On Aug. 14, 2024, a study co-led by Mass General Brigham found that one in four patients with severe brain injury who appeared unresponsive responded to instructions covertly. Understanding this phenomenon can help guide decisions about life-sustaining treatment, goals of care, and clinical management, according to the authors.

In the study, 241 participants with severe brain injury who do not respond when given a simple instruction were assessed with functional MRI (fMRI), electroencephalography (EEG), or both tests. The fMRI and EEG brain responses showed that 60 (25 percent) of participants repeatedly followed this instruction covertly over minutes. The study results were published in the New England Journal of Medicine.