By Cameron McKay
Many of us recall the tense legal battle over ten years ago surrounding the end-of-life medical care of Terri Schiavo, a Florida woman who went into a vegetative state after going into cardiac arrest in 1990. This case, which polarized much of the country over the so-called “right-to-die,” highlights the bioethical concerns of patients in a persistent vegetative state (PVS), characterized by “wakeful unresponsiveness” as well as a lack of consciousness and self-awareness. However, as Joseph J. Fins, MD of the Weill Cornell Medical College wants you to know, advances in neuroimaging techniques have revealed considerable neural plasticity in several patients who might normally receive a PVS diagnosis. Dr. Fins’ talk at the Society for Neuroscience meeting last month, titled “Giving Voice to Consciousness: Neuroethics, Human Rights, and the Indispensability of Neuroscience,” shed light on the minimally conscious state (MCS) and recommended critical reforms for more ethical care of MCS patients.
Drawing on his personal interactions with families touched by brain injury and breakthrough findings in the neuroscience literature, Dr. Fins compared the MCS to a flickering lightbulb: neural circuits are intact, but like the lightbulb, but they aren’t always “on.” Occasional reports of seemingly conscious behaviors, such as tracking moving objects with their eyes or reaching for a nearby cup, give hope to families of MCS patients, but these physical actions are not always reliably reproduced.
However, much of what doctors once perceived as wishful thinking from families actually has been supported by multiple neuroscience methodologies. Diffusion tensor imaging (DTI), a brain scan sensitive to white matter structure that researchers use to study connectivity, was used with early MCS patients to reveal the surprising plasticity due to the formation of new connections between old neurons. Furthermore, a breakthrough functional imaging study published in 2006 by Adrian Owen and colleagues showed integrative reactions in the brain of a young women who, behaviorally, was believed to be in a PVS. When the woman was given verbal instructions inside the scanner to imagine herself playing tennis and walking through her home, Owen observed activation in motor and spatial regions of her brain, respectively, which was consistent with brain activity in healthy controls.
Taking into account this experimental evidence about the minimally conscious brain, Fins argued that patients face the challenge of having “dynamic brains in a static healthcare system.” As scientists and physicians learn more about the remarkable cognitive abilities of MCS patients, there is a growing obligation for neuroscience to help these persons, otherwise sequestered from the broader human community, communicate with the outside world. To address the challenges of MCS, Fins advocates for the use of neuroimaging as a neuroprosthetic communication tool; the administration of drugs that can alter brain states and speed the recovery of MCS patients; and the application of thalamic deep brain stimulation as a therapeutic intervention.
Fins believes there is a moral obligation to “advance and sustain” these neuroscience and neurotechnology projects that aid in the diagnosis and treatment of patients who are minimally conscious. While it is unethical to deprive these patients of diagnostic accuracy, Fins considers it equally wrong to deprive them of proper rehabilitation, in the form of new drugs and devices that might allow for recovery and the ability to once again engage with others. It is therefore unethical, in his view, to deprive a conscious individual the opportunity to express human companionship and participate in the communities that arise from the ability to communicate. Moving forward, Fins believes scientists and society must recognize the civil rights of the minimally conscious so neuroscience can better serve and connect patients and their families.
Owen, A. M., Coleman, M. R., Boly, M., Davis, M. H., Laureys, S., & Pickard, J. D. (2006). Detecting awareness in the vegetative state. Science, 313(5792), 1402-1402. doi: 10.1126/science.1130197
Schiff, N. D., Giacino, J. T., Kalmar, K., Victor, J. D., Baker, K., Gerber, M., … & Rezai, A. R. (2007). Behavioural improvements with thalamic stimulation after severe traumatic brain injury. Nature, 448(7153), 600-603. doi: 10.1038/nature06041
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Any views expressed are those of the author, and do not necessarily reflect those of PLOS.
Cameron C. McKay is a first year neuroscience graduate student at Georgetown University. His research interests include the mechanisms underlying language processing and mathematical thinking. Find him on Twitter @HippocampusCam.