RPSGT Sleep Disorders & Pathophysiology Flashcards

Which polysomnographic finding is most characteristic of REM sleep behavior disorder (RBD)?

Answer: REM sleep without atonia (RSWA)

RBD is defined by the loss of normal REM muscle atonia, resulting in REM sleep without atonia on chin EMG.

In a patient with suspected upper airway resistance syndrome (UARS), which finding differentiates it from simple snoring?

Answer: Esophageal pressure swings with EEG arousals but no apneas

UARS is characterized by increased respiratory effort detected via esophageal manometry causing arousals without discrete apneas or significant desaturations.

A patient with Cheyne-Stokes respiration most commonly has which underlying condition?

Answer: Congestive heart failure

Cheyne-Stokes respiration is most commonly associated with congestive heart failure due to prolonged circulation time causing oscillating ventilatory drive.

Which sleep disorder is associated with the HLA-DQB1*06:02 allele in over 90% of cases?

Answer: Narcolepsy type 1

Narcolepsy type 1 (with cataplexy) shows a strong HLA-DQB1*06:02 association, reflecting its autoimmune destruction of hypocretin neurons.

During a PSG, a patient's airflow signal shows a crescendo-decrescendo pattern lasting 60 seconds cycling every 90 seconds. What is the most likely scoring?

Answer: Central sleep apnea with Cheyne-Stokes breathing pattern

The waxing-and-waning crescendo-decrescendo breathing with a cycle length typically 45–90 seconds is the hallmark of Cheyne-Stokes breathing.

Which neurotransmitter system is primarily implicated in the pathophysiology of narcolepsy type 1?

Answer: Hypocretin/orexin neurons in the lateral hypothalamus

Narcolepsy type 1 results from autoimmune loss of hypocretin (orexin)-producing neurons in the lateral hypothalamus, causing CSF hypocretin-1 levels below 110 pg/mL.

A patient is diagnosed with sleep-related hypoventilation. Which PSG parameter is most directly used to confirm this diagnosis?

Answer: End-tidal or transcutaneous CO2 exceeding 55 mmHg for more than 10 minutes

Sleep-related hypoventilation is confirmed by CO2 monitoring showing PaCO2 or surrogate (ETCO2/TcCO2) >55 mmHg for ≥10 minutes during sleep.