93b - Brain States and Coma

Question 1

List the following brain states from most responsive to least responsive:

Coma, obtundation, stupor

Answer 1

• Obtundation
  
  • Most responsive
• Stupor
  
  • Vague term, between alert an in a coma
  • Patient can respond peruposefully, but requires constant stimulation
• Coma
  
  • Unresponsive
    
    • Patient cannot be stimulated to responsd purposefully

Question 2

What is the medical definition of brain death?

Answer 2

• No purposeful response to any stimuli
  
  • Including noxious stimuli
• No brainstem reflexes
• No spontaneous respiratory movments
• Clear underlying etiology
  
  • Not due to medications or sedatives

May be present:

Simple reflexes, circadian rhythm, autonomic function

Question 3

How will a patient with abulia present/act?

Answer 3

• Slowing of cognitive and behavioral function
• Intact cognitive function
• Apathy

Often caused by medial frontal lobe injuries

Question 4

How can you tell if a patient is in a coma or “locked in”?

Answer 4

A person who is locked in may be able to move their eyes up in response to commands

• Patients with locked in syndrome are conscious, but unable to effectuate muscles

Question 5

What is the difference between a vegetative state and a minimally conscious state?

Answer 5

• Vegetative state
  
  • No purposeful response to stimuli
    
    • No environmental awareness
  • No brainstem reflexes
  • No spontaneous repsiratory movements
  • Eyes may open and rove randomly
• Minimally conscous state
  
  • May require respiratory support
  • Behavioral evidence of self or environmental awareness
  • Eyes may lock onto familiar faces, objects rather than just roving

Question 6

Which part of the brain mediates arousal and sleep/wake changes?

Answer 6

Ascending reticular activating system (ARAS)

Damage to ARAS and/or pathway results in impaired arousal

Question 7

What is the difference between a coma and a vegetative state?

Answer 7

Patinets who are brain-dead will progress from coma to vegetative state in 10-30 days

In both states, the patient cannot respond purposefully, has no respiratory drive, and no brainstem reflexes

• Coma
  
  • No eye opening
  • No circadian rhythm
• Vegetative state
  
  • Circadian rhythm restored
  • Periods of eye opening, roving eye movement
  • Autonomic changes observed

Question 8

Injury at which 3 areas of the brain can result in decreased level of arousal?

Answer 8

• Ascending Reticular Activating System in the midbrain
• Bilateral thalami
  
  • Before ARAS branches off
• Both cerebral hemispheres

Other focal deficits will not impair arousal

Question 9

What is the difference between abulia and akinetic mutism?

Answer 9

Both involve slowing of cognitive and behavior functions

Akinetic mutism is extreme abulia

Question 10

Injury to the ______ results in locked in syndrome

Describe the syndrome

Answer 10

Injury to the pons results in locked in syndrome

Patients are paralyzed except upward eye movments - no cognitive impairment