Vegetative Patients Can Still Learn

enigma48 writes to mention that a collaborative study between the Universities of Buenos Aires and Cambridge have demonstrated that individuals in a vegetative state can still learn and demonstrate at least a partial consciousness. Their findings are reported in a recent online edition of Nature Neuroscience. "It is the first time that scientists have tested whether patients in vegetative and minimally conscious states can learn. By establishing that they can, it is believed that this simple test will enable practitioners to assess the patient's consciousness without the need of imaging. The abstract is also available in the advance issue of Nature."

Comments

fMRI Strikes Again

[eldavojohn]

You might take this with a grain of salt as this Scientific American article points out it relies on fMRI (with the researcher also expressing caution). The same sort of scans were used to recently show that dead salmon think and also was called into question before that. From what I understand, there's a potentially huge problem with the statistical correlation done on the data to reach the images and conclusion (basically you are able to decide how much of a result you get). Given these sequential very controversial findings, I think it's time to push for research on these tools and research processes to ensure they are robust and reporting correct findings.

Re:fMRI Strikes Again

[gameweld]

Wrong. A earlier study in 2006 used fMRI. This study used a simple classical conditioning test where they played a tune before blowing in the patients eyelid.

Re:fMRI Strikes Again

[Marxist Hacker 42]

FTFA:

This study was done as a collaborative effort between the University of Buenos Aires (Argentina), the University of Cambridge (UK) and the Institute of Cognitive Neurology (Argentina). By using classical Pavlonian conditioning, the researchers played a tone immediately prior to blowing air into a patient's eye. After some time training, the patients would start to blink when the tone played but before the air puff to the eye.

Where in the description of the experiment involved do you find any mention of fMRI data?

In fact, I think you could mimic this experiment with a tuning fork and a turkey baster.

Re:fMRI Strikes Again

[sonnejw0]

Actually, I believe the report said it used an electrocardiogram to determine learned behaviour to an aversive eye-puff (meaning that the vegetative patient's sympathetic nervous system was being activated in anticipation of the aversive stimulus). Regardless, the fMRI data from the dead salmon actually indicates what you can get from an MR machine if you set your parameters incorrectly. There are lots of artifacts in an MRI, and the statistics of its output is very complex, but the dead-salmon article's conclusion was about proper parameters being used, not a blanket statement about reliability of MR.

The spinal cord itself is actually a smart cable and does its own processing and reflex computations, so the fact that these patients anticipated a negative stimulus is not in and of itself evidence of cognitive function. Having not read anything but the abstract, if the aversive stimulus was in fact an eye-puff, that is a strong indicator that the brainstem, cerebellum and parts of the cerebral cortex are intact and functioning. If it were a foot stimulus, that says little about the brain. The classic experiment of the hinter-years involving a cat with its brain removed except for the brain stem and spinal cord, and yet the cat possessed the autonomic reflexes required to walk on a treadmill when properly positioned, is evidence of this. However, the article probably goes in depth about how this is viable for fundamental brain function, as is indicated by the abstract.

Re:fMRI Strikes Again

[Protoslo]

Aside from the obvious objection that others have made (the dead fish paper was pointing out that some psych researchers use statistical analyses of dubious rigor, not that fMRI doesn't work!), there is an even more relevant fact. I just read this paper, and it has nothing whatsoever to do with fMRI. And if you had actually read the link that you included, you would realize that the SciAm article claims no such thing! That article indicates that other fMRI studies imply that the accepted criteria for distinguishing conciousness and vegetative states might be overly arbitrary. The SciAm author's point is that even someone who fails the test given in the paper in question might not be considerably less conscious than someone who does pass, and that a single criterion (conditioned response to audio tone/eye pressure) is overly limiting.

Indeed, you could make that objection based on the model's accuracy:

The model incorrectly classified 2 out of 11 individuals in the vegetative state and 4 out of 9 nonâ"vegetative state subjects, leaving the model with an accuracy of 72.7% (Ï2 = 3.61, P = 0.057).

The model was no better than a random choice for classifying the patients who were not in a vegetative state (they observed that learning was a poor differentiator of vegetative and minimally conscious states)...but luckily they are actually suggesting the test not for determine vegetative state diagnosis, but as a measure of improvement potential. The test had much better correlation with subsequent condition improvement in the subjects:

We performed a logistic regression to evaluate whether conditioned stimulus late anticipatory-baseline could differentiate between recovery and no recovery. Learning (conditioned stimulus late anticipatory-baseline, Ï2 = 5.02, P = 0.025) indicated, with an accuracy of 86%, whether a subject had shown signs of recovery or not.

In fact, it is clear from the appendix that there were no false negatives in that measure (i.e. no nonlearners improved); both of the misclassifications were learners who failed to improve. The point of the paper was not even to evaluate a specific test of learning, but rather to establish that learning ability is highly correlated with recovery potential.

Given the trend of sequential misinformed first posts, I think it's time to push for research on the moderation process, to ensure that slashdot moderators don't upmoderate based on the perceived confidence of the poster, independent of actual veracity.

Re:Humans Have Three Brains

[sonnejw0]

Holy cow, where did you learn that stuff? From Paul MacLean? None of that reflects anywhere near current neurobiological evidence, let alone terminology! And I think the Neo-Cortex must only exist inside the Matrix, most everyone that's not a loon from the 80s calls it the cerebral cortex, or simply cortex.

The cortex is actually responsible for muscle control and movement patterning, disinhibited in the basal ganglia, through sensory proprioception from the cerebellum. It's all nicely integrated. The cortex has nothing to do with cognition. Although it does store memory I would not consider memory to be the fundamental element of cognition.

At any rate, you are correct in the idea that there is not one core region of processing. For instance, the spinal cord itself is actually a smart cable and does its own processing and reflex computations, so the fact that these patients anticipated a negative stimulus is not in and of itself evidence of cognitive function. Having not read anything but the abstract, if the aversive stimulus was in fact an eye-puff, that is a strong indicator that the brainstem, cerebellum and parts of the cerebral cortex are intact and functioning. If it were a foot stimulus, that says little about the brain. The classic experiment of the hinter-years involving a cat with its brain removed except for the brain stem and spinal cord, and yet the cat possessed the autonomic reflexes required to walk on a treadmill when properly positioned, is evidence of this. However, the article probably goes in depth about how this is viable for fundamental brain function, as is indicated by the abstract.

Re:Humans Have Three Brains

[spectecjr]

Read, learn:
http://en.wikipedia.org/wiki/Neocortex

http://www.medterms.com/script/main/art.asp?articlekey=25283

Re:M+

[Abreu]

From Wikipedia's article: http://en.wikipedia.org/wiki/Horton_Hears_a_Who!

The book (most notably Horton the Elephant's recurring phrase "a person's a person, no matter how small") has found its way to the center of the recurring debate, in the United States, over abortion. Several pro-life groups have adopted the phrase in support of their views. Geisel himself did not approve of these groups co-opting the phrase, nor does his widow, Audrey Geisel, who "doesn't like people to hijack Dr. Seuss characters or material to front their own points of view." [5] According to Geisel biographer Philip Nel, Geisel threatened to sue a pro-life group for using his words on their stationery. [6]

I don't think the quote applies to vegetative state patients either...