Electrophysiological Signatures of Cognitive Disorders Related to ICU Delirium : a Pilot Study

Delirium is an altered mental status associated with specific manifestations such as reduced ability to direct, focus, maintain and shift attention Diagnostic Medical Systems V criteria (DSM). The vulnerability of critically-ill acute respiratory distress syndrome (ARDS) patients explains the high incidence of delirium (up to 80%) in this setting. Delirium is an independent predictor of post-traumatic stress disorder, long term cognitive decline and mortality. To reduce this medical and social burden, a more complete description of delirium is needed both in terms of cognitive impairments and long term neurological and neuropsychological impact. Actually, it could be argued that the current exclusive behavioral assessment of these patients is insufficient in terms of diagnosis and prognostic assessment. In recent years, the study of consciousness has made major progress thanks to the use of innovative electrophysiological exploration methods. This work has notably allowed the development of new non-behavioral tools for the exploration of brain function in brain damaged patients in response to complex auditory stimulations (multidimensional electrophysiological battery, mEEG). In this context, the investigators have recently demonstrated alterations in cognitive functions related to language- and self-processing in acute respiratory distress syndrome (ARDS) patients with severe acute respiratory syndrome (SARS) - COVID-19 infection. These electrophysiological cognitive alterations were particularly marked in COVID-19 patients with delirium. Further studies are needed to disentangle the cognitive impact specifically related to delirium from that related to a severe form of COVID-19. The primary objective of this study is to identify diagnostic electrophysiological signatures of cognitive dysfunctions associated with the acute phase of delirium in critically-ill acute respiratory distress syndrome (ARDS) patients using a multidimensional electrophysiological assessment (mEEG) recording at rest and during auditory stimulation (first visit). Secondary objectives are to characterize the impact of intensive care unit (ICU)-related delirium on neurocognitive and psychological dysfunctions observed at 6 months (second visit), in order to explore the prognostic predictive value of electrophysiological data acquired during the acute phase of delirium.