Facts About the Vegetative and Minimally Conscious States After Severe Brain Injury Mark Sherer, Ph.D., Monica Vaccaro, M.S., John Whyte, MD, Ph.D., Joseph T. Giacino, Ph.D., and the Consciousness Consortium, Model Systems of Knowledge Translation Center Page 1 of 4

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Severe brain injury causes a change in consciousness. Consciousness refers to awareness of the self and the environment. Brain injury can cause a wide range of disturbances of consciousness. Some injuries are mild and may cause relatively minor changes in consciousness such as brief confusion or disorientation.

The most severe injuries cause profound disturbance of consciousness. Twenty to 40% of persons with injuries this severe do not survive. Some persons who survive have a period of time of complete unconsciousness with no awareness of themselves or the world around them. The diagnosis given these people depends on whether their eyes are always closed or whether they have periods when their eyes are open. The state of complete unconsciousness with no eye opening is called coma. The state of complete unconsciousness with some eye opening and periods of wakefulness and sleep is called the vegetative state. As people recover from severe brain injury, they usually pass through various phases of recovery. Recovery can stop at any one of these phases.

Characteristics of coma

• No eye-opening
• Unable to follow instructions
• No speech or other forms of communication
• No purposeful movement

Characteristics of the vegetative state

• Return of a sleep-wake cycle with periods of eye opening and eye closing
• May moan or make other sounds especially when tight muscles are stretched
• May cry or smile or make other facial expressions without apparent cause
• May briefly move eyes toward persons or objects
• May react to a loud sound with a startle
• Unable to follow instructions
• No speech or other forms of communication
• No purposeful movement

Persons in coma or vegetative state require extensive care that may include:

1. Feeding using a feeding tube
2. Turning in bed to prevent pressure sores
3. Special bedding to help prevent pressure sores
4. Assistance with bowel and bladder relief using catheter and/or diapers
5. Management of breathing such as suctioning of secretions; this may include care for a tracheostomy tube
6. Management of muscle tone (excessive tightness of muscles)
7. Special equipment that may include a wheelchair or special bedding to help with proper posture and decrease muscle tightness
8. Management of infections such as pneumonia or urinary tract infections
9. Management of other medical issues such as fever, seizures, etc.

What happens after coma and vegetative state?

When people start to regain consciousness, they may:

• follow simple instructions from others such as, “Open your eyes,” “Squeeze my hand,” “Say your name,” etc.;
• communicate by speaking words or by indicating yes or no by head nods or gestures; and/or
• use a common object in a normal way such as brushing hair with a brush, using a straw to drink, holding a phone to the ear, etc.

Persons with brain injury transition through the period of unconsciousness and subsequent stages of recovery at a slower or faster rate, largely depending on the severity of injury. Those with less severe injuries may transition through these stages more rapidly and some of the stages described here may be poorly recognized or not occur at all. Those with very severe injuries may stall at one or another stage and not be able to make the transition to a higher level of recovery.

For persons with more prolonged periods of unconsciousness, emergence from unconsciousness is a gradual process. Coma rarely lasts more than 4 weeks. Some patients move from coma to the vegetative state but others may move from coma to a period of partial consciousness. It would be very rare for a person to move directly from coma, or vegetative state, to a state of full consciousness.

Persons who have shorter periods of unconsciousness likely had less severe brain injuries initially. Consequently, they are likely to go on to make better recoveries than persons who had longer periods of unconsciousness.

Traumatic brain injury refers to damage to the brain caused by external force such as a car crash or a fall. About 50% of persons who are in a vegetative state one month after traumatic brain injury eventually recover consciousness. They are likely to have a slow course of recovery and usually have some ongoing cognitive and physical impairments and disabilities. People in a vegetative state due to stroke, loss of oxygen to the brain (anoxia) or some types of severe medical illness may not recover as well as those with traumatic brain injury. Those few persons who remain in a prolonged vegetative state may survive for an extended period of time but they often experience medical complications such as pneumonia, respiratory failure, infections, etc. which may reduce life expectancy.

People who have a slow recovery of consciousness continue to have a reduced level of self-awareness or awareness of the world around them. They have inconsistent and limited ability to respond and communicate. This condition of limited awareness is called the minimally conscious state.

Characteristics of the minimally conscious state

• Sometimes follows simple instructions
• May communicate yes or no by talking or gesturing
• May speak some understandable words or phrases
• May respond to people, things, or other events by:
  • crying, smiling, or laughing;
  • making sounds or gesturing;
  • reaching for objects;
  • trying to hold or use an object or
  • keeping the eyes focused on people or things for a sustained period of time whether they are moving or staying still.

People in a minimally conscious state do these things inconsistently. For example, one time the person might be able to follow a simple instruction and another time they might not be able to follow any instructions at all. This makes it difficult to distinguish the vegetative state from the minimally conscious state.

While in a minimally conscious state, people need extensive care similar to that needed by people in a vegetative state.

Sherer M, Vaccaro M, Whyte J, Giacino JT, & the Consciousness Consortium. Facts about the Vegetative and Minimally Conscious States after Severe Brain Injury 2007. Houston: The Consciousness Consortium. Copyright © 2010 by University of Washington/MSKTC. 

Please check the MSKTC site for any recent updates on this article.

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