Vegetative States

oPatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.

Persistent vegetative state (PVS) is marked by ethical and medical dilemmas, often, if not always, requiring legal assistance. There are now several cases where patients diagnosed as being in PVS have subsequently regained consciousness. This has led to outrage especially if decisions were made to terminate hydration and nutrition. This has understandably led to tension between carers and healthcare professionals in these situations. Thus, probably the most important aspect of PVS is making the correct diagnosis - which the reader will see is no easy task.

Coma is a profound state of unconsciousness. The individual is alive but unable to move or respond to the environment. A PVS can follow a coma. There is loss of ability to think and of awareness of surroundings, but non-cognitive function and normal sleep patterns remain. Although they lose their higher brain functions, other key functions such as breathing and circulation remain relatively intact.

Spontaneous movements may occur, and the eyes may open in response to external stimuli. They may occasionally grimace, cry, or laugh. They do not speak and they are unable to respond to commands. There is no swallowing reflex and no control over bowels or bladder. This differs from brain death where there is loss of all brain function including the ability to breathe spontaneously.

The Royal College of Physicians has produced guidance on the subject that has also been accepted by the Scottish colleges.[1] It is important because it is authoritative and it represents British thinking on the subject. Furthermore, adherence to these guidelines may have important medicolegal implications.

Also see separate Coma article.

These are derived from the Royal College of Physicians' guidance on vegetative states.[1]

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Vegetative state

  • A patient in the vegetative state appears to be wakeful, with cycles of eye closure and opening resembling those of sleep and waking but there is no sign of awareness or of a functioning mind. There is no evidence that the patient can perceive the environment or his/her own body, communicate with others, or form intentions. Usually the patient can breathe spontaneously and has a stable circulation. This may be a transient stage in the recovery from coma or it may persist until death. The vegetative state results from severe injury to the brain, most commonly head injury, hypoxic or ischaemic injury.

Persistent vegetative state

  • Persistent vegetative state (PVS) occurs when the state has continued for 4 weeks or more.

Permanent vegetative state

  • Permanent vegetative state is when it is thought that there will never be recovery from the condition. There can never be absolute certainty about this but the longer the duration, the less the chance of eventual recovery.

Again this comes from the Royal College of Physicians' guidance on vegetative states.[1]

The following preconditions apply

  • The cause of the condition should be established as far as is possible. This may include acute cerebral injury, degenerative conditions, metabolic disorders, infections or developmental malformations.
  • Persisting effects of sedative drugs, including anticonvulsants, anaesthetic or neuromuscular blocking agents, should be excluded as a contributory factor or a cause.[2]
  • Continuing metabolic disturbance may be responsible for the clinical features and this must be excluded.
  • Imaging should be used to exclude a treatable structural lesion. Studies involving positron emission tomography (PET) and single-photon emission computed tomography (SPECT) have shown that the brain metabolises less glucose than in normal controls but such investigations are not useful in making the diagnosis.[3]
Of the following clinical criteria, the first criterion is essential. The other two are usual but not compulsory:
  • The essential requirement is that there must be no evidence of awareness of self or environment at any time. There is no response to visual, auditory, tactile or noxious stimuli of a kind to suggest volition or conscious purpose. There is no language comprehension or meaningful expression. All these conditions must be fulfilled.
  • There are typical cycles of eye opening and closure, suggesting a cycle of sleeping and awake.
  • There is spontaneous breathing and stable circulation.

Some features are typical, some unusual and some incompatible with the diagnosis.

Typical features

These are usually present but are not all essential for the diagnosis.

  • There is a cycle of sleep and wakefulness.
  • They may make a range of spontaneous movements including chewing, teeth grinding, swallowing, roving eye movements and purposeless limb movements.
  • They may show smiles, grimaces, shed tears or make grunting or groaning sounds. They do not usually display all these features.
  • A number of brainstem reflexes may be present such as pupillary response, oculocephalic - also called doll's eye - movement (if the head is moved the eyes open or close as with a doll), corneal reflex, oculovestibular reflex - also called caloric response - and gag reflex.
  • Noxious stimuli or noise can excite a generalised arousal response, with faster breathing, grimaces or movement of limbs. Noxious stimuli can cause the extensor or flexor withdrawal of a limb. The patient's eyes may turn fleetingly to follow a moving object or towards a loud sound.
  • The grasp reflex may be present.

Unusual features

These are not incompatible with the diagnosis but are a cause to reassess the situation.

  • It is unusual for patients to follow a moving target for more than a fraction of a second, to fix on a target or to react to visual menace but it has been described in patients who otherwise fulfil the diagnosis.
  • Patients have also been known to display isolated fragments of behaviour, such as the utterance of a single inappropriate word. It probably represents an island of surviving cerebral cortex.[4]
  • Sometimes there are epileptic seizures.
  • Incompatible features refute the diagnosis.

Features indicating recovery of awareness

  • Evidence of discriminative perception, purposeful actions and communicative acts such as a smile in response to the arrival of a friend or relative, an attempt to reach out for an object or the appropriate use of language would all indicate the presence of a functioning mind and the recovery of awareness, although such recovery is sometimes very limited.
  • Minimally conscious state, also called minimally responsive or low awareness state, refers to patients who show minimal but definite evidence of awareness despite profound cognitive impairment.[5][6] A move from a vegetative state to this condition may be a stage on the way to recovery or it may be the limit of recovery.
  • People with lifelong severe disabilities, with severe intellectual disabilities, often with severe physical disabilities, have limited ability to respond to surroundings. Carers insist that they do communicate and are aware. They should not be classified as vegetative.
  • Locked-in syndrome usually results from a brainstem stroke which abolishes voluntary control of movement without affecting either wakefulness or awareness. These patients are substantially paralysed but conscious, and can communicate using movements of the eyes or eyelids.
  • Coma is unconsciousness in which the eyes are closed and sleep-wake cycles absent. Coma is usually transient, lasting for hours or days, and a vegetative state is a possible outcome.
  • Death confirmed by brainstem death testing, implies the irreversible loss of all brainstem functions so that breathing is not spontaneous and the circulation is unstable. It is followed by cardiac arrest, usually within hours or days, despite intensive care.
  • It is important to be diligent about both the initial diagnosis of the vegetative state and the subsequent diagnosis that it is permanent. Causes of error include confusion about the meaning of the term, inadequate observation in suboptimal circumstances, failure to consult those who see most of the patient (especially family members), and the inherent difficulty of detecting signs of awareness in patients with major perceptual and motor impairments.[7][8]
  • There have been some patients with persistent vegetative state (PVS) who have been misdiagnosed as such, with subsequent regaining of consciousness. Understandably, there has been much media around this which makes patient-healthcare professional relationships more difficult in these circumstances.
  • When the diagnosis of the permanent state is considered, the patient should be examined by at least two doctors who are expert in assessing disorders of consciousness. They should take into account the views of the medical staff, other clinical staff including clinical neuropsychologists, occupational therapists and physiotherapists, carers and relatives about the patient's reactions and responses. They should make their clinical assessments separately and write the details in the notes. They should consider the investigations which have been performed to confirm the cause of the condition. As the patient's physical position can affect responsiveness, it may be valuable to assess the patient in more than one position. It may be helpful for nursing staff and relatives to be present during the examination.
  • If there is any uncertainty about the diagnosis, it should not be made and the patient should be reassessed at a later date. There is no hurry.
  • Structured observation may help to reveal signs of awareness in doubtful cases. The key consideration in making the diagnosis is whether the patient might be aware to some degree. It is always important to seek the views of nursing staff, relatives and carers.

The British Medical Association (BMA), in addition to the above guidance, mentions that decisions to withdraw or withhold treatment should not be made until the patient has been insentient for over 12 months.[9]

  • Persistent vegetative state (PVS) should be diagnosed with care and should not be rushed. During this diagnosis period patients should receive full medical care, eg artificial nutrition, and surgery if needed.
  • Nursing care is important in order to avoid complications.
  • Adequate nutrition often requires a percutaneous endoscopic gastrostomy (PEG) tube. Good skin care, passive joint exercises to minimise contractures, suction where necessary to help avoid aspiration, careful management of the incontinent bladder and bowel, and attention to oral and dental hygiene are all required.
  • In those who regain consciousness, an early intensive neurorehabilitation programme may be beneficial.[10]
  • Deep brain stimulation has been used to attempt to awake patients from a vegetative or minimally conscious state but the value is uncertain.[11]
  • When a permanent vegetative state has been confirmed, recovery cannot reasonably be expected and further therapy is futile. It merely prolongs an insentient life for the patient and a hopeless vigil entailing major emotional costs for relatives and carers.
  • In all reviews of treatment it is good practice to involve family and carers, staff who interact with the patient on a daily basis and the patient's general practitioner.
  • A formal review should occur and then the implications should be discussed with relatives and they should have time to consider the implications, including the possibility of withdrawing artificial feeding and hydration. In England and Wales, the decision has to be referred to a court. In Scotland, it is not compulsory but it may be prudent.
  • A decision to withdraw other life-sustaining medication, such as insulin for diabetes, may also need to be referred to the courts because the legal position is uncertain, but the decision not to intervene with cardiopulmonary resuscitation, antibiotics, dialysis or insulin can be taken clinically, in the best interests of the patient, after full discussion with those concerned.
  • Where there is an advance directive this must be respected. If not, efforts should be made to establish what the patient's views and preferences might have been, to help to make a decision in his or her best interests.
  • It is impossible ever to be certain that a patient is wholly unaware, although the evidence suggests this. It is still reasonable to administer sedation when hydration and nutrition are withdrawn to eliminate the possibility of suffering, however remote. The normal standards of palliative care should be observed.
  • The guidance refers to adults but it is probably applicable to older children too. The position with regard to younger children is more difficult both clinically and emotionally.

The prognosis is influenced by age, the underlying cause and its current duration. A little over half of those in a vegetative state one month after trauma will regain awareness. With other causes, after a month in a vegetative state fewer than 20% will recover. The chances of regaining awareness fall as time passes. Beyond one year following trauma, and beyond 6 months in nontraumatic cases, the chances of regaining consciousness are extremely low. In the very small number of well-documented cases, recovery has usually been to a state of exceptionally severe disability. Patients should be observed for 12 months after traumatic injury and 6 months after other causes before a diagnosis of permanent vegetative state is made.

Patients in a vegetative state may be in a nursing home or a hospital. Those who love them will have enormous emotional needs that they may take to the general practitioner. It is important to understand the nature of the condition to be able to explain and empathise. It is very easy for loving visitors to interpret smiles or tears as indicating a responsive emotion. It may be their deepest wish but it is not reality. They hold the patient's hand and the patient holds theirs. This is not love but a grasp reflex. In the early days, especially following trauma, an aura of reasonable optimism is appropriate but, if the months go by without significant improvement, it needs to be replaced by a mood of realism. Neither excessive zeal to suspend life support nor excessive zeal to maintain it is appropriate. This is a very emotional time to make decisions based on the balance of probabilities rather than absolute certainties.

  • Further imaging techniques may help to determine how consciousness is produced and regulated.[12]
  • It is also important to determine whether patients in persistent vegetative state (PVS) experience pain, and functional imaging may also be of help in this area.[13]
  • There is consideration for the role of postmortems in confirming the diagnosis - for epidemiological purposes. This may also provide some insight into how to diagnose the condition at an earlier stage.[9]
  • Some studies have reported short-lived improvements in consciousness in PVS patients, with levodopa or zolpidem.[14][15] At present it is unclear as to how these work and whether these represent a subgroup of patients. Furthermore, the effects appear to be short-lived.
  • Assessment scales to look at the degree of awareness and to determine appropriate rehabilitation programmes are also under research.[12]
  • Persistent vegetative state (PVS) has been under a lot of media and public scrutiny in the last two decades. This began with the case of Tony Bland in 1992-1993, a victim of the Hillsborough football disaster. The decision to discontinue artificial hydration and nutrition was made by the House of Lords. Following this, the BMA recommended that no decision to withdraw or withhold therapy should be made within the first 12 months.
  • The USA's case of Terri Schiavo has also received a lot of medical, ethical, legal and political attention. The dilemma here centred mainly around the removal of artificial nutrition and hydration. There was a difference in opinion amongst her parents and her husband. The case went on for seven years in the legal house. It highlighted the importance of not only treating the patient but also of considering the needs of carers and family.

As medical technology advances at a rapid pace, the ability to sustain patients who have irreversible brain damage will improve. We will no doubt have further similar cases to ponder and debate. However, whether the medical, pathological, ethical and legal issues will ever be resolved completely still remains a mystery.

Further reading & references

  • Wade DT, Johnston C; PVS - practical guidance on diagnosis and management. BMJ 1999
  • Rifkinson-Mann S; Legal consequences and ethical dilemmas of pain perception in persistent J Health Law. 2003 Fall;36(4):523-48.
  1. Report of a working party of the Royal College of Physicians; The Vegetative State: Guidance on diagnosis and management; 2003
  2. Strens LH, Mazibrada G, Duncan JS, et al; Misdiagnosing the vegetative state after severe brain injury: the influence of medication. Brain Inj. 2004 Feb;18(2):213-8.
  3. Beuthien-Baumann B, Handrick W, Schmidt T, et al; Persistent vegetative state: evaluation of brain metabolism and brain perfusion with PET and SPECT. Nucl Med Commun. 2003 Jun;24(6):643-9.
  4. Schiff ND, Ribary U, Moreno DR, et al; Residual cerebral activity and behavioural fragments can remain in the persistently vegetative brain. Brain. 2002 Jun;125(Pt 6):1210-34.
  5. Giacino JT, Ashwal S, Childs N, et al; The minimally conscious state: definition and diagnostic criteria. Neurology. 2002 Feb 12;58(3):349-53.
  6. Neppe VM; Differential cerebral cortical responsiveness examination in minimally conscious J Neuropsychiatry Clin Neurosci. 2007 Fall;19(4):478-9.
  7. Childs NL, Mercer WN, Childs HW; Accuracy of diagnosis of persistent vegetative state. Neurology. 1993 Aug;43(8):1465-7.
  8. Andrews K, Murphy L, Munday R, et al; Misdiagnosis of the vegetative state: retrospective study in a rehabilitation unit. BMJ. 1996 Jul 6;313(7048):13-6.
  9. BMA. Withdrawing & withholding life prolonging medical treatment, 3rd edtn. London: BMA, 2007
  10. Eilander HJ, Wijnen VJ, Scheirs JG, et al; Children and young adults in a prolonged unconscious state due to severe brain injury: outcome after an early intensive neurorehabilitation programme. Brain Inj. 2005 Jun;19(6):425-36.
  11. Yamamoto T, Kobayashi K, Kasai M, et al; DBS therapy for the vegetative state and minimally conscious state. Acta Neurochir Suppl. 2005;93:101-4.
  12. Bernat JL; Chronic disorders of consciousness. Lancet. 2006 Apr 8;367(9517):1181-92.
  13. Laureys S, Boly M; What is it like to be vegetative or minimally conscious? Curr Opin Neurol. 2007 Dec;20(6):609-13.
  14. Matsuda W, Komatsu Y, Yanaka K, et al; Levodopa treatment for patients in persistent vegetative or minimally conscious states. Neuropsychol Rehabil. 2005 Jul-Sep;15(3-4):414-27.
  15. Clauss R, Nel W; Drug induced arousal from the permanent vegetative state. NeuroRehabilitation. 2006;21(1):23-8.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Dr Gurvinder Rull
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Document ID:
2914 (v22)