from the world's big
Many vegetative patients are actually 'covertly conscious'
This unsettling new understanding of vegetative patients raises medical ethics issues.
- For a long time, doctors assessed whether patients were in vegetative states through behavioral tests.
- However, brain scans have revealed that some of these patients are actually in a state of "covert consciousness."
- Covertly conscious patients are aware of their surroundings, but cannot respond to external stimuli.
In 2005, a 23-year-old woman was caught in a traffic accident that gave her a traumatic brain injury. Her doctors diagnosed her as being in a vegetative state — that is, absent of awareness and responsiveness, but still able to keep her heart pumping, her lungs breathing, to fall asleep and become awake, and so on.
Five months after her accident, however, researchers conducted an experiment showing that she had not completely lost her conscious awareness. Using an fMRI, researchers asked her to imagine playing tennis or walking through her house. Though the patient had been unable to respond to any other cues, the fMRI showed that her brain lit up when asked to imagine these things, suggesting that she was, in fact, conscious to some degree — just unable to move her hands or open her eyes on command. This patient would be the first time that signs of consciousness were detected in an ostensibly vegetative state using fMRI.
The trouble with diagnosing vegetative states
Since then, more and more cases of this sort have come to light. In fact, over the years, researchers estimate that around 10 to 20 percent of supposedly vegetative patients in fact experience what's called "covert" consciousness. Patients with covert consciousness do not respond to behavioral tests of awareness yet show brain activity related to awareness. It is important to note that covertly conscious patients do not fail to respond to behavioral tests because they are paralyzed. Instead, they fail to respond because the parts of their brain that respond to stimuli are damaged — they can still move, and sometimes will, but typically not in response to external stimuli.
After a traumatic brain injury that lands a patient in an ostensibly vegetative state, many clinicians assume a poor prognosis. As a result, many families decide whether to keep their loved one on life support or to withdraw it within the first three days after admission.
"The problem with severe brain injury," said neuroscientist Nicholas Schiff in The Scientist, "is that you have people who all look the same who could have very different trajectories of recovery over time, response to treatment, or already achieved level of recovery." Better diagnostic tools are needed to "sort the variance and also to figure out who we should look at more closely and immediately."
A better method
A healthcare professional administers an EEG.
BSIP/Universal Images Group via Getty Images
Patients with covert consciousness have been shown to recover at higher rates than those in persistent vegetative states even though they appear to be the same from the outside. Deciding to pull the plug on a loved one is never an easy task, but the uncertainty of whether or not they are truly beyond help makes it even more difficult.
Fortunately, researchers are working on ways to improve diagnosing these cases of covert consciousness. While fMRIs were the original way that researchers detected covert consciousness, applying them in critical care settings can be challenging. Electroencephalographs (EEGs) are likely to be far more useful as a diagnostic tool.
The first large-scale demonstration of using EEGs to diagnose cases of covert consciousness was recently published in the New England Journal of Medicine, where doctors asked patients to move their hands (which neither vegetative nor covertly conscious patients can do), and then used machine learning to decipher their EEG readings to identify brain activity in response to the commands. Twelve months later, 44 percent of those patients who were detected to have some brain activity were no longer vegetative and could function independently compared to just 14 percent of patients with no sign of activity in the EEG.
"This is very big for the field," Nicholas Schiff told The New York Times. "The understanding that, as the brain recovers, one in seven people could be conscious and aware, very much aware, of what's being said about them, and that this applies every day, in every I.C.U. — it's gigantic."
What would it be like to experience the 4th dimension?
Physicists have understood at least theoretically, that there may be higher dimensions, besides our normal three. The first clue came in 1905 when Einstein developed his theory of special relativity. Of course, by dimensions we’re talking about length, width, and height. Generally speaking, when we talk about a fourth dimension, it’s considered space-time. But here, physicists mean a spatial dimension beyond the normal three, not a parallel universe, as such dimensions are mistaken for in popular sci-fi shows.
If machines develop consciousness, or if we manage to give it to them, the human-robot dynamic will forever be different.
- Does AI—and, more specifically, conscious AI—deserve moral rights? In this thought exploration, evolutionary biologist Richard Dawkins, ethics and tech professor Joanna Bryson, philosopher and cognitive scientist Susan Schneider, physicist Max Tegmark, philosopher Peter Singer, and bioethicist Glenn Cohen all weigh in on the question of AI rights.
- Given the grave tragedy of slavery throughout human history, philosophers and technologists must answer this question ahead of technological development to avoid humanity creating a slave class of conscious beings.
- One potential safeguard against that? Regulation. Once we define the context in which AI requires rights, the simplest solution may be to not build that thing.
Duke University researchers might have solved a half-century old problem.
- Duke University researchers created a hydrogel that appears to be as strong and flexible as human cartilage.
- The blend of three polymers provides enough flexibility and durability to mimic the knee.
- The next step is to test this hydrogel in sheep; human use can take at least three years.
Duke researchers have developed the first gel-based synthetic cartilage with the strength of the real thing. A quarter-sized disc of the material can withstand the weight of a 100-pound kettlebell without tearing or losing its shape.
Photo: Feichen Yang.<p>That's the word from a team in the Department of Chemistry and Department of Mechanical Engineering and Materials Science at Duke University. Their <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202003451" target="_blank">new paper</a>, published in the journal,<em> Advanced Functional Materials</em>, details this exciting evolution of this frustrating joint.<br></p><p>Researchers have sought materials strong and versatile enough to repair a knee since at least the seventies. This new hydrogel, comprised of three polymers, might be it. When two of the polymers are stretched, a third keeps the entire structure intact. When pulled 100,000 times, the cartilage held up as well as materials used in bone implants. The team also rubbed the hydrogel against natural cartilage a million times and found it to be as wear-resistant as the real thing. </p><p>The hydrogel has the appearance of Jell-O and is comprised of 60 percent water. Co-author, Feichen Yang, <a href="https://today.duke.edu/2020/06/lab-first-cartilage-mimicking-gel-strong-enough-knees" target="_blank">says</a> this network of polymers is particularly durable: "Only this combination of all three components is both flexible and stiff and therefore strong." </p><p> As with any new material, a lot of testing must be conducted. They don't foresee this hydrogel being implanted into human bodies for at least three years. The next step is to test it out in sheep. </p><p>Still, this is an exciting step forward in the rehabilitation of one of our trickiest joints. Given the potential reward, the wait is worth it. </p><p><span></span>--</p><p><em>Stay in touch with Derek on <a href="http://www.twitter.com/derekberes" target="_blank">Twitter</a>, <a href="https://www.facebook.com/DerekBeresdotcom" target="_blank">Facebook</a> and <a href="https://derekberes.substack.com/" target="_blank">Substack</a>. His next book is</em> "<em>Hero's Dose: The Case For Psychedelics in Ritual and Therapy."</em></p>
An algorithm may allow doctors to assess PTSD candidates for early intervention after traumatic ER visits.