T1 L14: Consciousness Flashcards
What us the Glasgow coma scale?
A clinical scale used to reliably measure a person’s level of consciousness after a brain injury
Give examples of disorders of consciousness
Sleep Psychedelic states General anaesthesia Coma PVS (persistent vegetative state) MCS (minimal conscious state) Locked in Syndrome
What is a Psychedelic state?
A temporary altered state of consciousness induced by the consumption of a psychedelic substance (most commonly LSD, mescaline, psilocybin mushrooms, or DMT)
Which types of waves are present in deep sleep?
Low frequency waves
What are some causes of coma?
Sedation (anaesthesia) Epilepsy Electrolyte/metabolic imbalance Disturbance of thermoregulation Raised intracranial pressure Structural damage to the brainstem/thalamus/cortex caused by: Stroke, Trauma, Tumour, Inflammation, or Infection
What is the definition of a coma?
Complete prolonged loss of wakefulness and unresponsiveness to external stimuli. It’s often reversible
What are some causes of metabolic coma?
Hepatic, Uraemia, Diabetic, Pancreatic, Adrenocorticoid failure
What is Triphasic theta?
Abnormal EEG waves indicating some pathologies like toxic, metabolic, and structural abnormalities
They appear as non-specific, high amplitude, sharply contoured waves with a unique morphology
What does the Glasgow coma scale include?
Eyes, verbal, and motor responses
The lowest you can get is 3 and the highest is 15.
What does absent eye-opening distinguish between?
Coma/brainstem death from PVS and MCS
What is a vegetative state characterised by?
When a person is awake but is showing no signs of awareness. They have no voluntary response to the environment
What is the time frame for a persistent vegetative state?
> 4 weeks
What is the time frame for a permanent vegetative state?
6 months (UK) 3 months (US)
1 year after a traumatic brain injury
What is unresponsive wakefulness syndrome (UWS)?
Describes patients who fail to show voluntary motor responsiveness in the presence of eyes-open wakefulness. It’s not yet fully defined
What is a minimal conscious state characterised by?
It's like a vegetative state by has one of the 11 following: Consistent movement to command Reproducible movement to command Object recognition Object localisation Reaching Visual pursuit Fixation Automatic motor response Object manipulation Localisation to noxious stimulation Intelligible but non-functional verbalisation
In an experiment, how was a vegetative state detected?
The participants were asked to imagine playing tennis and then imagine walking around their house. Different areas of the brain would light up
What is locked in syndrome characterised by?
Aroused and awake but unable to respond. These people can only move their eyes up and down but not horizontally
What causes locked in syndrome?
Ventral pontine damage or Severe Guillain-Barre syndrome
What is ventral pontine damage?
A type of bilateral damage to the pons
What is Guillain-Barre syndrome?
An acute disorder of the peripheral nerves, often preceded by a respiratory infection, causing weakness and often paralysis of the limbs. Most people will recover from it within a year
Which reflexes are absent in brainstem death?
Pupils Ice Caloric Corneal Pain Gag Cough
What are some legalities behind taking someone off life support?
- There must be a presence of an irreversible cause (Eg. Anoxia, Structural damage)
- There must be an absence of reversible causes (Eg. drugs, hypothermia, alcohol, poisons)
- There must be irreversible cessation of function of the brainstem, cerebral cortex, or the body
What are Von Economo neurons?
Have a large spindle-shaped soma. They have a single dendrite facing opposite
Where are Von Economo neurons found?
Only in the anterior cingulate cortex (ACC) and Fronto-insular cortex (FI)
