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
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).
