RST Practice Questions (2026) — Free Sample Questions with Answers

Answer: D

Low-frequency 0.3 Hz and high-frequency 35 Hz: These are the recommended settings for EEG and EOG, which need to show slow waves.

Low-frequency 0.1 Hz and high-frequency 15 Hz: These are typical of respiratory channels, not EMG.

Low-frequency 0.3 Hz and high-frequency 70 Hz: These are the recommended ECG filter settings.

Low-frequency 10 Hz and high-frequency 100 Hz: Correct. EMG is high-frequency muscle activity, so a 10 Hz low-frequency filter removes slow drift and a 100 Hz high-frequency filter preserves the muscle signal.

AASM filters: EEG/EOG 0.3–35 Hz; EMG 10–100 Hz; ECG 0.3–70 Hz; respiration (oronasal/belts) 0.1–15 Hz.

Answer: C

As soon as the first obstructive hypopnea occurs at the starting pressure: A single event at low pressure calls for a CPAP increase, not a mode change.

Whenever the patient enters REM sleep for the first time in the night: REM-related events are treated by continuing CPAP titration; REM alone is not a reason to switch.

If the patient cannot tolerate high CPAP or events persist at 15 cm H2O: Correct. BPAP may be tried if the patient is uncomfortable or intolerant of high CPAP, or if obstructive events continue at 15 cm H2O.

Only after reaching the maximum CPAP pressure of 30 cm H2O without success: The maximum recommended CPAP for adults is 20 cm H2O, and a switch can be considered at 15 cm H2O.

Consider BPAP for CPAP intolerance or persistent obstructive events at 15 cm H2O during the titration.

Answer: D

Obstructive apnea: An obstructive apnea has continued or increased effort throughout the entire event.

Central apnea: A central apnea has absent effort throughout the entire event.

Hypopnea: A ≥90% drop in the thermal signal meets apnea criteria, not hypopnea criteria.

Mixed apnea: Correct. A mixed apnea begins with absent effort and ends with resumed effort while airflow remains absent.

Apnea type by effort: continuous effort = obstructive; no effort = central; no effort first, then effort = mixed.

Answer: C

Stage N1: N1 may have slow, rolling eye movements but not rapid eye movements with atonia and sawtooth waves.

Stage N2: N2 is defined by K complexes or spindles, which are not described here.

Stage R: Correct. Low-amplitude mixed-frequency EEG, rapid eye movements and low chin tone define stage R; sawtooth waves are supportive.

Stage W: Wake shows alpha or eye blinks and reading movements with normal to high chin tone.

Stage R: low chin EMG + rapid eye movements + low-amplitude mixed-frequency EEG; sawtooth waves and transient muscle activity are common.

Answer: C

Mean sleep latency of 14 minutes with three SOREMPs: A mean sleep latency of 14 minutes is not short enough to support narcolepsy.

Mean sleep latency of 6 minutes with no SOREMPs: A short latency without SOREMPs is more consistent with idiopathic hypersomnia (if other criteria are met).

Mean sleep latency of 4 minutes with three SOREMPs: Correct. Narcolepsy requires a mean sleep latency of 8 minutes or less and at least two SOREMPs (a SOREMP on the preceding PSG can count as one).

Mean sleep latency of 18 minutes with one SOREMP: Both the latency and the number of SOREMPs fall short of narcolepsy criteria.

Narcolepsy MSLT: mean sleep latency ≤8 min + ≥2 SOREMPs. Type 1 also has cataplexy or low CSF hypocretin.

Answer: A

Cheyne-Stokes breathing: Correct. Cheyne-Stokes breathing is a crescendo–decrescendo pattern between central apneas or hypopneas, with a cycle length of at least 40 seconds, typical of heart failure.

Obstructive hypoventilation: Hypoventilation is a sustained rise in CO2, not cyclic central apneas with waxing and waning breathing.

Biot (ataxic) breathing: Ataxic breathing is irregular in timing and depth, seen with brainstem injury or opioids, without the smooth crescendo–decrescendo pattern.

Periodic breathing of infancy: Infant periodic breathing involves brief central pauses in newborns, not cycles of 60 seconds in an older adult with heart failure.

Cheyne-Stokes: ≥3 consecutive central events separated by crescendo–decrescendo breathing, cycle ≥40 s, plus ≥5 central events/h over ≥2 hours; strongly linked to heart failure.