RUS. Methods: EEG and BIS were sampled from 3 groups: 1. Patients undergoing sedation (n = 26); 2. Awake volunteers (n = 13, positive control for recall) 3. Patients undergoing general anesthesia (GA, n = 12, negative control for recall). In recovery, recall was assessed using the BRICE questionnaire. Of the 26 sedated patients, 12 experienced recall. Both The P/A index and BIS differentiated between patients with recall and no recall. However, BIS differentiation may have been sensitive to the main drug used for sedation (midazolam vs. propofol) and the P/A index did not show similar drug-based sensitivity. Furthermore, only BIS results were correlated with EMG. Conclusion: This pilot study provided support for the association between P/A index and recall after sedation. Further research is needed in integrating the index into clinical use: (1) it should be derived by an easy-to-use EEG system with a better signal-to-noise ratio; (2) its applicability to other drugs must be shown.