title: Multidimensional cognitive evaluation of patients with disorders of consciousness using EEG: A proof of concept study.
abstract: The use of cognitive evoked potentials in EEG is now part of the routine evaluation of non-communicating patients with disorders of consciousness in several specialized medical centers around the world. They typically focus on one or two cognitive markers, such as the mismatch negativity or the P3 to global auditory regularity. However it has become clear that none of these markers in isolation is at the same time sufficiently specific and sufficiently sensitive to be taken as the unique gold standard for diagnosing consciousness. A good way forward would be to combine several cognitive markers within the same test to improve evaluation. Furthermore, given the diversity of lesions leading to disorders of consciousness, it is important not only to probe whether a patient is conscious or not, but also to establish a more general and nuanced profile of the residual cognitive capacities of each patient using a combination of markers. In the present study we built a unique EEG protocol that probed 8 dimensions of cognitive processing in a single 1.5 h session. This protocol probed variants of classical markers together with new markers of spatial attention, which has not yet been studied in these patients. The eight dimensions were: (1) own name recognition, (2) temporal attention, (3) spatial attention, (4) detection of spatial incongruence (5) motor planning, and (6,7,8) modulations of these effects by the global context, reflecting higher-level functions. This protocol was tested in 15 healthy control subjects and in 17 patients with various etiologies, among which 13 could be included in the analysis. The results in the control group allowed a validation and a specific description of the cognitive levels probed by each marker. At the single-subject level, this combined protocol allowed assessing the presence of both classical and newly introduced markers for each patient and control, and revealed that the combination of several markers increased diagnostic sensitivity. The presence of a high-level effect in any of the three tested domains distinguished between minimally conscious and vegetative patients, while the presence of low-level effects was similar in both groups. In summary, this study constitutes a validated proof of concept in favor of probing multiple cognitive dimensions to improve the evaluation of non-communicating patients. At a more conceptual level, this EEG tool can help achieve a better understanding of disorders of consciousness by exploring consciousness in its multiple cognitive facets.
authors.affiliation: Laboratoire Psychologie de la Perception, Université Paris Descartes et Centre National de la Recherche Scientifique, UMR8242, 45 rue des Saints Pères, 75006 Paris, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Sergent
authors.affiliation: AP-HP, Groupe hospitalier Pitié-Salpêtrière, Department of Neurology, Paris, France; AP-HP, Hôpital Henri Mondor-Albert Chenevier, Neurological Unit, Créteil, France; AP-HP, Groupe hospitalier Pitié-Salpêtrière, Department of Neurophysiology, Paris, France; INSERM, U 1127, F-75013 Paris, France; Institut du Cerveau et de la Moelle épinière, ICM, PICNIC Lab, F-75013 Paris, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Faugeras
authors.affiliation: AP-HP, Groupe hospitalier Pitié-Salpêtrière, Department of Neurology, Paris, France; Institut du Cerveau et de la Moelle épinière, ICM, PICNIC Lab, F-75013 Paris, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Rohaut
authors.affiliation: Auditory Cognition and Psychoacoustics Team, Lyon Neuroscience Research Center (UCBL, CNRS UMR5292, Inserm U1028), Lyon, France.
authors.forename: Fabien
authors.initials: F
authors.lastname: Perrin
authors.affiliation: Institut du Cerveau et de la Moelle épinière, ICM, PICNIC Lab, F-75013 Paris, France.
authors.forename: Mélanie
authors.initials: M
authors.lastname: Valente
authors.affiliation: Cognitive Neuroscience Laboratory, Institut National de la Santé et de la Recherche Médicale (INSERM)-École Normale Supérieure (ENS), Paris, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Tallon-Baudry
authors.affiliation: AP-HP, Groupe hospitalier Pitié-Salpêtrière, Department of Neurology, Paris, France; Institut du Cerveau et de la Moelle épinière, ICM, PICNIC Lab, F-75013 Paris, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Cohen
authors.affiliation: AP-HP, Groupe hospitalier Pitié-Salpêtrière, Department of Neurology, Paris, France; Institut du Cerveau et de la Moelle épinière, ICM, PICNIC Lab, F-75013 Paris, France.
authors.forename: Lionel
authors.initials: L
authors.lastname: Naccache
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D015415:Biomarkers; D002985:Clinical Protocols / Q000592:standards*; D003244:Consciousness Disorders / Q000175:diagnosis*; D004569:Electroencephalography / Q000379:methods*; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D055815:Young Adult
chemical_list: D015415:Biomarkers
keywords: ADAN, Anterior Directing Attention Negativity; Attention; CNV, contingent negative variation; Cognition; DOC, disorders of consciousness; Disorders of consciousness; EEG; Event related potentials; LRP, lateralized readiness potential; MCS, minimally conscious state; Non-communicating patients; VS, vegetative state