Published February 7, 2018 | Version v1

Transcranial direct current stimulation unveils covert consciousness

Description

The present report shows the case of a patient who came with the diagnosis of UWS and who was then diagnosed as being in MCS minus following repeated standardized behavioral assessments. Neuroimaging data further suggested that the patient presented preservation of brain activity closer to what is usually observed in healthy subjects. The presence of a minimal sign of consciousness (i.e., localization to noxious stimuli) was only observed once out of seven behavioral assessments, and active tasks using fMRI and EEG suggested the presence of covert command-following. During this week of assessments, overt response to command was never observed at the patient's bedside. This behavior was solely seen following the experimental procedure of tDCS, after which the patient could reproducibly answer a simple behavioral command. Based on these findings, we hypothesize that tDCS may facilitate motor execution of the command when cognitive functions are preserved in patients with cognitive-motor dissociation.

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Additional details

Funding

European Commission
HBP SGA1 - Human Brain Project Specific Grant Agreement 1 720270
European Commission
LUMINOUS - Studying, Measuring and Altering Consciousness through information theory in the electrical brain 686764