Modern Imaging Techniques, Awareness, and the "Vegetative" State

William E. May
© 2010 Culture of Life Foundation.
Reproduced with Permission
Culture of Life Foundation

Why burden persons in the "vegetative" state and their families by keeping them "alive" by force feeding them through various kinds of tubes?

On February 8 the Chicago Tribune interviewed elderly Catholics who were horrified at the thought of lingering unconsciousness. "My pleasure is in being part of the human race," said one of them. "If that's gone, if I can't interact with other people, even if they could give me nutrition and keep me hydrated, I'm not interested in being preserved." This reaction is quite common and reflects the views, I think, of most ordinary men and women. I believe that most ordinary persons think that it is ridiculous to keep persons in the "persistent vegetative state" alive by "force feeding" them through various kinds of tubes. They believe that doing so is futile and in addition imposes horrible burdens on those kept "alive" in this way and on their families. I fully appreciate why so many people think this way. I did so for many years myself. I will tell you why I did in a future piece for the Culture of Life Foundation. In this one I will summarize recent scientific studies that bear on some of the reasons why I changed my mind.

What recent studies show about "consciousness" in "vegetative" persons

Using new brain scanning methods scientists have demonstrated that some "vegetative" persons experience consciousness and can perform complex mental tasks.

Among these scientists Adrian Owen of England has carried on very important tests on persons in the so-called "vegetative" state. A remarkable article by Jerome Groopman in the New Yorker on October 15, 2007, "Silent Minds," described one of Owen's most significant tests that he carried out between 1997-2007. Owen's more recent work, in which he collaborated with Morton Monti, Audrey Vanhaudenhuyse, and others, can be found on the on-line edition of the New England Journal of Medicine, February 3, 2010, "Willful Modulation of Brain Activity in Disorders of Consciousness."1

Owen's Work from 1997-2007 described in "Silent Minds"

In one experiment he used an older kind of brain scanner (PET)2 to scan the brain of a patient named Kate Bainbridge, who was diagnosed as "vegetative," and had for 4 months not spoken or responded to her family or her doctors. Owen placed her in a PET scanner and projected on a screen in front of her photographs of faces of her family members and some distorted images in which the faces were not recognizable. Whenever pictures of her family appeared, an area of her brain known to play a central role in face recognition lit up on the scan. Owen said that he and colleagues were stunned to discover that "The activation in her brain was not simply similar to normal; it was exactly the same as normal volunteers."

From 1997-2007 Owen studied several dozen persons, using speech sounds rather than photographs to stimulate their brains and in 2004 he began using an MRI3 scanner, faster than a PET. He scanned patients' brains while they listened to simple sentences interspersed with meaningless sounds. Some patients' scans showed the same response to the sentences as scans of healthy volunteers. To determine whether these patients comprehended what the sounds meant he tested their ability to associate words because psycholinguists have shown that when we hear a noun at the beginning of a sentence we tend to associate the word with its most common meaning. For example, "most people hearing a sentence that begins, 'The shell was . . .' think of an object typically found at the beach. But if the sentence is completed by the phrase 'fired at the tank,' the listener quickly corrects himself, a process that is evident on a brain scan. 'You can actually see it happening and image it on the scanner.'" He eventually identified two vegetative patients whose brains showed the same activity in response to ambiguous sentences as the brains of healthy volunteers.

His most ambitious experiment up to 2007 was a test to determine whether vegetative patients who seemed able to comprehend speech could also perform a complex mental task on command. He asked them to imagine playing tennis. He first did this with 34 healthy volunteers asked to picture themselves playing the game for at least thirty seconds. Their brains showed activity in a region of the brain that would be stimulated in an actual match. He repeated the experiment with one of the vegetative patients, a woman who had to be able to hear and understand Owen's instructions, retrieve a memory of tennis, and focus her attention for at least thirty seconds. "To Owen's astonishment," Groopman writes, she passed the test. "'Lo and behold, she produced a beautiful activation, indistinguishable from those of the group of normal volunteers,' he said. Another vegetative patient, a man in his twenties, also passed the test, though Owen, having learned that he was a soccer fan, asked him to imagine playing that sport instead of tennis."

Experiments reported in the February 3 on-line edition of New England Journal of Medicine

The "Abstract" of the article summarizes the background, methods, results, and conclusions. I summarize the Abstract and consider important passages from the "Discussion."

Abstract. Background. The diagnosis of disorders of consciousness is difficult, with some 40% of individuals misdiagnosed.

Methods used in experiments. 54 "vegetative" patients with apparently no conscious awareness were studied at two major centers in Cambridge, England, and Liege, Belgium, using MRIs to assess ability of each to give "willful, neuroanatomically specific, blood-oxygenation-level-dependent responses during two mental-imagery tasks." The scientists developed a technique to determine whether such tasks could be used to communicate yes-or-no answers to simple questions.

Results. Of the 54 patients, 5 were able willfully to change their brain activity. In three, additional bedside testing revealed some sign awareness, but in the other two patients, no voluntary behavior could be detected by means of clinical assessment. One patient was able to answer yes or no to questions during functional MRI; however, it was not possible to establish any form of communication at the bedside.

Conclusions. The results show that a small proportion of patients in a vegetative or minimally conscious state have brain activation reflecting some awareness and cognition. Techniques used may be helpful in establishing basic communication with patients who appear unresponsive.

Discussion. The experiments showed that 4 of the 5 patients able to provide voluntary, reliable, and repeatable conscious responses when prompted to perform imagery tasks had been diagnosed as being in the persistent vegetative state. Although this is a small minority of the 54 subjects, the tests show that patients who meet the criteria for the vegetative state can have residual cognitive function and even conscious awareness. One patient had the ability to answer simple yes-or-no questions accurately. In fact, for five of the six questions, he had a reliable neural response and was able to provide the correct answer with 100% accuracy.

Although the data provided clear evidence that the patient was aware and able to communicate, the scientists did not know whether he was able to do so when he was evaluated by others earlier. But, and this is most important, they said that it was possible that he "was in a vegetative state when the diagnosis was received at 17 months and again 3.5 years after injury and subsequently (emphasis added) regained some aspects of cognitive functioning." Another possibility is that "the patient may have been aware during previous assessments but unable to produce the necessary motor response required to signal his state of consciousness. If this was the case, then the clinical diagnosis of a vegetative state was entirely accurate in the sense that no behavioral markers of awareness were evident. That said, the diagnosis did not accurately reflect the patient's internal state of awareness and level of cognitive functioning at the time" (emphasis added).


The more clinicians discover about the so-called "persistent vegetative state" the more they realize the diagnosis is a moving target, not a monolithic state in which all possibility of consciousness has been irretrievably lost. This should give everybody pause before they (we) go on confidently to treat "vegetative" patients the way Michael Schiavo treated his wife Terri.


1 [Back]

2 Positron emission tomography (PET) is a nuclear medicine imaging technique which produces a three-dimensional image or picture of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionucline (tracer), which is introduced into the body. [Back]

3 Magnetic resonance imaging (MRI), or nuclear magnetic resonance imaging (NMRI), is primarily a medical imaging technique most commonly used to visualize detailed internal structure and limited function of the body. MRI provides much greater contrast between the different soft tissues of the body than other scanning methods, making it especially useful in brain imagine. [Back]