EEG oscillatory states as neuro-phenomenology of consciousness as revealed from patients in vegetative and minimally conscious states.
Alexander A Fingelkurts, Andrew A Fingelkurts, Sergio Bagnato, Cristina Boccagni, Giuseppe Galardi
Consciousness and cognition March 1, 2012 DOI: 10.1016/j.concog.2011.10.004 via PubMed
Summary
Resting electroencephalogram (EEG) microstates—brief, recurring patterns of brain activity—relate to levels of consciousness in brain-damaged patients and healthy individuals. A reduced number of microstate types was associated with altered consciousness, and unawareness corresponded to a lack of diversity in alpha-rhythmic microstates. Delta-, theta-, and slow-alpha-rhythmic microstates were more probable and longer during unawareness, whereas fast-alpha-rhythmic microstates were linked to consciousness. The findings suggest resting EEG can reveal neural correlates of consciousness, with potential implications for clinical care and medical-legal decisions for patients with disorders of consciousness.
Study at a glance
| Characteristics | Observational cohort Peer reviewed |
|---|---|
| Population | Brain-damaged patients with disorders of consciousness and healthy-conscious subjects |
| Citations | 91 |
| Key finding | The repertoire, duration, and oscillatory type of EEG microstates in resting conditions quantitatively relate to the level of consciousness expression, with specific microstate patterns distinguishing aware from unaware states. |
Abstract
The value of resting electroencephalogram (EEG) in revealing neural constitutes of consciousness (NCC) was examined. We quantified the dynamic repertoire, duration and oscillatory type of EEG microstates in eyes-closed rest in relation to the degree of expression of clinical self-consciousness. For NCC a model was suggested that contrasted normal, severely disturbed state of consciousness and state without consciousness. Patients with disorders of consciousness were used. Results suggested that the repertoire, duration and oscillatory type of EEG microstates in resting condition quantitatively related to the level of consciousness expression in brain-damaged patients and healthy-conscious subjects. Specifically, results demonstrated that (a) decreased number of EEG microstate types was associated with altered states of consciousness, (b) unawareness was associated with the lack of diversity in EEG alpha-rhythmic microstates, and (c) the probability for the occurrence and duration of delta-, theta- and slow-alpha-rhythmic microstates were associated with unawareness, whereas the probability for the occurrence and duration of fast-alpha-rhythmic microstates were associated with consciousness. In conclusion, resting EEG has a potential value in revealing NCC. This work may have implications for clinical care and medical-legal decisions in patients with disorders of consciousness.