HOME

TheInfoList



OR:

A persistent vegetative state (PVS) or post-coma unresponsiveness (PCU) is a
disorder of consciousness Disorders of consciousness are medical conditions that inhibit consciousness. Some define disorders of consciousness as any change from complete self-awareness to inhibited or absent self-awareness and arousal. This category generally includes min ...
in which patients with severe
brain damage Neurotrauma, brain damage or brain injury (BI) is the destruction or degeneration of brain cells. Brain injuries occur due to a wide range of internal and external factors. In general, brain damage refers to significant, undiscriminating t ...
are in a state of partial
arousal Arousal is the physiological and psychological state of being awoken or of sense organs stimulated to a point of perception. It involves activation of the ascending reticular activating system (ARAS) in the brain, which mediates wakefulness, th ...
rather than true
awareness Awareness is the state of being conscious of something. More specifically, it is the ability to directly know and perceive, to feel, or to be cognizant of events. Another definition describes it as a state wherein a subject is aware of some in ...
. After four weeks in a vegetative state (VS), the patient is classified as being in a persistent vegetative state. This diagnosis is classified as a permanent vegetative state some months (three in the US and six in the UK) after a non-traumatic brain injury or one year after a traumatic injury. The term unresponsive wakefulness syndrome may be alternatively used, as "vegetative state" has some negative connotations among the public.


Definition

There are several definitions that vary by technical versus layman's usage. There are different legal implications in different countries.


Medical definition

Per the British
Royal College of Physicians The Royal College of Physicians (RCP) is a British professional membership body dedicated to improving the practice of medicine, chiefly through the accreditation of physicians by examination. Founded by royal charter from King Henry VIII in 1 ...
of London, a persistent vegetative state is "a wakeful unconscious state that lasts longer than a few weeks is referred to as a persistent (or 'continuing') vegetative state".


"Vegetative state"

The vegetative state is a chronic or long-term condition. This condition differs from a
coma A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to respond normally to painful stimuli, light, or sound, lacks a normal wake-sleep cycle and does not initiate voluntary actions. Coma patients exhi ...
: a coma is a state that lacks both awareness and wakefulness. Patients in a vegetative state may have awoken from a coma, but still have not regained awareness. In the vegetative state patients can open their eyelids occasionally and demonstrate sleep-wake cycles, but completely lack cognitive function. The vegetative state is also called a "coma vigil". The chances of regaining awareness diminish considerably as the time spent in the vegetative state increases.


"Persistent vegetative state"

Persistent vegetative state is the standard usage (except in the UK) for a medical diagnosis, made after numerous neurological and other tests, that due to extensive and irreversible brain damage a patient is highly unlikely ever to achieve higher functions above a vegetative state. This diagnosis does not mean that a doctor has diagnosed improvement as impossible, but does open the possibility, in the US, for a judicial request to end life support. Informal guidelines hold that this diagnosis can be made after four weeks in a vegetative state. US caselaw has shown that successful petitions for termination have been made after a diagnosis of a persistent vegetative state, although in some cases, such as that of Terri Schiavo, such rulings have generated widespread controversy. In the UK, the term is discouraged in favor of two more precisely defined terms that have been strongly recommended by the Royal College of Physicians (RCP). These guidelines recommend using a ''continuous vegetative state'' for patients in a vegetative state for more than four weeks. A medical determination of a ''permanent vegetative state'' can be made if, after exhaustive testing and a customary 12 months of observation, a medical diagnosis is made that it is ''impossible'' by any informed medical expectations that the mental condition will ever improve. Hence, a "continuous vegetative state" in the UK may remain the diagnosis in cases that would be called "persistent" in the US or elsewhere. While the actual testing criteria for a diagnosis of "permanent" in the UK are quite similar to the criteria for a diagnosis of "persistent" in the US, the semantic difference imparts in the UK a legal presumption that is commonly used in court applications for ending life support. The UK diagnosis is generally only made after 12 months of observing a static vegetative state. A diagnosis of a persistent vegetative state in the US usually still requires a petitioner to prove in court that recovery is impossible by informed medical opinion, while in the UK the "permanent" diagnosis already gives the petitioner this presumption and may make the legal process less time-consuming. In common usage, the "permanent" and "persistent" definitions are sometimes conflated and used interchangeably. However, the acronym "PVS" is intended to define a "persistent vegetative state", without necessarily the connotations of permanence, and is used as such throughout this article.
Bryan Jennett William Bryan Jennett (1 March 1926 – 26 January 2008) was a British neurosurgeon, a faculty member at the University of Glasgow Medical School, and the first full-time chair of neurosurgery in Scotland. He was the co-developer of the assess ...
, who originally coined the term "persistent vegetative state", has now recommended using the UK division between continuous and permanent in his book ''
The Vegetative State ''The'' () is a grammatical article in English, denoting persons or things already mentioned, under discussion, implied or otherwise presumed familiar to listeners, readers, or speakers. It is the definite article in English. ''The'' is the m ...
'', arguing 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 for "vegetative state" in general.


Lack of legal clarity

Unlike
brain death Brain death is the permanent, irreversible, and complete loss of brain function which may include cessation of involuntary activity necessary to sustain life. It differs from persistent vegetative state, in which the person is alive and some aut ...
, permanent vegetative state (PVS) is recognized by '' statute law'' as
death Death is the irreversible cessation of all biological functions that sustain an organism. For organisms with a brain, death can also be defined as the irreversible cessation of functioning of the whole brain, including brainstem, and brain ...
in only a very few legal systems. In the US, courts have required petitions before termination of life support that demonstrate that any recovery of cognitive functions above a vegetative state is assessed as impossible by authoritative medical opinion. In England, Wales and Scotland, the legal precedent for withdrawal of clinically assisted nutrition and hydration in cases of patients in a PVS was set in 1993 in the case of Tony Bland, who sustained catastrophic anoxic brain injury in the 1989 Hillsborough disaster. An application to the Court of Protection is no longer required before nutrition and hydration can be withdrawn or withheld from PVS (or 'minimally conscious' – MCS) patients. This legal grey area has led to vocal advocates that those in PVS should be allowed to die. Others are equally determined that, if recovery is at all possible, care should continue. The existence of a small number of diagnosed PVS cases that have eventually resulted in improvement makes defining recovery as "impossible" particularly difficult in a legal sense. This legal and ethical issue raises questions about autonomy, quality of life, appropriate use of resources, the wishes of family members, and professional responsibilities.


Signs and symptoms

Most PVS patients are unresponsive to external stimuli and their conditions are associated with different levels of consciousness. Some level of consciousness means a person can still respond, in varying degrees, to stimulation. A person in a coma, however, cannot. In addition, PVS patients often open their eyes in response to feeding, which has to be done by others; they are capable of swallowing, whereas patients in a coma subsist with their eyes closed. Cerebral cortical function (e.g. communication, thinking, purposeful movement, etc.) is lost while brainstem functions (e.g. breathing, maintaining circulation and hemodynamic stability, etc.) are preserved.  Non-cognitive upper brainstem functions such as eye-opening, occasional vocalizations (e.g. crying, laughing), maintaining normal sleep patterns, and spontaneous non-purposeful movements often remain intact. PVS patients' eyes might be in a relatively fixed position, or track moving objects, or move in a '' disconjugate'' (i.e., completely unsynchronized) manner. They may experience
sleep Sleep is a sedentary state of mind and body. It is characterized by altered consciousness, relatively inhibited Perception, sensory activity, reduced muscle activity and reduced interactions with surroundings. It is distinguished from wakefuln ...
-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. Individuals in PVS are seldom on any life-sustaining equipment other than a feeding tube because the
brainstem The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is ...
, the center of vegetative functions (such as heart rate and rhythm, respiration, and
gastrointestinal The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and ...
activity) is relatively intact.


Recovery

Many people emerge spontaneously from a vegetative state within a few weeks. 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. A 1994 report found that of those who were in a vegetative state a month after a trauma, 54% had regained consciousness by a year after the trauma, whereas 28% had died and 18% were still in the vegetative state. For non-traumatic injuries such as
stroke A stroke is a disease, medical condition in which poor cerebral circulation, blood flow to the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemorr ...
s, only 14% had recovered consciousness at one year, 47% had died, and 39% were still vegetative. Patients who were vegetative six months after the initial event were much less likely to have recovered consciousness a year after the event than in the case of those who were simply reported vegetative at one month. A ''
New Scientist ''New Scientist'' is a magazine covering all aspects of science and technology. Based in London, it publishes weekly English-language editions in the United Kingdom, the United States and Australia. An editorially separate organisation publish ...
'' article from 2000 gives a pair of graphs showing changes of patient status during the first 12 months after head injury and after incidents depriving the brain of oxygen. 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. The medical literature also includes case reports of the recovery of a small number of patients following the removal of assisted respiration with cold oxygen. The researchers found 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 which the authors believe may contribute to the person's nonresponsive state. The researchers describe a small number of cases in which removal of the chilled oxygen was followed by recovery from the PVS and recommend either warming of oxygen with a heated nebulizer or removal of the assisted oxygen if it is no longer needed. The authors further recommend additional research to determine if this chilling effect may either delay recovery or even may contribute to brain damage. There are two dimensions of recovery from a persistent vegetative state: recovery of
consciousness Consciousness, at its simplest, is sentience and awareness of internal and external existence. However, the lack of definitions has led to millennia of analyses, explanations and debates by philosophers, theologians, linguisticians, and scien ...
and recovery of function. Recovery of consciousness can be verified by reliable evidence of
awareness Awareness is the state of being conscious of something. More specifically, it is the ability to directly know and perceive, to feel, or to be cognizant of events. Another definition describes it as a state wherein a subject is aware of some in ...
of self and the environment, consistent voluntary behavioral responses to visual and auditory stimuli, and interaction with others. Recovery of function is characterized by communication, the ability to learn and to perform adaptive tasks, mobility, self-care, and participation in recreational or vocational activities. Recovery of consciousness may occur without functional recovery, but functional recovery cannot occur without recovery of consciousness.


Causes

There are three main causes of PVS (persistent vegetative state): * Acute
traumatic brain injury A traumatic brain injury (TBI), also known as an intracranial injury, is an injury to the brain caused by an external force. TBI can be classified based on severity (ranging from mild traumatic brain injury TBI/concussionto severe traumatic br ...
* Non-traumatic:
neurodegenerative disorder A neurodegenerative disease is caused by the progressive loss of structure or function of neurons, in the process known as neurodegeneration. Such neuronal damage may ultimately involve cell death. Neurodegenerative diseases include amyotrophic ...
or
metabolic disorder A metabolic disorder is a disorder that negatively alters the body's processing and distribution of macronutrients, such as proteins, fats, and carbohydrates. Metabolic disorders can happen when abnormal chemical reactions in the body alter t ...
of the brain * Severe congenital abnormality of the
central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all p ...
Potential causes of PVS are: * Bacterial, viral, or fungal infection, including
meningitis Meningitis is acute or chronic inflammation of the protective membranes covering the brain and spinal cord, collectively called the meninges. The most common symptoms are fever, headache, and neck stiffness. Other symptoms include confusion or ...
* Increased intracranial pressure, such as a
tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...
or
abscess An abscess is a collection of pus that has built up within the tissue of the body. Signs and symptoms of abscesses include redness, pain, warmth, and swelling. The swelling may feel fluid-filled when pressed. The area of redness often extends ...
* Vascular pressure which causes intracranial hemorrhaging or stroke * Hypoxic ischemic injury (
hypotension Hypotension is low blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. Blood pressure is indicated by two numbers, the systolic blood pressure (the top number) and the di ...
,
cardiac arrest Cardiac arrest is when the heart suddenly and unexpectedly stops beating. It is a medical emergency that, without immediate medical intervention, will result in sudden cardiac death within minutes. Cardiopulmonary resuscitation (CPR) and possi ...
,
arrhythmia Arrhythmias, also known as cardiac arrhythmias, heart arrhythmias, or dysrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per minute in adult ...
, near-drowning) * Toxins such as uremia,
ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a ...
,
atropine Atropine is a tropane alkaloid and anticholinergic medication used to treat certain types of nerve agent and pesticide poisonings as well as some types of slow heart rate, and to decrease saliva production during surgery. It is typically given ...
, opiates,
lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, ...
,
dimethylmercury Dimethylmercury (( C H3)2 Hg) is an extremely toxic organomercury compound. A highly volatile, reactive, flammable, and colorless liquid, dimethylmercury is one of the strongest known neurotoxins, with a quantity of less than 0.1 mL capable of in ...
, endrin,
parathion Parathion, also called parathion-ethyl or diethyl parathion and locally known as "Folidol", is an organophosphate insecticide and acaricide. It was originally developed by IG Farben in the 1940s. It is highly toxic to non-target organisms, inclu ...
, and colloidal silver * Physical trauma: Concussion, contusion, etc. * Seizure, both nonconvulsive status epilepticus and postconvulsive state (postictal state) * Electrolyte imbalance, which involves hyponatremia, hypernatremia, hypomagnesemia,
hypoglycemia Hypoglycemia, also called low blood sugar, is a fall in blood sugar to levels below normal, typically below 70 mg/dL (3.9 mmol/L). Whipple's triad is used to properly identify hypoglycemic episodes. It is defined as blood glucose bel ...
,
hyperglycemia Hyperglycemia is a condition in which an excessive amount of glucose circulates in the blood plasma. This is generally a blood sugar level higher than 11.1  mmol/L (200  mg/dL), but symptoms may not start to become noticeable until even ...
,
hypercalcemia Hypercalcemia, also spelled hypercalcaemia, is a high calcium (Ca2+) level in the blood serum. The normal range is 2.1–2.6  mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L), with levels greater than 2.6 mmol/L defined as hypercalcem ...
, and hypocalcemia * Postinfectious:
Acute disseminated encephalomyelitis Acute disseminated encephalomyelitis (ADEM), or acute demyelinating encephalomyelitis, is a rare autoimmune disease marked by a sudden, widespread attack of inflammation in the brain and spinal cord. As well as causing the brain and spinal co ...
(ADEM) * Endocrine disorders such as adrenal insufficiency and thyroid disorders * Degenerative and metabolic diseases including urea cycle disorders,
Reye syndrome Reye syndrome is a rapidly worsening brain disease. Symptoms of Reye syndrome may include vomiting, personality changes, confusion, seizures, and loss of consciousness. While liver toxicity typically occurs in the syndrome, jaundice usually doe ...
, and mitochondrial disease * Systemic infection and
sepsis Sepsis, formerly known as septicemia (septicaemia in British English) or blood poisoning, is a life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage is follo ...
*
Hepatic encephalopathy Hepatic encephalopathy (HE) is an altered level of consciousness as a result of liver failure. Its onset may be gradual or sudden. Other symptoms may include movement problems, changes in mood, or changes in personality. In the advanced stage ...
In addition, these authors claim that doctors sometimes use the
mnemonic A mnemonic ( ) device, or memory device, is any learning technique that aids information retention or retrieval (remembering) in the human memory for better understanding. Mnemonics make use of elaborative encoding, retrieval cues, and image ...
device AEIOU-TIPS to recall portions of the differential diagnosis: Alcohol ingestion and acidosis, epilepsy and encephalopathy, infection, opiates, uremia, trauma, insulin overdose or inflammatory disorders, poisoning and psychogenic causes, and shock.


Diagnosis

Despite converging agreement about the definition of persistent vegetative state, recent reports have raised concerns about the accuracy of diagnosis in some patients, and the extent to which, in a selection of cases, residual
cognitive Cognition refers to "the mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses all aspects of intellectual functions and processes such as: perception, attention, thought ...
functions may remain undetected and patients are diagnosed as being in a persistent vegetative state. Objective assessment of residual cognitive function can be extremely difficult as motor responses may be minimal, inconsistent, and difficult to document in many patients, or may be undetectable in others because no cognitive output is possible. In recent years, a number of studies have demonstrated an important role for functional neuroimaging in the identification of residual cognitive function in persistent vegetative state; this technology is providing new insights into cerebral activity in patients with severe brain damage. Such studies, when successful, may be particularly useful where there is concern about the accuracy of the diagnosis and the possibility that residual cognitive function has remained undetected.


Diagnostic experiments

Researchers have begun to use functional neuroimaging studies to study implicit cognitive processing in patients with a clinical diagnosis of persistent vegetative state. Activations in response to sensory stimuli with
positron emission tomography Positron emission tomography (PET) is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in metabolic processes, and in other physiological activities including blood flow, ...
(PET),
functional magnetic resonance imaging Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area o ...
(fMRI), and electrophysiological methods can provide information on the presence, degree, and location of any residual brain function. However, use of these techniques in people with severe brain damage is methodologically, clinically, and theoretically complex and needs careful quantitative analysis and interpretation. For example, PET studies have shown the identification of residual cognitive function in persistent vegetative state. That is, an external stimulation, such as a painful stimulus, still activates "primary" sensory cortices in these patients but these areas are functionally disconnected from "higher order" associative areas needed for awareness. These results show that parts of the cortex are indeed still functioning in "vegetative" patients. In addition, other PET studies have revealed preserved and consistent responses in predicted regions of auditory cortex in response to intelligible speech stimuli. Moreover, a preliminary fMRI examination revealed partially intact responses to semantically ambiguous stimuli, which are known to tap higher aspects of speech comprehension. Furthermore, several studies have used PET to assess the central processing of noxious
somatosensory In physiology, the somatosensory system is the network of neural structures in the brain and body that produce the perception of touch (haptic perception), as well as temperature (thermoception), body position ( proprioception), and pain. It ...
stimuli in patients in PVS. Noxious somatosensory stimulation activated
midbrain The midbrain or mesencephalon is the forward-most portion of the brainstem and is associated with vision, hearing, motor control, sleep and wakefulness, arousal ( alertness), and temperature regulation. The name comes from the Greek ''mesos'', ...
, contralateral
thalamus The thalamus (from Greek θάλαμος, "chamber") is a large mass of gray matter located in the dorsal part of the diencephalon (a division of the forebrain). Nerve fibers project out of the thalamus to the cerebral cortex in all direct ...
, and
primary somatosensory cortex In neuroanatomy, the primary somatosensory cortex is located in the postcentral gyrus of the brain's parietal lobe, and is part of the somatosensory system. It was initially defined from surface stimulation studies of Wilder Penfield, and pa ...
in each and every PVS patient, even in the absence of detectable cortical evoked potentials. In conclusion, somatosensory stimulation of PVS patients, at intensities that elicited pain in controls, resulted in increased neuronal activity in primary somatosensory cortex, even if resting brain metabolism was severely impaired. However, this activation of primary cortex seems to be isolated and dissociated from higher-order associative cortices. Also, there is evidence of partially functional cerebral regions in catastrophically injured brains. To study five patients in PVS with different behavioral features, researchers employed PET, MRI and
magnetoencephalographic Magnetoencephalography (MEG) is a functional neuroimaging technique for mapping brain activity by recording magnetic fields produced by electrical currents occurring naturally in the brain, using very sensitive magnetometers. Arrays of SQUIDs ( ...
(MEG) responses to sensory stimulation. In three of the five patients, co-registered PET/MRI correlate areas of relatively preserved brain metabolism with isolated fragments of behavior. Two patients had had
anoxic The term anoxia means a total depletion in the level of oxygen, an extreme form of hypoxia or "low oxygen". The terms anoxia and hypoxia are used in various contexts: * Anoxic waters, sea water, fresh water or groundwater that are depleted of diss ...
injuries and demonstrated marked decreases in overall cerebral metabolism to 30–40% of normal. Two other patients with non-anoxic, multifocal brain injuries demonstrated several isolated brain regions with higher
metabolic Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
rates, that ranged up to 50–80% of normal. Nevertheless, their global metabolic rates remained <50% of normal. MEG recordings from three PVS patients provide clear evidence for the absence, abnormality or reduction of evoked responses. Despite major abnormalities, however, these data also provide evidence for localized residual activity at the cortical level. Each patient partially preserved restricted sensory representations, as evidenced by slow evoked magnetic fields and gamma band activity. In two patients, these activations correlate with isolated behavioral patterns and metabolic activity. Remaining active regions identified in the three PVS patients with behavioral fragments appear to consist of segregated corticothalamic networks that retain connectivity and partial functional integrity. A single patient who sustained severe injury to the tegmental mesencephalon and paramedian
thalamus The thalamus (from Greek θάλαμος, "chamber") is a large mass of gray matter located in the dorsal part of the diencephalon (a division of the forebrain). Nerve fibers project out of the thalamus to the cerebral cortex in all direct ...
showed widely preserved cortical metabolism, and a global average metabolic rate of 65% of normal. The relatively high preservation of cortical metabolism in this patient defines the first functional correlate of clinical–pathological reports associating permanent unconsciousness with structural damage to these regions. The specific patterns of preserved metabolic activity identified in these patients reflect novel evidence of the modular nature of individual functional networks that underlie conscious brain function. The variations in cerebral metabolism in chronic PVS patients indicate that some cerebral regions can retain partial function in catastrophically injured brains.


Misdiagnoses

Statistical PVS misdiagnosis is common. An example study with 40 patients in the
United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and ...
reported 43% of their patients classified as PVS were believed so and another 33% had recovered whilst the study was underway. Some PVS cases may actually be a misdiagnosis of patients being in an undiagnosed
minimally conscious state A minimally conscious state (MCS) is a disorder of consciousness distinct from persistent vegetative state and locked-in syndrome. Unlike persistent vegetative state, patients with MCS have partial preservation of conscious awareness. MCS is a r ...
. Since the exact diagnostic criteria of the minimally conscious state were only formulated in 2002, there may be chronic patients diagnosed as PVS before the secondary notion of the minimally conscious state became known. Whether or not there is any conscious awareness with a patient's vegetative state is a prominent issue. Three completely different aspects of this should be distinguished. First, some patients can be conscious simply because they are misdiagnosed (see above). In fact, they are not in vegetative states. Second, sometimes a patient was correctly diagnosed but is then examined during the early stages of recovery. Third, perhaps some day the notion itself of vegetative states will change so to include elements of conscious awareness. Inability to disentangle these three example cases causes confusion. An example of such confusion is the response to an experiment using
functional magnetic resonance imaging Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area o ...
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. In 2010, Martin Monti and fellow researchers, working at the MRC Cognition and Brain Sciences Unit at the
University of Cambridge , mottoeng = Literal: From here, light and sacred draughts. Non literal: From this place, we gain enlightenment and precious knowledge. , established = , other_name = The Chancellor, Masters and Schola ...
, reported in an article in the ''
New England Journal of Medicine ''The New England Journal of Medicine'' (''NEJM'') is a weekly medical journal published by the Massachusetts Medical Society. It is among the most prestigious peer-reviewed medical journals as well as the oldest continuously published one. His ...
'' that some patients in persistent vegetative states responded to verbal instructions by displaying different patterns of brain activity on
fMRI Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area ...
scans. Five out of a total of 54 diagnosed patients were apparently able to respond when instructed to think about one of two different physical activities. One of these five was also able to "answer" yes or no questions, again by imagining one of these two activities. It is unclear, however, whether the fact that portions of the patients' brains light up on
fMRI Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area ...
could help these patients assume their own medical decision making. In November 2011, a publication in ''The Lancet'' presented bedside EEG apparatus and indicated that its signal could be used to detect awareness in three of 16 patients diagnosed in the vegetative state.


Treatment

Currently no treatment for vegetative state exists that would satisfy the efficacy criteria of
evidence-based medicine Evidence-based medicine (EBM) is "the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients". The aim of EBM is to integrate the experience of the clinician, the values of t ...
. 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 Methylphenidate, sold under the brand names Ritalin and Concerta among others, is the most widely prescribed central nervous system (CNS) stimulant medication used to treat attention deficit hyperactivity disorder (ADHD) and, to a lesser extent ...
. Mixed results have been reported using dopaminergic drugs such as
amantadine Amantadine, sold under the brand name Gocovri among others, is a medication used to treat dyskinesia associated with parkinsonism and influenza caused by type A influenzavirus, though its use for the latter is no longer recommended due to wid ...
and bromocriptine and stimulants such as
dextroamphetamine Dextroamphetamine is a central nervous system (CNS) stimulant and an amphetamine enantiomer that is prescribed for the treatment of attention deficit hyperactivity disorder (ADHD) and narcolepsy. It is also used as an athletic performance an ...
. Surgical methods such as deep brain stimulation are used less frequently due to the invasiveness of the procedures. Stimulation techniques include sensory stimulation, sensory regulation, music and musicokinetic therapy, social-tactile interaction, and cortical stimulation.


Zolpidem

There is limited evidence that the hypnotic drug zolpidem has an effect. The results of the few scientific studies that have been published so far on the effectiveness of zolpidem have been contradictory.


Epidemiology

In the
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...
, it is estimated that there may be between 15,000 and 40,000 patients who are in a persistent vegetative state, but due to poor nursing home records exact figures are hard to determine.


History

The syndrome was first described in 1940 by
Ernst Kretschmer Ernst Kretschmer (8 October 18888 February 1964) was a German psychiatrist who researched the human constitution and established a typology. Life Kretschmer was born in Wüstenrot near Heilbronn. He attended Cannstatt Gymnasium, one of the o ...
who called it ''apallic syndrome''. The term ''persistent vegetative state'' was coined in 1972 by Scottish spinal
surgeon In modern medicine, a surgeon is a medical professional who performs surgery. Although there are different traditions in different times and places, a modern surgeon usually is also a licensed physician or received the same medical training as ...
Bryan Jennett William Bryan Jennett (1 March 1926 – 26 January 2008) was a British neurosurgeon, a faculty member at the University of Glasgow Medical School, and the first full-time chair of neurosurgery in Scotland. He was the co-developer of the assess ...
and
American American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, pe ...
neurologist
Fred Plum Fred Plum (January 10, 1924 – June 11, 2010) was an American neurologist who developed the terms "persistent vegetative state" and "locked-in syndrome" as part of his continuing research on consciousness and comas and care of the comatose. ...
to describe a syndrome that seemed to have been made possible by
medicine Medicine is the science and practice of caring for a patient, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care pr ...
's increased capacities to keep patients' bodies alive.


Society and culture


Ethics and policy

An ongoing debate exists as to how much care, if any, patients in a persistent vegetative state should receive in health systems plagued by limited resources. In a case before the New Jersey Superior Court, ''
Betancourt v. Trinitas Hospital ''Betancourt v. Trinitas Hospital'', 1 Atlantic Reporter, A.3d 823 (2010), is a New Jersey legal case concerning whether a hospital may unilaterally refuse care to a patient on the grounds that it is futile to prolong the person's life because ...
'', a community hospital sought a ruling that dialysis and CPR for such a patient constitutes futile care. An American bioethicist,
Jacob M. Appel Jacob M. Appel (born February 21, 1973) is an American author, poet, bioethicist, physician, lawyer and social critic.Nagamatsu, Sequoia "A Few Words with the Ubiquitous Jacob M. Appel" ''Prince Mincer'' Journal http://primemincer.com/ confirmed ...
, argued that any money spent treating PVS patients would be better spent on other patients with a higher likelihood of recovery. The patient died naturally prior to a decision in the case, resulting in the court finding the issue moot. In 2010, British and Belgian researchers reported in an article in the ''
New England Journal of Medicine ''The New England Journal of Medicine'' (''NEJM'') is a weekly medical journal published by the Massachusetts Medical Society. It is among the most prestigious peer-reviewed medical journals as well as the oldest continuously published one. His ...
'' that some patients in persistent vegetative states actually had enough consciousness to "answer" yes or no questions on
fMRI Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area ...
scans. However, it is unclear whether the fact that portions of the patients' brains light up on
fMRI Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area ...
will help these patient assume their own medical decision making. Professor Geraint Rees, Director of the Institute of Cognitive Neuroscience at University College London, responded to the study by observing that, "As a clinician, it would be important to satisfy oneself that the individual that you are communicating with is competent to make those decisions. At the moment it is premature to conclude that the individual able to answer 5 out of 6 yes/no questions is fully conscious like you or I." In contrast,
Jacob M. Appel Jacob M. Appel (born February 21, 1973) is an American author, poet, bioethicist, physician, lawyer and social critic.Nagamatsu, Sequoia "A Few Words with the Ubiquitous Jacob M. Appel" ''Prince Mincer'' Journal http://primemincer.com/ confirmed ...
of the Mount Sinai Hospital told the ''Telegraph'' that this development could be a welcome step toward clarifying the wishes of such patients. Appel stated: "I see no reason why, if we are truly convinced such patients are communicating, society should not honour their wishes. In fact, as a physician, I think a compelling case can be made that doctors have an ethical obligation to assist such patients by removing treatment. I suspect that, if such individuals are indeed trapped in their bodies, they may be living in great torment and will request to have their care terminated or even active euthanasia."


Notable cases

* Tony Bland – first patient in English legal history to be allowed to die * Paul Brophy – first American to die after court-authorization * Sunny von Bülow – lived almost 28 years in a persistent vegetative state until her death *
Gustavo Cerati Gustavo Adrián Cerati (11 August 1959 – 4 September 2014) was an Argentine singer-songwriter, composer and producer, considered one of the most important and influential figures of Ibero-American rock. Cerati along with his band Soda Stereo ...
– Argentine singer-songwriter, composer and producer who died after four years in a coma *
Prichard Colón Prichard Colón Meléndez (born September 19, 1992) is an American-born Puerto Rican former professional boxer, honorary WBC World Champion, and gold medal winner at the 2010 Panamerican Youth Championship in the category. After Prichard was dis ...
– Puerto Rican former professional boxer and gold medal winner who spent years in a vegetative state after a bout *
Nancy Cruzan ''Cruzan v. Director, Missouri Department of Health'', 497 U.S. 261 (1990), was a landmark decision of the Supreme Court of the United States involving a young adult incompetent. The first " right to die" case ever heard by the Court, ''Cruzan'' ...
– American woman involved in a landmark United States Supreme Court case * Gary Dockery – American police officer who entered, emerged and later reentered a persistent vegetative state * Eluana Englaro – Italian woman from Lecco whose life was ended after a legal case after spending 17 years in a vegetative state *
Elaine Esposito Elaine Esposito (December 3, 1934 – November 25, 1978) held the record for the longest period of time in a coma according to ''Guinness World Records'', having lost consciousness in 1941 and eventually dying in that condition more than 37 y ...
– American woman who was a previous record holder for having spent 37 years in a coma * Lia Lee – Hmong person who spent 26 years in a vegetative state and was the subject of a 1997 book by
Anne Fadiman Anne Fadiman (born August 7, 1953) is an American essayist and reporter. Her interests include literary journalism, essays, memoir, and autobiography. She has received the National Book Critics Circle Award, the Los Angeles Times Book Prize for ...
* Martin Pistorius South African man who is a rare example of a survivor as his state progressed to minimally conscious after 3 years, locked in syndrome after another 4 more years, and fully came out of a coma after another 5 years. He is now a web designer, developer, and author. In 2011, he wrote a book called Ghost Boy, in which he describes his many years of being comatose. * Annie Shapiro Canadian woman who is also another rare example of a survivor as it is known that she could not think for her first 2 years of her 29 total years of being comatose. In 1992 she awakened fully recovered and lived her last 10 years peacefully. It is the longest a person has been in a coma and woken up apart from the catatonic stupor patients described in '' Awakenings''. *
Haleigh Poutre Haleigh Poutre (born February 24, 1994) is an American woman who became the subject of a legal controversy regarding the removal of life support for patients in persistent vegetative states. In 2006, eleven-year-old Poutre awoke from a coma shor ...
*
Karen Ann Quinlan Karen Ann Quinlan (March 29, 1954 – June 11, 1985) was an American woman who became an important figure in the history of the right to die controversy in the United States. When she was 21, Quinlan became unconscious after she consumed Valium ...
* Terri Schiavo * Rita Greene *
Aruna Shanbaug Aruna Ramchandra Shanbaug (1 June 1948 – 18 May 2015), was an Indian nurse who was at the centre of attention in a court case on euthanasia after spending nearly 42 years in a vegetative state as a result of sexual assault. In 1973, while wo ...
– Indian woman in persistent vegetative state for 42 years until her death. Owing to her case, the Supreme Court of India allowed passive
euthanasia Euthanasia (from el, εὐθανασία 'good death': εὖ, ''eu'' 'well, good' + θάνατος, ''thanatos'' 'death') is the practice of intentionally ending life to eliminate pain and suffering. Different countries have different eut ...
in the country. *
Ariel Sharon Ariel Sharon (; ; ; also known by his diminutive Arik, , born Ariel Scheinermann, ; 26 February 1928 – 11 January 2014) was an Israeli general and politician who served as the 11th Prime Minister of Israel from March 2001 until April 2006. S ...
*
Chayito Valdez María del Rosario Valdez Campos (28 May 1945 – 20 June 2016), known professionally as Chayito Valdez, was a Mexican singer and actressLent. "Pictures: Film Reviews - Tierra De Valientes." ''Variety (Archive: 1905-2000)''329, no. 6 (Dec 02, 1987 ...
*
Vice Vukov Vinko "Vice" Vukov (3 August 1936 – 24 September 2008) was a Croatian singer and politician. Biography Vukov was born in Šibenik. In 1959, he achieved instant fame by winning the Opatija Music Festival in his singing debut, with the song "Mir ...
*
Helga Wanglie Helga M. Wanglie (October 20, 1903 – July 4, 1991) was an elderly woman in a persistent vegetative state who became the object of a 1991 lawsuit over whether to continue life-sustaining care. Wanglie suffered a fall on December 14, 1989, and su ...
* Otto Warmbier


See also

*
Anencephaly Anencephaly is the absence of a major portion of the brain, skull, and scalp that occurs during embryonic development. It is a cephalic disorder that results from a neural tube defect that occurs when the rostral (head) end of the neural tube ...
*
Brain death Brain death is the permanent, irreversible, and complete loss of brain function which may include cessation of involuntary activity necessary to sustain life. It differs from persistent vegetative state, in which the person is alive and some aut ...
*
Botulism Botulism is a rare and potentially fatal illness caused by a toxin produced by the bacterium ''Clostridium botulinum''. The disease begins with weakness, blurred vision, feeling tired, and trouble speaking. This may then be followed by weakne ...
*
Catatonia Catatonia is a complex neuropsychiatric behavioral syndrome that is characterized by abnormal movements, immobility, abnormal behaviors, and withdrawal. The onset of catatonia can be acute or subtle and symptoms can wax, wane, or change during ...
* Karolina Olsson * Locked-in syndrome * Process-oriented coma work, an approach to working with residual consciousness in patients in comatose and persistent vegetative states


References

''This article contains text from the NINDS public domain pages on TBI

an

''


Further reading

* * * * * * {{DEFAULTSORT:Persistent Vegetative State Consciousness Medical mnemonics Personhood Symptoms and signs of mental disorders