Assessment of Brain Fxn (Lecture 18) Flashcards
EEG measures electrical activity from neurons in what part of the brain?
cortex
what happens to the frequency of the wave forms in an EEG as you become less alert?
lower frequency
info that can be determined from an EEG
seizure risk look for areas of cortex dysfunction (ie Coma) diagnose herpes encephalitis evaluate fetal brain age brain death sleep studies
can you use an EEG to determine location of a specific function in the brain?
no
what is electrocerebral silence
brain death, no waves
advantages of EEG
gives info about what is going on in cerebral cortex at any given moment
no risks
disadvantages of EEG
info very general
only evaluate cortex
cannot give precise location
3 types of evoked potential
somatosensory (stimulate median nerve and measure somatosensory cortex)
auditory (listen to clicks and measure auditory cortex)
visual (focus on moving checker square and measure visual cortex)
what do evoked potentials tell you
info about activity in brain in response to specific stimuli (time it takes for response in brain)
how is a PET scan performed?
radioactive glucose injected into body
after ~1hr, images are taken
causes active areas of the brain to light up
advantages of fMRI
can detect small changes
disadvantages of fMRI
resolution is not good pt has to stay still cant use if pt has pacemaker or metal in body expensive loud
advanages of PET
more precise when combined with CT
substances other than glucose can be made radioactive
disadvantages of PET
injections required
VERY expensive
pt must be cooperative
