Fluctuation of Rhymicity to Predict Recovery

Study Overview
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Brief Summary
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BRIEF SUMMARY : In the most severe cases of brain injuries, intensive care may allow patients with altered consciousness to survive despite a significant risk of heavy sequelae. Persistent impairments of consciousness are currently categorized according to behavior in three main neurological categories: comatose state, vegetative state (recently named unresponsive wakefulness syndrome) and minimally conscious state. Refining the diagnosis of internal state is a major goal to determine the abilities for an optimal recovery of cognitive deficit. Circadian rhythms are implicated in the regulation of sleep-wake cycles but also in cognitive functions. Their role is actually revaluated in the mechanisms of consciousness impairment. First, it is well known that cognitive performances partially depend on such rhythms as they are more elevated during the day and correlated to the hormonal secretion. In a prognostic point of view, fewer rhythmic perturbations during the initial resuscitation period (with reorganized sleep rhythms and the presence of paradoxical sleep) could be associated to a higher functional outcome. However, this internal state of alertness could be highly variable during the day as it might be influenced by specific rhythms such as the circadian rhythm. Only a continuous assessment could help defining them properly. Thus, investigators hypothesize that the circadian restauration, assessed in a dynamic perspective, is associated with the improvement of content and level of awareness. The main challenge of our study is to capture the long-term changes in the evolution of circadian and ultradian rhythms and to keep a part of the natural history of the clinical recovery of these patients. To achieve this goal, the investigators plan to analyze during more than 2 days both neurophysiological rhythms (EEG) and behavioral rhythms of alertness (Eyes scale from of the Glasgow coma scale) in a dataset collected retrospectively from the population of patients continuously monitored by EEG for medical purposes (to identify seizures and prevent status epilepticus) in an intensive care unit of teaching hospital as far as acquisitions last more than 48h and present no prolonged epileptic discharges or artifacts leading to uninterpretable EGG.

Official Title
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Longitudinal Evaluation of Circadian and Ultradian Rhythmic Fluctuations Measured by Continuous EEG During Coma to Predict the Recovery of Consciousness

Conditions
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Coma

Intervention / Treatment
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* Combination Product: No intervention


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult patient Admitted in ICU Altered level of consciousness not explained by a continuous sedation EEG during more than 48h consecutively Exclusion Criteria: Prolonged epileptic discharges leading to uninterpretable EEG rhythms Prolonged artifacts leading to uninterpretable EEG trace

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| One groupe without distinction of age, sexe, and pathology.<br>Patients with strok in coma, with or without wake up, and with disorder of consciousness. No limit in age (maybe give the younger age). We obtain this data from medical record. Every assessment was made of clinical purposes. We use the Glasgow coma recovery scale for assessment of behavior to check the variation of wakefulness. The scale was performed by the nursing staff every 2 to 8 hours depending on the severity of the medical condition. The continuous analysis of neurophysiologic data was based on EEG with a bipolar montage composed of the less noisy electrodes per recording period. The EEG features will include: spectral analysis (relative and absolute power in 4 canonical bands: Delta/Theta/Alpha/Beta) and complexity analysis (DFA, determinism, SVD entropy and permutation entropy). The patient outcome at the ICU and hospital discharges were collected from the medical files. | Combination Product: No intervention<br>* No intervention<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Status of awakening at the end of the period in the hospital | The final outcome to assess the respective predictive value of behavioural assessment in ICU and EEG assessment of circadian and ultradian rhythms will be obtained by the medical record when the patient leave the hospital using a unique functional scale, namely the GOSE (Glasgow Outcome Scale - Extended). We use the Glasgow coma recovery scale for assessment of behavior to check the variation of wakefulness. The scale was performed by the nursing staff every 2 to 8 hours depending on the severity of the medical condition. The continuous analysis of neurophysiologic data was based on EEG with a bipolar montage composed of the less noisy electrodes per recording period. The patient outcome at the ICU and hospital discharges were collected from the medical files. | We analyze data obtained in a period between 2014 to 2017. The analysis is made since January 2020. |