EEG Could be Read “Hidden Consciousness” in Brain-Injured Patients

Technology does not just expand on its own, exponentially; sometimes we learn new ways to use technology that give them new purpose. For example, a brand new study reveals that electroencephalography (EEG) might offer some benefit to coma patients. 

Essentially, for this study, researchers used EEG to look for any sign of brain activity in a group “brain-injured” patients.  Among those observed using EEG, 15 percent appeared to have despite the loss of mobility and/or speech.

Now, EEG is already a tool commonly used to diagnose other brain disorders, like epilepsy.  This study, however, is the first to show the tool could detect what some researchers have named “preserved consciousness,” in some severe brain injury patients who have not been responsive.  With this tool in hand, the team suspects the method could make it easier for doctors to predict if a brain-injured patient will definitely wake up from their coma; and, in turn, this could help doctors and families make more informed end-of-life decisions. 

Lead study author Jan Classen, MD, PhD is an associate professor of neurology with the Columbia University Vagelos College of Physicians and Surgeons. Classen’s team used EEG to track and measure brain activity of 10 healthy volunteers and 104 patients diagnosed with an acute brain injury and unable to respond to verbal commands. 

Using headphones to deliver a focused but simple list of verbal instructions for each patient, the team analyzed EEG readings. The verbal cues were simple commands like “open” and “close” and “stop”.  The EEG readings indicated that 15 percent of those with an acute brain injury (and unable to respond to spoken commands) actually showed some brain activity in response to these spoken cues. In addition, the study found that 44 percent of these patients showed brain activity on year after injury; and this could be accomplished even without any other assistance for as many as eight hours. 

Only 14 percent of those who did not show brain activity could show any kind of independence at this degree.

He notes, “Though are study was small, it suggests that EEG—a tool that’s readily available at the patient’s bedside in the ICU in almost any hospital across the globe, has the potential to completely change how we manage patients with acute brain injury.”

Director of the Neurological Intensive Care Unit at the New York-Presbyterian/Columbia University Irving Medical Center

The study was published this week in the New England Journal of Medicine.