‘Covert Consciousness’ Can Shine a Light on Brain Health

·3 min read
Kateryna Kon / Science Photo Library
Kateryna Kon / Science Photo Library

Families of people in an unresponsive state due to a severe brain injury are faced with the ongoing, impossible decision of whether to continue life-supporting care. To make matters even more complicated, there is no definitive way to know what a patient’s odds of recovery are, and traditional bedside examinations can miss important signs.

In the early aughts, neurologists discovered the first whispers of a promising method to learn what was really going on in a patient’s brain, through brain activity scans. The idea was to analyze these measurements for signs of covert consciousness, which are signals that patients cannot otherwise express with motion or speech but are present in neuroimaging.

Researchers from Columbia University and New York Presbyterian Hospital have made a big stride in this line of research. A new study published Wednesday in Lancet Neurology shows that patients with evidence of covert consciousness had shorter recovery times and improved outcomes than those without.

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Brian Edlow, a neurologist at Massachusetts General Hospital and Harvard Medical School who was not involved with the study, called the new research “groundbreaking.”

“What families want to know is, ‘Will my loved one be able to recover back to a quality of life that is meaningful to them and acceptable to them, and how long will it take for my loved one to get there?’” he told The Daily Beast. “This study goes a long way in answering both of those questions.”

The study followed 193 acute brain injury patients through their first year of recovery, checking in at three, six, and 12 months post-injury. The researchers applied a machine learning model to the electroencephalograms (EEGs, which record brain waves) of unresponsive patients to detect brain activity in response to verbal commands and determine if a patient displayed covert consciousness.

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Of the patients who recovered within one year, 64 percent who showed covert consciousness did so within three months, compared to 29 percent of patients without covert consciousness.

Jan Claassen, the director of critical care neurology at Columbia University and a senior author of the study, told The Daily Beast the work builds off of a 2019 paper by his team that found an association between covert consciousness and positive outcomes but was too small to draw a causal link. This new study replicates their findings in a larger cohort and was able to show a marked benefit when controlling for other factors that influence recovery, like age.

“We as an academic community need to replicate and validate these findings in larger multicenter studies, but, in my opinion, it is not too soon to start thinking about how these findings might affect our approach to prognostication in the ICU,” Edlow said.

Claassen said that independent validation will help make a convincing case for changing the current standard of care and that “this paper will feed into the discussion.” In the meantime, he is already devising ways to scale the technology equitably across health care centers—publishing the code for his team’s machine learning algorithm is one step, he said, but centers will have to work together to collect and analyze brain activity data.

“What needs to happen is that you can do this in any place, in any hospital, in any rehabilitation place, ideally,” Claassen said.

Read more at The Daily Beast.

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