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Somatosensory attention identifies both overt and covert awareness in disorders of consciousness

Gibson, R. M., Chennu, S., Fernandez-Espejo, D., Naci, L., Owen, A. M., Cruse, D. (2016) Somatosensory attention identifies both overt and covert awareness in disorders of consciousness. Annals of Neurology, 80 (3). pp. 412-423. ISSN 0364-5134. E-ISSN 1531-8249. (doi:10.1002/ana.24726) (KAR id:58786)

Abstract

Objective

Some patients diagnosed with disorders of consciousness retain sensory and cognitive abilities beyond those apparent from their overt behavior. Characterizing these covert abilities is crucial for diagnosis, prognosis, and medical ethics. This multimodal study investigates the relationship between electroencephalographic evidence for perceptual/cognitive preservation and both overt and covert markers of awareness.

Methods

Fourteen patients with severe brain injuries were evaluated with an electroencephalographic vibrotactile attention task designed to identify a hierarchy of residual somatosensory and cognitive abilities: (1) somatosensory steady-state evoked responses, (2) bottom-up attention orienting (P3a event-related potential), and (3) top-down attention (P3b event-related potential). Each patient was also assessed with a clinical behavioral scale and 2 functional magnetic resonance imaging assessments of covert command following.

Results

Six patients produced only sensory responses, with no evidence of cognitive event-related potentials. A further 8 patients demonstrated reliable bottom-up attention-orienting responses (P3a). No patient showed evidence of top-down attention (P3b). Only those patients who followed commands, whether overtly with behavior or covertly with functional neuroimaging, also demonstrated event-related potential evidence of attentional orienting.

Interpretation

Somatosensory attention-orienting event-related potentials differentiated patients who could follow commands from those who could not. Crucially, this differentiation was irrespective of whether command following was evident through overt external behavior, or through covert functional neuroimaging methods. Bedside electroencephalographic methods may corroborate more expensive and challenging methods such as functional neuroimaging, and thereby assist in the accurate diagnosis of awareness.

Item Type: Article
DOI/Identification number: 10.1002/ana.24726
Subjects: Q Science
Divisions: Divisions > Division of Computing, Engineering and Mathematical Sciences > School of Computing
Depositing User: Srivas Chennu
Date Deposited: 18 Nov 2016 14:04 UTC
Last Modified: 04 Mar 2024 17:18 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/58786 (The current URI for this page, for reference purposes)

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