For nearly two decades, scientists have been delving into the phenomenon of “cognitive motor dissociation,” a condition in which patients appear unresponsive to standard cognitive tests yet exhibit signs of consciousness when examined through advanced techniques like fMRI and EEG. A recent 15-year study has revealed that nearly one-quarter of such patients may indeed experience a form of hidden consciousness, a discovery that underscores the importance of improving the quality of life for these individuals.
Consciousness remains one of science’s greatest enigmas, with numerous theories attempting to explain its existence. Some even speculate that consciousness may arise from quantum processes beyond our current understanding. Despite the ongoing debates in both scientific and philosophical circles, experts have become increasingly skilled at detecting consciousness, even in individuals who show no overt signs of it.
This progress can largely be attributed to our growing understanding of brain function and the development of sophisticated technologies like functional MRI (fMRI) and electroencephalography (EEG). These tools provide researchers with unprecedented insight into how the brain responds to external stimuli. In a 15-year study involving 241 patients in an unresponsive, “vegetative” state across six research institutions in the U.S., U.K., and Europe, nearly one-quarter of the patients exhibited evidence of consciousness when examined using fMRI and EEG.
This finding sheds light on the relatively understudied disorder known as “cognitive motor dissociation,” where patients do not respond to traditional cognitive tests but show signs of consciousness when asked to imagine specific tasks. The study’s results were published in *The New England Journal of Medicine*.
“Some patients with severe brain injury do not appear to be processing their external world,” explained Yelena Bodien of Massachusetts General Hospital, the study’s lead author. “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 promote further recovery?”
While the discovery of hidden cognition in unresponsive patients is not entirely new, the prevalence of this condition was previously unknown. In 2006, scientists identified consciousness in a patient in Cambridge, England, by asking her to imagine playing tennis. When the brain activity was compared to that of a healthy individual imagining the same task, the results were strikingly similar. To further explore the prevalence of this condition, Nicolas Schiff, a leading neuroscientist at Cornell University and senior author of the new study, decided to conduct additional tests on patients in similar states.
The researchers selected 241 patients who did not respond to conventional bedside cognitive tests. These tests typically include various tasks and questions designed to assess consciousness, as well as executive function, memory, and attention. Like the 2006 patient, the study participants were asked to imagine specific tasks, such as “imagine opening and closing your hand,” and healthy volunteers were asked to perform the same function. The data collected was then analyzed by statisticians at the Icahn School of Medicine at Mount Sinai, who were unaware of which results came from which research group. The analysis revealed that 60 out of the 241 patients displayed signs of consciousness similar to the healthy control group.
“We find that this kind of sharp dissociation of retained cognitive capabilities and no behavioral evidence of them is not uncommon,” Schiff noted in a press statement. “I think we now have an ethical obligation to engage with these patients, to try to help them connect to the world. What we need here is what we in our consortium have been trying to get started for twenty years: a sustained effort to benefit patients who have disorders of consciousness with systematic medical research, technology development, and better clinical infrastructure.”
The growing awareness of the widespread nature of cognitive motor dissociation, coupled with ongoing advancements in brain implant technology, could significantly mitigate the trauma experienced by these patients. Now that we understand that some “vegetative” patients may be aware of their surroundings, it becomes a moral imperative to assist them in leading more fulfilling lives.
