Circadian Rhythmicity During Coma Awakening

Acute brain injury is a major cause of admission to intensive care units, as well as of mortality and morbidity, worldwide and for all age groups. With most patients surviving these injuries thanks to recent medical advances, society is facing not only the growing burden of disability, but above all the ethical issues involved in withdrawal of life-sustaining therapies (WSLT). To resolve this dilemma, effective treatment would be necessary, but this is hampered by our limited knowledge of the pathophysiological mechanisms of the natural history of coma, from onset to recovery. A more systematic description of coma awakening using a multimodal battery in intensive care unit patients would enable us to refine the awakening and re-emergence of consciousness and define appropriate biomarkers for selecting candidates in interventional studies. The investigators hypothesize that the current postulate of successive stages (i.e. from one clinical class to the next) of coma recovery is incomplete, as it does not take into account the rhythmic nature of wakefulness. The investigators propose that the best correlate of the natural history of coma recovery is a gradual shift from the loss of physiological cycles to a circadian rhythmicity of arousal indices (behavioural and neurophysiological) and a wide amplitude of metric fluctuations in assessing content richness.