Study: Patients in vegetative state show awareness

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Using a newly developed brain scan technique, researchers in the U.K. and Belgium revealed that some patients in vegetative states or states of minimal consciousness show signs of awareness, and in one exceptional case, could even answer yes/no questions posed by doctors during a visualization exercise. The findings, published online this week in the New England Journal of Medicine, suggest that previous tests to assess patients’ cognition may not fully tap into all potential aspects of awareness. The 29-year-old patient who, on brain scans exhibited responses to yes/no questions, had been in a vegetative state for five years. As one of the study’s authors, Martin Monti of the Medical Research Council Cognitive and Brain Sciences Unit in Cambridge, England, summed it up to the Associated Press, “We were stunned when this happened… I find it literally amazing.”

The study that yielded this neurological breakthrough included 54 patients at medical centers in Cambridge, England and Liege, Belgium, who were either in a vegetative state, or a state of minimal consciousness, as well as 16 control subjects in healthy mental condition. While undergoing functional magnetic resonance imaging (fMRI) brain scans, patients were asked to perform what the researchers refer to as “imagery tasks”: in the first one, they were asked to imagine themselves standing on a tennis court swinging a racket; in the second, they were to imagine themselves wandering along the streets of a familiar city, or through the rooms of their homes. Of the 54 patients, the brain scans revealed that five showed clear signs of awareness during the motor activity exercise (tennis), and four of those five showed signs of awareness during the spatial task (wandering through a city). Four out of five of these patients were in a vegetative state, and all five patients had suffered traumatic brain injury—as opposed to suffering oxygen starvation, (as had been the case with controversial vegetative patient Terri Schiavo).

During a subsequent communication task, one vegetative patient and the 16 control patients were asked to utilize the imagined scenes to represent either yes or no—that is, the motor visualization represented yes, while the spatial visualization represented no, for example. The participants were then asked simple yes/no questions, such as, “Do you have any brothers?” The patient in a vegetative state was asked six questions, five of which elicited responses indicative of awareness. For example, when asked, “Is your father’s name Alexander?” the patient responded with the visualization task consistent with “yes,” the correct answer. When asked, “Is your father’s name Thomas?” he responded, “no.”

The researchers are careful to emphasize that the technique is still an experimental research tool, and that, for the majority of patients—49 of 54—they were unable to elicit signs of awareness. That said, they do see promise in the potential for this technique to enable physicians to go beyond current methods for clinical assessment, which target more “readily observable behavior,” with tests that can also assess “residual cognitive function,” specifically in patients whose cognitive state is a result of traumatic brain injury.