A 7-year-old boy's parents report episodes in which he sits up, walks around the house with a blank stare, is unresponsive to commands, and has no memory of the event next morning. These events typically occur within the first third of the night. During which sleep stage do these episodes arise?

• A Stage N1
• B Stage N3 slow-wave sleep ✓
• C Stage N2
• D REM sleep

Explanation

Somnambulism, sleep terrors, and confusional arousals are disorders of arousal arising out of stage N3 slow-wave sleep, which predominates in the first third of the night, explaining the timing described. They represent incomplete dissociation between deep sleep and wakefulness. Acting out elaborate dreams points instead to REM sleep behavior disorder, which affects older men and features preserved dream mentation.

Reference: Kandel, Principles of Neural Science, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.