A (PVS) is a condition of patients with severe
Brain Damage in whom
Coma has progressed to a state of wakefulness without detectable
Awareness .
The syndrome was first described in 1940 by
Ernst Kretschmer who called it ''apallic Syndrome''.Das apallische Syndrom, in .Neurol.Psychiat, 169,576-579 (1940).
The term was coined in
1972 by
Scottish Spinal Surgeon Bryan Jennett and
American Neurologist Fred Plum to describe a syndrome that seemed to have been made possible by
Medicine 's increased capacities to keep patients' bodies alive.
"The Vegetative State: Medical facts, ethical and legal dilemmas" (9 page PDF file) Bryan Jennett, University of Glasgow, Scotland.
Patients in a persistent vegetative state are usually considered to be
Unconscious and unaware. They are unresponsive to external stimuli, except, possibly, pain stimuli. Unlike
Coma , in which the patient's eyes are closed, PVS patients often open their eyes. Their eyes might be in a relatively fixed position, or track moving objects, or move in a ''disconjugate'' (i.e. completely unsynchronised) manner. They may experience
Sleep -wake cycles, or be in a state of chronic wakefulness. They may exhibit some behaviors that can be construed as arising from partial consciousness, such as grinding their teeth, swallowing, smiling, shedding tears,
Grunting ,
Moaning , or screaming without any apparent external
Stimulus .
Many patients emerge from a vegetative state within a few weeks, but those who do not recover within 30 days are said to be in a persistent vegetative state. The chances of recovery depend on the extent of injury to the brain and the patient's age—younger patients having a better chance of recovery than older patients. Generally, adults have a 50 percent chance and children a 60 percent chance of recovering consciousness from a PVS within the first 6 months. After a year, the chances that a PVS patient will regain consciousness are very low and most patients who do recover consciousness experience significant disability. The longer a patient is in a PVS, the more severe the resulting disabilities are likely to be. Rehabilitation can contribute to recovery, but many patients never progress to the point of being able to take care of themselves.
In the
United States , it is estimated that there may be between 15,000-40,000 patients who are in a persistent vegetative state, but due to poor nursing home records exact figures are hard to determine.Hirsch, Joy. (May 2, 2005). "Raising consciousness".
The Journal of Clinical Investigation . American Society for Clinical Investigation. (5): 1102.
Recovery after long periods of time in a PVS have been reported on several occasions and are often treated as spectacular events. In fact on March 7, 2007, a woman named Christa Lilly awakened from a vegetative state after 6 years of being in a coma that involved her eyes being open most of the time, tracking moving objects. She spoke to family and a local news group saying she was fine. The hardest part she said was learning how to speak again. Lilly slipped back into the vegetative state after 3 days. Augé, Karen and Emery, Erin (March 8, 2007). "Woman awakes after 6-year coma, slips back"
The Denver Post
Misdiagnosis of PVS is not uncommon. One study of 40 patients in the . Giacino JT, et al. Neurology 2002, v. 58, p. 349-353. Since the exact criteria of the minimally conscious state were formulated only in 2002, there may be chronic patients diagnosed as PVS before the notion of the minimally conscious state became known.
Can there be conscious awareness in vegetative state? Three completely different aspects of this issue should be distinguished. First, some patients can be conscious simply because they are misdiagnosed (see above). In fact, they are not in vegetative state. Second, sometimes a patient was correctly diagnosed but, then, examined during a beginning recovery. Third, perhaps some day the very notion of the vegetative state will change so that to include elements of conscious awareness. The inability to disentangle these three cases leads to confusion. An example of such confusion are the responses to a recent experiment using
Magnetic Resonance Imaging which revealed that a woman diagnosed with PVS was able to activate predictable portions of her brain in response to the tester's requests that she imagine herself playing tennis or moving from room to room in her house. The brain activity in response to these instructions was indistinguishable from those of healthy patients. Owen AM, Coleman MR, Boly M, Davis MH, Laureys S, Pickard JD.
Detecting awareness in the vegetative state. Science. 2006 Sep 8;313(5792):1402. Because such activations can only be obtained if a patient has clear awareness and concentrated attention, this was obviously a diagnostic error. Therefore, the experiment did not show awareness in vegetative state in any reasonable sense of word; rather, it showed that magnetic resonance imaging, combined with sophisticated stimulation, can effectively be used to disclose major diagnostic errors.
Additional controversy has been caused by the discovery that in many nursing homes and hospitals unheated oxygen is given to non-responsive patients via tracheal intubation. This bypasses the warming of the upper respiratory tract and causes a chilling of aortic blood and chilling of the brain. In a small number of cases, removal of the chilled oxygen has been followed by recovery from the PVS. Additional research has been recommended to determine if this chilling effect may either delay recovery or even may contribute to brain damage. Ford GP, Reardon DC.
Prolonged unintended brain cooling may inhibit recovery from brain injuries: case study and literature review. Med Sci Monit. 2006 Aug;12(8):CS74-9. Epub 2006 Jul 12.
As of April 2007, no treatment for vegetative state exists that would satisfy the efficiency criteria of
Evidence-based Medicine . Several methods have been proposed which can roughly be subdivided into four categories: pharmacological methods, surgery, physical therapy, and various stimulation techniques. Pharmacological therapy mainly uses activating substances such as tricyclic antidepressants or methylphenidate. Promising results have been reported on dopaminergic drugs, particularly amantadine. Presently the first randomized controlled trial amantadine versus placebo is running; its results have not been published yet. Surgical methods such as deep brain stimulation are rarely used. Stimulation techniques include sensory stimulation, sensory regulation, music and musicokinetic therapy, social-tactile interaction, etc.
Terminology in this area is somewhat confused. While the term ''persistent vegetative state'' is the most frequent in media usage and legal provisions, it is discouraged by neurologists, who favour the use of the Royal College of Physicians (RCP) (1996) typology which refers only to the ''vegetative state'', the ''continuing vegetative state'', and the ''permanent vegetative state''. This typology distinguishes various stages of the condition rather than using one term for them all. In his most recent book ''
The Vegetative State '', Jennett himself adopts this usage, on the grounds that "the 'persistent' component of this term ... may seem to suggest irreversibility". The Australian National Health and Medical Research Council has suggested "post coma unresponsiveness" as an alternative term.
As opposed to
Brain Death , PVS is not recognized as
Death in any known legal system. This legal
Grey Area has led to several court cases involving people in a PVS, those who believe that they should be
Allowed To Die , and those who are equally determined that, if recovery is possible, care should continue. Well-known cases include
Paul Brophy ,
Sunny Von Bülow and
Tony Bland , whose case created a precedent in the UK. The highly publicised case of
Terri Schiavo in the
United States involved disputes over a diagnosis of PVS given by several court-appointed doctors. Ultimately the court challenges were unsuccessful and Schiavo's
Feeding Tube was removed, leading to her subsequent death.
- Jennett, B. The vegetative state: Medical facts, ethical and legal dilemmas, New York, CUP, 2002
- Jennett B, Plum F. (1972). Persistent vegetative state after brain damage. A syndrome in search of a name. '' Lancet '' (7753), 734–737. PMID 4111204.
- Multi-Society Task Force on PVS (1994). Medical aspects of the persistent vegetative state. '' N Engl J Med '' (330), 1499–508. PMID 7818633, PMID 8177248.
- National Health and Medical Research Council, Post-coma unresponsiveness (Vegetative State): a clinical framework for diagnosis, NHMRC, Canberra, 2003 {Link without Title}
- Royal College of Physicians, Guidance on diagnosis and management: Report of a working party of the Royal College of Physicians, London, Royal College of Physicians, 1996
- Borthwick C (1996) The permanent vegetative state: ethical crux, medical fiction? Issues Law Med. 1996 Fall;12(2):167-85. The author questions the validity of most PVS diagnoses, and the validity of the basic nosology. The fulltext is available on the author's website.
- Andrews K, Murphy L, Munday R, Littlewood C. (1996). Misdiagnosis of the vegetative state: retrospective study in a rehabilitation unit . '' BMJ '' (313), 13–16. PMID 8664760.
- Ford GP, Reardon DC. "Prolonged unintended brain cooling may inhibit recovery from brain injuries: case study and literature review." Med Sci Monit. 2006 Aug;12(8):CS74-9. Epub 2006 Jul 12. http://www.medscimonit.com/pub/vol_12/no_8/8795.pdf
''This article contains text from the NINDS public domain pages on TBI at http://www.ninds.nih.gov/health_and_medical/disorders/tbi_doc.htm and http://www.ninds.nih.gov/health_and_medical/pubs/tbi.htm ''
