Key points:
- A new study provides early evidence of activity that correlates with consciousness in the dying brain.
- Patients taken off ventilator support showed an increase in heart rate along with a surge in brain activity.
- The researchers say larger, multi-center studies are needed.
Those who have had near-death experiences often report the same elements—white lights, visits from departed loved ones, voices, etc. Is this merely a coincidence? Maybe not. A new study published in the Proceedings of the National Academy of Science, provides early evidence of a surge of activity correlated with consciousness in the dying brain.
The study, by researchers at Michigan Medicine, is a follow-up to animal studies conducted almost 10 years ago. Similar signatures of gamma activation were recorded in the dying brains of both animals and humans upon a loss of oxygen following cardiac arrest.
For the new study, the team identified four patients who died due to cardiac arrest in the hospital while under EEG monitoring. All four of the patients were comatose and unresponsive. They were determined to be beyond medical intervention and their families made the decision to remove them from life support.
Upon removal of ventilator support, two of the patients showed an increase in heart rate along with a surge of gamma wave activity, considered the fastest brain activity and associated with consciousness.
Furthermore, the activity was detected in the hot zone of neural consciousness areas of the brain, between the temporal, parietal and occipital lobes. This area has been correlated with dreaming, visual hallucinations in epilepsy, and altered states of consciousness in other brain studies.
The other two patients did not display the same increase in heartrate upon removal from life support nor did they have increased brain activity.
“We are unable to make correlations of the observed neural signatures of consciousness with a corresponding experience in the same patients in this study. However, the observed findings are definitely exciting and provide a new framework for our understanding of covert consciousness in the dying humans,” said study author Nusha Mihaylova, M.D., a clinical associate professor at Michigan Medicine.
Larger, multi-center studies with EEG-monitored ICU patients who survive cardiac arrest could provide much needed data to determine whether or not these bursts in gamma activity are evidence of hidden consciousness—even near death.