Vegetative and Minimal Conscious State After Severe Brain Injury

Posted on December 28, 2021

Severe traumatic brain injury can cause loss of consciousness either complete or incomplete. A state of complete unconsciousness with no eye-opening is called a coma. The ability to maintain respiration, blood pressure, and cardiac function but not cognitive function, a chronic condition aka a vegetative state. 

The most common conditions that lead to a vegetative or minimally conscious state are TBI and diffuse cerebral hypoxia. Damage to the cerebral hemispheres, but intact brain stem function, may simulate awareness despite its absence. 

Vegetative state

A vegetative state is characterized by no sign of awareness of self or surroundings and cannot relate to other people. Responses to external stimuli are absent, language expression and understanding also absent.

Patients in vegetative state present with:

  • Periods of eye-opening and closing, return of the sleep-wake cycle
  • Complex brain stem reflexes such as chewing, swallowing, yawning and other guttural sounds. 
  • Startling to a loud sound 
  • Briefly eyes moving towards objects or persons
  • Watering or tearing eyes, smiling  or frowning without reason
  • Instantaneous roving eye movements
  • No speech, no purposeful movement or communication
  • Fecal and urinary incontinence
  • Pain may elicit a response but not avoidance.
  • Cannot react to visual threats and cannot follow instructions.

Brain activity as detected by fMRI or EEG is minimal; response to commands is seen even though no physical activity is possible. 

Minimally conscious state: Is a reduced level of self-awareness, inconsistent or limited ability to communicate or respond. 

Patients can exhibit one or more than one of these signs:

  • Communicate yes or no by head nods or talking.
  • Follows simple commands, such as ‘squeeze my hand’ or ‘open your eyes’.   
  • Can speak some words or phrases that are understandable
  • Establish eye contact, and maintain contact
  • Trying to hold or use an object, such as using a straw, brushing hair with a comb.
  • Cry, smile or laugh.

All these actions are done inconsistently, one time a person may respond and another time he/she may not be able to follow even simple instructions. Hence it is difficult to distinguish a vegetative state from a minimally conscious state. 

Prognosis of vegetative and minimally conscious state:
People with brain injury fluctuate through periods of unconsciousness, the rate, and extent of recovery will depend mainly upon the severity of the injury. If these states extend for prolonged periods of time, patients can experience complications such as respiratory failure, pneumonia, and other infections that can reduce life expectancy.  

If the vegetative state due to TBI extends for more than a year, recovery may be quite unlikely. If recovery does happen after a long interval, most people may be seriously disabled. And most TBI patients die within six months if a vegetative state persists, due to the original brain damage. Life expectancy may be about 2-5 years, and only 25% live more than 5 years.

Many TBI patients can remain in a state of minimally conscious state indefinitely. The longer a patient remains in this state, the more he or she is likely to have permanent damage to multiple brain areas. People mostly experience confusion, when emerging from this state. 


Supportive care is the only treatment that can be given to patients in a vegetative or minimally conscious state. This may include providing good nutrition, preventing pressure ulcers and complications that may develop due to immobility (UTIs, Pneumonia, and thromboembolism). Also physical therapy to prevent joint pain and muscle rigidity can help. 

Patients with severe TBI may or may not recover from a vegetative or minimally conscious state, and may require in-patient rehab, long-term nursing and skilled care services.