In the wake of John Paul II's March 2004 allocution on "Life-Sustaining Treatment and the Persistent Vegetative State," a number of commentators expressed doubt and even challenged some of the allocution's more scientifically-oriented statements. Several studies in the ensuing years,¹ however, and the attention being given to them,² should perhaps give critics and non-critics alike some pause.

One of the most recent such studies is a publication in the February 18, 2010 issue of the New England Journal of Medicine, "Willful Modulation of Brain Activity in Disorders of Consciousness," (Monti, et al.). The article reports a study of 54 patients with disorders of consciousness (vegetative state and minimally conscious state) who underwent functional magnetic resonance imaging (fMRI) to determine whether or not they were able to generate willful responses to two mental-imagery tasks — playing tennis and walking from room to room in their home. As the authors note, "Such a capacity, which suggests at least partial awareness, distinguishes minimally conscious patients from those in a vegetative state and therefore has implications for subsequent care and rehabilitation, as well as for legal and ethical decision making" (580). Of the 54 patients studied, the researchers found five who could willfully modulate their brain activity. Four of the five had been diagnosed as being in a vegetative state. All five suffered a traumatic brain injury. There were no such responses in patients with non-traumatic brain injuries. The authors observe that in "a minority of cases, patients who meet the behavioral criteria for a vegetative state have residual cognitive function and even conscious awareness" (585). In other words, some patients seem to have a limited degree of awareness despite the lack of any behavioral responsiveness on bedside examination. As a result, the diagnosis of vegetative state "did not accurately reflect the patient's internal state of awareness and level of cognitive functioning at the time" (588). Currently, clinical audits put the number of misdiagnoses of vegetative state at "approximately 40%" (580) though some place it as high as 43%.

In another recent study (M.R. Coleman, et. al., "Towards the Routine Use of Brain Imaging to Aid the Clinical Diagnosis of Disorders of Consciousness," Brain 132 (2009): 2541-2552), the authors observe that the "accurate assessment of persons with impaired consciousness following brain injury is a considerable challenge for any clinician. At present a diagnosis is made largely on the basis of the patient's clinical history with further support gleaned from the observation of the patient's behavior in response to stimulation" (2542). The assessment procedure has remained essentially unchanged since Jennett and Plum coined the term "vegetative state" in 1972. It is highly subjective, note Coleman and colleagues, and completely dependent upon the patient's exhibited behavior. As a result, some patients who do retain some degree of awareness fall victim to attitudes and behaviors associated with patients deemed to be in a vegetative state. In their neuroimaging study, two of 22 patients judged to be in a vegetative state were found to have some higher order function.

The clinical conclusions of both of these studies (among several others, see below) is that functional MRI can provide both diagnostic and prognostic information about brain injured patients, helping to distinguish between patients who are truly vegetative and those in a minimally conscious state. "In patients without a behavioral response, it is clear that functional MRI complements existing diagnostic tools by providing a method for detecting covert signs of residual cognitive function and awareness" (Monti, 588). Or, as Coleman and colleagues put it: "hence this study reiterates the conclusions of many fMRI studies — namely, appropriately designed fMRI paradigms may provide additional information to inform the clinical diagnostic decision-making process that is not available from standard bedside behavioral assessments" (Coleman, 2550).

But this is not all. Coleman and colleagues found that "the higher the level of speech processing demonstrated by a patient during fMRI investigation, the more likely they are to demonstrate an improvement in their behavior profile six months post-investigation" (Coleman, 2550). Hence, neuroimaging may also provide prognostic information for the medical team which, in turn, might affect the attitudes of caregivers and families, as well as care plans. Monti and colleagues further suggest that neuroimaging, at some point, might be able to be used to assist some patients to express themselves and to have some control over their lives and their environment (Monti, 589).

The clinical implications of these and other studies are indeed fascinating and promising. But what about the ethical implications? Do all these studies, along with the very high rate of misdiagnoses of vegetative state, suggest anything about the appropriate and ethical care of patients deemed to be in such a state — decisions about treatment and about rehabilitation efforts? At some point, should fMRI become part of the ordinary response to patients who suffer traumatic brain injury? Perhaps these are conversations we need to begin in our organizations as well as within society. At minimum, these studies suggest that we proceed cautiously diagnostically, prognostically, and therapeutically with brain injured patients. John Paul II may have been on to something.

R.H.

Notes

1. Among these studies are the following: M. M. Monti et al., "Willful Modulation of Brain Activity in Disorders of Consciousness," New England Journal of Medicine 362, no. 7 (February 18, 2010): 579-589; M. R. Coleman et al., "Towards the Routine Use of Brain Imaging to Aid the Clinical Diagnosis of Disorders of Consciousness," Brain 312 (2009): 2541-2552; M. R. Coleman et al., "A Multimodal Approach to the Assessment of Patients with Disorders of Consciousness," Progress in Brain Research 177 (2009): 231-48; S. Marino and P. Bramanti, "Neurofunctional Imaging in Differential Diagnosis and Evaluation of Outcome in Vegetative and Minimally Conscious State," Functional Neurology 24, no. 4 (2009): 185-88;H. Di et al., "Neuroimaging Activation Studies in the Vegetative State: Predictors of Recovery?" Clinical Medicine 8, no. 5 (October 2008): 502-07; A. Owen, et al., "Functional Neuroimaging of the Vegetative State," National Review of Neuroscience 9 (2008): 235-43; A. Owen et al., "Using Functional Magnetic Resonance Imaging to Detect Covert Awareness in the Vegetative State," Archives of Neurology 64, no. 8 (August 2007): 1098-1102; M. R. Coleman et al., "Do Vegetative Patients Retain Aspects of Language Comprehension? Evidence from fMRI," Brain 130 (2007): 2494-2507; S. Laureys et al., "Cortical Processing of Noxious Somatosensory Stimuli in the Persistent Vegetative State," Neuroimage 17 (2002): 732-41.
2. For example, the use of neuroimaging with brain injured patients was discussed at three professional meetings that I attended over the past six months.

Copyright © 2011 CHA. Permission granted to CHA-member organizations and Saint Louis University to copy and distribute for educational purposes. For reprint permission, contact Betty Crosby or call (314) 253-3490.