A recent study found that 25% of patients in the unresponsive state responded cognitively to instructions in a brain scan.
A recent study has found that approximately one in four people with disorders of consciousness, such as coma or a state of minimal consciousness, can still have cognitive functions.
Although they cannot move or speak, brain scans showed that these people are sometimes able to perform cognitive tasks by following instructions.
The study analyzed the participant data between 2006 and 2023collected in various health centers of six multinationals, some of them European.
It was analyzed the prevalence of “cognitive motor dissociation” based on data from 353 patients who had suffered severe brain injuries following events such as severe trauma, stroke or lack of oxygen following a myocardial infarction.
What is cognitive motor dissociation
“Cognitive motor dissociation” describes a state in which individuals who cannot physically respond to commands continue to show brain activity in areas typically responsible for movement.
“Some patients with severe brain injuries do not appear to be processing their external world. However, when evaluated with advanced techniques such as task-based fMRI and electroencephalography, we can detect brain activity that suggests otherwise,” he says in a statement from Dr. Yelena Bodienlead author of the study, from Harvard Medical School and the Massachusetts General Hospital Research Institute (USA).
Inconclusive but promising results
The results were published in the journal ‘New England Journal of Medicine‘. The patients were divided into two groups: 241 who did not respond to the bedside tests and 112 who did.
The study found that about 25% of those in the non-responsive group could perform mental tasks and showed patterns of brain activity similar to those of healthy people when given the same instructions.
The other group fared a little better, since 38% showed constant brain activity during scans.
However, although they responded observably to orders received at the patient’s bedside, more than 60% of them showed no response to commands on the scanners.
Conscious responses despite brain damage, this was the study
The state of consciousness, or mental activity, was assessed using one or both types of brain scans. The first, the fMRI (fMRI), was used to measure brain activity by observing blood flow and oxygen levels in the brain.
The other scanner was a electroencephalography (EEG), which involved using a cap covered with electrodes on the person’s scalp to directly measure their brain wave activity.
According to the study, “most participants underwent fMRI or EEG, and some (35%) underwent both.” During the scans, patients were given instructions such as “imagine opening and closing your hand,” and after 15 to 30 seconds, “stop imagining opening and closing your hand.”
The scientists were able detect brain activity following instructions in some of the patients for several minutes, even in the absence of physical response.
“We found that this type of abrupt dissociation between preserved cognitive abilities and the absence of behavioral evidence of them is not uncommon,” declared in a statement Dr. Nicholas Schiff, lead author of the study, from Weill Cornell Medical College in the United States. “I think that We now have an ethical obligation to commit to these patientsto try to help them connect with the world,” he added.
