Friday, February 22, 2013

Hello! Anybody in there?

At what point can be say without a shout of a doubt that no one is left inside that lifeless corpse laying there motionless in that hospital bed? The first major problem we encounter when discussing “disorders of consciousness1” is that we still don’t have a definitive definition of what consciousness even is. Is it a tangible mass in the brain? Does it light up in response to stimuli during a brain scan? We are still fighting these issues about people’s mental states and their level of consciousness yet we have no idea what that even is. It seems to be a losing battle that will only end in debate. Some are trying to go a step farther and implement modern technology into the better accessing a patient’s mental abilities and whether or not it is safe to define that as being in a vegetative state.

Premotor cortex activity in a vegetative state (Source)

The reasoning for challenging the standard operation of care is that, in 2008, it was reported that 43% of patients were diagnosed as being “vegetative” when in actuality they should have been classified in one of the other mental states1. So Owen et al. suggested that another tool to access ones mental awareness could be to use functional magnetic resonance imaging (fMRI) to determine with patients brains could respond to external stimuli or perhaps even more complex mental tasks. They suggested that this not replace the behavioral assessments that are already in practice but an additional resource that may decrease the alarming misdiagnosis rate.

So how this would be used in a clinical situation? Boly et al. describe a way in which a patient was told to image all the motions and actions associated with playing tennis against an imaginary opponent2. The goal of this experiment was to compare the areas of the brain the lit up in the vegetative state patients compared to control subject who were asked to perform the same mental task2. Surprisingly, the patient showed tremendous activation in the supplementary motor area (SMA) that was comparable to the same patterns found in the control subjects2. Does this mean the patient still had higher cognitive processing abilities and should not be defined as being in a vegetative state? The authors of this study decided this was a case in which the patient was misdiagnosed and still retained the ability to processes spoken commands.

I definitely think it is necessary to improve the assessments of patients’ mental state before declaring them as vegetative; however I feel that this is open to interpretation based on the fact that we don’t have a definitive term of what consciousness is. It makes for a difficult argument trying to speak out against a diagnosis when the foundation of that diagnosis isn’t well defined. Perhaps fMRI can help better define this state but with all techniques there comes flaws. For example, are can specific neuronal networks be activated without high order processing? Even though the patients might be in a vegetative state doesn’t necessarily mean that the neuronal networks that process that information are no longer intact and cannot be activated.

--Travis Rotterman


Want to cite this post?
Rotterman, T. (2012). Hello! Anybody in there? The Neuroethics Blog. Retrieved on , from http://www.theneuroethicsblog.com/2013/02/hello-anybody-in-there.html


References

1. Coleman, M. R. and A. M. Owen (2008). "Functional neuroimaging of disorders of consciousness." Int Anesthesiol Clin 46(3): 147-157.

2. Boly, M., et al. (2007). "When thoughts become action: an fMRI paradigm to study volitional brain activity in non-communicative brain injured patients." Neuroimage 36(3): 979-992.

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