Results of a ground-breaking study, the first of its kind and which has been published in The New England Journal of Medicine at an international level, reveal the shocking truth that at least one in four patients who have suffered serious brain trauma and seem unresponsive is conscious. It is such a discovery that knocked off previous theories on the patients in vegetative and minimally conscious states, that they were farther away from the real awareness of their surroundings.
One such study, led by Nicholas Schiff, a neurologist at Weill Cornell Medicine in New York City, studied 353 brain-injured patients from trauma, cardiac, or stroke origins. Of these 353, 241 could not physically respond to bedside tests—for example, raising an arm on command or flicking their thumbs up. Advanced brain scans told a different story.
Using functional magnetic resonance imaging and electroencephalography, researchers asked a group of participants to imagine themselves performing activities such as playing tennis or just merely opening and closing their hands. Astonishingly, about 25% of those who otherwise showed no physical response demonstrated the same brain activity patterns as healthy people. Known as cognitive motor dissociation, this means such patients can process commands in their brains, even when they cannot act on them physically.
Daniel Kondziella, a neurologist from Rigshospitalet, the teaching hospital for Copenhagen University, commented: “This is one of the very big landmark studies in the field of coma and other consciousness disorders.” This means that a lot of probably vegetative patients who seem unresponsive can actually hear the world around them and potentially even communicate back if taught to use brain-computer interfaces. Implanted in patients’ brains, these devices decode neural activity in a way that may allow the patients to interact with the real world.
“The implications of this study are huge,” said Schiff. “We should be allocating resources to go out and find these people and help them.”if a patient is known to be conscious, this can change everything in terms of decisions about life support and treatment, offering hope to the family and medical team.
The study, involving 238 patients at six medical centers in Belgium, France, the UK, and the US, noted some of its limitations. Differences in the numbers and types of stimuli that the patients were subjected to for the EEG and fMRI testing, and the number of electrodes placed for the EEGs, could all have influenced the results. Even so, the study probably lowballs the number of patients who are awake and cognizant but unable to respond.
Furthermore, Kondziella also commented that the highest rates of cognitive motor dissociation had been achieved from patients tested with both EEG and fMRI. It is safe to say that if every participant had been tested with both method combinations, overall rates might even be higher. However, these tests are of high computational and logistic demand, so that their use cannot be general.
The researchers also noted that the patients best responsive to showing brain activity were younger, had suffered the injury through physical trauma, and had been living with their injury for longer periods. Further studies, however, are required to indicate the trajectories of recovery of consciousness with time and across different types of brain injuries.
In the end, the work highlights a critically important reason to try to identify and assist all of these conscious patients. “There are going to be people we can help get out of this condition,” Schiff said, by BCIs, other treatments, or continued medical care. Every time a responsive patient is discovered, it can have a profound impact, not only on the patient’s care but on the decisions made by his or her family.