CBT-I Sleep Physiology & Disorders 3 — Questions and Answers
Question 1: Which of the following best describes 'sleep efficiency' as used in CBT-I assessment?
- Hours of deep sleep divided by total time in bed
- Total sleep time divided by total time in bed, expressed as a percentage (Correct answer)
- Number of awakenings divided by total sleep time
- REM sleep percentage relative to NREM sleep
Correct answer: Total sleep time divided by total time in bed, expressed as a percentage
Sleep efficiency = (total sleep time ÷ time in bed) × 100, with 85% or above considered normal.
Question 2: Adenosine accumulation in the brain primarily promotes sleep by inhibiting which region?
- Ventrolateral preoptic area
- Basal forebrain wake-promoting neurons (Correct answer)
- Dorsal raphe nucleus
- Suprachiasmatic nucleus
Correct answer: Basal forebrain wake-promoting neurons
Adenosine inhibits wake-promoting neurons in the basal forebrain, thereby increasing sleepiness.
Question 3: A patient with narcolepsy type 1 would be expected to have low levels of which neuropeptide in cerebrospinal fluid?
- Melatonin
- Cortisol
- Orexin (hypocretin) (Correct answer)
- Serotonin
Correct answer: Orexin (hypocretin)
Narcolepsy type 1 is caused by loss of orexin-producing neurons, resulting in very low or absent CSF orexin levels.
Question 4: Which polysomnographic finding is characteristic of REM sleep?
- High-amplitude delta waves
- Sleep spindles and K-complexes
- Low-voltage mixed-frequency EEG with REMs (Correct answer)
- Vertex sharp waves
Correct answer: Low-voltage mixed-frequency EEG with REMs
REM sleep is characterized by a desynchronized, low-voltage mixed-frequency EEG pattern along with rapid eye movements and muscle atonia.
Question 5: In the two-process model of sleep regulation, Process C refers to:
- The homeostatic sleep drive
- The circadian rhythm of alertness (Correct answer)
- The cortisol awakening response
- Cognitive arousal before bedtime
Correct answer: The circadian rhythm of alertness
Process C is the circadian component that modulates alertness across the 24-hour day independent of prior sleep.
Question 6: Which sleep stage is associated with the consolidation of declarative (explicit) memory?
- Stage N1
- Stage N2
- Stage N3 (slow-wave sleep) (Correct answer)
- REM sleep
Correct answer: Stage N3 (slow-wave sleep)
Slow-wave sleep (N3) is critical for the consolidation of declarative memories, including facts and events.
Question 7: A patient reports vivid, frightening dreams accompanied by calling out and physically acting out the dream content. Which disorder does this suggest?
- Sleepwalking (somnambulism)
- Sleep terrors
- REM sleep behavior disorder (Correct answer)
- Nightmare disorder
Correct answer: REM sleep behavior disorder
REM sleep behavior disorder involves loss of normal REM atonia, causing people to physically enact dream content.
CBT-I Sleep Physiology & Disorders 3
Which of the following best describes 'sleep efficiency' as used in CBT-I assessment?