Swallowing dysfunctions in patients with disorders of consciousness: Evidence from neuroimaging data, assessment, and management

Issue title: Disorders of Consciousness: A Field in Flux

Guest editors: Caroline Schnakers and Nathan D. Zasler

Article type: Research Article

Authors: Regnier, Amandine^{a; b; c} | Mélotte, Evelyne^a | Aubinet, Charlène^{a; b; d} | Alnagger, Naji^{a; b} | Fischer, David^e | Lagier, Aude^f | Thibaut, Aurore^{a; b} | Laureys, Steven^{a; b; g} | Kaux, Jean-François^c | Gosseries, Olivia^{a; b; *}

Affiliations: [a] Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium | [b] Centre du Cerveau, University Hospital of Liège, Liège, Belgium | [c] Department of Physical and Rehabilitation Medicine, University Hospital of Liège, Liège, Belgium | [d] Psychology and Neuroscience of Cognition Research Unit, University of Liège, Liège, Belgium | [e] Department of Neurology, Division of Neurocritical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA | [f] Department of Otorhinolaryngology, University Hospital of Liège, Liège, Belgium | [g] Joint International Research Unit on Consciousness, CERVO Brain Research Centre, CIUSS, Laval University, Québec, QC, Canada

Correspondence: [*] Address for correspondence: Olivia Gosseries. E-mail: ogosseries@uliege.be.

Abstract: Following severe brain injuries, a subset of patients may remain in an altered state of consciousness; most of these patients require artificial feeding. Currently, a functional oral phase and the presence of exclusive oral feeding may constitute signs of consciousness. Additionally, the presence of pharyngo-laryngeal secretions, saliva aspiration, cough reflex and tracheostomy are related to the level of consciousness. However, the link between swallowing and consciousness is yet to be fully understood. The primary aim of this review is to establish a comprehensive overview of the relationship between an individual’s conscious behaviour and swallowing (reflexive and voluntary). Previous studies of brain activation during volitional and non-volitional swallowing tasks in healthy subjects are also reviewed. We demonstrate that the areas activated by voluntary swallowing tasks (primary sensorimotor, cingulate, insula, premotor, supplementary motor, cerebellum, and operculum) are not specific to deglutitive function but are shared with other motor tasks and brain networks involved in consciousness. This review also outlines suitable assessment and treatment methods for dysphagic patients with disorders of consciousness. Finally, we propose that markers of swallowing could contribute to the development of novel diagnostic guidelines for patients with disorders of consciousness.

Keywords: Deglutition, deglutition disorders, dysphagia, consciousness disorders, neuroimaging, speech therapy

DOI: 10.3233/NRE-230135

Journal: NeuroRehabilitation, vol. 54, no. 1, pp. 91-107, 2024