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
What are artifacts? Examples?
Signals which are non-cerebal in origin and generarated from the body or enviroment (e.g. electrical noise from equipment, facial or eye movements)
What happens to aloha wave amp and frequency during mental tasks?
amp decreased and frequency depleted
What does genurea of music do to alpha wave?
decrease amplitude
