Vegetative State (Unresponsive Wakefulness Syndrome)
A vegetative state is when a person is awake but showing no signs of awareness. On recovery from the coma state, VS/UWS is characterised by the return of arousal without signs of awareness. In contrast, a coma is a state that lacks both awareness and wakefulness. Absence of awareness can only be inferred by lack of responsiveness to the environment and not as lack of consciousness that we may not be able to detect by behavioural measures. For this reason, many authors have suggested that the term ‘Unresponsive Wakefulness Syndrome’ (UWS) (Laureys et al., 2010) or ‘post-coma unresponsiveness’ (NHMRC, 2004) are more accurate descriptive terms for VS.
A person in a vegetative state may open their eyes, wake up and fall asleep at regular intervals and have basic reflexes, such as blinking when they're startled by a loud noise, or withdrawing their hand when it's squeezed hard. They're also able to regulate their heartbeat and breathing without assistance.
However, a person in a vegetative state doesn't show any meaningful responses, such as following an object with their eyes or responding to voices. They also show no signs of experiencing emotions nor of cognitive function.
VS/UWS patients' eyes might be in a relatively fixed position, may track moving objects (visual pursuit), or move in a completely unsynchronised manner. Sleep-wake cycles may resume or patients may appear to be in a state of chronic wakefulness. They may grind their teeth, swallow, smile, shed tears, grunt, moan, or scream without any apparent external stimulus. VS/UWS patients do not respond to sound, hunger, or pain. Patients cannot obey verbal commands and lack local motor responses. Additionally VS/UWS patients cannot talk in comprehensible terms and may become noisy, restless, and hypermobile.
One of the most challenging tasks facing clinicians is that of differentiating VS/UWS from minimally conscious (MCS) states.
Whilst neuroimaging such as MRI is widely used in assessing brain damage and functional abilities, behavioural assessment has, until now, been the "gold standard" for detecting signs of consciousness and thereby for determining diagnosis.
If a person is in a vegetative state for a long time, it may be considered to be:
- a continuing vegetative state – when it's been longer than four weeks
- a permanent vegetative state – when it's been more than six months if caused by a non-traumatic brain injury, or more than 12 months if caused by a traumatic brain injury
If a person is diagnosed as being in a permanent vegetative state, recovery is extremely unlikely but not impossible.
Careful, ongoing assessment of the patient, using empirically validated assessment tools (eg the Coma Recovery Scale-Revised) is essential in order to evaluate and measure signs of progress, improvement or deterioration. Treatment is addressed at presenting symptoms and the patient’s needs; VS/UWS patients require constant monitoring and assistance with feeding, hydration, hygiene, assisted movement and physical therapies (to help prevent ulcers and blood clots in the legs), and elimination of waste products.
Currently no treatment for VS/UWS exists that would satisfy the efficacy criteria of evidence-based medicine. Pharmacological methods, surgery, physical therapy, and various stimulation techniques have been suggested. Pharmacological therapy mainly uses activating substances such as tricyclic antidepressants or methylphenidate (Dolce et al. 2002). Surgical methods (eg. deep brain stimulation) are used infrequently due to the invasiveness of the procedures. Stimulation techniques include sensory stimulation, sensory regulation, music and musicokinetic therapy, social-tactile interaction, etc.
Treatment can't ensure recovery from a state of impaired consciousness, however supportive treatment is used to give the best chance of natural improvement. This can involve:
- providing nutrition through a feeding tube
- making sure the person is moved regularly so they don't develop pressure ulcers
- gently exercising their joints to prevent them becoming tight
- keeping their skin clean
- managing their bowel and bladder – for example, using a catheter to drain the bladder
- keeping their teeth and mouth clean
- efforts should be made to establish functional communication and environmental interaction when possible. Offering opportunities for periods of meaningful activity – such as listening to music or watching television, being shown pictures or hearing family members talking
- visual – showing photos of friends and family, or a favourite film
- hearing – talking or playing a favourite song
- smell – putting flowers in the room or spraying a favourite perfume
- touch – holding their hand or stroking their skin with different fabrics
While not empirically validated, families have reported benefits from arousal regimes, such as those implemented by Dr Ted Freeman (eg Coma Arousal Therapy). This intensive therapy involves family members taking the patient through a regimen of controlled auditory, visual and physical stimulation for up to six hours a day every day.
Prognosis (outlook for recovery)
Many patients emerge spontaneously from VS/UWS within a few weeks. Some people improve gradually, whereas others stay in a state of impaired consciousness for years. Many people never recover consciousness.
The chances of recovery depend on the extent of injury to the brain and age, with younger patients having a better chance of recovery than older patients. Generally, adults have about a 50 percent chance and children a 60 percent chance of recovering consciousness from VS/UWS within the first 6 months in the case of traumatic brain injury. For non-traumatic injuries such as strokes, the recovery rate falls within the first year. After this period the chances that VS/UWS patient will regain consciousness are very low and, of those patients who do recover consciousness, most experience significant disability. The longer a patient is in VS/UWS the more severe the resulting disabilities are likely to be.
Some patients who have entered a vegetative state go on to regain a degree of awareness (see Minimally Conscious State). The likelihood of significant functional improvement for VS/UWS patients diminishes over time. There are only isolated cases of people recovering consciousness after several years. The few people who do regain consciousness after this time often have severe disabilities caused by the damage to their brain.
Further Information and Support
Click here for access to the Australian Register for Disorders of Consciousness (ARDoC)
For information about Coma Arousal Therapy (which has been found to be beneficial in patients in Vegetative State), see Dr Edward (Ted) Freeman (1987) The Catastrophe of Coma. Publisher: David Bateman
Brain Injury Australia
Coma Science Group
National Institute of Neurological Disorders and Stroke
ReNew Neurobehavioural Services
Brain Injury Resource Center
Reviewed February 2017 by: Shannan Keen, MBMSc, Brain and Mind Research Institute, University of Sydney