Trapped Thoughts: Consciousness In A Vegetative State

In the final year of my undergraduate degree in psychology, I came across Owen et al’s (2006) article, “Detecting awareness in a vegetative state”. This research sparked my interest and had a hugely inspiring effect on my academic direction; it was certainly a contributing factor to my pursuit of a career in neuroscience.

This case study involves a 23-year-old woman who suffered from severe traumatic brain injury, who received the clinical diagnosis of a vegetative state. The researchers conducted a fMRI study to investigate the patient’s neural responses to spoken sentences. Activation was observed in the middle and superior temporal gyri. However, due to the nature of the experiment, these results could not decisively determine awareness in the patient, as studies have previously shown that such aspects of human cognition can occur even in an unconscious state.

A second fMRI study was conducted in order to assess consciousness in the patient. She was given spoken instructions for two mental imagery tasks: to imagine playing tennis and to imagine walking around her home. During the tennis task, her supplementary motor cortex showed significant activation while her parahippompal gyrus, the posterior parietal cortex and the lateral premotor cortex were activated during the spatial navigation task. These responses were concurrent with those of the control group. Not only did this study demonstrate that the patient understood the spoken instructions and could follow them, it also implied that she intended to engage in this activities. This was a compelling finding, as it holds implications for the criteria of clinical diagnosis of a vegetative state and the question of possible communication with vegetative and minimally conscious patients.

Research into the investigation of consciousness in vegetative states has continued, which can be seen from the results of Chennu et al.’s (2014) article just a few months ago. This study used EEG and a branch of mathematics called “graph theory” to investigate activity in the brain of 32 vegetative and minimally conscious patients in comparison to healthy controls. This research revealed that there are networks in the brain of healthy controls and some vegetative patients that support awareness. The patients that such networks were observed in had shown neural activity during neuroimaging tasks, such as imagining to play tennis. These results once again demonstrate the need to re-evaluate the method of diagnosis for vegetative state and provides a technique that is less expensive and more easily administered than fMRI.

I was reminded of these articles and the importance of research in this area today when this story appeared on my Twitter feed: http://www.npr.org/blogs/health/2015/01/09/376084137/trapped-in-his-body-for-12-years-a-man-breaks-free?utm_campaign=storyshare&utm_source=twitter.com&utm_medium=social. It is often forgotten that clinical subjects in science are people who have or who had lives, families, friends, hopes and ambitions. This heartrending piece presents a more human, less analytical reason for such research to be funded and conducted. We should be striving towards making cases such as Martin a myth, not reality.

References

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.

Chennu, S., Finoia, P., Kamau, E., Allanson, J., Williams, G. B., Monti, M. M., … & Bekinschtein, T. A. (2014). Spectral signatures of reorganised brain networks in disorders of consciousness. PLoS computational biology, 10(10), e1003887.

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