Mind Matters News and Analysis on Natural and Artificial Intelligence
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New Evidence That Some Comatose People Really Do Understand

Researchers found mental activity in response to verbal commands even in some “completely unresponsive” patients

A recent paper in the New England Journal of Medicine titled “Detection of brain activation in unresponsive patients with acute brain injury” has fascinating implications for the understanding of the mind-brain relationship, as well as important implications for our treatment of patients in coma.

The researchers from Columbia University and New York University conducted a prospective study involving 104 patients with acute brain injury. The patients were in a deep coma with no motor response to verbal commands. They gave alternating commands to the patients and used machine learning analysis of each patient’s brain waves during these commands. They found that cognitive responses to verbal commands could be detected in some patients using analysis of the brain waves. Fifteen percent of the completely unresponsive patients had brain activation on EEG that correlated with these verbal commands, despite having no physical motion in response. They called this dissociation between the absence of behavior and brain activation “cognitive–motor dissociation.” They also suggested that their finding could help doctors with prognoses—determining the likely outcomes for patients with brain injury.

Patients who showed evidence for brain activation were twice as likely to recover to the point of physically following verbal commands in the future as compared with patients who showed no brain activation. On longer follow-up, patients with brain activation in a deep coma were three times as likely to be able to carry out independent activities of life as compared with patients with no activation.

Of particular interest for the mind-brain question is the finding of dissociation between behavior and brain activation. When the body doesn’t respond but the brain does, the authors use the term “cognitive-motor dissociation.” Their findings are not unique; they support previous studies where EEG and functional MRI imaging confirmed activation of parts of the brain in response to spoken commands in deeply unresponsive patients.

This work is relevant to the question of the relationship between the mind and the brain. It is another piece of evidence in a long line of evidence that some aspects of mental activity, most notably abstract thought, are to a significant degree dissociated from the material function of the brain.

It also highlights a significant limitation we face in evaluating the capacity for abstract thought in people who have severe brain damage: severe brain damage causes physical immobility and severely compromises behavioral responses. That makes the assessment of the capacity for abstract thought very difficult. How can we know if somebody who has severe brain damage and is in a deep coma can understand what we are saying if the brain damage prevents the patient from expressing thoughts by physical movement?

This study is consistent with the work of Wilder Penfield, who showed that higher-level abstract thought did not seem to arise from the brain in a material way. It is also consistent with the research of Roger Sperry, who found that split-brain surgery, which disconnected the cerebral hemispheres, caused no significant change in consciousness or abstract mental function. It is also consistent with the work of Adrian Owen and other coma researchers who have used fMRI imaging to show conscious awareness in as many as 40% of patients in a persistent vegetative state.

And, of course, these findings raise very disturbing questions regarding the induced death by starvation of Terry Schiavo, who was diagnosed as “mindless” and in a permanent coma. There is growing evidence that many of these patients are quite aware of what is going on around them. This awareness is well-known to doctors and nurses who care for these patients on a daily basis and also to the patients’ families. For example, nurses caring for comatose patients are often very careful not to say upsetting things that the patient can hear because, when such things are said, blood pressure often rises dramatically, even in deeply “unaware” comatose patients.

The materialist understanding of the relationship between the brain and the mind is deeply flawed. There is a growing body of research that strongly suggests that there is an aspect to mental function that is not material. The philosophical and theoretical implications of this are profound. But the implications for the medical treatment of people with brain injury are vitally important as well.

The growing evidence that the human mind is not merely the product of the brain means that we need to treat people who have brain injuries with respect and compassion, and we need to make the default assumption that they are aware and that they can feel what is being done to them.

The scientific inference to the immateriality of the mind is of vital importance, not only for a theoretical understanding of the mind and the brain but for the practical and compassionate medical care of people with brain injuries.

Also by Michael Egnor: Science Points To An Immaterial Mind. If one did not start with a materialist bias, materialism would not be invoked as an explanation for a whole range of experiments in neuroscience


Can buzzwords about “neural networks” save materialist neuroscience? No. Experiments that support an immaterial consciousness often involve split or massively damaged neural networks

Michael Egnor

Senior Fellow, Center for Natural & Artificial Intelligence
Michael R. Egnor, MD, is a Professor of Neurosurgery and Pediatrics at State University of New York, Stony Brook, has served as the Director of Pediatric Neurosurgery, and award-winning brain surgeon. He was named one of New York’s best doctors by the New York Magazine in 2005. He received his medical education at Columbia University College of Physicians and Surgeons and completed his residency at Jackson Memorial Hospital. His research on hydrocephalus has been published in journals including Journal of Neurosurgery, Pediatrics, and Cerebrospinal Fluid Research. He is on the Scientific Advisory Board of the Hydrocephalus Association in the United States and has lectured extensively throughout the United States and Europe.

New Evidence That Some Comatose People Really Do Understand