Core Concepts & Fundamentals Flashcards

K-complexes are characteristic of which sleep stage?

Answer: Stage N2

K-complexes are the defining EEG feature of Stage N2, appearing as sharp negative deflection followed by a positive component.

What is the standard low-frequency filter (LFF) setting typically used for EEG channels in PSG?

Answer: 0.3 Hz

A low-frequency filter of 0.3 Hz is the standard for EEG to preserve slow-wave components while removing DC drift.

The international 10-20 electrode placement system gets its name from what?

Answer: The 10% and 20% intervals measured between skull landmarks

Electrode positions are placed at 10% and 20% intervals between four skull landmarks (nasion, inion, and preauricular points).

During REM sleep, which of the following is NOT typically observed?

Answer: Sleep spindles

Sleep spindles are a feature of NREM sleep (N2) and do not occur during REM sleep.

What is the typical duration of a sleep spindle?

Answer: 0.5–3 seconds

Sleep spindles last 0.5–3 seconds and appear as waxing-and-waning oscillations at 11–16 Hz.

In PSG, the EOG channels are used primarily to detect which event?

Answer: Eye movements associated with sleep stages

Electro-oculography (EOG) records eye movements that help distinguish REM from NREM and wakefulness.

Which brain region is considered the master circadian pacemaker in humans?

Answer: Suprachiasmatic nucleus (SCN)

The suprachiasmatic nucleus in the hypothalamus is the primary circadian clock, synchronizing to light-dark cycles.