Dysfunction of Consciousness Flashcards
Arousal
Physiological state of being alert and awake
Awareness
Being responsive to stimuli
Disorders of consciousness
Alteration in arousal and awareness
3 scales to differentiate between conscious states
Wakefulness: alert and responsive
Awareness: consciousness of environment and self
Ability to produce motor behaviour
Coma
No awareness/wakefulness
Absence of arousal/awareness
No eye opening after stimulation
No verbal responses, no motor responses
Causes of Coma and damage to which part of brain?
Variety of injuries
Bihemispheric lesions, bilateral lesions of pons, widespread dysfunction in corticothalamic system
Causes of injury for coma
TBI, stroke, global decrease in blood flow to brain following cardiac event, seizure
Dysfacilitation
Resting membrane potential becomes negative in cortex, thalamus, and striatum
Due to the absence of excitatory synaptic input, there is less neuron activity
UWS (unresponsive wakefulness syndrome)
No awarenss, but awake
vegetative state
Preserved physiological functions without clear signs of awareness of the self or the environment
only reflexive behaviours
Teri Schiavo
Wake/sleep, gag, and swallowing response, but no awareness
Expert consensus that she could not recover
Ethics for this situation is typically a huge debate. She died when husband won the legal battle to withdraw interventions
Cognitive motor dissociation
Brain activity is found when trying to do functional tasks, but no irl actions. this demonstrates intentionality and awareness
Covert consciousness or “locked-in syndrome”: volitional brain activity is detectable by imaging with no external behaviour
How to detect covert consciousness
EEG or fMRI
aroudn 20% of people have covert consciousness although they appear unaware
Minimally conscious state
Minimal and inconsistent awareness
shows some oriented behaviours not attributable to reflexes
MCS+ (with language)
MCS- (without language)
How is consciousness assessed?
Glasgow coma scale
simple standardized way to evaluate patients with brain injury
Eyes, verbal, motor
Reponse to stimuli in glasgow coma scale
Eyes: spontaneous to none
Verbal: oriented to none
Motor: obey command to none
Treatments for DoC
Treatment with RCT evidence right now is amantadine 4-16 weeks after injury
experimental therapies being tested (management of pain and complications)
Moral Questions
How should the people with DoC be handled?
Personhood is brought into question because the person cannot speak for themselves
