A team of London-based researchers has developed a groundbreaking bedside brain imaging technique capable of detecting conscious awareness in ICU patients with severe brain injuries who appear to be in a coma. This innovation, known as functional near-infrared spectroscopy (fNIRS), could revolutionize the way doctors assess and care for unresponsive patients.
Researchers from Lawson Health Research Institute and Western University say the portable fNIRS technology offers a new way to improve the accuracy of prognoses for patients who show no outward signs of consciousness. The technique was recently used to identify a patient who, despite appearing comatose, was fully conscious and aware of their surroundings.
“If you knew a patient was conscious, that would significantly influence decisions about continuing aggressive life-sustaining care versus transitioning to comfort-focused care,” said Dr. Karnig Kazazian, co-lead author of the study and a research scientist at London Health Sciences Centre (LHSC). “If we know they’re aware, we may even be able to ask them simple questions, allowing them to make decisions about their own care.”
How the Technique Works
The study, published in The Proceedings of the National Academy of Sciences (PNAS), involved using fNIRS to detect brain activity in ICU patients who were clinically unresponsive. The researchers aimed to determine whether these patients could feel pain, hear their surroundings, or retain conscious awareness.
During the tests, conducted at the patient’s bedside, participants were asked to imagine themselves playing tennis. The fNIRS device, which uses light waves to measure brain activity, detected responses in the part of the brain responsible for imagining movement.
“To imagine playing tennis, a person must hear the instructions, remember them, and then consistently perform the task,” explained Kazazian. “By detecting activity in the specific brain region associated with imagining movement, we can confirm that the person is aware.”
The fNIRS system involves a cap worn on the head that emits light waves, which bounce off the brain. Researchers then analyze the properties of blood flow in the brain to determine which areas are active. According to Dr. Derek Debicki, a neurologist at LHSC and study co-author, this non-invasive method allows for real-time monitoring of brain function without the need to move patients or disrupt life support systems.
Promising Results and Future Applications
The study tested the fNIRS technique on over 100 healthy participants before applying it to three ICU patients at LHSC. One patient showed no brain activity, while another exhibited responses to auditory stimuli in areas of the brain associated with hearing and comprehension. The third patient, who was asked to imagine playing tennis, demonstrated clear signs of conscious awareness.
The researchers believe this technology could become a standard tool in intensive care units, helping doctors better understand the level of awareness in unresponsive patients. They also envision using fNIRS as part of a brain-computer interface, enabling communication with select ICU patients in the future.
“This technology could be transformative,” said Debicki. “It’s portable, non-invasive, and can be used at the bedside, making it ideal for both clinical and research settings.”
Expanding the Research
The team is now recruiting additional ICU patients for further studies to expand the sample size and validate their findings. They hope that within the next few years, fNIRS will become a widely available tool, improving the care and outcomes for patients with severe brain injuries.
This breakthrough not only offers hope for families of comatose patients but also underscores the potential of innovative technologies to transform medical diagnostics and patient care.