Self-Motivation
David Goggins
Former Navy Seal
Career Development
Bryan Cranston
Actor
Critical Thinking
Liv Boeree
International Poker Champion
Emotional Intelligence
Amaryllis Fox
Former CIA Clandestine Operative
Management
Chris Hadfield
Retired Canadian Astronaut & Author
Learn
from the world's big
thinkers
Start Learning

Many vegetative patients are actually 'covertly conscious'

This unsettling new understanding of vegetative patients raises medical ethics issues.

Photo by Daan Stevens on Unsplash
  • 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."

Hulu's original movie "Palm Springs" is the comedy we needed this summer

Andy Samberg and Cristin Milioti get stuck in an infinite wedding time loop.

Gear
  • Two wedding guests discover they're trapped in an infinite time loop, waking up in Palm Springs over and over and over.
  • As the reality of their situation sets in, Nyles and Sarah decide to enjoy the repetitive awakenings.
  • The film is perfectly timed for a world sheltering at home during a pandemic.
Keep reading Show less

Two MIT students just solved Richard Feynman’s famed physics puzzle

Richard Feynman once asked a silly question. Two MIT students just answered it.

Surprising Science

Here's a fun experiment to try. Go to your pantry and see if you have a box of spaghetti. If you do, take out a noodle. Grab both ends of it and bend it until it breaks in half. How many pieces did it break into? If you got two large pieces and at least one small piece you're not alone.

Keep reading Show less

Our ‘little brain’ turns out to be pretty big

The multifaceted cerebellum is large — it's just tightly folded.

Image source: Sereno, et al
Mind & Brain
  • A powerful MRI combined with modeling software results in a totally new view of the human cerebellum.
  • The so-called 'little brain' is nearly 80% the size of the cerebral cortex when it's unfolded.
  • This part of the brain is associated with a lot of things, and a new virtual map is suitably chaotic and complex.

Just under our brain's cortex and close to our brain stem sits the cerebellum, also known as the "little brain." It's an organ many animals have, and we're still learning what it does in humans. It's long been thought to be involved in sensory input and motor control, but recent studies suggests it also plays a role in a lot of other things, including emotion, thought, and pain. After all, about half of the brain's neurons reside there. But it's so small. Except it's not, according to a new study from San Diego State University (SDSU) published in PNAS (Proceedings of the National Academy of Sciences).

A neural crêpe

A new imaging study led by psychology professor and cognitive neuroscientist Martin Sereno of the SDSU MRI Imaging Center reveals that the cerebellum is actually an intricately folded organ that has a surface area equal in size to 78 percent of the cerebral cortex. Sereno, a pioneer in MRI brain imaging, collaborated with other experts from the U.K., Canada, and the Netherlands.

So what does it look like? Unfolded, the cerebellum is reminiscent of a crêpe, according to Sereno, about four inches wide and three feet long.

The team didn't physically unfold a cerebellum in their research. Instead, they worked with brain scans from a 9.4 Tesla MRI machine, and virtually unfolded and mapped the organ. Custom software was developed for the project, based on the open-source FreeSurfer app developed by Sereno and others. Their model allowed the scientists to unpack the virtual cerebellum down to each individual fold, or "folia."

Study's cross-sections of a folded cerebellum

Image source: Sereno, et al.

A complicated map

Sereno tells SDSU NewsCenter that "Until now we only had crude models of what it looked like. We now have a complete map or surface representation of the cerebellum, much like cities, counties, and states."

That map is a bit surprising, too, in that regions associated with different functions are scattered across the organ in peculiar ways, unlike the cortex where it's all pretty orderly. "You get a little chunk of the lip, next to a chunk of the shoulder or face, like jumbled puzzle pieces," says Sereno. This may have to do with the fact that when the cerebellum is folded, its elements line up differently than they do when the organ is unfolded.

It seems the folded structure of the cerebellum is a configuration that facilitates access to information coming from places all over the body. Sereno says, "Now that we have the first high resolution base map of the human cerebellum, there are many possibilities for researchers to start filling in what is certain to be a complex quilt of inputs, from many different parts of the cerebral cortex in more detail than ever before."

This makes sense if the cerebellum is involved in highly complex, advanced cognitive functions, such as handling language or performing abstract reasoning as scientists suspect. "When you think of the cognition required to write a scientific paper or explain a concept," says Sereno, "you have to pull in information from many different sources. And that's just how the cerebellum is set up."

Bigger and bigger

The study also suggests that the large size of their virtual human cerebellum is likely to be related to the sheer number of tasks with which the organ is involved in the complex human brain. The macaque cerebellum that the team analyzed, for example, amounts to just 30 percent the size of the animal's cortex.

"The fact that [the cerebellum] has such a large surface area speaks to the evolution of distinctively human behaviors and cognition," says Sereno. "It has expanded so much that the folding patterns are very complex."

As the study says, "Rather than coordinating sensory signals to execute expert physical movements, parts of the cerebellum may have been extended in humans to help coordinate fictive 'conceptual movements,' such as rapidly mentally rearranging a movement plan — or, in the fullness of time, perhaps even a mathematical equation."

Sereno concludes, "The 'little brain' is quite the jack of all trades. Mapping the cerebellum will be an interesting new frontier for the next decade."

Economists show how welfare programs can turn a "profit"

What happens if we consider welfare programs as investments?

A homeless man faces Wall Street

Spencer Platt/Getty Images
Politics & Current Affairs
  • A recently published study suggests that some welfare programs more than pay for themselves.
  • It is one of the first major reviews of welfare programs to measure so many by a single metric.
  • The findings will likely inform future welfare reform and encourage debate on how to grade success.
Keep reading Show less
Videos

Unhappy at work? How to find meaning and maintain your mental health

Finding a balance between job satisfaction, money, and lifestyle is not easy.

Scroll down to load more…
Quantcast