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Functional neuroimaging of the vegetative state

Nature Reviews Neuroscience volume 9, pages 235–243 (2008)Cite this article

Abstract

A number of recent studies have demonstrated a role for state-of-the-art neuroimaging methods in the assessment of patients in the vegetative state and other so-called 'disorders of consciousness'. In several cases, functional MRI has been used to show that aspects of speech perception, emotional processing, language comprehension and even conscious awareness might be retained in some patients who behaviourally meet all of the criteria that define the vegetative state. This work has profound implications for clinical care, diagnosis, prognosis and medical–legal decision making (relating to the prolongation, or otherwise, of life after severe brain injury), as well as for more basic scientific questions about the nature of consciousness and the neural representation of our own thoughts and intentions.

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Figure 1: A proposed hierarchical approach to the use of fMRI to assess residual cognitive function in patients in the vegetative state.
Figure 2: Residual language function in patients diagnosed as either vegetative or minimally conscious.
Figure 3: Changes in brain activity when one imagines performing a task.
Figure 4: Conscious responses to stimuli in a patient who fulfilled all the clinical criteria defining the vegetative state.

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Author information

Authors and Affiliations

  1. Adrian M. Owen is at the Medical Research Council Cognition and Brain Sciences Unit, 15 Chaucer Road, Cambridge, CB2 7EF, UK. adrian.owen@mrc-cbu.cam.ac.uk,

    Adrian M. Owen

  2. Martin R. Coleman is at the Cambridge Impaired Consciousness Research Group, Wolfson Brain Imaging Centre, BOX 65, Addenbrooke's Hospital, Cambridge, CB2 OQQ, UK. mrc30@cam.ac.uk,

    Martin R. Coleman

Authors
  1. Adrian M. Owen
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  2. Martin R. Coleman
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Supplementary information

Supplementary information S1 (Box)

Notable recent cases of vegetative state (PDF 147 kb)

Related links

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FURTHER INFORMATION

Adrian M. Owen's homepage

Cambridge Impaired Consciousness Research Group homepage

Glossary

Classifier

A mathematical algorithm used to categorize data into one of a number of groups or classes. Where imaging data is concerned, a classifier is often used to identify activation patterns and assign these to particular 'mental states'.

Coma

An acute state of unconsciousness immediately after a brain injury, during which the patient exhibits no evidence of arousal or awareness.

Event-related fMRI

A technique that measures the brain's haemodynamic response to events (for example, stimuli) occurring at specific moments in time.

Locked-in syndrome

A condition in which an individual is fully conscious but unable to move or speak due to quadriplegia and anarthria.

Masked information

Stimuli that are presented in such a way that they are not consciously perceived.

Minimally conscious state

A condition in which an individual demonstrates wakefulness and inconsistent but reproducible evidence of awareness of self or environment.

PET activation studies

Studies that use radioactive tracers to measure blood flow or metabolism in the brain in response to a particular stimulus or task.

Vegetative state

A condition of wakefulness without awareness. An individual in the vegetative state might open their eyes and show sleep–wake cycles, but shows no purposeful response to stimulation.

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Owen, A., Coleman, M. Functional neuroimaging of the vegetative state. Nat Rev Neurosci 9, 235–243 (2008). https://doi.org/10.1038/nrn2330

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