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February 13, 2011

BehindTheMedspeak: The brain-dead can't dance — but they'd like to

A new scientific study just published in the journal Frontiers in Human Neuroscience has demonstrated that some individuals in a vegetative state — classically described as "the absence of awareness of self or the environment [with] preserved autonomic functions" — may be conscious but unable to communicate.

This demonstration may be a step toward unlocking the minds of countless individuals around the world who perceive yet remain imprisoned in a body unable to offer evidence of same.

The abstract of the paper follows.

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Functional imaging reveals movement preparatory activity in the vegetative state

The vegetative state (VS) is characterized by the absence of awareness of self or the environment and preserved autonomic functions. The diagnosis relies critically on the lack of consistent signs of purposeful behavior in response to external stimulation. Yet, given that patients with disorders of consciousness often exhibit fragmented movement patterns, voluntary actions may go unnoticed. Here we designed a simple motor paradigm that could potentially detect signs of purposeful behavior in VS patients with mild to severe brain damage by examining the neural correlates of motor preparation in response to verbal commands. Twenty-four patients who met the diagnostic criteria for VS were recruited for this study. Eleven of these patients showing preserved auditory evoked potentials underwent functional magnetic resonance imaging (fMRI) to test for basic speech processing. Five of these patients, who showed word related activity, were included in a second fMRI study aimed at detecting functional changes in premotor cortex elicited by specific verbal instructions to move either their left or their right hand. Despite the lack of overt muscle activity, two patients out of five activated the dorsal premotor cortex contralateral to the instructed hand, consistent with movement preparation. Our results may reflect residual voluntary processing in these two patients. We believe that the identification of positive results with fMRI using this simple task, may complement the clinical assessment by helping attain a more precise diagnosis in patients with disorders of consciousness.

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The paper in its entirety, including figures, tables and references, is here.

February 13, 2011 at 04:01 PM | Permalink


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Comments

Shades of Roald Dahl's "William and Mary."

http://en.wikipedia.org/wiki/William_and_Mary_(short_story)

Posted by: Kay | Feb 13, 2011 8:36:10 PM

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