RPSGT Sleep Disorders & Pathophysiology Flashcards

Which criterion best distinguishes idiopathic hypersomnia from narcolepsy type 1 on MSLT?

Answer: Mean sleep latency under 8 minutes with fewer than 2 SOREMPs

Idiopathic hypersomnia shows a mean sleep latency ≤8 minutes on MSLT with fewer than 2 sleep-onset REM periods, distinguishing it from narcolepsy which requires ≥2 SOREMPs.

Restless legs syndrome (RLS) is most closely associated with dysfunction in which physiological system?

Answer: Iron-dopamine metabolism in the basal ganglia and spinal cord

RLS pathophysiology involves impaired iron metabolism reducing dopaminergic function in the basal ganglia and spinal cord, explaining the response to dopaminergic medications.

A 35-year-old shift worker complains of inability to sleep at the right times and excessive sleepiness at work. Actigraphy over 14 days shows normal total sleep time but misaligned timing. What is the most likely diagnosis?

Answer: Shift work sleep disorder

Shift work sleep disorder is characterized by insomnia and/or excessive sleepiness caused by a work schedule that overlaps with the usual sleep period.

Which of the following is the minimum SpO2 threshold and duration used by AASM to score sleep-related hypoxemia in adults?

Answer: SpO2 below 88% for at least 5 minutes cumulative during sleep

Per AASM criteria, sleep-related hypoxemia in adults is scored when SpO2 is below 88% for ≥5 cumulative minutes during sleep.

In the pathophysiology of obstructive sleep apnea, which anatomical factor is the PRIMARY determinant of pharyngeal collapsibility?

Answer: Negative intraluminal pressure during inspiration relative to upper airway muscle tone

OSA occurs when inspiratory negative intraluminal pressure exceeds the capacity of pharyngeal dilator muscles (especially genioglossus) to maintain airway patency.

A patient's PSG shows frequent brief arousals after each PLMS. Which AASM rule governs whether a PLMS-associated arousal is scored?

Answer: The arousal must begin within 2 seconds of PLMS onset and last at least 3 seconds

AASM rules score a PLMS-associated arousal when the arousal begins no more than 2 seconds before or after PLMS onset (not termination) for limb movements ≥0.5 seconds.

Which feature on PSG distinguishes central sleep apnea from obstructive sleep apnea during an apnea event?

Answer: Absence of respiratory effort on thoracic and abdominal channels during airflow cessation

Central apneas are scored when both respiratory effort channels (thoracic and abdominal) show absent effort throughout the entire airflow cessation, unlike obstructive events which maintain effort.