EEG Sleep Staging and Sleep EEG

Question 1

Which EEG feature is the hallmark of Stage N2 sleep?

Accepted Answer

Sleep spindles and K-complexes

Answer

Stage N2 sleep is defined by the presence of sleep spindles (12–14 Hz bursts) and K-complexes on EEG.

Question 2

What percentage of total sleep time must be occupied by high-amplitude delta activity to score Stage N3?

Accepted Answer

30% or more

Answer

AASM scoring criteria require that delta waves (0.5–2 Hz, >75 µV) occupy 20% or more of the epoch to score N3, though older criteria used 20% for N3 staging; current AASM requires >20% per epoch.

Question 3

Sawtooth waves during REM sleep are best described as:

Accepted Answer

Sharply notched 2–6 Hz theta waves maximal over central regions

Answer

Sawtooth waves are notched, sharply contoured theta-range (2–6 Hz) waves seen over central leads during REM sleep.

Question 4

Which sleep stage is characterized by a low-amplitude, mixed-frequency EEG without sleep spindles, K-complexes, or delta waves?

Accepted Answer

N1

Answer

N1 is the lightest NREM stage showing low-voltage, mixed-frequency activity and vertex sharp waves, but lacking spindles and K-complexes.

Question 5

Vertex sharp waves (V-waves) are most prominent during which sleep stage?

Accepted Answer

N1

Answer

Vertex sharp waves are surface-negative transients maximal at Cz that appear during N1 sleep as a normal feature.

EEG - Electroencephalography Practice Test

EEG - Electroencephalography Practice Test

EEG Sleep Staging and Sleep EEG