Sleep-wake behaviour and the EEG in altered states of consciousness
-
1
University of Wollongong, Illawarra Health & Medical Research Institute, School of Psychology, Australia
-
2
University of Zurich, Institute for Pharmacology and Toxicology, Switzerland
-
3
Helios Clinic, Switzerland
-
4
ETH Zurich and University of Zurich, Sensory-Motor Systems Lab, Institute of Robotics and Intelligent Systems, Switzerland
-
5
ETH Zurich and University of Zurich, Neuroscience Center, Switzerland
-
6
University of Zurich, Zurich Center for Integrative Human Physiology, Switzerland
Aims: Sleep-wake behaviour in patients with severe brain damage remains poorly understood. The severe brain damage seen in vegetative and minimal conscious state patients is generally accompanied by alterations in electrical brain activity. Despite this, only few studies have addressed this and generally reported large discrepancies in observations, while also suffering from methodological weaknesses. One important consideration is whether scoring sleep based on standard criteria is appropriate due to the large changes in brain activity. Therefore, in view of these shortcomings and to improve our understanding, there is an urgent need for systematic sleep-wake assessment in these patients, which was the aim of the current study.
Methods: Three ~24h polysomnographic recordings were collected as part of a collaborative project assessing the effectiveness of verticalisation treatment on various physiological parameters in vegetative and minimal conscious state patients. Nine patients (4 males, 5 females) between 18 and 63 years of age (mean ±SEM: 43.9 ± 4.5y) were evaluated at three-week intervals. Data was visually scored, however, as predicted, scoring according to standard criteria was not appropriate and therefore scoring criteria were developed based on common physiological signals seen across patients as well as spectral analysis techniques.
Results: Overall, patients exhibited similar physiological patterns across all three of their recordings, whereas a high variability between patients was observed. A combination of physiological signals and video recordings were required to score sleep and wake-like states. All patients showed signs of sleep and wake-like states, however none showed a clear or typical sleep-wake rhythm.
Conclusion: Sleep and waking in altered states of consciousness disorders does not show a common pattern and is different to that seen in healthy populations. Accordingly, scoring based on standard criteria seems to be inappropriate and quantitative EEG analysis provides additional important information. These aspects should be taken into account for more accurate diagnosis and prognosis, and our understanding of these conditions in the future.
Keywords:
EEG,
vegetative state,
Consciousness Disorders,
Sleep Stages,
brain damage
Conference:
ASP2013 - 23rd Annual meeting of the Australasian Society for Psychophysiology, Wollongong, Australia, 20 Nov - 22 Nov, 2013.
Presentation Type:
Oral Presentation
Topic:
Other...
Citation:
Loughran
S,
Regel
S,
Buetler
L,
Wieser
M,
Riener
R and
Achermann
P
(2013). Sleep-wake behaviour and the EEG in altered states of consciousness.
Conference Abstract:
ASP2013 - 23rd Annual meeting of the Australasian Society for Psychophysiology.
doi: 10.3389/conf.fnhum.2013.213.00052
Copyright:
The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers.
They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.
The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.
Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.
For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.
Received:
02 Oct 2013;
Published Online:
05 Nov 2013.
*
Correspondence:
Dr. Sarah Loughran, University of Wollongong, Illawarra Health & Medical Research Institute, School of Psychology, Wollongong, Australia, loughran@uow.edu.au