Disorders on Consciousness (oct 16) Flashcards
Differentiate between different conscious states: coma, vegetative state, minimally conscious state.
coma - unaware/unwakeful
unresponsive wakeulness syndrome - unaware but wakeful
- minimally conscious state - awake and minimally and inconsistently aware.
Describe the prognosis for different disorders of consciousness
coma- very unlikely to come out of
unresponsive wakefulness syndrome - 66%-90% improve consciousness but usually only to a minimally conscious state.
cognitive motor dissociation- once UWS insues 80% of those with CMD improve consciousness ususally to a minimally conscious state.
minimally conscious state - more likely to recover but still unlikely.
Permanent severe disability is still the best outcome for most.
What is the definition for our class of disorders of consciousness
Alternations in arousal and/or awareness
Arousal: physiological state of being alert and awake.
Awareness: being responsive to stimuli (beyond reflexes)
Where is coma on the arousal and awake scales?
No arousal and no wakefulness.
what are some injuries that can cause a coma?
- bihemispheric lesions (both side of the cortex)
- bilateral lesions of pons (where white matter tracts connect)
- widespread dysfunction affecting corticothalamic system
- other combinations of brainstem structures
What are some possible causes of the injury that induce comas
- TBI, stroke (ischemic, hemorrhagic), global decrease in blood flow to the brain following a cardiac event, seizure, sedating medication.
What is the key component that causes coma from the injuries/causes of the injuries?
Widespread downregulation of neural firing resulting in disfacilitation. Resting membran potential becomes more negative (hyperpolarizes) more than -75. In cortex, thalamus, and striatum (component of basal ganglia)
where does unresponsive wakefulness syndrome land on the arousal and wakefulness scale?
they have arousal but not awareness. They have preserved physiological functions without clear signs of awareness of the self or enviroment. Only use reflexive behaviours e.g., pushing away pain or following something with their eyes.
What is cognitive motor dissociation?
it is when the patient is awake and aware but has no behavior/movement. can be called locked in syndrome, wakefulness and awareness can only be found in brain imaging showing activity. Some amount estimated at 20% of thos who appear unaware.
How can we tell someone has cognitive motor dissociations?
via EEG or fMRI we can see brain activity. However this isnt standard practice in canada yet.
What is minimally conscious state, where is it on the aware and wakeful scale?
Awake but minimal and inconsistent awareness. MCS+ are people with language - is without.
what is the Glasgow coma scale?
simple, standardized way to evaluate the level of consciousness of the patients with brain injury.
what are the 3 parts of evaluation of the Glasgow coma scale? what does a 3/3 mean?
- eyes - spontaneous, to sound, to pressure, none.
- verbal - orientated, confused, words, sounds, none
- motor - Obey command (2 steps), localizes (reacts to pinch), normal flexion (indirection of stimulus), abormal flexion, extension, none.
if you score none on all of them ten you get a 3/3 meaning no consciousness
What are treatment options for those with DoC’s
only one with evidence is amantadine (drug that promotes dopamine signaling) 4-16 weeks after injury.
some therapies being trialed: anti-inflammatories, deep brain stimulation of thalamus (implanted electrodes), rTMS
