Tracking attention in a visual active paradigm for the diagnosis of disorders of consciousness

A bstract Background Clinical assessment of patients with disorders of consciousness (DOC) relies on the clinician’s ability to detect a behavioral response to an instruction (e.g., “squeeze my hand”). However, recent studies have shown that some of these patients can produce volitional brain responses to command while no behavioral response is present. This highlights the importance of developing motor-independent diagnostic tool for this population, complementing standardized behavioral evaluation. We here evaluate the ability of a novel gaze-independent attention-based EEG paradigm to detect volitional attentional processes in patients with disorders of consciousness. Methods Thirty patients with DOC were included in the study: 12 with an unresponsive wakefulness syndrome, 16 in a minimally conscious state (MCS), two who emerged from a MCS. Patients were randomly instructed to either concentrate on a task or rest while brain activity was recorded using EEG during a gaze-independent paradigm. Results One of two EMCS, one of 16 MCS and one of 12 UWS patients showed a response to command using the attention task. Interestingly, this method could detect a brain-based response to command in one MCS patient who did not present a behavioral response to command at the bedside the day of the assessment. Conclusion This study show that task-related variation of attention during an active task could help to objectively detect response to command in patients with DOC.