Consciousness

Question 1

Objective definition of consciousness

Answer 1

The ability to respond to stimuli.
Sensation: pain, touch, proprioception.
Auditory: verbal or non-verbal
Visual
Olfactory
Taste

The ability to spontaneously move
- spontaneous eye, head or limb movements
The ability to speak

The ability to orientate in time and place

Question 2

Subjective definition of consciousness

Answer 2

The experience of sensory stimuli

The experience of:

• Emotion
• Memory
• Thought
• Agency
• Self and non-self

Question 3

Sleep

- Definition

Answer 3

Physiological state of unconsciousness

State of decreased arousal

Active process that is reversible and cyclical

Question 4

Cyclical nature of sleep

Answer 4

Sleep happens in cycles of around 90mins.

1. Drowsiness: alpha waves
2. Stage 1 NREM: theta waves
3. Stage 2 NREM: spindle waves and K complex
   4: Stage 3 deep sleep: delta wabes
   5: REM sleep

Cycle ascends and descends

Question 5

Coma

• Definition
• Causes [5]

Answer 5

The complete loss of wakefulness and unresponsiveness to stimuli.

Usually reversible

Cause:

• Sedation
• Epilepsy
• Electrolyte imbalance
• Brainstem/ thalamus/ cortex structural damage
• Thermoregulation disruption

Question 6

Metabolic causes of coma

Answer 6

Hepatic
Uraemia
Diabetes
Pancreatic
Adrenocorticoid failure

Shows triphasic theta waves of EEG

Question 7

Possible outcomes of a coma [3]

Answer 7

1. Reversal and recovery
2. Survival into—> persistent vegetative state or minimally conscious state
3. Irreversible cessation of function for:
   - Brainstem
   - Neocortex
   - Body

Question 8

Glasgow coma scale

Answer 8

Used to assess consciousness of an individual.

Eye opening [1-5]

Motor response to verbal command [1-6]

Verbal response [1-5]

8= just about conscious

Question 9

Glasgow coma scale

• distinction between coma/brainstem death
• PVS/MCS

Answer 9

Eye opening

- Its absence distinguishes from the different states

Question 10

Permanent vegetative state

Answer 10

PVS that lasts for a lengthier time.

If after non-traumatic brain injury
- Lasts for at least 6 months in UK [3 months in US]

If after traumatic brain injury
- Lasts for at least a year.

Question 11

Persistent vegetative state

Answer 11

Vegetative state that lasts for at least 4 weeks.

Question 12

Vegetative state

Answer 12

Absent awareness but preserved arousal

No voluntary response to environment
- Reflex responses variably preserved

Question 13

Cause of vegetative state

Answer 13

Neocortical brain death

- Anoxia, brain injury

Question 14

Minimally conscious state

Answer 14

Slightly more conscious than vegetative state

Emergence can occur if:

• Functional communication happes
• Object use occurs.

Question 15

Locked-in syndrome

Answer 15

Aroused and aware but unable to respond

Partially locked in
- Eye movements [vertical and eye opening]

Causes:

• Ventral pontine damage
• Severe guillain barre syndrome

Question 16

Reflexes absent in brain stem death

Answer 16

Pupillary reflex

Ice calorics

Corneal

Pain

Gag

Cough

Question 17

Brainstem death

Answer 17

Irreversible cessation of brainstem function.

Apnoea
- 5 min test after pre-oxygenation, allowing CO2 to reach 6Kpa

Legal requirements:

• Presence of irreversible cause
• Absence of reversible cause
• Irreversible cessation of brainstem, cerebral cortex and body.