Canadian researchers discover signs of consciousness in comatose patient, study says – Canada News

Photo: The Canadian Press

Researchers in London, Ontario, are using a functional near-infrared spectroscopy (fNIRS) cap – pictured on a mannequin – to shine light into the brains of unconscious patients in a coma and detect signs of consciousness. THE CANADIAN PRESS/HO-London Health Sciences Centre

Researchers from London, Ontario, say they have been able to detect consciousness in a comatose patient with a brain injury. This discovery “opens doors” to better care and offers hope of being able to more accurately predict the prognosis of recovery for those with serious injuries.

Using an imaging technique called functional near-infrared spectroscopy (fNIRS), light waves were sent into the brains of three patients to detect activity in response to various commands, according to a study recently published in the journal The Proceedings of the National Academy of Sciences (PNAS).

The patients were already considered clinically unresponsive, meaning they did not respond when asked to give a thumbs up, wiggle their toes or open and close their eyes, said Karnig Kazazian, one of the study's lead authors.

“When you see that some patients may still be 'in there' even though they're not showing any behavioral signs, you can imagine that this would really impact the decision whether to stay on life support or die peacefully,” said Kazazian, a research fellow at the Lawson Health Research Institute and the London Health Sciences Centre.

The fNIRS technology was first tested on more than 100 healthy participants to find out which tasks and commands most effectively trigger brain activity. The more light that is absorbed, the more brain activity there is in a particular part of the brain, Kazazian said.

When the technology was applied to three comatose patients, one of them showed significant neurological activity in the premotor cortex – the part of the brain that imagines movement – ​​when asked to imagine playing tennis.

“Previous work from our group has shown that you have to be conscious to imagine playing tennis. You have to be 'there' because it's not something you just do automatically and without awareness,” Kazazian said.

The researchers repeated this exercise five times to make sure the reaction was not a one-time occurrence, he said.

When playing “complex stories,” the researchers were also able to observe that activity occurred in the part of the patients’ brains responsible for processing acoustic information, Kazazian said.

Another patient who did not respond appeared to have the ability to passively perceive speech in a less pronounced response, the study found. A third patient did not respond to any of the task commands.

The findings build on previous research suggesting that 15 percent of comatose patients have some cognitive awareness, even if they appear unresponsive, he said.

Functional near-infrared spectroscopy is performed through a cap on the patient's head, eliminating the need to take the patient to another location in the hospital, such as an MRI department, for the brain scan, Kazazian said.

He said the technology needs to be made available to intensive care units across the country as it can help doctors and family members decide whether to continue intensive care if the patient shows signs of consciousness.

Dr. Derek Debicki, the study's lead author, said the results were promising, although it was still “very early” to detect consciousness in otherwise unresponsive patients and link that to predicting whether and how they will recover.

“If you first show that this is actually possible in the intensive care unit, it opens the door for further development of this technology,” says Debicki, a neurologist specializing in neurological intensive care at Western University.

Kazazian, Debicki and the rest of their research team are currently enrolling more patients in the study with consent from their relatives in order to obtain a larger sample and find out whether or not the brain activity detected is related to a patient's prognosis.

“(We want to) try to understand what the recovery process is like after a coma or severe brain injury, and are there any markers that can help us better predict what the functional outcomes might be?” Debicki said.

The team will also investigate whether fNIRS technology can be used to communicate with patients in a coma, Kazazian said.