Consciousness Flashcards
What term describes a state of wakefulness + awareness of self and environment?
Consciousness
What is interoception?
The perception of sensations from inside the body e.g. sensing your own breathing, heart beat or internal pain.
Where is interoception controlled in the brain?
Anterior Insular Cortex with involvement from Von Economo neurons
How long would someone be unconscious for, for it to be classed as a coma?
6 hours
Which cycle is not present in a coma?
Sleep-wake cycle
What is a doll’s head manoeuvre and when would it be used?
To test for Oculocephalic reflex in a coma to assess the brainstem.
Patients head is moved quickly from side to side to see if pupils stay fixed or move - If no movement can suggest brain stem damage.
What are some common causes of impaired consciousness?
Neurological; Trauma, CVA, Infection
Metabolic; Hypoglycaemia, Hypoxia, Drugs + Toxins
What is GCS?
Glasgow Coma Score
Scoring system used to assess consciousness.
What is the lowest and highest score on a GCS?
3
15
At what score on a GCS would someone not be able to protect their airway?
<8
What categories are assessed in a GCS?
Eye opening
Best verbal response
Best motor response
Which questionnaires can be used to measure cognitive impairment and screen for dementia, delirium and confusion?
MMSE (mini-mental state examination)
CAM (confusion assessment method)
4AT (4 A’s Test)
What is syncope?
A temporary loss of consciousness, usually attributed to a neuro/cardiogenic cause.
What is orthostatic syncope?
Syncope related to posture - usually when someone stands from a sitting or laying position.
What is neurocardiogenic syncope?
‘Vasovagal’
Body overreacts to a trigger e.g. emotional response, heat, pain.
Carotid sinus syndrome can cause syncope. What is this?
An activity that puts pressure on the carotid sinus, causing syncope. Usually a neck movement.
Which parts of the brain are thought to be correlated with consciousness?
Posterior cortical ‘hot zone’ in cerebral cortex of parietal, occipital and temporal regions.
‘Global neuronal workspace’
What is the global neuronal workspace?
Information processing where neurons from multiple areas of the brain integrate + can have access to the same information.
Which theory suggests consciousness is a product of a highly complex and integrated nature of the brain’s structure?
Integrated information theory
What is the most densely connected structure in the brain and is thought to be involved with consciousness?
Claustrum
General anaesthetics suppress brain activity in what area?
Intralaminar thalamic nuclei
Which system located in the brain stem regulates sleep-wake cycles and behaviour?
Reticular activation system
Which anatomical regions of the brain are involved in consciousness?
Midbrain
Pons
Hypothalamus
Basal Forebrain
Anterior Cingulate Cortex
Which form of consciousness would involve someone having a preserved sleep/wake cycle, but with minimal awareness?
Minimally conscious state
If someone is in a vegetative state, would they be able to produce any response?
Vegetative patients have wakefulness but absent awareness.
There is capacity for spontaneous or stimulus induced arousal, shown through reflexive responses.
fMRI showed some activity when vegetative patients were asked to think about playing tennis (motor) or walking around their house (spatial navigation).
After brain stem death, can any function be restored?
No - brain stem death is permanent + means the loss of all brainstem functions.
For brain stem death to be diagnosed, what brain stem testing is undertaken?
Pupillary response
Corneal reflex
Motor response (elicit pain)
Oculovestibular response (cold water injected into ear. No eye movement = dead)
Gag + cough reflex
Apnoea testing - take off ventilator, see if Co2 rises.
Before diagnosing brain stem death, what conditions need to be excluded?
Any reversible cause of the coma
Pharmacology, temperature, endocrine, metabolic, cardiovascular.
What is locked in syndrome?
Someone has normal wakefulness and awareness but they are unable to respond.
There is loss of voluntary control of movement, but sometimes they are able to communicate using eye movements/blinking.
What tools can be used to evaluate neurological function?
EEG (Surface electroencephalogram)
SPECT
PET
fMRI
Which activities have been associated with syncope?
Exercise
Cough
Swallow
Defecation
Orgasm
What is AVPU?
Used to assess consciousness.
Alert
Voice
Pain
Unresponsive
