As an MGH Research Scholar, Brian Edlow Will Pursue Detection of ‘Covert Consciousness’ in the ICU

Gary Boas

Martinos researcher Brian Edlow, MD has been announced as a 2023 MGH Research Scholar. The five-year funding accompanying the honor will support his project, “Detecting Covert Consciousness in the Intensive Care Unit.”

Every year, more than one million people across the globe are impacted by severe brain injury. Bedside behavioral examination has long been the gold standard test for assessing the level of consciousness in patients who experience such injury, but not all patients are able to respond to the clinician’s commands during the test — because they cannot express themselves by speaking or writing, they have arm and leg weakness that prevents them from moving in response to a command, or for some other reason.

In fact, studies have shown that 15-20 percent of patients in the intensive care unit (ICU) may have higher levels of consciousness than their bedside behavioral examination suggests. Consciousness that cannot be detected with the bedside exam is described as “covert consciousness.”

The prevalence of covert consciousness is important because the results of the bedside exam often inform decisions by clinicians and families as to whether to continue life support. Without a fuller understanding of the patient’s level of consciousness, they may prematurely withdraw the support. Discontinuation of life-sustaining therapy is the cause of death for up to 80 percent of patients with acute severe brain injuries.

Dr. Edlow is working to provide this fuller understanding. In recent years, for example, he and colleagues have shown that stimulus-based functional MRI (fMRI) and EEG could reveal covert consciousness in patients in the intensive care unit receiving treatment for acute severe traumatic brain injury.

In a study reported in 2017 in Brain, he and collaborators including Ona Wu, PhD, of the MGH Martinos Center for Biomedical Imaging and Eric Rosenthal, MD, of the MGH Department of Neurology, found evidence of covert consciousness in four patients, including three whose bedside neurological examination suggested a vegetative state.

However, fMRI is both expensive and not commonly available in clinical settings. Seeking a more practical solution, Dr. Edlow explored other neuromonitoring techniques and found a well-suited alternative option in transcranial magnetic stimulation electroencephalography (TMS-EEG). This approach works by inducing electric currents in the brain using changing magnetic fields and measuring those currents with electrodes attached to the scalp.

In his project supported by the MGH Research Scholars program, Dr. Edlow will lead a multidisciplinary team in optimizing and implementing TMS-EEG to detect consciousness in the ICU and predict recovery in patients with severe brain injuries.

“TMS-EEG has shown unparalleled accuracy at detecting consciousness in patients with chronic brain injuries, providing a compelling clinical and ethical rationale for translating TMS-EEG to the ICU,” he says. “This project has the potential to save lives by detecting signs of covert consciousness and preventing premature withdrawal of life-sustaining therapy.”

Dr. Edlow is associate director of the Center for Neurotechnology and Neurorecovery at Massachusetts General Hospital and an affiliated faculty member in the Athinoula A. Martinos Center for Biomedical Imaging.

The MGH Research Scholars program was launched in 2011 to provide forward-thinking researchers with the unrestricted funding they need to take their work into new and uncharted territories. Funded 100% through philanthropy, this program gives researchers the freedom and flexibility they need to follow the science wherever it leads.