Covert consciousness: what’s in a name?

Over the past decade, it has become apparent that up to 25% of behaviorally unresponsive patients with acute or chronic disorders of consciousness either reveal high spatio-temporal complexity following a direct electrical or magnetic pulse to the brain, or highly differentiated electroencephalographic responses, or can, voluntarily modulate their brain activity on command, each of which has been interpreted, to varying degrees, as evidence of consciousness. Practitioners designate this phenomenon using a dizzying variety of terms. The realization that unresponsiveness does not equate to unconsciousness changes the way patients should be assessed and how the medical team communicates with the patient, their families and the world at large. We here propose that the term covert consciousness be used in all such communications to designate this subcategory of behavioral unresponsive patients, with context-appropriate qualifiers and counseling accompanying its use.