What names for covert awareness? A systematic review

• Published in: Frontiers in human neuroscience 2022-08, Vol.16, p.971315-971315
• Main Authors: Schnakers, Caroline, Bauer, Chase, Formisano, Rita, Noé, Enrique, Llorens, Roberto, Lejeune, Nicolas, Farisco, Michele, da Conceição Teixeira, Liliana, Morrissey, Ann-Marie, De Marco, Sabrina, Veeramuthu, Vigneswaran, Ilina, Kseniya, Edlow, Brian L., Gosseries, Olivia, Zandalasini, Matteo, De Bellis, Francesco, Thibaut, Aurore, Estraneo, Anna
• Format: Article
• Language: English
• Subjects: Brain injury; Cognitive ability; Cognitive motor dissociation; Consciousnes; Consciousness; Cortex (motor); Covert awareness; functional locked-in; Human Neuroscience; Interfaces; MCS; Medical imaging; Minimally conscious state; Names; Neuroimaging; Neurologi; Neurology; Neurosciences & behavior; Neurosciences & comportement; Nomenclature; non-behavioral MCS; Patients; Sciences sociales & comportementales, psychologie; Social & behavioral sciences, psychology; Systematic review; Taxonomy; Traumatic brain injury; Unresponsive wakefulness syndrome; Vegetative state
• ISSN: 1662-5161; 1662-5161
• DOI: 10.3389/fnhum.2022.971315

Funding: MF was supported by the European Union’s Horizon 2020 Framework Programme for Research and Innovation under the Specific Grant Agreement (No. 945539) (Human Brain Project SGA3). After a severe brain injury, some patients do not fully recover consciousness and remain in a prolonged Disorder of Consciousness (DoC) such as the vegetative state/unresponsive wakefulness syndrome (VS/UWS) or the minimally conscious state (MCS). Patients in a VS/UWS open their eyes and present preserved autonomic functions, but they are not conscious and show only reflexive behaviors while the MCS is being characterized by the presence of inconsistent but clearly discernible behavioral signs of consciousness (e.g., visual tracking, command following) (The Multi-Society Task Force on Persistent Vegetative State, 1994; Giacino et al., 2002). More recently, the MCS has been subdivided in two clinical entities, MCS+ and MCS– (characterized by the presence/absence of command-following, intelligible verbalization, and intentional communication) supported by metabolic differences in areas associated with both consciousness and language (e.g., lower metabolism in the precuneus and thalamus and in the left middle temporal cortex in MCS-) (Thibaut et al., 2020). Prolonged DoCs are a relatively rare condition (estimated prevalence of 5,000–42,000 and 112,000–280,000 for VS/UWS and MCS, respectively, in the US) implying severe disability and complete dependence, which can last from 28 days to decades (Giacino et al., 2018)