Researchers at the Neuroimaging for Coma Emergence and Recovery Consortium are using MRI and a multimodal MRI sequence to predict if comatose patients will regain full cognitive function when they emerge from their comas.
Their study published in Radiology, specifically focused on comatose patients who have suffered from heart attacks. In around 80 percent of cases, patients who suffered from cardiac arrest take hours or weeks to emerge from their coma. Even when they wake up, there’s no way to predict if they’ll have cognitive impairment or return to their normal cognitive state.
The researchers used resting-state functional and structural MR imaging to examine the higher order brain networks of 46 comatose patients no more than four weeks after their heart attacks. They then compared the scans to a control group of 48 participants whose ages aligned with those in the experimental group.
Only 11 of the comatose patients recovered full or nearly full brain function a year after their heart attacks. The researchers found that those 11 had stronger preservation of connectivity between the resting networks, especially in the default mode resting network and the salience resting network. These markers indicate that high connectivity is associated with a higher chance of cognitive recovery. Despite these findings, the researchers also detected abnormalities in the resting networks in the comatose patients in comparison with the control group.
“The results demonstrate that abnormalities in long-range connectivity occur within and between canonical brain networks in the acute phase of anoxic brain injury, and these abnormalities are associated with long-term functional outcome,” write the researchers. “These data suggest that anatomic and functional disconnection occurs early after [cardiac arrest] and could represent a biomarker of recovery potential,” they added.