sleep stages and polysomnography Flashcards
(28 cards)
What is polysomnography (PSG)?
A reference standard sleep study measuring physiological signals to diagnose sleep disorders.
Who defined sleep as dynamic in 1989?
J Allan Hobson – “Sleep is a dynamic behaviour…”
What are the two main sleep states?
NREM (Stages N1, N2, N3) and REM (Stage R)
What is the order of sleep stages in a cycle?
N1 → N2 → N3 → REM
How long is one typical sleep cycle?
Around 90 minutes
What happens to N3 and REM across cycles?
N3 decreases, REM increases
What % of sleep is N2?
~50%
What stage has vivid dreams and muscle atonia?
REM sleep
Which stage has hypnic jerks and slow eye movements?
Stage N1
Which sleep stage is most restorative and releases GH?
Stage N3
What stage consolidates short to long term memory?
Stage N2
What is a hypnogram?
A graphical representation of sleep architecture over the night
What device measures brainwaves during sleep?
EEG (Electroencephalogram)
What does EOG measure?
Eye movements
What does EMG measure?
Muscle tone (especially under the chin)
What does ECG monitor?
Heart activity
What are sleep spindles associated with?
Memory consolidation during N2
What is an epoch in sleep scoring?
A 30-second segment of sleep data used to score sleep stages
Define REM latency.
Time from sleep onset to first REM stage
What is WASO?
Wake After Sleep Onset (periods of waking up after falling asleep)
What’s the gold standard sleep study type?
Type 1 Polysomnography (in-lab, attended, full PSG)
Which type of study is done at home with full PSG setup?
Type 2 sleep study
Which type measures breathing only, no EEG?
Type 3
What’s the minimal channel sleep screening study?
Type 4
