Scientists repurpose EEG to detect brain activity in comatose patients
Electroencephalogram tests, or EEGs, are commonly used to diagnose epilepsy and sleep disorders. But researchers may have found a new application for the widely used technology: detecting brain activity in comatose patients.
Neurologists at Columbia University and NewYork–Presbyterian Hospital gathered EEG data from 104 adult patients in an intensive care unit who recently sustained a brain injury and were unable to talk or respond to commands to move.
The researchers gave patients commands and retrieved EEG data from small discs attached to the patients’ scalps during the sessions.
In a study published in The New England Journal of Medicine on Wednesday, they found that 16 of 104 unresponsive patients (15%) had brain activation detected by EEG even though they couldn’t talk or move.
The findings could help develop future methods to predict who will wake up from a coma.
“Impairment of consciousness is frequent and prediction of recovery challenging — often it is inaccurate. Many patients in the ICU do not show movements on commands and typically this is interpreted as unconsciousness,” Dr. Jan Claassen, lead author of the study, told CNN in a statement.
However, the new study suggests that EEG — a readily available tool in almost all hospitals — can potentially change how doctors manage patients with brain injury.
When the reseachers revisited the patients a year later, they found that 44% who showed brain activity patterns were able to function independently for up to eight hours a day, while only 14% of those without such signals could function independently.
Classen said the study “shows that some patients who are unresponsive for days or longer may have cognitive processing capabilities sufficient to distinguish commands, and those patients have a higher chance of recovering.”
There’s still a long way to go in understanding neurological injuries
Claassen acknowledged that the study only involved a “relatively small cohort of patients.”
“We now have to make sure that the findings are replicated in an independent larger study and hope that it could be integrated into clinical practice in the future,” Claassen said.
Dr. Joshua Rosenow, who was not part of the study, says the findings conform with prior research that people who appear outwardly responsive to commands exhibit brain activity that can be detected through other means.
“These patients who have this brain activity have the possibility of recovering significant neurological function,” Rosenow, a professor of neurological surgery at Northwestern University Feinberg School of Medicine, told CNN.
“But the study did not show that every responsive patient is going get better despite significant neurological injury. We see there is an ability to recover and there’s more brain activity than is outwardly visible.”
Rosenow said this study found “preliminary data” but doesn’t believe “this one study is itself the answer.”
Scientists still have a ways to go in terms of predicting and enhancing recovery from neurological injuries, Rosenow added.