Eating and sleep disorders: multiple sleep latency test in narcolepsy: practice question

A Psychiatry question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Psychiatry · Eating and sleep disorders: multiple sleep latency test in narcolepsy

Sample item

A 22-year-old with excessive daytime sleepiness undergoes overnight polysomnography followed by a daytime nap study with five nap opportunities. Which result supports narcolepsy?

AMean sleep latency of 8 minutes or less with two or more sleep-onset REM periodsBMean sleep latency of 20 minutes with no REM during napsCReduced sleep latency with only N3 sleep in napsDNormal REM latency at night and normal nap latency

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Mean sleep latency of 8 minutes or less with two or more sleep-onset REM periods

The Multiple Sleep Latency Test measures how quickly a person falls asleep across several naps. In narcolepsy the mean latency is short (8 minutes or less) and REM sleep appears within 15 minutes of sleep onset in at least two naps. A latency near 20 minutes is normal.

Option by option

A. Mean sleep latency of 8 minutes or less with two or more sleep-onset REM periods (correct)
Correct. Short latency with repeated sleep-onset REM is the characteristic result.
B. Mean sleep latency of 20 minutes with no REM during naps
A mean latency of 20 minutes without REM is a normal result.
C. Reduced sleep latency with only N3 sleep in naps
N3-only naps do not represent the REM intrusion typical of narcolepsy.
D. Normal REM latency at night and normal nap latency
Normal latencies argue against pathological sleepiness.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Psychiatry question

What is the answer to this Psychiatry question?

The best answer is A, Mean sleep latency of 8 minutes or less with two or more sleep-onset REM periods. The Multiple Sleep Latency Test measures how quickly a person falls asleep across several naps.

Why is "Mean sleep latency of 20 minutes with no REM during naps" not the answer?

A mean latency of 20 minutes without REM is a normal result.

Why is "Reduced sleep latency with only N3 sleep in naps" not the answer?

N3-only naps do not represent the REM intrusion typical of narcolepsy.

Why is "Normal REM latency at night and normal nap latency" not the answer?

Normal latencies argue against pathological sleepiness.

What concept does this question test?

It tests Eating and sleep disorders: multiple sleep latency test in narcolepsy in Psychiatry. In narcolepsy the mean latency is short (8 minutes or less) and REM sleep appears within 15 minutes of sleep onset in at least two naps. A latency near 20 minutes is normal.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Eating and sleep disorders: multiple sleep latency test in narcolepsy?

Learn each diagnosis by its core features and its first-line treatment. Then use the flashcards and the other Psychiatry questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.