Towards an electroencephalographic measure of awareness based on the reactivity of oscillatory macrostates to hearing a subject's own name

Cosmin Andrei Șerban, Andrei Barborică, Adina Maria Roceanu, Ioana Raluca Mîndruță, Jan Ciurea, Mihai Stancu, Alexandru C. Pâslaru, Ana Maria Zăgrean, Leon Zăgrean, Mihai Moldovan*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

2 Citations (Scopus)

Abstract

We proposed that the brain's electrical activity is composed of a sequence of alternating states with repeating topographic spectral distributions on scalp electroencephalogram (EEG), referred to as oscillatory macrostates. The macrostate showing the largest decrease in the probability of occurrence, measured as a percentage (reactivity), during sensory stimulation was labelled as the default EEG macrostate (DEM). This study aimed to assess the influence of awareness on DEM reactivity (DER). We included 11 middle cerebral artery ischaemic stroke patients with impaired awareness having a median Glasgow Coma Scale (GCS) of 6/15 and a group of 11 matched healthy controls. EEG recordings were carried out during auditory 1 min stimulation epochs repeating either the subject's own name (SON) or the SON in reverse (rSON). The DEM was identified across three SON epochs alternating with three rSON epochs. Compared with the patients, the DEM of controls contained more posterior theta activity reflecting source dipoles that could be mapped in the posterior cingulate cortex. The DER was measured from the 1 min quiet baseline preceding each stimulation epoch. The difference in mean DER between the SON and rSON epochs was measured by the salient EEG reactivity (SER) theoretically ranging from −100% to 100%. The SER was 12.4 ± 2.7% (Mean ± standard error of the mean) in controls and only 1.3 ± 1.9% in the patient group (P < 0.01). The patient SER decreased with the Glasgow Coma Scale. Our data suggest that awareness increases DER to SON as measured by SER.

Original languageEnglish
JournalEuropean Journal of Neuroscience
Volume59
Issue number5
Pages (from-to)771-785
Number of pages15
ISSN0953-816X
DOIs
Publication statusPublished - 2024

Bibliographical note

Publisher Copyright:
© 2023 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Keywords

  • (un)consciousness
  • brain oscillations
  • clinical neurophysiology
  • coma
  • stroke

Cite this