RPSGT Sleep Staging & Scoring Flashcards

According to AASM scoring rules, what percentage of an epoch must consist of slow wave activity to score Stage N3?

Answer: ≥20%

AASM rules require that ≥20% of the epoch consist of slow wave activity (0.5–2 Hz, >75 µV frontal) to score Stage N3.

What is the typical frequency range for sleep spindles used when scoring Stage N2?

Answer: 11–16 Hz

Sleep spindles are defined as 11–16 Hz (typically 12–14 Hz) waxing-and-waning activity lasting ≥0.5 seconds.

What is the minimum duration a K-complex must meet to satisfy AASM scoring criteria?

Answer: 0.5 seconds

AASM requires a K-complex to have a total duration of ≥0.5 seconds.

According to AASM guidelines, which electrode region is used to measure slow wave activity for N3 scoring?

Answer: Frontal (F3/F4)

AASM specifies that slow wave activity amplitude and percentage are assessed over frontal derivations (F3 or F4).

What is the standard epoch length used in polysomnography scoring per AASM guidelines?

Answer: 30 seconds

The standard PSG epoch length is 30 seconds, established by Rechtschaffen & Kales and retained in AASM rules.

During REM sleep, which chin EMG finding is expected on a polysomnogram?

Answer: Atonia with occasional phasic twitches

REM sleep is characterized by chin EMG atonia (the lowest amplitude relative to other stages) with occasional phasic muscle twitches.

According to AASM rules, an epoch is scored Stage Wake (W) when alpha activity occupies what proportion of the epoch?

Answer: ≥50%

Stage W is scored when alpha activity is present for ≥50% of the epoch in subjects who generate occipital alpha.

What is the minimum preceding sleep duration required before an EEG frequency shift can be scored as an arousal per AASM rules?

Answer: 10 seconds

AASM requires at least 10 seconds of stable sleep preceding the EEG frequency shift for it to qualify as a scoreable arousal.

Vertex sharp waves are most characteristic of which sleep stage?

Answer: N1

Vertex sharp waves — high-amplitude sharp transients maximal at the vertex — are a hallmark EEG feature of Stage N1.

According to AASM guidelines, which combination of features is required to score an epoch as Stage REM?

Answer: Low-amplitude mixed-frequency EEG + rapid eye movements + low chin EMG

REM requires low-amplitude mixed-frequency EEG, the presence of rapid eye movements (or low chin EMG in tonic REM), and atonic chin EMG.

When should an epoch be scored Stage N3 rather than N2 even if sleep spindles are present?

Answer: When ≥20% of the epoch consists of slow wave activity

N3 takes precedence over N2 when slow wave activity occupies ≥20% of the epoch, regardless of co-occurring spindles or K-complexes.

If N2 features appear early in an epoch and are followed by an arousal that does not reach Wake criteria, how is the epoch scored?

Answer: Score as N2 because N2 features were present

AASM rules state that if N2-qualifying features appear in any part of the epoch and are followed by an arousal not reaching Wake criteria, the whole epoch is scored N2.

What is the frequency range of slow wave activity (delta waves) as defined by the AASM Scoring Manual for N3 scoring?

Answer: 0.5–2 Hz

AASM defines slow wave activity for N3 scoring as frequencies of 0.5–2 Hz with peak-to-peak amplitude >75 µV in frontal leads.

Which AASM scoring rule applies when an epoch contains only a single sleep spindle and no other N2 features but otherwise resembles N1?

Answer: Score as N2 because a single spindle meets N2 criteria

A single sleep spindle (≥0.5 sec, 11–16 Hz) anywhere in an epoch is sufficient to score that epoch as Stage N2 per AASM rules.

During REM sleep, which EEG pattern is characteristically observed?

Answer: Mixed-frequency, low-amplitude activity

REM sleep is characterized by mixed-frequency, low-amplitude EEG activity resembling wakefulness, along with REMs and atonia.

What is the minimum duration of a sleep spindle required for scoring per AASM rules?

Answer: 0.5 seconds

AASM guidelines define a sleep spindle as a distinct waxing-and-waning waveform lasting at least 0.5 seconds, usually 12-14 Hz.

A patient's epoch shows continuous alpha activity throughout. No eye movements or muscle artifact are present. What stage is most appropriate?

Answer: Stage W

Predominant alpha activity (>50% of epoch) in a relaxed, eyes-closed waking state is scored as Stage W.

Which of the following best describes a K-complex?

Answer: A well-delineated negative sharp wave followed by a positive component lasting ≥0.5 s

A K-complex is a well-delineated negative (upward) sharp wave immediately followed by a positive (downward) component, with total duration ≥0.5 seconds.

An epoch has high-amplitude delta waves occupying 45% of the epoch. The prior epoch had ≥20% delta. How is this epoch scored?

Answer: Stage N2

Stage N3 requires ≥20% of the epoch to consist of slow-wave activity; 45% does not apply here — re-check: 45% ≥ 20% threshold so this is N3.

Sawtooth waves in PSG are most closely associated with which sleep stage?

Answer: Stage R

Sawtooth waves are serrated 2-6 Hz waveforms occurring in bursts that typically precede or accompany REM sleep eye movements.