1. (C): Transaction experiments by Jouvet demonstrated that REM sleep is generated in the pons. The cholinergic neurons are essential for the generation of REM sleep. Cholinergic cells of the median and dorsolateral pons increase their firing rates during the REM sleep. (Aldrich 1999, p. 32)

2. (A): Stage 2 sleep is characterized on electroencephalogram (EEG) by sleep spindles and K-complexes on background of mixed frequencies predominantly in the theta range in the first half of an epoch. Slow eye movements are much less evident during stage 2 sleep than during stage 1 sleep, although they may reappear for short intervals. By convention, a sleep epoch is 30 seconds. (Aldrich 1999, p. 11)

3. (D): The K-complex has a voltage maximal over the vertex or less commonly over the vertex or midline frontal scalp. The K-complex must be at least 0.5 seconds in duration and it need not be followed by sleep spindles. There is no voltage criterion for K-complex. The K-complex is first apparent at approximately age 5 months. K-complex is an evoked response, that is, during stage 2 sleep the K-complex can be easily elicited by auditory stimuli, such as the tap of a pencil and other forms of stimulation. (Aldrich 1999, p. 12)

4. (A): The REM sleep is characterized by lack of K-complexes and sleep spindles. The REM is divided into phasic and tonic REM. The phasic REM is characterized by periods of muscle twitching with bursts of eye movements. The tonic REM is characterized by lack of eye movements and muscle twitches. The muscle atonia of REM sleep involves the facial, postural muscles of the neck and accessory muscles of respiration. (Aldrich 1999, p. 14)

5. (C): Obstructive sleep apnea is a common disorder and is associated with snoring and excessive daytime sleepiness. Obstructive sleep apnea is characterized by apnea and hypopnea index of >5. It is worse on lying on the back and in REM sleep than in NREM sleep stage. (Aldrich 1999, p. 207)

6. (B): REM sleep behavior disorder is associated with dread-enacting behaviors and loss or impairment of normal muscle atonia during REM sleep. REM behavior disorder is a major cause of behavioral disturbance during sleep. For unknown reasons, it is more common in men than in women by a ratio of 2:1 to 5:1. The timing and duration of episodes parallel the distribution of REM sleep across the night. (Aldrich 1999, p. 271)

7. (D): Narcolepsy is a disorder characterized by brief episodes of irresistible sleep and fall associated with emotional stimuli. Cataplexy is pathognomonic of narcolepsy, with brief episode of bilateral weakness without alteration of awareness, usually brought on by excitement or emotion. Sleep paralysis is a feeling of paralysis that prevents limb movement and eye opening may be accompanied by a sensation of struggling to move. Hypnogoggic and hypnopompic hallucinations are seen in transition to sleep or waking. Acting out the dreams is seen with REM behavior disorder and is not related to narcolepsy. (Aldrich 1999, p. 154)

8. (B): Maintenance of wakefulness test is a less frequently used variant of MSLT. This is not a test for sleepiness but measures the ability of the patient to remain awake. It should not be used to diagnose narcolepsy. However, it is very helpful in assessing the response to stimulants. It is also helpful to assess patient’s fitness to drive or to fly an airplane. (Daube 2002, p. 496)

9. (D): Narcolepsy is characterized by the occurrence of REM sleep within minutes of falling asleep, called sleep onset REM. Sleep paralysis and cataplexy appears to be related to muscle atonia of REM sleep in waking and related to emotional excitement in case cataplexy. Hypnogoggic hallucination often occurs just as the narcoleptic passes from REM to and out of REM stage. In narcolepsy, frequent nighttime awakenings are seen, indicating that the ability to sustain is also impaired. (Aldrich 1999, p. 159)

10. (A): An MSLT diagnostic of narcolepsy is characterized by classical sleep onset REM in <15 minutes in two of the four trials. The sleep onset latency is decreased and is usually <8 minutes. However, some patients with unequivocal narcolepsy and cataplexy do not have two or more sleep onset REM even with repeated studies. (Aldrich 1999, p. 167)

11. (D): Alpha intrusions are scored if alpha activity is superimposed on normal activity of NREM sleep. This phenomenon is called alpha-delta sleep or nonrestorative sleep and is often associated with chronic pain syndrome, for example, fibromyalgia or rheumatoid arthritis. It can also occur in patients with no medical problems. (Daube 2002, p. 500)

12. (D): Apnea is characterized by a complete sensation of airflow and hypopnea is characterized by a partial decrease in airflow. Apnea/hypopnea must last 10 seconds or longer with a clear decrease >50% from baseline or is associated with oxyhemoglobin desaturation of >3% or arousal. (Daube 2002, p. 504)

13. (B): Stage 1 sleep is characterized on EEG by low-amplitude mixed frequency EEG. Vertex waves and rudimentary sleep spindles <0.5 seconds in duration may occur toward the end of stage 1. Stage 2 sleep is characterized by sleep spindles and K-complexes on background of mixed frequencies predominantly in the theta range. Slow eye movements are much less evident during stage 2 sleep than during stage 1 sleep, although they may reappear for short intervals. (Daube 2002, p. 497)

14. (B): Stage slow wave sleep is characterized on EEG by large-amplitude slow waves >20%. Stage 3 being 20% to 50% delta wave and stage 4 being >50% delta activity. With increasing age, overall amplitude of the EEG diminishes. In elderly, considerable activity may still occur in the 0.5 to 2 Hz range, but amplitudes may only reach 50 µV. (Daube 2002, p. 498)