Question

Narcolepsy is characterized by all of the following except:

• A. Sleep paralysis.
• B. Cataplexy.
• C. Hallucination.
• D. Snoring.

Hint:

Recall the narcolepsy tetrad: sleepiness, cataplexy, sleep paralysis, hallucinations.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
We need the one feature that is NOT part of narcolepsy, a chronic sleep disorder marked by sudden, uncontrollable sleep attacks.

Step 2: Key Concept:
Narcolepsy classically has a group of features remembered as a tetrad: excessive daytime sleepiness, cataplexy, sleep paralysis and hypnagogic or hypnopompic hallucinations.

Step 3: Detailed Explanation:
Sleep paralysis is a brief inability to move or speak while falling asleep or waking up, it is a recognised feature of narcolepsy.
Cataplexy is a sudden loss of muscle tone triggered by strong emotion like laughter, it is the most specific feature of narcolepsy and is caused by loss of hypocretin/orexin neurons.
Hallucinations that occur just before falling asleep (hypnagogic) or just after waking (hypnopompic) are also part of the classic tetrad.
Snoring is loud breathing during sleep, it is linked to obstructive sleep apnea, not to narcolepsy. Narcolepsy is a disorder of REM sleep regulation, not of upper airway obstruction.

Step 4: Why the other options are wrong:
Options 1, 2 and 3 are all genuine parts of the narcolepsy tetrad, so they are correctly associated with the disease and are not the answer to an "except" question.

Step 5: Final Answer:
Snoring is not a feature of narcolepsy.
\[ \boxed{\text{Snoring}} \]