EEG Basics Flashcards
What does an EEG record ?
Post-synaptic potentials (majority), action potentials and chronic neuronal depolarization but most likely the voltage of the EC matrix.
Two types of Post-synaptic potentials
Inhibitory and Excitatory
What is the PDR
posterior dominant rhythm is the basic rhythmic frequency of the normal awake adult brain.
What leads to rhythmic cortical activation
thalamic pacemaker cells.
Potential fields are ___ in shape and have a ____ effect.
oval/ripple.
Bipolar Recording: If input 1 is negative with respect to input 2 the deflection is
upward
If input 2 is negative with respect to input 1 the deflection is ?
downward
Bipolar recording
two successive electrodes are compared
Three types of montages
double bannana, transverse, circumferential
Multifocal definition
discharge in more than 3 non-contiguous leads and two different hemispheres
Impedence should not exceed
5 kohms
Standard sensitivity and brain death criteria
7 microvolts should be turned down to 2 for brain death criteria.
Purpose of notch filter
set at 60hz to block out electronic devices.
Gamma, beta, alpha, theta and delta frequencies
> 30, 13-30, 8.5-13, 4-8.5, and 0-4
Acceptable asymmetry of PDR
2:1
Stage 1 sleep: 2 features
vertex waves and POSTs
Stage 2 sleep: 2 features
sleep spindles and k-complexes
Def of a slow PDR
<8.5 hz
Def sleep spindles
sinusoidal, synchronous and at 12-14 hz
Def of k-complexes
bi/triphasic waves >500ms
4 normal variants
alpha, mu, lambda, 14/6
Define alpha variants
half to double the PDR is okay
define mu rhythm
se over c3/c4 (motor strip, attenuates with movement of the opposite limb
define lambdas
electropositive transients in occipital regions
