Consciousness

Question 1

Define sleep

Answer 1

Decreased arousal

Physiological state of unconsciousness

Active process that is reversible and cyclical

Question 2

Cyclical nature of sleep

Answer 2

Sleep happens in cycles of around 90 mins

Awake [alpha or beta rhythm] 
Non-REM sleep 
Stage 1: Theta waves 
Stage 2: Spindle waves and K complex 
Stage 3: Delta waves- deep sleep 
 REM: beta and alpha waves, desynchronised. Similar to being awake

Question 3

Coma

• define
• is it reversible
• causes[5]

Answer 3

complete loss of wakefulness and reactivity, unresponsive to stimuli, prolonged unconsciousness

Usually reversible

Causes

• sedation
• epilepsy
• metabolic disturbance
• thermoregulation disturbance
• structural damage to brain (stroke, trauma, tumour etc.)

Question 4

Metabolic causes of coma

-What can be seen on EEG?

Answer 4

hepatic
uraemia
diabetic
pancreatic
adrenocorticoid failure

Shows triphasic theta waves on EEG

Question 5

What are the 3 possible outcomes after coma?

Answer 5

• reversal and recovery
• Survival into vegetative state or minimally conscious sate
• Irreversible cessation of function of brainstem, cortex or body

Question 6

Glasgow coma scale

Answer 6

used to assess consciousness of an individual.

Eye opening [1-4]

Motor response to verbal command [1-6]

Verbal response [1-5]

8=just about conscious

Question 7

In the Glasgow Coma Scale, what does absent eye opening show?

Answer 7

Absent Eye Opening distinguishes
Coma / brainstem death
from PVS and MCS

Question 8

Persistent Vegetative State

Answer 8

> 4 weeks

Question 9

Permanent Vegetative State

Answer 9

Lasts for longer

After a non-traumatic Brain Injury
6 months in the UK
3 months in the US

After Traumatic Brain Injury
1 year

Question 10

Causes of vegetative state

Answer 10

Neocotical Brain death

-anoxia, brain injury

Question 11

Minimally Conscious State

Answer 11

Slightly more conscious than VS

Question 12

Locked In Syndrome

• describe
• causes

Answer 12

Aroused and aware but unable to respond

Partially locked in
-Eye movements preserved vertical eye movements
reserved eye opening

Causes

• Ventral Pontine Damage
• Severe Guillain Barre Syndrome

Question 13

Reflexes absent in brain stem death

Answer 13

Pupillary reflex

Ice Calorics

Corneals

Pain

Gag

Cough

Question 14

Intralaminar Thalamic Nuclei

Answer 14

General anaesthetics suppress activity in ILN

Bilateral lesions of C-M nucleus

Coma or severe delirium
Death
Persistent vegetative state
Mutism

Unilateral lesions of C-M nucleus

unilateral neglect

Question 15

How does one enter into a coma?

Answer 15

bilateral lesion of the centro-median nucleus which is contained within the intralaminar thalamic nuclei