Persistent vegetative state
A vegetative state is a rare condition, caused by brain damage, in which a person comes out of a coma and is fully awake but they have no sense of awareness.
Someone who is in a vegetative state is:
- not aware of their surroundings
- not aware of bodily sensations, such as feeling pleasure or pain
- not able to follow and understand speech
- not able to have thoughts, memories, emotions, and intentions of any kind
So while technically they may be awake, what they are experiencing is no different from when they were in a coma.
However, as some sections of their brain are still functioning, they may perform a number of reflex actions that they are unaware of, such as:
- sleeping and waking at regular intervals
- making movements with their mouth such as smiling and grimacing
- gripping objects or other people's hands
Read more about the symptoms of a vegetative state.
A vegetative state is caused by injury to the parts of the brain which control functions such as thinking, awareness and emotion. The damage can be:
- a traumatic brain injury - caused by a severe head injury such as that sustained during a car accident or a fall from a great distance
- non-traumatic brain injury - where the injury to the brain is caused by a health condition such as a stroke or Alzheimer's disease
Read more about the causes of a vegetative state.
Types of vegetative state
Vegetative states are grouped into two types depending on the length of time that a person has been in one. These are:
- persistent vegetative state - where a person has been in a vegetative state for more than four weeks
- permanent vegetative state - where a person has been in a vegetative state for more than six months as a result of non-traumatic brain damage, or 12 months as the result of traumatic brain damage
Confirming vegetative state
Health professionals have to be very precise in diagnosing vegetative state as there is always the possibility that a person could have awareness but is unable to express it.
For example, there is a condition called "locked-in syndrome" where a person is fully aware but is unable to move any of their muscles, so they are unable to move or speak.
There is a rigorous checklist that has to be followed when diagnosing a vegetative state, such as checking whether the symptoms may actually be due to a treatable condition such as a brain tumour.
Read more about diagnosing a vegetative state.
Chances of recovery
The chances of a person recovering from a vegetative state depend on:
- the type of brain damage they had
- their age
- the amount of time they have spent in a vegetative state
In a young person under the age of 20 who experiences traumatic brain damage, the chances of making a recovery are around 1 in 5.
An older person over the age of 40, who is an persistent vegetative state due to a non-traumatic brain damage, has an extremely small chance of making a recovery.
People who do make a recovery are often likely to have life-long physical and mental disabilities resulting from the damage to their brain.
Read more about recovering from a vegetative state.
If health professionals and family members agree that there is no point in continuing treatment then a court order can be sought to withdraw treatment.
This would usually be recommended if a person was in a vegetative state for 12 months and showed no sign of recovery.
In such a circumstance nutritional support is withdrawn and then the person is sedated so they can die peacefully in their sleep.
- The brain controls thought, memory and emotion. It sends messages to the body controlling movement, speech and senses.
- Pain is an unpleasant physical or emotional feeling and your body's way of warning you it has been damaged.
Symptoms of vegetative state
A vegetative state is caused when parts of the brain called the cerebral hemispheres are extensively damaged - but another part of the brain, called the brainstem, is undamaged or only partially damaged.
The cerebral hemispheres
The cerebral hemispheres are responsible for all the higher functions of the brain, such as:
- being aware of your surroundings
If the cerebral hemispheres suffer extensive damage then a person will lose all the functions listed above. They will be unable to think and have no sense of awareness and experience.
In addition, they will be unable to feel any pain or sensations such as hunger or thirst. However, due to the possibility that the condition may be misdiagnosed, a person who is in a vegetative state will never be subjected to any unnecessary pain and every effort will be made by the hospital to ensure that they are as comfortable as possible.
The reason that people in a vegetative state will still carry out some actions is because another part of the brain, called "the brainstem", is undamaged.
The brainstem is responsible for regulating most of the automatic functions of the body that are essential for life, such as:
- blood pressure
As the brainstem is still intact, a person who is in a vegetative state will have some basic, but random, physical movements and behaviour. For example, they may be able to:
- grind their teeth
- make random eye movements
- make random limb movements
- make random facial movements, such as smiling or grimacing
- make grunting or moaning noises
The may have a normal pattern of sleeping and waking.
The brainstem also controls some basic automatic reflexes. This means that someone in a vegetative state will automatically react to some types of stimulation. For example:
- They may gag if something is placed in their throat.
- They may grip an object or another person hand if placed in their hand.
- Their pupils will widen if a light is shone into their eyes.
- They may blink or turn their head briefly if they hear a sudden, loud noise.
- They may grimace if they smell something unpleasant.
Read about how vegetative state is diagnosed.
- The bladder is a small organ near the pelvis that holds urine until it is ready to be passed from the body.
Causes of vegetative state
People enter a vegetative state after waking from a coma that is caused by:
- either a traumatic brain injury
- or a non-traumatic brain injury
Either of these brain injuries will be severe enough to have caused extensive damage to the parts of the brain responsible for higher brain functions, such as thinking and awareness.
Traumatic brain injury
Traumatic brain injury occurs when an object or outside force causes severe trauma to the brain.
The most common causes of traumatic brain injuries are
- traffic accidents
- violent assault
For more informationc, read about severe head injury.
Non-traumatic brain injury
Non-traumatic brain injuries can occur if:
- A person has a health condition that deprives their brain of oxygen, as without a continuous supply of oxygen the tissue that makes up the brain will begin to die.
- A person has a health condition that directly attacks the tissue of their brain.
Specific causes of non-traumatic brain injury include:
- heart attacks
- severe brain infections, such as meningitis (an infection of the outer layer of the brain) or encephalitis (an infection of the brain itself)
- conditions that cause progressive damage to the cells and tissue of the brain, such as Alzheimer's disease or Parkinson's disease
- brain tumour
- drug overdoses
- near drowning or other types of suffocation, such as smoke inhalation
- a blood vessel bursting leading to bleeding inside the brain - the medical term for this is a ruptured aneurysm
- the kidneys or liver stop working (kidney failure and liver failure) - both of these organs are responsible from removing toxins from the body so if they stop working toxins can build up inside the brain damaging it
- The brain controls thought, memory and emotion. It sends messages to the body controlling movement, speech and senses.
- A coma is a sleep-like state when someone is unconscious for a long period of time.
- The heart is a muscular organ that pumps blood around the body.
- Oxygen is an odourless, colourless gas that makes up about 20% of the air we breathe.
Diagnosing vegetative state
Doctors have to be very rigorous and careful when diagnosing a vegetative state. This is because there is always the possibility that the person's symptoms could be caused by another health condition that may be treatable.
Two conditions that are known to have similar symptoms to vegetative state are:
- locked-in syndrome
- minimally conscious state
Locked-in syndrome is when a person experiences total paralysis of all the muscles. This means they are unable to speak or move.
People with locked-in syndrome can usually move their eyes and are sometimes able to communicate by blinking.
Minimally conscious state
Someone in a minimally conscious state is not in a vegetative state but finds it very difficult to remain aware and communicate for prolonged periods.
People often enter a minimally conscious state after they have been in a vegetative state.
Unlike someone who is in a vegetative state, a person in a minimally conscious state should be able to do at least one of the following:
- Follow simple commands.
- Answer simple "yes" or "no" questions, either verbally or using gestures.
- Speak intelligibly.
- Act in a purposeful way, for example by pressing a button on a remote control to change a television channel.
Confirming a diagnosis
Due to the risk of misdiagnosis, health professionals have to follow strict rules when diagnosing their patient as being in a permanent vegetative state. A confident diagnosis can only be made if all the following have been met:
- The cause of the brain injury has been established - for example, if a case of meningitis is suspected then a diagnosis can be confirmed by testing the fluid that surrounds the brain for infection.
- Six months have passed since the onset of symptoms after a non-traumatic brain injury, or 12 months after a traumatic brain injury.
- It has been confirmed that drugs or medication are not responsible for the symptoms.
- It has been confirmed that treatable problems with the body's chemistry (a metabolic disorder) are not responsible for the symptoms of loss of awareness - an example of a metabolic disorder is a diabetic coma, where people lose consciousness because their blood sugar levels are either dangerous high or dangerously low.
- The possibility of a treatable cause in the brain, such as a brain tumour, has been ruled out by brain imaging scans, such as a MRI scan.
- Two doctors with experience in this field have independently confirmed that there is no evidence of awareness, meaningful movement or any attempt to communicate.
- Medical staff, nursing staff and other therapists agree that the person is in a persistent vegetative state.
- Family members and friends (or at least the majority of them) agree with diagnosis.
If there is any doubt in the diagnosis, an expert assessment should be carried out by a neurologist (a doctor who specialises in treating condition that affects the brain) and a psychiatrist (a doctor who specialises in treating mental health).
Treating vegetative state
There is no treatment that can increase a person's chances of recovering from a vegetative state. Any treatment given is purely supportive, ensuring the person is as physically healthy and comfortable as possible.
This supportive treatment usually involves:
- providing nutritional support through a feeding tube
- making sure that the person is regularly moved so that they don't develop pressure ulcers
- gently exercising their joints to prevent these from becoming tight
- keeping their skin clean
- managing their bowel and bladder, such as using a tube known as a catheter to drain the bladder
- keeping their teeth and mouth clean
Withdrawing nutritional support
Once a diagnosis of a permanent vegetative state has been confirmed, it is recommended that nutritional support should be withdrawn. There are a number of reasons for this:
- There is practically no chance of a recovery.
- Prolonging life would have no benefit to the individual concerned.
- Prolonging treatment would offer only false hope and cause unnecessary emotional distress to the friends and family of the person concerned.
The medical team will discuss the issue with those who are closest to the person being supported, and will give them time to consider all the implications.
If agreement is reached about withdrawing life support, the decision has to be referred to the courts before any further action can be taken.
If the court agrees with the decision to withdraw support, the individual will be sedated (made unconscious with medication) and their nutritional support will be withdrawn. They will then die peacefully in their sleep.
- Intravenous drip
- Intravenous (IV) means the injection of blood, drugs or fluids into the bloodstream through a vein.
- The stomach is the sac-like organ of the digestive system. It helps digest food by churning it and mixing it with acids to break it down into smaller pieces.
Recovering from a vegetative state
Because a vegetative state is such a rare condition, it is hard to estimate accurately how likely it is that a specific person will recover.
From the evidence available, it appears the most significant factors in determining the chance of a person making a recovery from a vegetative state are:
- their age
- whether they experience a traumatic brain injury or a non-traumatic brain injury
- the length of time they have been in a vegetative state
One study found that:
- People under the age of 20 had a 1 in 5 chance of making a partial or complete recovery.
- People aged between the ages of 20 to 39 had around a 1 in 10 chance of making a partial or complete recovery.
- People aged 40 or above had virtually no chance of making a recovery.
Type of injury
A non-traumatic brain injury, such as that which occurs during a stroke, usually causes more extensive brain damage so the chance of recovery is less than when a traumatic injury occurs.
Research has found that:
- People with a traumatic brain injury have a 1 in 2 chance of regaining consciousness and a 1 in 5 chance of making a partial or complete recovery.
- People with a non-traumatic brain injury have a 1 in 8 chance of regaining consciousness and a 1 in 20 chance of making a partial or complete recovery.
The longer a person is in a vegetative state the less chance they have of coming out of that state.
One study carried out in America found that:
- People who have been in a vegetative state for a month have a 1 in 5 chance of making a partial or complete recovery.
- People who have been in a vegetative state for three months have a 1 in 8 chance of making a partial or complete recovery.
- People who have been in a vegetative state for six months have a 1 in 35 chance of making a recovery.
Once a person has been in a vegetative state for 12 months or more, the chances of them making any sort of recovery is extremely small.