Clinical Review

The vegetative state

BMJ 2010; 341 doi: http://dx.doi.org/10.1136/bmj.c3765 (Published 02 August 2010) Cite this as: BMJ 2010;341:c3765
  1. Martin M Monti, post-doctoral research fellow1,
  2. Steven Laureys, clinical professor of neurology2,
  3. Adrian M Owen, senior scientist, assistant director1
  1. 1MRC Cognition and Brain Sciences Unit, Cambridge CB2 7EF
  2. 2Coma Science Group, Cyclotron Research Center and Neurology Department, Université de Liège, Bât B30 Allée du 6 août no 8, B-4000 Liège, Belgium
  1. Correspondence to: M M Monti martin.monti{at}mrc-cbu.cam.ac.uk

    Summary points

    • The vegetative state is a complex neurological condition in which patients appear to be awake but show no sign of awareness of themselves or their environment

    • Current clinical methods of diagnosis are limited in scope, evidenced by a high rate (about 40%) of misdiagnosis (that is, patients who are aware are considered to be unconscious)

    • The main causes of misdiagnosis are associated with a patient’s disability (such as blindness), confusion in terminology, and lack of experience of this relatively rare condition

    • Furthermore, standard behavioural assessments cannot distinguish an aware (that is, minimally conscious) but completely immobile patient from a non-aware patient (one with vegetative state)

    • In such behaviourally non-responsive patients, functional neuroimaging methods (such as magnetic resonance imaging or electroencephalography) can detect residual cognition and awareness and can even establish two way communication, without requiring any behavioural output from patients

    • Current guidelines should therefore be modified to include functional neuroimaging as an independent source of diagnostically relevant information

    The vegetative state may develop suddenly (as a consequence of traumatic or non-traumatic brain injury, such as hypoxia or anoxia; infection; or haemorrhage) or gradually (in the course of a neurodegenerative disorder, such as Alzheimer’s disease). Although uncommon, the condition is perplexing because there is an apparent dissociation between the two cardinal elements of consciousness: awareness and wakefulness.1 Patients in a vegetative state appear to be awake but lack any sign of awareness of themselves or their environment.w1 Large retrospective clinical audits have shown that as many as 40% of patients with a diagnosis of vegetative state may in fact retain some level of consciousness. Misdiagnosis has many implications for a patient’s care—such as day to day management, access to early interventions, and quality of life—and has ethical and legal ramifications pertaining to decisions on the discontinuation of life supporting …

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