Consciousness Flashcards
What is Locked-in syndrome?
Person appears unconscious, but actually has complete awareness but an inability to respond.
Person goes through sleep-wake cycles which can be measures on an ECG, and may make some isolated meaningful movements e.g eye movements.
What is a minimally conscious state?
Patient has intermittent periods of wakefulness and sleep, and displays some meaningful behaviour.
What is a persistent vegetative state?
Patient lacks awareness, but goes through sleep-wake cycles.
The patient will only display reflexive and non-purposeful behaviour.
What is a chronic coma?
The patient lacks awareness and lacks sleep-wake cycles. The patient only displays reflexive behaviour.
What is brain death?
Patient lacks awareness, lacks sleep-wake cycles, lacks brain-stem reflexes and only has spinal reflexes.
The patient has lost the ability to ever regain consciousness and has lost the capacity to breathe on their own.
How do PET scans measure brain activity, and what particular consciousness disorder can they be used to show?
The patient is injected with radioactive glucose, and the brain takes up a lot of glucose so this can be used to show brain activity. Where the glucose is taken up it releases positrons.
Areas of higher brain activity are warmer colours (orange and red). Areas of lower brain activity are cooler colours (green, blue, black).
Locked-in syndrome can be shown when a patient with no outward signs of awareness has lots of brain activity.
What is normal loss of consciousness?
Going to sleep.
What does AVPU mean when you are assessing someone’s consciousness?
Awake?
Respond to verbal stimuli?
Respond to painful stimuli?
Completely unresponsive?
What is the maximum and minimum score on the Glasgow Coma Scale?
Max = 15 Min = 3
What are the three categories of the Glasgow Coma Scale?
Best eye response
Best verbal response
Best motor response
What are the scores available in best eye response?
4 = spontaneous eye opening 3 = eye opening in response to speech 2 = eye opening in response to pain 1 = no response
What are the scores available in best verbal response?
5= orientated 4 = confused conversation 3 = inappropriate speech 2 = incomprehensible speech 1 = no verbal response
What are the scores available in best motor response?
6 = obeying command 5 = localising response to pain 4 = withdraws from pain 3 = abnormal flexor response to pain 2 = extensor posturing to pain 1 = no response to pain
What does a GCS score more than 9 mean?
You’re not in a coma?
What is true of 90% of patients with a GCS score less than or equal to 8?
They are in a coma
What is meant by a GCS score between 9 and 11?
Moderately severe injury?
What is meant by a GCS score above or equal to 12?
Minor injury.
What is the definition of brain death?
Patient has irreversibly lost the capacity for consciousness and the capacity to breathe on their own.
What are the 3 NHS criteria for brain death?
1) person is unconscious and not responding to outside stimulation
2) person’s heartbeat and breathing can only be maintained by a ventilator
3) there is clear evidence that serious brain damage has occurred, so the unconsciousness isn’t being caused by primary hypothermia, depressant drugs, circulatory or metabolic or endocrine disturbances, apnoea caused by muscle relaxants or cervical cord injury, which are all potentially reversible
What are some of the reflexes tested when diagnosing brain death?
Pupillary reflex (shine light in eye)
Corneal reflex (stroke cornea with cotton bud, do they blink?)
Vestibulo-ocular reflex (ice cold water in ear, eyes move?)
Gag reflex (stimulate posterior pharynx, or catheter into trachea)
Respiratory (breathe on their own within 5 minutes of ventilator being disconnected?)
What is the Reticular Activating System?
Top part of the reticular formation in the brainstem, involved in consciousness.
Define consciousness.
The state of being both aware of and responsive to your surroundings.
What are the 4 sets of nuclei in the reticular formation, their locations and their neurotransmitters?
1) Locus coeruleus - noradrenaline, in the pons
2) Raphe nuclei - midline of midbrain and pons and medulla, serotonin
3) Ventral tegmental area - ventral region of the midbrain, dopamine
4) Cholinergic nuclei - in the basal forebrain and dorsolateral pons, acetylcholine
Which of the reticular formation nuclei contribute to synaptic plasticity and are involved in learning and memory?
Cholinergic nuclei
