By Sherry Soliman
For many patients diagnosed as being in a vegetative state, the prospects of recovery are grim. They are alive in body only, unable to interact or communicate with the world around them. No one knows what occurs in the minds of these individuals or if they have any awareness of their surroundings.
However, all of that may be about to change by a team of international scientists offering a glimpse into the minds of these patients. For the first time, brain scans showed that patients who demonstrated no external signs of alertness could understand the spoken commands of others. One patient could even answer basic biographical questions.
The study was published in the New England Journal of Medicine and provided hope for different means of communicating with those deemed no longer awake to the outside world.
Dr. Adrian Owen, one of the lead neuroscientists on the study, noted that some patients may have cognitive abilities beyond what they appear capable of achieving. Indeed, some estimates place the misdiagnosis of the vegetative state as high as 40%.
In the present study, the group of 54 subjects tested included 23 in vegetative state and 31 in a minimally conscious state. Patients in a vegetative state are thought to have absolutely no awareness of their environment. Whereas those in a minimally conscious state display deliberate behavior frequently enough for physicians to distinguish it from responses that are exclusively reflexive or unconscious (they may sometimes laugh or cry and might even reach for objects). These types of diagnoses are usually made at the bedside through a set of neurological exams to determine the degree of awareness.
One of the most fascinating examples of the study involves a young man whose brain was damaged following a car accident in 2003. Remarkably, he correctly answered five out of six questions posed to him. The man had spent two years in a coma prior to transitioning into a persistent vegetative state.
Doctors had been unable to communicate with the man for five years before Dr. Owen and his team of investigators realized that they could communicate with him through the use of brain scans.
The researchers from Europe came up with a unique way of using fMRI brain imaging techniques to communicate with patients in a vegetative state by linking “yes” or “no” answers to imagery tasks. The scientists employed this method because it is difficult to tell apart the brain signals corresponding to “yes” or “no.”
For the motor imagery task, the young man was asked to imagine swinging his arm back and forth while playing tennis. In the spatial imagery task, he was asked to picture familiar places, i.e. going through rooms in his home or traveling through streets common to him.
In normal individuals, each task activated specific regions of the brain. Thus, scientists could use the brain scan to decipher which task the person was visualizing. The motor aspect in the tennis task ignited the supplementary motor area, which is involved in carrying out a series of movements from memory. In contrast, the spatial task stimulated the parahippocampal gyrus, a region important in the recognition of topographical scenery such as landscapes or rooms.
Amazingly, the young man could hear and understand the investigators’ speech, as well as, imagine the various activities.
The man then completed a communication task where he was asked “yes” or “no” questions, such as his father’s name and whether he had any siblings. He was told to use the motor imagery for “yes” and the spatial imagery for “no”.
Researchers did not know the correct answers to these questions and confirmed the accuracy of the responses with patient’s mother after they conducted the test. When comparing the man’s brain responses to the questions with those of healthy volunteers, the scientists discovered that this patient had the ability for willful thought and communication.
“We were astonished when we saw the results of the patient’s scan and that he was able to correctly answer the questions that were asked by simply changing his thoughts,” said Dr. Owen. “Not only did these scans tell us that this patient was not in a vegetative state but, more importantly, for the first time in five years it provided the patient with a way of communicating his thoughts.”
Researchers were able to interact with the man through this approach, even though they had not been able to establish any form of communication at the bedside. This indicated that something in his system was simply not allowing him to produce behaviors that matched his level of cognition.
Investigators are unsure why the patient showed no brain activity on the last question, citing that he may have fallen asleep, slipped out of consciousness or simply decided not to answer the question.
Four other vegetative patients were also able to alter their brain activity with these imagery tasks illustrating that they were aware of what was going on, but none of them responded to the questions by changing their thoughts in exactly the same way as this man. Their brain activity was sustained for more than thirty seconds, which eliminates the chance that the activity was a random artifact, and it was consistent with the verbal cues.
The use of these imagery tasks required patients to understand the command given to them, recall it in the test and then perform the visualization portion, all of which involve complicated cognition processes. The brain activity in the patients was on par with the results from healthy control subjects.
Intriguingly, the patients remained unresponsive outside of the fMRI machine. They appeared to be “locked in” with no physical capability to express themselves. However, this breakthrough use of the fMRI scan may now unleash the “inner voice” of vegetative patients and let them reach out to others after so many years trapped in isolation.
The brain imaging technique had success with patients who suffered traumatic brain injury, but not with those whose brains had been deprived of oxygen. In cases of brain trauma, some parts of the brain are more damaged than others, whereas in anoxia, all of the brain cells are deprived of oxygen, which could explain why the brain trauma patients still had some level of consciousness.
“It will now be difficult for physicians to tell families confidently that their unresponsive loved ones are not ‘in there somewhere,’” said Dr. Allan H. Ropper, a neurologist at Brigham and Women’s Hospital in Boston. “However, we cannot be certain whether we are interacting with a sentient, much less a competent, person.”
Dr. Ropper thinks that the line between consciousness and unconsciousness will be blurred as scientists continue to delve further into examining and comprehending the vegetative state. Despite the uncertainty, the study may supply an additional test for physicians to utilize when dealing with patients who remain unresponsive.
The findings of the study demonstrate that patients diagnosed as being in a vegetative state still have some cognitive function and conscious awareness, holding the promise that these patients may someday be able to partake in decisions regarding their medical care.
The implications of this study might mean the rediagnosis of many patients labeled as vegetative. It highlights the need for more research to ascertain the level of consciousness in brain-damaged patients, permitting doctors to make more informed decisions about which patients have the potential for recovery and those whose chances are slim.
The research also brings complex legal and ethical questions to the forefront. Inevitably, there will be questions regarding whether the patient will be able to communicate if they wish to keep on living, as well as, questions about when doctors should discontinue life support.
Dr. Owen emphasized that the research may help doctors in determining if patients are in pain and improve their quality of life, but admitted that it was a stretch to allow these patients to decide whether they live or die.
Much debate lingers about how to apply the new information from the study in order to handle these ethical and legal ramifications, particularly how long unresponsive patients should continue receiving life supportive care.
The results of this research could further provide insight into human thought, which has eluded scientists. In the meantime, scientists are working on cheaper and more convenient alternatives to the expensive and challenging fMRI technique.
Dr. Owen and his team are currently examining the measurement of brain activity with EEG recordings. Since the electrical activity can be detected through sensors on the surface of the scalp, EEG devices are more portable and cheaper.
While much more analysis and exploration are needed, the outcome of this research provides optimism that there may finally be a way to tap into the thoughts of vegetative state patients.