New research co-led by experts at Mass General Brigham found that brain scans can detect consciousness in some patients with brain injury who are unresponsive. 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. During these tests, participants heard instructions, such as "imagine opening and closing your hand" followed, 15-30 seconds later by "stop imagining opening and closing your hand.
" The fMRI and EEG brain responses showed that 60 (25 percent) of participants repeatedly followed this instruction covertly over minutes. According to the authors of the study, published August 15 in the New England Journal of Medicine, patients who demonstrate this phenomenon, called cognitive motor dissociation, understand language, remember instructions and can sustain attention, even though they appear unresponsive. For these patients, cognitive (i.
e., thinking) abilities exceed, and are therefore dissociated from, motor abilities. Some patients with severe brain injury do not appear to be processing their external world.
However, when they are assessed with advanced techniques such as task-based fMRI and EEG, we can detect brain activity that suggests otherwise. These results bring up critical ethical, clinical, and scientific questions – such as how can we harness that unseen cognitive capacity to establish a system of communication and promot.