Chapter 6

Question 1

Anoxic brain injury

Answer 1

Caused by complete lack of oxygen provided to the brain. Results in the death of brain cells after approximately four minutes of oxygen deprivation.

Question 2

Hypoxic brain injury

Answer 2

Due to restriction of the oxygen supplied to the brain. Results in gradual death and impairment of brain cells.

Question 3

Ischemic vs hemorrhagic stroke

Answer 3

Ischemis = blood vessel is blocked
Hemorrhagic = ruptured blood vessel

Question 4

ARAS: ascending reticular activating system

Answer 4

Set of connected nuclei in the brain that are responsible for regulating wakefulness and sleepwake transitions. Neurotransmitters involved are: DA, NA, Ach, 5-HT. Damage to this area leads to coma or death.

Question 5

Coma

Answer 5

• No signs of being awake
• Eyes closed and no response to environment or pain
• Lasts for 2 to 4 weeks. At some point the person may wake up and progress into a vegetative state or minimally conscious state.
• Can be caused by damage to reticular activating system or cortex.
• Use of assisted breathing is sometimes necessary.

Question 6

Brain death

Answer 6

• Total absence of brainstem reflexes
• Flat EEG and inability to initiate breathing.
• PET and other measures show that cortical metabolism and perfusion of blood to the brain are annihilated.
• Once hypothermia is excluded, and effects of substances, diagnosis of brain death can be established within a day.
• Cortical and thalamic neurons quickly degenerate, therefore irreversible.

Question 7

Difference between coma and brain death

Answer 7

Coma patients show reflexes. EEG of coma patients is also not a flatline. It fluctuates at a slow rate. Many neurons are still alive in coma patients but are in an inappropriate network state.

Question 8

Locked in Syndrome

Answer 8

• Typical cause: damage to brain stem (pons)
• Patient is fully conscious and awake but unable to move or communicate due to complete paralysis except for the eyes.
• Total locked-in syndrome means the eyes are also paralyzed.

Question 9

Minimally conscious state

Answer 9

• Patients with rare, inconsistent, and limited responses that suggest residual comprehension and volition.
• Respond to a verbal order by blinking or may follow a mirror with their eyes.
• Express emotions that are appropriately linked to the current context.

Question 10

Vegetative state/Unresponsive wakefulness syndrome (UWS)

Answer 10

• Functions that depend on the autonomous nervous system, such as the regulation of cardiac frequency, vascular tone, and body temperature are generally intact.
• The spinal chord and brain stem often generate purely involuntary movements, undirected toward a specific goal.
• Crucially, the patient never responds to any verbal orders, nor do they say a word, though they may emit random grunts.

Question 11

Prognosis on brain damage

Answer 11

Prognosis is worse for non-traumatic injury compared to TBI

Question 12

Diagnosis of disorders of consciousness

Answer 12

43% diagnosis error based on bedside assessment.
Inability to move and speak is a frequent outcome of chronic brain injury and does not necessarily imply lack of awareness.
Behavioural assessment is highly subjective. Smiling and crying are typically reflexive and automatic, but in certain contexts they may be the only means of communication and therefore reflect a willful, volitional act of intention.