ABDSM FINAL EXAM - DENTAL SLEEP MEDICINE 300
PRACTICE QUESTIONS WITH ANSWERS AND
RATIONALES
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SECTION 1: SLEEP PHYSIOLOGY & NEUROBIOLOGY (Questions 1-50)
Question 1
Which stage of sleep is characterized by delta waves with amplitude >75 μV
and frequency 0.5-2 Hz?
A. N1 (Stage 1)
B. N2 (Stage 2)
C. N3 (Stage 3/Slow-wave sleep)
D. REM sleep
Correct Answer: C
Rationale: N3 (slow-wave/deep sleep) is characterized by high-amplitude
(>75 μV), low-frequency (0.5-2 Hz) delta waves. This stage represents the
deepest non-REM sleep and is essential for physical restoration, growth
hormone release, and memory consolidation.
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Question 2
,What is the typical duration of a complete sleep cycle in adults?
A. 30-45 minutes
B. 60-75 minutes
C. 90-110 minutes
D. 120-150 minutes
Correct Answer: C
Rationale: A complete sleep cycle typically lasts 90-110 minutes in adults.
Most adults experience 4-6 complete cycles per night, with early cycles
containing more N3 (slow-wave) sleep and later cycles containing more REM
sleep.
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Question 3
During REM sleep, which physiological characteristic is most prominent?
A. Increased muscle tone throughout the body
B. Muscle atonia (loss of muscle tone) in postural muscles
C. Decreased brain metabolic activity
D. Absence of dreaming
Correct Answer: B
Rationale: REM sleep is characterized by muscle atonia (loss of muscle tone)
in postural muscles, mediated by inhibition of spinal motor neurons. This
prevents acting out dreams. The brain is highly active during REM, and
dreaming is common.
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Question 4
What percentage of a normal adult's sleep is spent in REM sleep?
A. 5-10%
B. 10-15%
C. 20-25%
D. 30-35%
Correct Answer: C
Rationale: In normal adults, REM sleep comprises approximately 20-25% of
total sleep time. REM sleep cycles occur every 90 minutes and lengthen
throughout the night. NREM sleep (Stages 1-3) makes up the remaining 75-
80%.
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Question 5
The suprachiasmatic nucleus (SCN) is responsible for:
A. Regulating the sleep-wake cycle (circadian rhythm)
B. Controlling respiratory drive during sleep
C. Initiating REM sleep
D. Maintaining muscle tone during sleep
Correct Answer: A
, Rationale: The suprachiasmatic nucleus (SCN) is the master biological clock
located in the hypothalamus. It regulates the circadian rhythm (sleep-wake
cycle) by responding to light-dark cycles and coordinating peripheral clocks
throughout the body.
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Question 6
In Stage 1 NREM sleep, which of the following physiological changes occurs?
A. Complete muscle atonia and loss of all muscle tone
B. Relaxation of muscles and a drop in body temperature
C. Rapid eye movements and vivid dreaming
D. Delta wave activity predominates on EEG
Correct Answer: B
Rationale: Stage 1 NREM sleep is the lightest stage of sleep, characterized by
relaxation of muscles, a slight drop in body temperature, and slowing of the
heart rate. The EEG shows theta wave activity. Complete muscle atonia and
REM sleep occur in REM stage.
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Question 7
Which of the following is the MOST common cause of excessive daytime
sleepiness?
A. Narcolepsy
B. Obstructive Sleep Apnea (OSA)
PRACTICE QUESTIONS WITH ANSWERS AND
RATIONALES
---
SECTION 1: SLEEP PHYSIOLOGY & NEUROBIOLOGY (Questions 1-50)
Question 1
Which stage of sleep is characterized by delta waves with amplitude >75 μV
and frequency 0.5-2 Hz?
A. N1 (Stage 1)
B. N2 (Stage 2)
C. N3 (Stage 3/Slow-wave sleep)
D. REM sleep
Correct Answer: C
Rationale: N3 (slow-wave/deep sleep) is characterized by high-amplitude
(>75 μV), low-frequency (0.5-2 Hz) delta waves. This stage represents the
deepest non-REM sleep and is essential for physical restoration, growth
hormone release, and memory consolidation.
---
Question 2
,What is the typical duration of a complete sleep cycle in adults?
A. 30-45 minutes
B. 60-75 minutes
C. 90-110 minutes
D. 120-150 minutes
Correct Answer: C
Rationale: A complete sleep cycle typically lasts 90-110 minutes in adults.
Most adults experience 4-6 complete cycles per night, with early cycles
containing more N3 (slow-wave) sleep and later cycles containing more REM
sleep.
---
Question 3
During REM sleep, which physiological characteristic is most prominent?
A. Increased muscle tone throughout the body
B. Muscle atonia (loss of muscle tone) in postural muscles
C. Decreased brain metabolic activity
D. Absence of dreaming
Correct Answer: B
Rationale: REM sleep is characterized by muscle atonia (loss of muscle tone)
in postural muscles, mediated by inhibition of spinal motor neurons. This
prevents acting out dreams. The brain is highly active during REM, and
dreaming is common.
,---
Question 4
What percentage of a normal adult's sleep is spent in REM sleep?
A. 5-10%
B. 10-15%
C. 20-25%
D. 30-35%
Correct Answer: C
Rationale: In normal adults, REM sleep comprises approximately 20-25% of
total sleep time. REM sleep cycles occur every 90 minutes and lengthen
throughout the night. NREM sleep (Stages 1-3) makes up the remaining 75-
80%.
---
Question 5
The suprachiasmatic nucleus (SCN) is responsible for:
A. Regulating the sleep-wake cycle (circadian rhythm)
B. Controlling respiratory drive during sleep
C. Initiating REM sleep
D. Maintaining muscle tone during sleep
Correct Answer: A
, Rationale: The suprachiasmatic nucleus (SCN) is the master biological clock
located in the hypothalamus. It regulates the circadian rhythm (sleep-wake
cycle) by responding to light-dark cycles and coordinating peripheral clocks
throughout the body.
---
Question 6
In Stage 1 NREM sleep, which of the following physiological changes occurs?
A. Complete muscle atonia and loss of all muscle tone
B. Relaxation of muscles and a drop in body temperature
C. Rapid eye movements and vivid dreaming
D. Delta wave activity predominates on EEG
Correct Answer: B
Rationale: Stage 1 NREM sleep is the lightest stage of sleep, characterized by
relaxation of muscles, a slight drop in body temperature, and slowing of the
heart rate. The EEG shows theta wave activity. Complete muscle atonia and
REM sleep occur in REM stage.
---
Question 7
Which of the following is the MOST common cause of excessive daytime
sleepiness?
A. Narcolepsy
B. Obstructive Sleep Apnea (OSA)
