EEG Sleep Staging and Sleep EEG 2

Question 1

A K-complex is defined as a well-delineated negative sharp wave followed by a positive component with a total duration of at least:

Accepted Answer

0.5 seconds

Answer

AASM criteria define a K-complex as a biphasic wave lasting ≥0.5 seconds, maximal over frontal regions.

Question 2

Hypnagogic hypersynchrony in children refers to:

Accepted Answer

High-amplitude 3–4.5 Hz rhythmic activity at drowsiness onset

Answer

Hypnagogic hypersynchrony is a normal pediatric variant of high-amplitude slow rhythmic activity seen during drowsiness that should not be mistaken for a seizure.

Question 3

Sleep spindles are generated primarily by thalamocortical circuits involving which thalamic nucleus?

Accepted Answer

Reticular nucleus of the thalamus

Answer

The thalamic reticular nucleus acts as a pacemaker for sleep spindles through rhythmic inhibitory postsynaptic potentials to relay nuclei.

Question 4

During a routine EEG, the patient closes his eyes and 10 Hz activity appears posteriorly. When he opens his eyes this activity disappears. This is consistent with:

Accepted Answer

Normal alpha rhythm with eye-opening attenuation

Answer

Alpha rhythm (8–13 Hz) generated in the occipital cortex is reactive to eye opening and represents a normal, awake, relaxed EEG finding.

Question 5

Which of the following best describes POSTS (Positive Occipital Sharp Transients of Sleep)?

Accepted Answer

Surface-positive sharply contoured occipital waves occurring in NREM sleep

Answer

POSTS are surface-positive sharp waves in the occipital regions during NREM sleep and are a normal variant that must not be misread as epileptiform activity.

EEG - Electroencephalography Practice Test

EEG - Electroencephalography Practice Test

EEG Sleep Staging and Sleep EEG 2