Recent research shows that in patients who are unable to react to their environment, 25% of them still possess unrecognized cognitive functions.
Over the past two decades of research, scientists have been exploring the prevalence of “cognitive motor dissociation,” where patients are unable to respond to traditional bedside cognitive tests but show signs of consciousness through functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) tests.
A 15-year study found that close to a quarter of these patients still have some level of hidden consciousness. This new finding highlights the importance of these patients being able to live a more fulfilling life with appropriate external assistance, despite facing cognitive impairments. The research results were published on August 14 in the
New England Journal of Medicine
.
Human consciousness remains a major mystery in the scientific community. Many theories have been proposed to explore its nature, some even questioning whether this incomprehensible cognition stems from quantum processes that we do not yet understand. As debates in science and philosophy continue to heat up, experts have become more adept at detecting consciousness even in patients who show no outward signs of awareness.
Part of these scientific breakthroughs is due to our deeper understanding of how the brain operates, with technologies like fMRI and EEG providing unprecedented opportunities for scientists to observe how our neurons and synapses in the brain respond to external stimuli.
Currently, a study spanning 15 years and involving six major research institutions in the US, UK, and Europe, on 241 unresponsive “vegetative state” patients, found that when examined using fMRI and EEG, nearly a quarter of the patients exhibited signs of consciousness.
“Some severely brain-injured patients may seem unaware of the external world,” said Dr. Yelena Bodien from Massachusetts General Hospital, the lead author of the study, in a press release. “However, when we conducted assessments using advanced techniques like task-based fMRI and EEG, we found evidence of brain activity that suggests the situation may be different than previously thought. These results raise a series of crucial ethical, clinical, and scientific questions – such as how we can harness these unrecognized cognitive abilities to establish communication bridges and promote further recovery for patients?”
While the discovery of hidden cognition in unresponsive patients is not new, the extent of this phenomenon has always been unclear. In 2006, scientists in the UK identified signs of consciousness in a patient at Cambridge by having her imagine playing tennis, with the brain scan results surprisingly resembling those of healthy individuals imagining the same activity. To explore the prevalence of this phenomenon, neuroscientist authority from Cornell University and lead author of the new study, Nicolas Schiff, began conducting more tests on patients in similar conditions.
The research team selected 241 patients who showed no response in routine bedside cognitive tests, which included various tasks and questions to measure consciousness, executive function, memory, and attention. Patients were asked to imagine performing a specific action (e.g., “imagine clapping hands”), while healthy volunteers physically carried out the same action. After collecting data, the results were sent to statisticians at the Icahn School of Medicine at Mount Sinai without revealing which study group they came from. The results showed that 60 patients exhibited consciousness signs similar to the healthy control group.
Schiff stated in a press release, “The preservation of cognitive abilities without behavioral evidence is not uncommon. We now have an ethical responsibility to reach out to these patients and help them connect with the world. What is needed is sustained action, as our alliance has strived for over the past two decades, through systematic medical research, technological advancements, and improvement of clinical infrastructure, to assist these patients with consciousness impairments.”
With an increasing awareness of the prevalence of cognitive motor dissociation and advancements in brain implant technology, scientists are hopeful in alleviating the trauma experienced by these patients.