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Detecting the Potential for Consciousness in Unresponsive Patients Using the Perturbational Complexity Index

Covert Cognition in Disorders of Consciousness: A Meta-Analysis

Casa Colina Hospital and Centers for Healthcare, Pomona, CA 917697, USA
Department of Psychology, University of California Los Angeles, Los Angeles, CA 90095, USA
NEURORHB, Servicio de Neurorrehabilitación de Hospitales Vithas, 46011 València, Spain
Neurorehabilitation and Brain Research Group, Instituto de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, 46022 València, Spain
GIGA-Consciousness, Coma Science Group, University of Liège, 4000 Liège, Belgium
ReGen Rehabilitation Hospital, Petaling Jaya 46200, Malaysia
Servicio de Terapia Ocupacional, Clínica Universitaria Reina Fabiola, Universidad Católica de Córdoba, Córdoba X5000 IYG, Argentina
School of Physical and Occupational Therapy, McGill University, Montreal, QC H3A 0G4, Canada
Ageing Research Centre, Health Research Institute, School of Allied Health, University of Limerick, V94 T9PX Limerick, Ireland
IRCCS Fondazione Don Carlo Gnocchi, 50143 Florence, Italy
Neurology Unit, Santa Maria della Pietà General Hospital, 80035 Nola, Italy
Author to whom correspondence should be addressed.
Brain Sci. 2020, 10(12), 930;
Received: 1 October 2020 / Revised: 16 November 2020 / Accepted: 24 November 2020 / Published: 2 December 2020
(This article belongs to the Special Issue Recent Advances in the Study of Altered State of Consciousness)
Covert cognition in patients with disorders of consciousness represents a real diagnostic conundrum for clinicians. In this meta-analysis, our main objective was to identify clinical and demographic variables that are more likely to be associated with responding to an active paradigm. Among 2018 citations found on PubMed, 60 observational studies were found relevant. Based on the QUADAS-2, 49 studies were considered. Data from 25 publications were extracted and included in the meta-analysis. Most of these studies used electrophysiology as well as counting tasks or mental imagery. According to our statistical analysis, patients clinically diagnosed as being in a vegetative state and in a minimally conscious state minus (MCS−) show similar likelihood in responding to active paradigm and responders are most likely suffering from a traumatic brain injury. In the future, multi-centric studies should be performed in order to increase sample size, with similar methodologies and include structural and functional neuroimaging in order to identify cerebral markers related to such a challenging diagnosis. View Full-Text
Keywords: severe brain injury; consciousness; vegetative state; minimally conscious state; covert cognition; cognitive motor dissociation severe brain injury; consciousness; vegetative state; minimally conscious state; covert cognition; cognitive motor dissociation
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MDPI and ACS Style

Schnakers, C.; Hirsch, M.; Noé, E.; Llorens, R.; Lejeune, N.; Veeramuthu, V.; De Marco, S.; Demertzi, A.; Duclos, C.; Morrissey, A.-M.; Chatelle, C.; Estraneo, A. Covert Cognition in Disorders of Consciousness: A Meta-Analysis. Brain Sci. 2020, 10, 930.

AMA Style

Schnakers C, Hirsch M, Noé E, Llorens R, Lejeune N, Veeramuthu V, De Marco S, Demertzi A, Duclos C, Morrissey A-M, Chatelle C, Estraneo A. Covert Cognition in Disorders of Consciousness: A Meta-Analysis. Brain Sciences. 2020; 10(12):930.

Chicago/Turabian Style

Schnakers, Caroline, Michaela Hirsch, Enrique Noé, Roberto Llorens, Nicolas Lejeune, Vigneswaran Veeramuthu, Sabrina De Marco, Athena Demertzi, Catherine Duclos, Ann-Marie Morrissey, Camille Chatelle, and Anna Estraneo. 2020. "Covert Cognition in Disorders of Consciousness: A Meta-Analysis" Brain Sciences 10, no. 12: 930.

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