The potential for cognitive motor dissociation in patients who are behaviourally unresponsive after a severe brain injury poses profound ethical challenges. An international study revealed that one in four patients who appear unresponsive to verbal commands is capable of doing cognitive tasks detected through functional MRI or EEG (ie, has cognitive motor dissociation). Cognitive motor dissociation can be considered a subset of covert consciousness—that is, preserved consciousness that evades routine bedside detection.