Research Suggests About 25 Percent of Coma Patients are Conscious

MRI scans showed about a quarter of unresponsive patients with severe brain injuries responded to specific instructions

Hiya!

When people are in a coma, their friends and family are encouraged to talk to them, and a common question the loved ones have is: “Can they hear me?” The answer has remained a mystery as researchers relied on reports from people who managed to awaken from their comas and learn more about a person’s experience from one. The issue is that people report varying experiences, and many don’t remember anything.

However, these days, technology exists for scientists to find out what happens in the brain while a person is in a coma — and whether they can hear us. More specifically, researchers want to know whether people in a coma can be conscious, even when they don’t appear to be. Remarkably, so far, the evidence says yes. This incredible experience has many names, including “locked-in syndrome,” “covert consciousness,” and “cognitive motor dissociation.” Now, a new study suggests it’s far more common than we realized.

Levels of Consciousness

People who are in a coma may appear the same at first glance, unresponsive as if asleep, but there are levels or categories of coma.

A patient is considered in a coma or comatose when they’re in a particularly deep coma state. These patients don’t respond to stimuli like pain or instructions and have reduced basic functions like swallowing. They may require machines like ventilators and feeding tubes to keep them alive. Recovery time for those who manage to emerge from the comatose state can last weeks to months.

Meanwhile, someone in a vegetative state can typically breathe on their own and doesn’t require life support to survive. Like people considered comatose, patients in vegetative states also appear in a prolonged sleep, except some will open their eyes, respond to some sensations, and seemingly spontaneously cry, laugh, or scream. But any responses or actions people in vegetative states perform are usually more random than deliberate.

Distinguishing between coma states and the degrees of each could help countless people while teaching us more about the human brain. For most of history, scientists have been limited to relying on external signals, such as how a coma patient responds to physical stimulation, to learn about coma states. However, such limitations meant the internal conditions and experiences of a coma patient remained a mystery.

Nowadays, however, scientists have electroencephalography (EEG), which measures electrical activity in the brain, and functional magnetic resonance imaging (fMRI), which uses strong magnetic fields, radio waves, and nuclear spin to create images of the body’s soft tissue, including the brain. These techniques allow scientists to observe the brain activity of coma patients, and more than a few patients appear conscious despite their body’s inactivity.