CPT1: EEG KC Flashcards
What does EEG stand for?
Electroencephalography
What is an EEG influenzed by?
State of aurosal. Shows changes in sleep stages
What does an EEG show?
- Slow changes in membrane potential of cortical neurons, especially Excitatoy/ inhibitory post synaptic potentials.
- Not really from AP propagating along axons
What do large amplitudes of synchronized activity of a large number of neurons reflex?
Activity in thalamus
What components make up the EEG wave?
- Alpha
- beta
- theta
- Delta
- Gamma
- What does the alpha wave represnet?
- What alters its activity
- What brain stucture is it thought to represent?
- Closed eyes and relaxed
- opening eyes or perfoming mental calculations decrease its activity
- Thought to indicate degree of cortical activation. More activation, lower the alpha activity
- What does the B wave represnet?
- When would it be reduced?
- In alert, awake individuals with their eyes open B wave is the most dominant wave
- In areas of coritcal damage the activity may be reduced or abcent
Can be assentuated by hypnotic/sedative drugs
What is theta waves associated with?
- Not present in awake adults, but normal in awake children
- Present in everyone when sleeping
- splt into low and high theta activty. High assoicated with memory tasks. Low associated with decreased arousal and increased drowsiness
When is delta wave most prominant/ not?
- dominant rhythm in sleep stages 3 and 4
- not seen in conscious adults
- prodcues highest amplitude (neck muscle and jaw movemtns produce same frequency)
What are gamma waves associated with?
- Higher mental acitviteis involving perception and consciousness
- reflexs me ntal activities involving objects to produce a coherent picture
- disapears in general anaesthesia and not present in schizophrenics
When interpretating the results of an EEG, what effect does amplitude and frequency have?
- The higher the frequency and lower the amplitude the greater the brain activity
- The lower the frequency and higher the amplitude the less the brain activity
What are the different sleepstages?
- REM (rapid eye movement)
- Non-REM - stage 1,2,3,4
goes from REM –> Non-REM and does repeative cycles of 90 mins
What happens to latter sleep cycles?
REM increases and stage 3/4 shorten
Which sleep stages are deep and which are light?
- 1&2 light
- 3&4 deep
What changes in EEG waves are assoicated with stage 1?
- decreasing beta activity, less obvious alpha activity and emergence of theta activity
What changes in EEG waves are assoicated with stage 2?
- Irregular theta waves and short bursts of sleep spindles (12-14Hz) and sudden increase in amplitude (K complex)
What happens do EGG in stage 3?
- Predominantly delta actvity
- delta activity present for less than 50% of time
What happens to the EGG in stage 4?
- Delta ctivity
What is the EGG waves like for REM? what is this state associated with?
like stage one but alpha and beta mising and dreming
What are secreted during:
- REM cycles
- Non-REM cycles
- Testosterone, corticosteriods, norephidrine
- seretonin
What signs are present in people in
- REM
- Non-REM
- Irregular breathing, variations in HR/ BP
- Decreased BP, HR, RR
What are the left and right side of the brain associated with?
- left logcial
- right creatice
What happens to alpha waves during listening to musci?
decreases
What is the amplitude of waves of an EEG compared to ECG and EMG. Why?
Less - measured through skull and CSF
