Compelling advances in the ability to detect signs of consciousness in unconscious patients who have experienced traumatic brain injury (TBI) are leading to unprecedented changes in the field. There is now hope of improving outcomes and even sparing lives of patients who may otherwise have been mistakenly assessed as having no chance of recovery.
A recent key study represents a tipping point in the mounting evidence of the ability to detect “covert consciousness” in patients with TBI who are in an unconscious state. That research, published in The New England Journal of Medicine (NEJM) in June 2019, linked the promising signals of consciousness in comatose patients, detected only on imaging, with remarkable outcomes a year later.
“This was a landmark study,” said Brian L. Edlow, MD, in a presentation on the issue of covert consciousness during the American Neurological Association’s 2020 virtual annual meeting.
“Importantly, it is the first compelling evidence that early detection of covert consciousness also predicts 1-year outcomes in the Glasgow Outcome Scale Extended (GOSE), showing that covert consciousness in the ICU appears to be relevant for predicting long-term outcomes,” said Edlow, who is associate director of the Center for Neurotechnology and Neurorecovery, Massachusetts General Hospital, in Boston.
The researchers showed that 15% of unconscious patients with acute brain injury in the study exhibited significant brain activity on EEG in response to stimuli that included verbal commands such as envisioning that they are playing tennis.
Although other studies have shown similar effects with task-based stimuli, the NEJM study further showed that a year later, the patients who had shown signs of covert consciousness, also called “cognitive motor dissociation” (CMD), were significantly more likely to have a good functional outcome, said the study’s senior author, Jan Claassen, MD, director of critical care neurology at Columbia University, in New York City, who also presented during the ANA session.
“Importantly, a year later after injury, we found that 44% of patients with CMD and only 14% of non-CMD patients had a good functional outcome, defined as a GOSE score indicating a state where they can at least take care of themselves for 8 hours in a day,” he said.
“[Whether] these patients in a CMD state represent a parallel state or a transitory state on the road to recovery remains to be shown,” he said.
Jennifer Frontera, MD, a professor in the Department of Neurology at NYU Langone in New York City and co-moderator of the session, agreed that the research is “remarkable.”
“Also, it is practical, since many could potentially apply and validate his algorithms, since EEG technology is portable and widely available,” she told Medscape Medical News.
Research Has Ushered in a “Sea Change” in Neuro-Critical Care
The research has helped push forward recommendations on the treatment of unconscious patients, Edlow said.
“This has led to a sea change in our field just over the last 2 years, with multiple guidelines published suggesting that it may be time for us to consider incorporating task-based fMRI and EEG