EEG and Sleep Flashcards
What is EEG and what is it used for?
Electroencephelogram, measures the pattern of brain activity, used to determine state of consciousness
What two electrical measurements are used to determine consciousness?
Amplitude = bigger wave is more synchronised cell activity Frequency = rate of fluctuation in the cells
What is the EEG reading like in the awake state?
Low amplitude
High frequency
When relaxed, these are inverted slightly
Why would amplitude be low in an alert brain?
amplitude = synchronicity
When busy, many different things going on, therefore not synched.
Why is amplitude large in synchronicity?
If the two actions have the same timing, they will be in the same direction ie peak-peak, therefore a kind of wave addition
Why is amplitude small in unsynchronised actions?
If they meet trough to peak, then the waves cancel each other out, reducing amplitude and increasing frequency, try and draw this to illustrate
What happens to the EEG in S-wave sleep?
Gradual increase in amplitude, smaller frequency.
This is as activity synchronises
Why is paradoxical sleep so named?
EEG reading is high frequency low amplitude, which is very like the awake state, which is paradoxical as you are asleep.
Describe the normal progression of an adults night sleep
Short REM period - increases throughout night
S-sleep starts deep (3/4) and gets shallower. (all 3/4 is first half of night)
What type of sleep is restorative and repairing?
stage 3/4 S-sleep
What happens to the amount of REM sleep per night as you age?
Decreases significantly, almost absent at around 80yrs.
Can be as high as 80% in premature infants.
What’s the definition of insomnia?
Chronic inability to obtain the necessary amount of sleep to maintain adequate daytime behaviour
What is REM behaviour disorder?
People do not have the motor shut off and so are free to act out their dreams in reality ie murder and serious accidents can occur
Are night terrors REM or nonREM phenomena?
Non REM
What stage of sleep is commonly associated with somnambulism?
Stage 4
What can trigger an episode of narcolepsy?
Strong emotional situations, such as laughter or during sex
What condition is dangerous due to an abrupt loss of muscle tone?
Narcolepsy
What transmitter has been linked to narcolepsy?
Low levels of orexin/hypocretin.
Potential area for treatment
