Conciousness

Question 1

Give examples of roles that will have different views on the definition of consciousness.

Answer 1

Philosopher
Psychologist
Neuroscientist
Neurosurgeon

Question 2

What is consciousness?

Answer 2

‘Awareness of Awareness’ - some suggest it is fundamentally a function of the brain with neural mechanisms involved whereas others resist reducing consciousness believing that it cannot be explained in reductionalist physical terms

Question 3

Damage to what structures change a patient’s level of consciousness?

Answer 3

• Reticular formation
• Intralaminar thalamic nuclei (bilateral lesion)
• Cerebral hemispheres (bilateral involvement)
• Dominant hemisphere (major involvement)
• NS (generalised depression)

Question 4

What is the reticular formation?

Answer 4

Network of reticular fibres synapsing with ascending and descending tracts beginning in medulla and extending to mid-brain with long dendrites radiating to brainstem occupying a significant portion of dorsal brainstem

Question 5

What is the major role of the reticular formation?

Answer 5

Sleep/wake cycle

Question 6

What is the reticular activating system?

Answer 6

A network of structures including brainstem, thalamus and neural pathways that function together to produce and maintain arousal

Question 7

What is the medical perspective of consciousness?

Answer 7

A state of being aware of (or responsive) to the environment with the ability to perceive, physically or mentally, what is happening

Question 8

What is the role of the reticular activating system?

Answer 8

The part of reticular formation in brainstem playing a central role in bodily and behavioural alertness (arousal)

Question 9

What are causes of a decrease in conscious level?

Answer 9

Trauma
Infection
Tumour 
Metabolic 
Intoxication

Question 10

What types of trauma can cause a decrease in consciousness?

Answer 10

Minor concussion
Cerebral contusion
Intracranial/intraparaenchymal aemorrhage

Question 11

What types of infection can cause a decrease in consciousness?

Answer 11

Meningitis
Encephalitis
Brain abscess
Subdural empyema

Question 12

What types of tumour can cause a decrease in consciousness?

Answer 12

Benign (e.g. meningioma and malignant (e.g. glioma) all of which can be complicated by development of surrounding oedema due to raised ICP

Question 13

What types of metabolic problems can cause a decrease in consciousness?

Answer 13

Hypoperfusion/hypoxaemia
Hypoglycaemia
Hyperglycaemia/DKA
Hyper/hypo-natraemia
Hypercalcaemia
Renal/liver failure
Hypothermia

Question 14

What different ways can a person become hypoperfused/hypoxaemic?

Answer 14

Syncope
Stroke
TIA

Question 15

What types of intoxication can cause a decrease in consciousness?

Answer 15

Medication
Illegal drugs
Toxins 
Alcohol
Narcotics

Question 16

What did the old assessment of consciousness include?

Answer 16

Scales of different levels:

1. Normal
2. Obtundation (confusion)
3. Stupor
4. Coma (unconsciousness)

Question 17

What is obtundation?

Answer 17

Awareness impaired but may become normal or nearly so on arousal, speech slow, voluntary movements diminished + slow, EECG mildly abnormal with some sleep pattern (GCS = 11-12/15)

Question 18

What is stupor?

Answer 18

No real awareness, speech only in response to pain, voluntary movements minimal or there may be mass movements in response to pain, EEG abnormal but distinguishable from normal sleep pattern (GCS = 8-10/15)

Question 19

What is coma?

Answer 19

No awareness, speech absent, movements absent or only reflex in response to pain, EEG grossly abnormal or absent (GCS 0-8/15)

Question 20

What does the modern assessment of consciousness use?

Answer 20

Glasgow Coma Score (GCS)

Question 21

What does the Glasgow Coma Score (GCS) test?

Answer 21

Best eye (E), verbal (V) and motor (M)response

Question 22

How is best eye response (E) ranked in the Glasgow Coma Score (GCS)?

Answer 22

4 - eyes open spontaneously
3 - eyes open to speech
2 - eyes open to painful stimulus
1 - no eye opening

Question 23

How is best verbal response (V) ranked in the Glasgow Coma Score (GCS)?

Answer 23

5 - fully orientated in time, place + person
4 - confused (disorientated)
3 - inappropriate words
2 - incomprehensible sounds
1 - none

Question 24

How is best motor response (M) ranked in the Glasgow Coma Score (GCS)?

Answer 24

6 - obeys commands
5 - localises to painful stimulus
4 - withdrawal from pain
3 - abnormal flexes to pain
2 - extends to pain
1 - no motor response

Question 25

What painful stimuli do you utilise when testing best motor response (M) in the Glasgow Coma Score (GCS)?

Answer 25

Squeeze supraoptic area

Question 26

What does a score of 3 and 2 mean on the best motor response (M) scale of the Glasgow Coma Scale (GCS)?

Answer 26

3 = abnormal flexes to pain means the cerebral cortex is not functioning properly 2 = extends to pain so anything above the brainstem is not functioning

Question 27

How do you interpret the Glasgow Coma Scale (GCS)?

Answer 27

``` 15 = best possible i.e. normal 3 = worst possible ``` E.G. GCS 7 (E1, V2, M4)

Question 28

What scores will different severity of head injury show on the Glasgow Coma Scale (GCS)?

Answer 28

``` Minor = More than 13 Moderate = GCS 9-12 Severe = GCS less than 8 ```

Question 29

What is a persistent vegetative state?

Answer 29

Reticular formation intact but connection with cerebral cortex non-functional so person is awake (eyes open, move around but dont fix on anything + sleep/wake cycles present) but awareness is absent along with meaningful response to verbal command or pain

Question 30

What would an electroencephalography (EEG) show on a patient in a persistent vegetative state?

Answer 30

Contains rhythmic activity resembling sleep cycles

Question 31

What is locked-in syndrome?

Answer 31

Sensation, reticular formation and cortical function intact so person is fully awake and aware but motor function is absent although vertical eye movements and eyelid elevation may be spared usually due to infarct in ventral pons involving CBT/CST

Question 32

What is the pneumonic for cranial nerves (CNs)?

Answer 32

``` Oh Oh Oh To Touch A Fair Virgin Girls Vagina And Hymen ```

Question 33

What are the 12 cranial nerves (CNs)?

Answer 33

``` Olfactory (I) Optic (II) Occulomotor (III) Trochlear (IV) Trigeminal (V) Abducens (VI) Facial (VII) Vestibulocochlear (VIII) Glossopharyngeal (IX) Vagus (X) Accessory (XI) Hypoglossal (XII) ```

Question 34

What does a peripheral neurological evaluation test?

Answer 34

``` Tone (normal/hypo/hyper) Power (scoring system) Reflexes Co-ordination Sensation (dermatomes/myotomes) ```

Question 35

What is the scoring system for tone?

Answer 35

``` 1 = none 2 = move but not against gravity 3 = able to move against gravity 4 = less than normal power 5 = normal ```

Question 36

Why do a peripheral neurological examination?

Answer 36

To check for UMN and/or LMN lesions