Persistent Vegetative State

Question 1

What is consciousness?

Answer 1

State of full awareness of self and the environment

Question 2

What are the 2 parts of consciousness?

Answer 2

Arousal - sleep and wake up cycle

Content - sum of all our interactions with environment

Question 3

What is a vegetative state?

Answer 3

Complex condition
Spontaneous eye-opening signalling wakefulness but no evidence of purposeful behaviour suggesting awareness of self or environment
No purposeful behaviours when exposed to stimuli and no language comprehension or expression
Patient appears to be awake but shows no sign of awareness of themselves/environment

Question 4

What are the 2 types of vegetative state?

Answer 4

• persistent (persistent for 1 month)

- permanent (12 months after traumatic brain injury, 3 months after non traumatic causes - anoxia/hypoxia)

Question 5

What are the anatomical correlations of consciousness?

Answer 5

Small region in rostral dorsolateral pontine tegmentum

• connected to 2 cortical regions: ventral anterior insula and pregenual ACC
• disconnection = disorders of consciousness

Question 6

How is vegetative state diagnosed?

Answer 6

• clinical history
• repeated observation of spontaneous and elicited behaviour
• imaging (anatomical and functional)
• electrophysiology

Question 7

What do you look for on an electrophysiology?

Answer 7

• absent somato-sensory evoked potentials

- EEG: global slowing

Question 8

Which anatomical tests do you carry out?

Answer 8

MRI

Question 9

Which functional tests do you carry out?

Answer 9

PET
MRI - reduction in default mode neurons
Diffusion Tensor Imaging

Question 10

What do you look for on an observation of spontaneous and elicited behaviour?

Answer 10

Sustained reproducible purposeful or voluntary response to visual/olfactory/auditory/tactile or noxious stimuli
- comprehension of language/expression

Question 11

How do you assess consciousness?

Answer 11

• Auditory Stimulation

- imaging: PET or blood oxygenation level dependent MRI imaging to see central blood flow associated with brain activity

Question 12

How can a misdiagnosis occur?

Answer 12

Assessor Factors: lack of training, limited knowledge

Patient Factors: physical disability, visual impairment

Question 13

What is a minimally conscious state?

Answer 13

wakefulness with inconsistent signs of awareness:

• non-reflexic response to sensory stimulus
• language comprehension/expression
• visual tracking
• appropriate smiling/crying to visual/linguistic stimuli

Akinetic Mutism

Question 14

What is akinetic mutism?

Answer 14

Awake but diminished drive to respond

• apparent alertness along with lack of almost all motor functions including speech, gestures and facial expression
• often misdiagnosed as depression or delirium

Question 15

What factors affect recovery?

Answer 15

• time spent in vegetative state (inversely proportional)
• age (younger better)
• type of brain injury (traumatic better outcome than anoxic)

Question 16

What pharmacological treatment is there?

Answer 16

Amantadine - weak NMDA receptor antagonist and blocks dopaminergic reuptake
Zolpidem - indirect GABAa receptor agonist, ST treatment

Question 17

What surgical treatment is there?

Answer 17

Central thalamic DBS

Question 18

What other problems would need supportive treatment?

Answer 18

Spasticity
UTI
Sleep problems
Agitation/hyperkinesia

Question 19

What is the ethical perspective?

Answer 19

• only made if patient shown to be unaware of self/environment
• stopping artificial nutrition/hydration requires approval of high court
• is continued treatment in patients best interest?

Question 20

What structures of the brain control consciousness?

Answer 20

Rostral dorsolateral pontine tegmentum connected to 2 cortical regions: ventral anterior insula and pregenual anterior cingulate cortex

Question 21

What is the function of the pontine tegmentum?

Answer 21

Controls sleep states and levels of arousal and vigilance

Question 22

What is the seat consciousness?

Answer 22

Lateral prefrontal cortex
Posterior parietal cortex
(responsible for high-level complex thought)

Question 23

What is the global workspace theory?

Answer 23

We taken on sights/sounds/taste and combine into global workspace, selects all the ones we want filtering it and merge it into a single person object

Question 24

What can alter consciousness?

Answer 24

Traumatic brain injury
Severe stroke
Haemorrhage
Hypoxia

Question 25

How do you assess consciousness?

Answer 25

Glasgow Coma Scale - lower it is the worse, lowest is 3, but more for motor assessment AVPU - alert, verbal stimuli, painful stimuli, unresponsive

Question 26

What are the types of coma?

Answer 26

Brain death Vegetative state Locked in syndrome Recover wakefulness (happens at the end)

Question 27

What are the types of vegetative state?

Answer 27

Permanent | Minimally conscious state

Question 28

What are the centres for sleep?

Answer 28

Preoptic region of hypothalamus

Question 29

What are the 3 main categories of consciousness disorders?

Answer 29

``` Comatose State (asleep and unconscious) Vegetative State (awake and unconscious) Minimally conscious state (awake and some consciousness) ```

Question 30

What is a comatose state?

Answer 30

State of complete unresponsiveness in which patient lies with eyes closed and cannot be aroused to respond to any stimuli - transitional state which lasts for a few weeks and rarely longer than 1 month - Temporary State

Question 31

What is stupor?

Answer 31

Similar to coma but will respond to strong stimuli

Question 32

What is locked in syndrome?

Answer 32

State of unresponsiveness in which patient lies within eyes closed and cannot be aroused to respond appropriately to any stimuli - However patient retains eye movement only up and down and are fully conscious - Profound paralysis of everything

Question 33

What is the mechanism of locked in syndrome?

Answer 33

Primarily due to injury to ventral pons = CSP and CTB tract interruption = quadriplegia and anarthria (mute) - often misdiagnosed with coma/vegetative state - can communicate via e-tran frame/brain computer interface

Question 34

What are the important areas damaged in akinetic mutism?

Answer 34

Frontal Lobe Basal Ganglia Mesencephalothalamic regions

Question 35

What is akinetic mutism associated with?

Answer 35

Alzheimer's | Pick's

Question 36

What is minimally conscious state?

Answer 36

Severely altered consciousness in which there is definite but often subtle and inconsistent, behavioural evidence of self or environmental awareness

Question 37

How does minimally conscious state present?

Answer 37

- recognise verbal/gestural yes or no responses - provide simple verbal - follow simple commands - provide purposeful movements - often after passing through coma and vegetative state

Question 38

How does a confusional state present?

Answer 38

- interactive communication - amnesia/confusion - hypokinetic or agitated - labile behaviour - after recover

Question 39

How does post-confusional state present?

Answer 39

- resolution in amnesia/confusion - cognitive impairments in higher levels (attention, memory retrieval, executive functioning) - deficits in self awareness, social awareness, behavioural and emotional regulation - achieve functional independence in daily self care

Question 40

What is the prognosis of vegetative state?

Answer 40

- absent brain stem reflexes is poor prognosis - favourable if return of speech, spontaneous eye movements that can track objects, normal resting muscle tone, ability to follow commands - even if emerge from state = physical, intellectual and psychological problems for life

Question 41

What does prognosis of vegetative state depend on

Answer 41

Cause, severity, site of damage, duration and depth of consciousness

Question 42

Define wakefulness?

Answer 42

ability to have basic reflexes such as open eyes, cough, swallow suck

Question 43

What is awareness?

Answer 43

ability to carry out complex thought processes

Question 44

What is the function of the ascending reticular activating system?

Answer 44

- alerts/arousal | - involves number of structures in rostral brain stem, tegmentum, diencephalon and projections to cerebral cortex

Question 45

What are some future treatments?

Answer 45

- vagal stimulation (to activate pontine tegmentum/thalamo-cortical network)