CBT-I Sleep Restriction & Stimulus Control Therapy 1 — Questions and Answers
Question 1: What is the primary mechanism by which sleep restriction therapy improves sleep in patients with chronic insomnia?
- It increases melatonin production by limiting artificial light exposure before bed
- It builds homeostatic sleep pressure by restricting time in bed to match actual sleep time (Correct answer)
- It trains the brain to fall asleep faster through classical conditioning of the sleep environment
- It reduces cortisol levels by establishing a consistent, earlier bedtime
Correct answer: It builds homeostatic sleep pressure by restricting time in bed to match actual sleep time
Sleep restriction builds homeostatic sleep drive (Process S) by limiting TIB to match actual TST, creating sleep pressure that consolidates and deepens sleep over time.
Question 2: In sleep restriction therapy, how is the initial time in bed (TIB) prescription typically determined?
- It is set to exactly 6 hours for all patients regardless of baseline data
- It is based on the patient's subjective report of how much sleep they feel they need
- It is set equal to the patient's average total sleep time derived from a 1-2 week sleep diary (Correct answer)
- It is calculated by subtracting reported sleep latency from the patient's desired bedtime
Correct answer: It is set equal to the patient's average total sleep time derived from a 1-2 week sleep diary
Initial TIB is individualized by matching it to the patient's average TST from a baseline sleep diary, ensuring time in bed reflects actual sleep obtained.
Question 3: How is sleep efficiency (SE) correctly calculated in CBT-I protocols?
- Total time in bed divided by total sleep time, multiplied by 100
- Total sleep time divided by time in bed, multiplied by 100 (Correct answer)
- Wake after sleep onset divided by total sleep time, multiplied by 100
- REM sleep time divided by total sleep time, multiplied by 100
Correct answer: Total sleep time divided by time in bed, multiplied by 100
SE = (TST ÷ TIB) × 100; it measures the percentage of time in bed that is actually spent asleep, serving as the primary indicator for titrating TIB.
Question 4: What is the minimum time in bed (TIB) typically prescribed during sleep restriction therapy to protect patient safety?
- 4 hours
- 5 hours (Correct answer)
- 6.5 hours
- 7 hours
Correct answer: 5 hours
A floor of 5 hours TIB is maintained in standard sleep restriction protocols to prevent the excessive sleep deprivation that could impair daytime functioning or driving safety.
Question 5: According to standard sleep restriction protocols, under what condition should a patient's TIB be increased?
- When the patient reports feeling well-rested upon awakening on most mornings
- When sleep efficiency exceeds 85% for approximately five of seven nights (Correct answer)
- After completing a fixed two-week period at the initial TIB prescription
- When total sleep time increases by more than 45 minutes from the baseline diary
Correct answer: When sleep efficiency exceeds 85% for approximately five of seven nights
TIB is expanded when SE consistently exceeds 85%, indicating that sleep has consolidated sufficiently to allow gradual extension of the sleep window.
Question 6: What is the recommended increment for expanding TIB when sleep efficiency criteria are met in sleep restriction therapy?
- 60 to 90 minutes per week
- 15 to 30 minutes per week (Correct answer)
- 5 to 10 minutes per night
- 1 full hour every two weeks
Correct answer: 15 to 30 minutes per week
Standard protocols increase TIB by 15-30 minutes per week when SE ≥85%, allowing gradual adjustment while preserving the sleep consolidation achieved.
Question 7: A patient's sleep diary shows an average total sleep time of 5.5 hours and an average time in bed of 8 hours. What is their sleep efficiency?
- 55%
- 69% (Correct answer)
- 75%
- 82%
Correct answer: 69%
SE = (5.5 ÷ 8) × 100 = 68.75%, approximately 69%, indicating poor sleep efficiency and a strong candidate for sleep restriction therapy.
CBT-I Sleep Restriction & Stimulus Control Therapy 1
What is the primary mechanism by which sleep restriction therapy improves sleep in patients with chronic insomnia?