Coma and Persistent Vegetative State
Coma can be defined as a state of depressed consciousness where the patient is unresponsive to the outside world. Unconsciousness follows traumatic brain injury, whether for a few seconds or for a few weeks, and is the most typical symptom of a head injury.
A small number of people sustain a head injury so severe that they remain in a state of coma for months and years without recovering sufficient consciousness to make any form of communication, but can breathe without mechanical assistance. This is called 'Persistent Vegetative State (PVS)'.
Coma
There are different levels of coma, and the Glasgow Coma Scale is used to rate the unconscious patient's ability to open his eyes, move and speak.
- A patient is assigned a number in each of three categories, namely eye opening, motor response and verbal response.
- The minimum number is 3 and the maximum possible number is 15.
- The more severe the injury, the lower the performance, and the lower the number.
Awakening from a coma is gradual, starting with eyes opening, then responses to pain, and then responding to speech. The longer a person stays in coma, the more likely it is that the long-term effects will be severe.
This is a very distressing time for family and friends, and it is easy to feel helpless and to long to do something constructive. It is generally accepted that someone in a coma may be able to hear speech, but not be able to respond. Talk to the person as if they can hear.
Coma stimulation programmes, in which carefully planned periods of stimulation (in the form of sound, touch, smell and taste) are combined with periods of complete rest in order not to overload the person's senses, are still controversial. However, they give relatives and friends something useful to do, and may well have some beneficial effect.
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Persistent Vegetative State
Various terms are used to describe this condition, including Vegetative State, Minimum Conscious State or Minimally Responsive State.
A small number of people sustain a head injury so severe that they remain in a state of coma for months and years without recovering sufficient consciousness to make any form of communication, but can breathe without mechanical assistance. They may have sleeping and waking cycles allowing them to be fed, but they do not speak, follow commands or have any understanding of what has been said. The Glasgow Coma Scale score for such people is usually below 9.
In their guidance document 'Treatment of patients in persistent vegetative state' (2007), the British Medical Association recommend that "...the diagnosis of irreversible PVS should not be considered confirmed (and therefore treatment not be withdrawn) until the patient has been insentient for at least 12 months". This guidance does, however, recognise the difficulty associated with making an accurate diagnosis and that the opinions of doctors and relatives need to be taken into account.
There are normally just less than 100 people in the UK in PVS at any one time.
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