According to a new study, people with brain injuries who otherwise appear to be utterly unresponsive may really be showing symptoms of covert consciousness—subtle brainwaves that may be picked up by an EEG—which are the best predictors of future recovery.

The findings show that brainwave analysis has the potential to revolutionize the management of patients with severe brain damage who are unresponsive.

The findings of the study were presented in Lancet Neurology.

One of the most challenging aspects of ICU care, according to study leader Jan Claassen, is determining whether a non-responsive patient with a brain injury is likely to get better and identifying those who may benefit most from rehabilitation.

Even with standard bedside examinations, clinical results are not always predictable.

Doctors commonly assess the prognosis of brain-injured patients in the intensive care unit by asking them to respond to a simple verbal instruction, such as “move your hand” or “stick out your tongue.”

It is assumed that those who do not comply with these directives are unconscious. Injuries may be deemed so serious that patients are unlikely to regain consciousness in the absence of any other possible explanations for this lack of responsiveness.

According to Claassen, “but in some rare cases, unresponsive patients do eventually regain consciousness and may make meaningful progress toward recovering many day-to-day functions many months later.” 

“We just don’t have a reliable way to predict who those patients are.” 

In a prior study, Claassen and colleagues discovered that while many brain-damaged patients are unable to physically respond to spoken directions, a small number of them do so through generating brainwave activity, indicating they may still be conscious.

“We found that covert consciousness is an independent predictor of recovery, stronger than any other established factor we looked at, including the patient’s age, initial Glasgow Coma Scale score (a standard measure of the extent of the neurological injury), or the cause of the brain injury,” Claassen adds. “In the future, cognitive-motor dissociation may be another factor to consider when assessing a patient’s prognosis.” 

Currently, only a few centers are employing EEG to examine covert consciousness, and it requires a great degree of biomedical skill to detect it.

The artificial intelligence software and methodology are being improved by Claassen’s team so that EEG might be used to detect hidden consciousness in all ICUs.

The researchers are looking at the fundamental principles of covert awareness in order to better understand why a patient who displays brainwave activity in response to various motor orders but is not paralyzed cannot physically act on these commands.

They are also interested in investigating the relationships between covert consciousness levels and therapeutic outcomes.

This is known as cognitive-motor dissociation or hidden consciousness, and it can be detected using specialized artificial intelligence software applied to regular EEG data recorded while patients listen to motor directions. (The investigators made this machine learning algorithm publicly accessible with their prior publication.)

The previous study discovered that patients with covert consciousness had a higher chance of making a full recovery, but the sample size was insufficient to assess the potential utility of EEG in predicting patient outcomes when combined with other established predictors.

The question of whether the presence of hidden consciousness can accurately predict which patients will make a significant recovery over the course of the following 12 months was addressed in the new study, which involved a bigger group of patients.

27 out of 193 patients had hidden consciousness (14 percent ). The rates of recovery were consistently greater and quicker for those with covert consciousness than for those without it.

Within a year, 41 percent of patients with covert consciousness recovered completely, compared to 10 percent of patients who did not have covert consciousness.

While individuals without covert consciousness who recovered took far longer to exhibit symptoms of improvement, the majority of patients with covert consciousness started to heal after three months.

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