A1 Refereed original research article in a scientific journal
Alpha band frontal connectivity is a state-specific electroencephalographic correlate of unresponsiveness during exposure to dexmedetomidine and propofol
Authors: Roosa E. Kallionpää, Katja Valli, Annalotta Scheinin, Jaakko Långsjö, Anu Maksimow, Tero Vahlberg, Antti Revonsuo, Harry Scheinin, George A. Mashour, Duan Li
Publisher: ELSEVIER SCI LTD
Publication year: 2020
Journal: British Journal of Anaesthesia
Journal name in source: BRITISH JOURNAL OF ANAESTHESIA
Journal acronym: BRIT J ANAESTH
Volume: 125
Issue: 4
First page : 518
Last page: 528
Number of pages: 11
ISSN: 0007-0912
DOI: https://doi.org/10.1016/j.bja.2020.05.068
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/49645053
Background: Coherent alpha electroencephalogram (EEG) rhythms in the frontal cortex have been correlated with the hypnotic effects of propofol and dexmedetomidine, but less is known about frontal connectivity as a state-specific correlate of unresponsiveness as compared with long-range connectivity. We aimed to distinguish dose- and state-dependent effects of dexmedetomidine and propofol on EEG connectivity.Methods: Forty-seven healthy males received either dexmedetomidine (n=23) or propofol (n =24) as target-controlled infusion with stepwise increments until loss of responsiveness (LOR). We attempted to arouse participants during constant dosing (return of responsiveness [ROR]), and the target concentration was then increased 50% to achieve presumed loss of consciousness. We collected 64-channel EEG data and prefrontal-frontal and anterior-posterior functional connectivity in the alpha band (8-14 Hz) was measured using coherence and weighted phase lag index (wPLI). Directed connectivity was measured with directed phase lag index (dPLI).Results: Prefrontal-frontal EEG-based connectivity discriminated the states at the different drug concentrations. At ROR, prefrontal-frontal connectivity reversed to the level observed before LOR, indicating that connectivity changes were related to unresponsiveness rather than drug concentration. Unresponsiveness was associated with emergence of frontal-to-prefrontal dominance (dPLI: -0.13 to -0.40) in contrast to baseline (dPLI: 0.01-0.02). Coherence, wPLI, and dPLI had similar capability to discriminate the states that differed in terms of responsiveness and drug concentration. In contrast, anterior-posterior connectivity in the alpha band did not differentiate LOR and ROR.Conclusions: Local prefrontal-frontal EEG-based connectivity reflects unresponsiveness induced by propofol or dexmedetomidine, suggesting its utility in monitoring the anaesthetised state with these agents.Clinical trial registration:NCT01889004
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